HELCOM Guidelines for Management of Dredged Material at Sea

Page

of 39

Baltic Marine Environment

Protection Commission

and

HELCOM Reporting Format for Management of Dredged Material at Sea

Adopted by HELCOM 36-2015 on 4 March 2015 and

amended by HELCOM 41-2020 on 4 March 2020

Katajanokanlaituri 6 B

Phone:

+358 207 412 649

E-mail:

firstname.lastname@helcom.fi

FI-00160 Helsinki

Web:

http://helcom.fi

secretariat@helcom.fi

Finland

Page

of 39

PREFACE

These Guidelines were adopted by HELCOM 36-2015 after the revision, in accordance with the 2013 IMO

London Protocol and London Convention Specific Guidelines for Assessment of Dredged Material. The

Contracting Parties should apply these guidelines in their authorisation or regulation procedures for dredged

material. However, the guidelines also contain recommendations that will not be applicable in all national or

local circumstances.

1. INTRODUCTION

1.1 Dredging is essential to maintain navigation to, in and from ports and harbours, for the development of

port facilities as well as for remediation, flood management and to maintain the carrying capacity of

marine and coastal systems. Much of the material removed during these necessary activities requires

deposit at sea. Most of the material dredged from within the Baltic Sea Area is, by its nature, either

uncontaminated or only slightly contaminated by human activity (i.e. at, or close to, natural background

levels). However, a smaller proportion of dredged material is contaminated to an extent that major

environmental constraints need to be applied when developing management options (cf. Section 7.

Management Options).

1.2 Dredged sediments are recognised as part of the natural sediment cycle. Therefore, when considering

suitable management options, it is generally the preferred option to retain dredged material within the

same aquatic sedimentary system from where it originated, if it is environmentally, technically, socially

and economically feasible to do so.

Overview of Dredging Activities

1.3 The different types of dredging activities are outlined below:

a. Dredging for water-based infrastructure, includes:

•

Capital (or new-work) dredging for navigation involves enlarging or deepening existing channel

and port areas or creating new ones; and for engineering purposes includes constructing trenches

for pipes, cables, immersed tube tunnels, and removal of material unsuitable for foundations or

for aggregate extraction, and for hydraulic purposes this involves increasing the flow capacity of

the waterway;

•

Maintenance dredging to maintain channels, berths or construction works, etc. at their designed

dimensions (i.e. to counteract sedimentation and changes in morphology);

•

Dredging for coastal protection: use of sediments for such activities as beach nourishment and

construction of levees, dykes, jetties, etc.

b. Dredging for the purposes of ecosystem enhancement:

•

Environmental dredging to remove contaminated sediment for the purpose of reducing risks to

the environment and to human health;

•

Restoration dredging to restore or create environmental features or habitats to establish

ecosystem functions, benefits, and services; e.g., wetlands creation, island habitat

construction/nourishment, construction of offshore reefs and topographic features for fisheries

enhancement, etc.; and

•

Dredging to support local and regional sediment processes retaining sediment within the natural

sediment system to support sediment-based habitats, shorelines, and infrastructure.

Page

of 39

2. SCOPE

2.1 The guidelines are designed to assist Contracting Parties in the management of dredged material in ways

that will prevent and eliminate pollution in accordance with Article 3 to the 1992 Helsinki Convention,

and protect marine species and habitats in the Baltic Sea Area in accordance with Article 15

. Dredged

materials have been listed in Regulation 1 of Annex V as being permitted to be dumped at sea, as an

exception from the general prohibition from dumping in Article 11 (1) of the Convention.

2.2 Any deposit into the maritime area of dredged materials, independently of whether it is considered as

“dumping” or “placement” within the Helsinki Convention (cf. Article 4(a) and Article 2(b)(ii) respectively),

should be assessed on a case-by-case basis in order to ensure that it complies with the objectives of the

Convention, as outlined in these Guidelines.

2.3 For the Contracting Parties that are also EU Member States, the Guidelines are conceived as a tool assisting

them in the management of dredged material that is subject to current European Directives (e.g. Water

Framework Directive 2000/60/EC, Marine Strategy Framework Directive 2008/56/EC, Natura2000 areas

under the Birds and Habitat Directives 2009/147/EC and 92/43/EEC). Also, the Directive 2008/98/EC of

the Parliament and of the Council of 19 November 2008 on waste, (hereinafter the Waste Framework

Directive), has been identified by Contracting Parties as having implications on the management of

dredged material. Which implications those are exactly, and how this affects national legislation, remains

in many cases unclear. Clarifications regarding the relationship between the existing national

interpretations in the application of the Waste Framework Directive to dredged material and the dredged

material management guidelines shared in HELCOM Area are provided in the technical background

document (cf. 14 REFERENCES).

2.4 The guidelines in particular address the management of dredged material in the maritime area,

subsequent to any dredging technique including hydrodynamic and sidecast dredging. In addition to

preventing and eliminating adverse effects the guidelines, where appropriate, seek to maintain or

enhance the existing environmental conditions and to create new opportunities.

2.5 The guidelines are primarily a scientific and technical framework for assessing dredged material proposed

for deposit at sea. While economic considerations are acknowledged, they are not dealt with in detail in

these guidelines. This implicates that the detailed procedures described in the guidelines will not be

applicable in all national or local circumstances.

2.6 In the context of these guidelines, dredged materials are deemed to be sediments or rocks with associated

water, organic matter etc. removed from areas that are normally or regularly covered by water, using

dredging or other excavation equipment.

2.7 It is recognised that both removal and deposit of dredged sediments may cause harm to the marine

environment. Contracting Parties are encouraged to exercise control over both dredging and dredged

material management using a Best Environmental Practice (BEP) approach designed to minimise both the

quantity of material that has to be dredged and the impact of the dredging and depositing activities in the

maritime area - see Technical Annex III. Contracting Parties are encouraged to develop regional dredged

material management plans in order to minimize the possible impacts and maximizing possible benefits

from dredging and depositing. Advice on environmentally acceptable dredging techniques is available

from a number of international organisations e.g. the Permanent International Association of Navigation

Congresses (PIANC), the European and Central Dredging Association (EuDA and CEDA).

2.8 The schematic shown in Figure 1 presents the steps involved in the application of these Guidelines where

important decisions should be made. In general, national authorities should use this schematic in an

All Article, Annex or Regulation references mentioned in this chapter refer to the 1992 HELCOM Convention.

EU Member Countries should take into account the Directive 2011/92/EU of the European Parliament and of the Council of 13 December

2011 on the assessment of the effects of certain public and private projects on the environment. Where applicable, the EU Habitat Directive

(92/43/EEC) may require an appropriate assessment and the EU-Landfill (99/31/EC) and Water Framework Directives (2000/60/EC) may

have implications for dredging and deposit operations. Additionally Directive 2008/56/EC Establishing a Framework for Community Action in

the Field of Marine Environmental Policy (Marine Strategy Framework Directive) specifies the deposit of dredged material as a possible

pressure with regard to physical loss or damage which needs to be considered when assessing the status of the marine environment.

Page

of 39

iterative manner (revisiting steps in the processes as needed) ensuring that all steps receive

consideration, including consideration of BAT and BEP, before a decision is made to issue or decline a

permit. The following sections of this document describe the steps and activities relevant to the

Guidelines.

3. REQUIREMENTS OF THE 1992 HELSINKI CONVENTION

3.1 Within the framework of the Convention for the Protection of the Marine Environment of the Baltic Sea

(hereinafter called the 1992 Helsinki Convention), dredged materials may, in accordance with Article 11

of the Convention and Annex V, be permitted to be dumped at sea.

3.2 With regard to the dumping of dredged material at sea, Article 11 (2) of the Helsinki Convention requires

Contracting Parties to ensure that no such materials are dumped without permission issued by their

appropriate competent authorities.

3.3 Regulation 1 a) of Annex V of the Convention requires that dumping of dredged material containing

harmful substances indicated in annex I of the Convention is only permitted according to these guidelines

adopted by the Commission.

3.4 Regulation 2 (3) of Annex V requires Contracting Parties to report to the Commission on the nature and

quantities of dumped material in accordance with Regulation 2 (1c) of this Annex. To this end, HELCOM

has agreed on reporting formats for the submission of data on wastes dumped at sea.

3.5 Furthermore, according to the HELCOM Recommendation 20/4 the Contracting Parties are

recommended to report on organic tin concentrations in the marine environment in areas where its

compounds may be entering to marine environment.

4. PRELIMINARY CONSIDERATIONS FOR DREDGED MATERIAL MANAGEMENT

4.1 Before beginning a full assessment of the material and the deposit options the first considerations should

be the scale and need for the dredging project. In the event of a subsequent full assessment indicating no

acceptable options for deposit it will be necessary to re-address this question in a broader context.

4.2 Reducing adverse effects on the marine environment can be accomplished through the following three

activities:

.1 Controlling and reducing sources of contamination;

.2 Maximizing the use of dredged material for beneficial purposes;

.3 Minimizing the volumes of sediment that must be dredged by using improved Best Environmental

Practices (BEP), as discussed in Technical Annex III

4.3 Contamination of the aquatic environment, both as a consequence of historical and present day inputs,

presents a problem for the management of freshwater, estuarine, and marine sediments. High priority

should be given to the identification of sources, as well as the reduction and prevention of further

contamination of sediments from both point and diffuse sources. Successful implementation of

prevention strategies will require collaboration among competent authorities with responsibility for the

control of contaminant sources.

It would be recommendable to include the following sources of contamination, e.g.:

− industrial and domestic discharges;

− storm water;

− surface runoff from agricultural areas;

− sewage and waste-water treatment effluents;

− transport from upstream contaminated sediments.

− accidental pollution

4.4 In developing and implementing a source control strategy, competent authorities should take into

account:

Page

of 39

.1 the risks posed by contaminants and the relative contributions of the individual sources to these

risks;

.2 existing source control programmes and other regulations or legal requirements;

.3 best available techniques (BAT) and BEP as defined in Annex II of the 1992 Helsinki Convention, inter

alia, as regards the technical and economic feasibility;

.4 evaluations of the performance or effectiveness of measures taken

.5 consequences of not implementing source control.

4.5 In cases where control measures are not fully effective in reducing contamination and high levels of

contamination persist then specific dredged material management options may be required, for example

confined deposit facilities or treatment methods.

4.6 Sediment is a valuable natural resource. Beneficial uses of dredged material (which are described further

in Section 7) should be pursued to the maximum extent practicable. Beneficial use of sediments includes

retaining sediments that meet national assessment criteria within freshwater, estuarine, and marine

systems.

4.7 There is a need to minimize the release of contaminants to the environment while maximizing the re-

use of sediment for beneficial purposes. Progress toward more sustainable practice in respect to

sediment management (including dredged material management) can be seen in initiatives being

undertaken by Contracting Parties, such as Building with Nature and Observers to the Convention, such

as Working with Nature (PIANC 2011).

4.8 In addition, attention needs to be given to ensuring that the quantities of material needing to be dredged

and deposited of at sea are minimised as far as is practicable. Application of BEP (technical annex III) to

dredging operations minimises the quantity of material that must be dredged and deposited of at sea

thereby reducing the environmental impact of dredging activities (e.g., PIANC 2009 and CEDA 2010).

5. DREDGED MATERIAL SAMPLING

Sampling for the purpose of issuing a depositing permit

5.1 Dredged material that is not exempted under paragraph 6.3 will require analysis and testing (cf. Technical

Annex I) to obtain sufficient information for permitting purposes. Judgement and knowledge of local

conditions will be essential when deciding what information is relevant to any particular operation.

5.2 A survey of the area to be dredged should be carried out. The distribution and depth of sampling should

reflect the size and depth of the area to be dredged, the amount to be dredged and the expected

variability in the horizontal and vertical distribution of contaminants. Core samples should be taken where

the depth of dredging and expected vertical distribution of contaminants suggest that this is warranted.

In other circumstances, grab sampling may be sufficient. Pollutant load calculations should take into

consideration sampling depth and the depth of dredging as well as appropriate weighting of heavily

polluted spots. Sampling from dredgers or barges is not advisable for permitting purposes.

5.3 The number of sample stations can be determined on the basis of the amount of dredged material or

the area to be dredged. If the thickness of the sediment to be dredged on average is small (e.g. up to 1

meter depth) area-focused approach is recommended to determine the number of sampling stations.

Otherwise if the thickness of the sediment to be dredged on average exceeds 1 meter then amount

approach is considered to determine the numbers of sampling stations.

The following tables give an indication of the minimum number of separate sampling stations depending

on which approach is taken into account to obtain representative results:

Page

of 39

Amount approach

Amount dredged (m

) Number of Stations

Up to 25 000 3

25 000 - 100 000 4 – 6

100 000 - 500 000 7 – 15

500 000 - 2 000 000 16 – 30

>2 000 000 extra 10 per million m

Area approach

Dredged area (m

) Number of Stations

<10 000 1 - 3

10 000 – 50 000 4 – 8

50 000 – 100 000 9 – 10

>100 000 extra 5 per 100 000 m

The number of sample stations should take account of the exchange characteristics of the area; more

samples may be required in enclosed and semi-enclosed areas and less in open areas. Contracting Parties

are encouraged to use the Guidelines for the Sampling and Analysis of Dredged Material Intended for

Disposal at Sea (IMO, 2005).

5.4 Normally, the samples from each sampling station and different depths in the sediment should be

analysed separately. However, if the sediment is clearly homogenous with respect to sediment texture, it

may be possible to analyse composite samples from two or more adjacent sampling stations at a time,

providing there are no distinctly different contaminant concentrations in different sub samples and care

is taken to ensure that the results allow derivation of valid mean contaminant values. The original

individual samples should, however, be retained until the permitting procedure has been completed, in

case further analyses are necessary.

Frequency of sampling

5.5 If the results of the analyses indicate that the material is essentially ‘clean (i.e. below the lower action

level (paragraph 6.13), sampling in the same area need not be repeated more frequently than once every

3 years, provided that there is no indication that the quality of the material has deteriorated.

5.6 It may be possible, following assessment of the results of an initial survey, to reduce either the number

of sampling stations or the number of determinants and still provide sufficient information for permitting

purposes. If a reduced sampling programme does not confirm the earlier analyses, the full survey should

be repeated. If the list of determinants is reduced, further analysis of the complete list of determinants

is advisable every 5 years.

5.7 In areas where there is a tendency for sediments to exhibit high levels of contamination, analysis of all

the relevant determinants should be frequent and linked to the permit renewal procedure.

6. DREDGED MATERIAL CHARACTERISATION

6.1 Characterisation should take into consideration physical and chemical characteristics, while biological

characteristics are optional. A list of the data to be collected and analysed during the characterization

process should be developed on a project-specific basis. This data should be sufficient to describe and

Page

of 39

assess possible impacts as a basis for management decisions (e.g. PIANC 1996; 1998a and b). Guidance

on the selection of determinants and methods of contaminant analysis, together with procedures to be

used for normalisation and quality assurance purposes, will be found in the Technical Annexes. It is

envisaged that developments in biological testing techniques might eventually provide sufficient

information to assess the potential impact of the contaminants in the material, so that less reliance

would need to be placed on chemical testing.

6.2 If dredged material is so poorly characterised that proper assessment cannot be made of its potential

impacts on human health and the environment, it shall not be deposited at sea unless there is an

overriding public interest e.g. in relation to safety and civil protection.

Exemptions from detailed characterisation

6.3 Dredged material may be exempted from the testing referred to in paragraphs 6.5 to 6.7 of these

Guidelines (but note that the information listed in paragraph 6.4 below will still be required) if any of the

criteria below are met:

a. it is composed of previously undisturbed geological material; or

b. it is composed almost exclusively of sand, gravel or rock; or

c. in the absence of appreciable past and present pollution sources and when the quantity of dredged

material from operations does not exceed 10.000 tonnes per year (use conversion factors between

cubic meters and tonnes (dry weight) from the HELCOM Reporting Format for Management of

Dredged Material at Sea (Attachment 1)).

In relation to 6.3b and 6.3c the exemption from testing should be supported by local information so as to

provide reasonable assurance that the dredged material has not been contaminated.

Dredged material that does not meet at least one of these requirements will need further stepwise

characterisation to assess its potential impact (i.e. see paragraphs 6.4-6.11).

Physical characterisation

6.4 The following information is required:

a. the amount of material;

b. anticipated or actual deposit rate of material at the deposit site;

c. sediment characteristics by grain size analysis (laser or sieving methods) or exceptionally on the

basis of visual determination (i.e. clay/silt/sand/gravel/boulder).

Evaluation of the physical characteristics of sediments for deposit is necessary to determine potential impacts

and the need for subsequent chemical and/or biological testing (cf. Technical Annex I for further guidance).

Conversion factors for cubic meters of dredged material to metric tonnes are given in the HELCOM Reporting

Format for Management of Dredged Material at Sea (Attachment 1).

Chemical characterisation

6.5 Sufficient information for chemical characterisation may be available from existing sources, i.a. for similar

material in the vicinity. In such cases new measurements of the potential impact may not be required,

provided that this information is still reliable and has been obtained within the last 5 years. Details of the

substances to be determined are listed in Technical Annex I.

Considerations for additional chemical characterisation of dredged material are as follows:

a. major geochemical characteristics of the sediment including redox status;

b. potential routes by which contaminants could reasonably have been introduced to the sediments;

for example, tin compounds reaching marine environment from previous use of antifouling paints

and others can be expected in harbours and marinas

c. industrial and municipal waste discharges (past and present);

Page

of 39

d. probability of contamination from agricultural and urban surface runoff;

e. spills of contaminants in the area to be dredged;

f. source and prior use of dredged materials (e.g., beach nourishment); and

g. natural deposits of minerals and other natural substances.

6.6 Further information may also be useful in interpreting the results of chemical testing (see Technical

Annex I).

Biological characterisation

6.7 If the potential impacts of the dredged material to be deposited cannot be adequately assessed on the

basis of the chemical and physical characterisation and available biological information, biological testing

may be conducted. Further detailed guidance on biological testing is provided in Technical Annex I.

6.8 Biological tests should incorporate species that are considered appropriately sensitive and

representative and should determine, where appropriate.

a. acute toxicity;

b. chronic toxicity;

c. the potential for bioaccumulation; and

d. the potential for tainting.

6.9 Assessment of habitats communities and populations may be conducted in parallel with chemical and

physical characterisation, e.g. triad approach. It is important to ascertain whether adequate scientific

information exists on the characteristics and composition of the material to be deposited and on the

potential impacts on marine life and human health. In this context, it is important to consider information

about species known to occur in the area of the deposit site and the effects of the material to be deposited

and of its constituents on organisms.

Action List

6.10 The Action List is used as a screening mechanism for assessing properties and constituents of

dredged material with a set of criteria for specific substances e.g. toxicity, persistence and bio-

accumulation It should be used for dredged material management options (cf. Section 7), including the

identification and development of source control measures as described in Section 4. The criteria should

reflect experience gained relating to the potential effects on human health or the marine environment.

6.11 Action List levels should be developed on a national or regional basis and might be set on the

basis of concentration limits, biological responses, environmental quality standards, flux considerations

or other reference values. They should be derived from studies of sediments that have similar

geochemical properties to those from the ones to be dredged and/or to those of the receiving system.

Thus, depending upon natural variation in sediment geochemistry, it may be necessary to develop

individual sets of criteria for each area in which dredging or deposit is conducted. With a view to

evaluating the possibilities for harmonising or consolidating the criteria referred to above, Contracting

Parties are requested to inform the Helsinki Commission of the criteria adopted, as well as the scientific

basis for the development and refinement of these criteria.

6.12 An Action List should specify an upper level and may also specify a lower level giving these

possible actions:

a. material, which contains specified contaminants or which causes biological responses, in excess of

the relevant upper levels should generally be considered unsuitable for deposit at sea

b. material of intermediate quality which contains contaminants below the upper level but exceeding

the lower level, requires more detailed assessment before suitability for deposit at sea can be

determined; and

Page

of 39

c. material, which contains contaminants, below the lower levels should generally be considered of

little environmental concern for deposit at sea.

6.13 Action levels need to be established at least for determinants on the Primary list in Technical

Annex I.

6.14 If, as an option of least detriment, dredged material is deposited at sea when one or more

criteria exceed the upper level, a Contracting Party should:

a. where appropriate, identify and develop source control measures with a view to meeting the criteria

(see paragraphs 4.3 - 4.4 above); and

b. utilise deposit management techniques, including the confined disposal or treatment methods, to

mitigate the impact of the deposit operation on the marine environment (see paragraphs 7.3 - 7.5

below); and

c. report the fact to the Secretariat, including the reason for permitting the deposit, in accordance

with the reporting form for the annual reporting.

7. DREDGED MATERIAL MANAGEMENT OPTIONS

7.1 Generally it is the preferred option to keep the sediment in the aquatic, estuarine, or marine system,

however the results of the physical/chemical/biological characterisation will determine the dredged

material management options. Examples of management options include beneficial use, unrestricted,

open-water deposit, confined aquatic deposit or confined deposit facilities. In some cases the best option

may be to leave the material in-situ. Additional information about beneficial uses of dredged material,

including case studies, can be found at the Central Dredging Association’s website. PIANC (2009) provides

technical information on the assessment of options for beneficial use and recommendations on how to

overcome constraints based on “lessons learned” from numerous cases studies in different situations in

various countries.

Options for material assessed to be uncontaminated

7.2 There is a wide variety of beneficial use depending on the physical and chemical characteristics of the

material. Generally, a characterisation carried out in accordance with these guidelines will be sufficient

to match a material to possible uses such as:

.1 Sustainable Placement by retaining sediment within the natural sediment system to support

sediment-based habitats, shorelines, and infrastructure.

.2 Habitat Restoration and Development using direct placement of dredged material for enhancement

or restoration of natural habitat associated with wetlands, other near-shore habitats, coastal

features, offshore reefs, fisheries enhancement, etc.

.3 Beach Nourishment using dredged material (primarily sandy material) to restore and maintain

beaches.

.4 Shoreline Stabilization and Protection through the placement of dredged material with the intent

of maintaining or creating erosion protection, dike field maintenance, berm or levee construction,

and erosion control.

.5 Engineering uses (e.g. as capping material or for land reclamation).

Options for material assessed to be contaminated

7.3 Where the characteristics of' the dredged material are such that normal sea deposit would not meet the

requirements of the 1992 Helsinki Convention, treatment or other management options should be

considered. These options can be used to reduce or control impacts to a level that will not constitute an

unacceptable risk to human health, or harm living resources, damage amenities or interfere with

legitimate uses of the sea.

according to national assessment criteria

Page

of 39

7.4 Treatment, such as separation of contaminated fractions, may make the material suitable for a beneficial

use and should be considered before opting for sea deposit. Deposit management techniques to reduce

or control impacts may include e.g. deposit on or burial in the sea floor followed by clean sediment

capping, or methods of containing dredged material in a stable manner. Advice on dealing with

contaminated dredged material is available from PIANC (see references).

7.5 The practical availability of other means than deposit at sea should be considered in the light of a

comparative risk assessment involving both deposit and the alternatives.

8. SITE SELECTION

8.1 The selection of a site for sea deposit involves considerations of an environmental nature and also

economic and operational feasibility. Site selection should try to ensure that the deposit of dredged

material does not interfere with, or devalue, legitimate commercial and economic uses of the marine

environment nor produce undesirable effects on vulnerable marine ecosystems or species and habitats

on the HELCOM Red List of Baltic Sea species in danger of becoming extinct (BSEP140) and the Red List of

Baltic Sea underwater biotopes, habitats and biotope complexes (BSEP138)

8.2 For the evaluation of a sea deposit site information should be obtained and assessed on the following,

as appropriate:

a. the physical, chemical and biological characteristics of the seabed (e.g., topography, sediment

dynamics and transport, redox status, benthic biota);

b. the physical, chemical and biological characteristics of the water column (e.g., hydrodynamics,

dissolved oxygen, pelagic species); and

c. proximity to:

(i). areas of natural beauty or significant cultural or historical importance;.

(ii). areas of specific scientific or biological importance;

(iii). recreational areas;

(iv). subsistence, commercial and sport fishing areas;

(v). spawning, recruitment and nursery areas;

(vi). migration routes of marine organisms;

(vii). shipping lanes;

(viii). military exercise zones;

(ix). past munitions disposal sites;

(x). engineering uses of the sea such as undersea cables, pipelines, etc.

(xi). areas of mineral resources (e.g. sand and gravel extraction areas)

d. the capacity of the site should be assessed, taking into account:

− the anticipated loading rates per day, week, month, or year;

− the degree to which the site is dispersive;

− the allowable reduction in water depth over the site because of mounding of material.

Such information can be obtained from existing sources, complemented by field work where

necessary.

8.3 The information on the characteristics of the sea deposit site referred to above is required to determine

the probable fate and effects of the deposited material. The physical conditions in the vicinity of the sea

deposit site will determine the transport and fate of the dredged material. The physico-chemical

conditions can be used to assess the mobility and bioavailability of the chemical constituents of the

material. The nature and distribution of the biological community and the proximity of the site of sea

Page

of 39

deposit to marine resources and amenities will, in turn, define the nature of the effects that are to be

expected. Careful evaluation will allow determination of environmental processes that may dominate the

transport of material away from the sea deposit site. The influence of these processes may be reduced

through the imposition of permit conditions.

8.4 In some cases, depositing of dredged material can augment existing effects attributable to inputs of

contaminants to coastal areas through land runoff and discharge, from the atmosphere, resource

exploitation and maritime transport. These existing stresses on biological communities should be

considered as part of the assessment of potential impacts caused by the deposit operation. The proposed

method of depositing and potential future uses of resources and amenities in the marine receiving area

should also be taken into account.

8.5 Information from baseline and monitoring studies at already established deposit sites will be important

in the evaluation of any new depositing activity at the same site or nearby.

8.6 For contaminated material the use of open-sea sites at distant off-shore locations is seldom an

environmentally desirable solution to the prevention of marine pollution by contaminated dredged

material.

8.7 The dredged material which is acceptable for sea deposit and the sediments at the chosen site, or in case

of a dispersive deposit site for the sediments of the receiving area, should be similar as far as possible.

9. ASSESSMENT OF POTENTIAL EFFECTS

Deposit sites

9.1 Assessment of potential effects should lead to a concise statement of the expected consequences of the

deposit option (i.e., the Impact Hypothesis). Its purpose is to provide a basis for deciding whether to

approve or reject the proposed deposit option and for defining environmental monitoring requirements.

9.2 This assessment should integrate information on the characteristics of the dredged material and the

proposed deposit site conditions. It should comprise a summary of the potential effects on human health,

living resources, amenities and other legitimate uses of the sea and should define the nature, temporal

and spatial scales and duration of expected impacts based on reasonably pessimistic assumptions.

9.3 In order to develop the hypothesis, it may be necessary to conduct a baseline survey which describes not

only the environmental characteristics, but also the variability of the environment. It may be helpful to

develop sediment transport, hydrodynamic and other models, to determine possible effects of deposit.

9.4 For a retentive site, where the material deposited will remain within the vicinity of the site, the assessment

should delineate the area that will be substantially altered by the presence of the deposited material and

what the severity of these alterations might be. At the extreme, this may include an assumption that the

immediate receiving area is entirely smothered. In such a case, the likely timescale of recovery or re-

colonisation should be projected after deposit operations have been completed as well as the likelihood

that re-colonisation will be similar to, or different from, the existing benthic community structure. The

assessment should specify the likelihood and scale of residual impacts outside the primary zone.

9.5 In the case of a dispersive site, the assessment should include a definition of the area likely to be altered

in the shorter term by the proposed deposit operation (i.e., the near-field) and the severity of associated

changes in that immediate receiving environment. It should also specify the likely extent of long-term

transport of material from this area and what this flux represents in relation to existing transport fluxes

in the area, thereby permitting a statement regarding the likely scale and severity of effects in the long-

term and far-field.

9.6 For the Contracting Parties that are also EU Member States, the Directive 2011/92/EU of the European

Parliament and of the Council of 13 December 2011 on the assessment of the effects of certain public

and private projects on the environment should be taken into account when assessing potential impacts

of dredged material deposit. Where applicable, the EU-Habitats Directive (92/43/EEC) may require an

appropriate assessment and the EU-Landfill (99/31/EC) and Water Framework Directives (2000/60/EC)

Page

of 39

may have implications for dredging and deposit operations. Additionally Directive 2008/56/EC

Establishing a Framework for Community Action in the Field of Marine Environmental Policy (Marine

Strategy Framework Directive) specifies the deposit of dredged material as a possible pressure with

regard to physical loss or damage which needs to be considered when assessing the status of the marine

environment.

Nature of the impact

9.7 All dredged materials have a significant physical impact at the point of deposit. This impact includes

covering of the seabed and local increases in suspended solids levels. Physical impact may also result from

the subsequent transport, particularly of the finer fractions, by wave and tidal action and residual current

movements.

9.8 Biological consequences of these physical impacts include smothering of benthic organisms in the deposit

area and potentially in the surrounding area. In specific circumstances, the physical impacts can also

interfere with sensitive life stages and/or the migration of fish (e.g. egg,larvae stages and the impact of

high levels of turbidity on salmonids in estuarine areas) or crustaceans (e.g. if deposition occurs in the

coastal migration path of crabs).

9.9 The toxicological and bioaccumulation effects of' dredged material constituents should be assessed.

Deposit of sediments with low levels of contamination is not devoid of environmental risk and requires

consideration of the fate and effects of dredged material and its constituents. Substances in dredged

material may undergo physical, chemical and biochemical changes when entering the marine

environment and these changes should be considered in the light of the eventual fate and potential

effects of the material. It should also be taken into account that deposit at sea of certain substances may

disrupt the sensory capabilities of the fish and may mask natural characteristics of sea water or tributary

streams, thus confusing migratory species which e.g. fail to find spawning grounds or food.

9.10 In relatively enclosed waters, such as some estuarine, archipelagic and fjordic situations,

sediments with a high chemical or biological oxygen demand (e.g. organic carbon-rich) could adversely

affect the oxygen regime of the receiving environment while sediments with high levels of nutrients

could significantly affect the nutrient flux.

9.11 An important consequence of the physical presence of dredged material deposit activities is

interference with fishery activities and in some instances with navigation and recreation. These problems

can be aggravated if the sediment characteristics of the dredged material are very dissimilar to that of

the ambient sediment or if the dredged material is contaminated with bulky harbour debris such as

wooden beams, scrap metal, pieces of cable etc.

9.12 Particular attention should be given to dredged material containing significant amounts of oil

or other substances that have a tendency to float following re-suspension in the water column. Such

materials should not be deposited in a manner or at a location which may lead to interference with

protected species and habitats (cf. 8.1), fishing, shipping, amenities or other beneficial uses of the marine

environment.

10. PERMIT OR REGULATION BY OTHER MEANS

10.1 If sea deposit is the selected option, then a permit or regulation by other means (which is in

compliance with these guidelines) authorizing sea deposit must be issued in advance. In granting a permit,

the immediate impact of dredged material occurring within the boundaries of the deposit site such as

alterations to the local, physical, chemical and biological environment is accepted by the permitting or

supervising authority, provided that adverse effects on ecosystems components and ecosystem

functions are avoided. Notwithstanding these consequences, the conditions under which a permit for sea

deposit is issued should be such that environmental change beyond the boundaries of the deposit site are

as far below the limits of allowable environmental change as practicable. The deposit operation should

be permitted subject to conditions which further ensure that environmental disturbance and detriment

are minimised and benefits maximised.

Page

of 39

10.2 The permit is an important tool for managing sea deposit of dredged material and will contain

the terms and conditions under which sea deposit may take place as well as provide a framework for

assessing and ensuring compliance.

10.3 Permit conditions should be drafted in plain and unambiguous language and will be designed

to ensure that:

a. only those materials which have been characterised or considered exempted from detailed

characterisation according to paragraph 6.3 and found acceptable for sea deposit, based on

the impact assessment, are deposited;

b. solid waste

contained within the dredged material should be separated and managed on

land;

c. the material, up to licensed quantity, is deposited at the selected deposit site;

d. any necessary deposit management techniques identified during the impact analysis are

carried out; and

e. any monitoring requirements are fulfilled and the results reported to the permitting or

supervising authority.

10.4 A permit to deposit contaminated dredged material exceeding national criteria should

generally be considered unsuitable / shall be be refused, if the permitting authority determines that

appropriate opportunities exist to reuse, recycle or treat the material without undue risks to human

health or the environment or disproportionate costs.

11. MANAGEMENT OF THE DEPOSIT OPERATION

11.1 This section deals with management techniques to minimise the physical effects of dredged

material deposit. The key to management lies in careful site selection and an assessment of the potential

for conflict with other interests and activities. In addition, appropriate methods of dredging and of deposit

should be chosen in order to minimise the environmental effects. Guidance is given in Technical Annex III.

11.2 Where appropriate, deposit vessels should be equipped with accurate positioning systems

which shall be switched on recording mode during deposit operations and the activity of the vessels may

be reported to the permitting and supervising authority. Deposit vessels and operations should be

inspected regularly to ensure that the conditions of the deposit permit are being complied with and that

the crew are aware of their responsibilities under the permit. Ships' records and automatic monitoring

and display devices (e.g. black-boxes), where these have been fitted, should be inspected to ensure that

deposit is taking place at the specified deposit site.

11.3 In most cases, blanketing of a comparatively small area of seabed is considered to be an

acceptable environmental consequence of deposit. To avoid excessive degradation of the seabed as a

whole, the number of sites should be limited as far as possible and each site should be used to the

maximum extent that will not interfere with navigation or any other legitimate use of the sea.

11.4 Effects can be minimised by ensuring that, as far as possible, the dredged material and the

sediments in the receiving area are similar. Locally, impacts may also be reduced if the deposition area

is subject to natural physical disturbance. In areas where natural dispersion is low or unlikely to be

significant and where reasonably clean, finer-grained dredged material is concerned, it may be

appropriate to use a deliberately dispersive deposit strategy to prevent or reduce blanketing, particularly

of a smaller site (see also 9.5).

11.5 The rate of deposition of dredged material can be an important consideration since it will often

have a strong influence on the impacts at the deposit site. It may therefore need to be controlled to

ensure that the environmental management objectives for the site are not exceeded.

as defined in the glossary

Page

of 39

11.6 Engineering controls, such as method of dredging and deposit, remediation of contaminated

materials, infilling of depressions, deliberate capping or other contained methods of deposit of dredged

material deposits may be appropriate in certain circumstances to avoid interference with fishing or other

legitimate activities.

11.7 Operational controls can include temporal restrictions on depositing activities such as tidal

and/or seasonal restrictions to prevent interference with e.g. nature protection, anthropogenic uses,

migration, spawning or seasonal fishing activity.

12. MONITORING

12.1 Monitoring in relation to deposit of dredged material is defined as measurements of

compliance with permit requirements and of the condition and changes in condition of the receiving area

to assess the Impact Hypothesis upon which the issue of a deposit permit was approved.

12.2 The effects of dredged material deposit are likely to be similar in many areas, and it would be

very difficult to justify (on scientific or economic grounds) monitoring all sites, particularly those receiving

small quantities of dredged material. It is therefore more appropriate, and cost effective, to concentrate

on detailed investigations at a few carefully chosen sites (e.g. those subject to large inputs of dredged

material) to obtain a better understanding of processes and effects.

12.3 It may usually be assumed that suitable specifications of existing (pre-deposit) conditions in the

receiving area are already contained in the application for deposit

12.4 The Impact Hypothesis forms the basis for defining the monitoring programme. The

measurement programme should be designed to ascertain that changes in the receiving environment are

within those predicted. In designing a monitoring programme the following questions must be answered:

what testable hypotheses can be derived from the Impact Hypothesis?

what measurements (e.g. type, location, frequency, performance requirements) are required to

test these hypotheses?

what should be the temporal and spatial scale of measurements?

how should the data be managed and interpreted?

12.5

The permitting or supervising authority is encouraged to take account of relevant research

information in the design and modification of monitoring programmes. Measurements should be

designed to determine two things:

a. whether the zone of impact differs from that projected; and

b. whether the extent of change protected outside the zone of impact is within the scale predicted.

The first of these questions can be answered by designing a sequence of measurements in space and

time that circumscribe the projected zone of impact to ensure that the projected spatial scale of change

is not exceeded. The second question can be answered by the acquisition of measurements that provide

information on the extent of change that occurs outside the zone of impact after the deposit operation.

Frequently, this latter suite of measurements will only be able to be based on a null hypothesis - that no

significant change can be detected.

Feedback

12.6 Information gained from field monitoring, (or other related research studies) can be used to:

a. modify or terminate the field monitoring programme;

b. modify or revoke the permit; and

c. refine the basis on which applications to deposit dredged material at sea are assessed.

Page

of 39

12.7 Concise statements of monitoring activities should be prepared. Reports should detail the

measurements made, results obtained and how these data relate to the monitoring objectives. The

frequency of reporting will depend upon the scale of deposit activity and the intensity of monitoring.

13. REPORTING

13.1 According to 1992 Helsinki Convention Annex V Regulation 2 and Article 11 item 5 the

Contracting Parties should report on nature and quantities of material that has been deposited in the

Baltic Sea Area. This should be done according to the HELCOM Reporting Format for Management of

Dredged Material at Sea (Attachment 1).

13.2 Contracting Parties should also inform the Secretariat of their monitoring activities and submit

reports when they are available.

Figure 1: Steps to be considered in assessing permits application for sea deposit

Page

of 39

13.3 According to the decision of (HELCOM 41-2020), the HELCOM Secretariat annually reports to the London

Convention and its 1996 Protocol on behalf of HELCOM Contracting Parties. The Consolidated report is to

be prepared utilizing the data on handling of dredged material at sea that are annually reported by the

Contracting Parties, pursuant to HELCOM Recommendation 36-2 REV. The format and technical

requirements for the consolidated reporting were agreed between the Secretariats of the London

Convention and the Helsinki Convention taking into account the availability of relevant data in the

Contracting Parties to the Helsinki Convention. The annual consolidated report to LC/LP is to be prepared in

the format given in the Attachment 2 to this Guideline.

- The report consists of two excel sheets: “summary” and “details of sites”. In addition, the report

includes a word file with definitions used in the HELCOM reporting on handling of dredged material at

sea.

- The “summary sheet” is comprised of a country wise summary of activities on the reporting year. It

includes information on the number of activities and the amount material deposited, both separated

between capital and maintenance dredging. In addition, it includes a map on the distribution of

activities around the Baltic Sea.

- The “details of sites” sheet is comprised of information on individual depositing activities, including

deposit site code, location of site (coordinates of the site), sub basin and amount material deposited.

Information on the beneficial use is also provided and the last two columns includes the potential

amount and purpose of beneficial use.

The procedure and timeframe of the reporting include the following steps:

- An overview of the data reported in accordance with the Annex 1 to this Guideline is to be presented

to the relevant HELCOM working group at the first convenience after the reporting deadline for taking

necessary actions to accomplish the reporting.

- The reported data will be processed by the Secretariat and compiled into the unified geo-database by

1 December of the same year including all needed clarifications with national data reporters.

- The compiled national datasets will be available for national data reporters after 1 December in

Shapefile format. National experts will be invited to verify and approve the datasets in two months’

time by 1 February of the following year.

- After expert’s approval HELCOM Secretariat will compile the consolidated report from the verified

data by 1 March and submit it LC/LP after approval by relevant HELCOM working group.

Page

of 39

14. REFERENCES

Background information and supplementary literature to the HELCOM Guidelines for the Management of

Dredged Material at Sea

Application of ecosystem principles for the location and management of offshore dumping sites in the SE Baltic

Region (ECODUMP Project)

Clarifications regarding the relationship between the existing national interpretations in the application of the

Waste Framework Directive to dredged materials and the dredged material management guidelines, HELCOM

LAND-MONAS EWS DREDGE 2-2014 (document 4-1, Annex II)

EPA/CE, 1992. Evaluating Environmental Effects of Dredged Material Management Alternatives - A Technical

Framework, EPA 842-B-92-008.

IMO 2005. Sampling of Dredged Material guidelines for the sampling and analysis of dredged material intended

for disposal at sea. IMO publication 1537E.

International Association of Dredging Companies (IADC)/Central Dredging Association (CEDA), 1997.

Environmental Aspects of Dredging, Guide 2a: Conventions, Codes and Conditions: Marine Disposal.

International Association of Dredging Companies (IADC)/Central Dredging Association (CEDA), 1997.

Environmental Aspects of Dredging. Guide 3 (Investigation, Interpretation and Impact). ISBN 90-75254-08-3.

International Association of Dredging Companies (IADC)/Central Dredging Association (CEDA), 1998.

Environmental Aspects of Dredging, Guide 4: Machines, Methods and Mitigation.

International Association of Dredging Companies (IADC)/Central Dredging Association (CEDA), 1999.

Environmental Aspects of Dredging, Guide 5: Reuse, Recycle or Relocate.

PIANC, 1992. Beneficial Uses of Dredged Material: A Practical Guide, Report of Working Group No. 19.

PIANC, 1996. Handling and Treatment of Contaminated Dredged Material from Ports and Inland Waterways,

Report of Working Group No. 17 of the Permanent Technical Committee 1 -Supplement to PIANC Bulletin No. 89.

PIANC, 1997. Dredged Material Management Guide. Special Report of the Permanent Environmental Commission

– Supplement to Bulletin no.96.

PIANC, 1998. Handling and Treatment of Contaminated Dredged material from Ports and Inland Waterways, Vol.

2., Report of Working Group No. 17 of the Permanent Technical Committee 1.

PIANC, 1999. Management of Aquatic Disposal of Dredged Material. Report of ENVICOM Working Group 1 of the

Permanent Environmental Commission.

Sustainable Management of Contaminated Sediments (SMOCS Project); Guidelines for applying sustainability

approach for management of contaminated sediments in dredging projects.

Page

of 39

Glossary and Acronyms

These terms are defined for the purpose of these guidelines

Annex I

Action Levels

Guidance values used to trigger action

anoxic

Without oxygen.

anthropogenic

Originating from the activity of humans.

benthic

Of, relating to, or occurring at the bottom of a body of water.

Best Available

Techniques (BAT)

The latest stage of development (state of the art) of processes, of facilities or of

methods of operation, which indicate the practical suitability of a particular

measure for limiting discharges, emissions and waste. (Regulation 2, Annex II of

the Helsinki Convention 1992)

Best Environmental

Practice (BEP)

The application of the most appropriate combination of environmental control

measures and strategies. (Regulation 3, Annex II of the Helsinki Convention 1992)

bioaccumulation

Accumulation of environmental contaminants in living tissue.

bioassay

Tests in which organisms are exposed to dredged materials to determine their

effects or toxicity.

biological testing

Testing via bioassays.

biota

Living organisms.

Building with Nature

New approach to maritime

infrastructure

projects using the dynamics of the natural system

as a starting point.

CEDA

Central Dredging Association, one of the three autonomous sister organizations,

along with WEDA and EADA, that constitute WODA.

clay

Sedimentary mineral particles 0.2 to 2.0 µm in size, usually with a negative charge

(anion); the size and charge have profound implications for sediment chemistry

and other physical interactions.

Contaminated dredged

material

Dredged material not meeting national assessment criteria (e.g. exceeding upper

action levels).

confined disposal

Deposit in a structure planned and designed to contain dredged material and

safely contain any released contaminants, preventing their re-entry into the

aquatic environment.

deposit

Any deposit into the maritime area of dredged materials, independently of

whether it is considered as “dumping” or “placement”

dredged material

Material arising from dredging operations.

dredged material

management

Is an overarching term describing a variety of handling methods of dredged

materials including, inter alia: dumping (deliberate disposal), re-use, beneficial

use, re-location, placement and treatment.

Page

of 39

dumping

any deliberate disposal at sea or into the seabed of dredged material; subject to a

prior special permit issued by the appropriate national authority in accordance

with the provisions of Annex V of the 1992 Helsinki Convention (Article 2 (4ai), 11

(2))

eco-toxicological

testing

Biological testing via bioassays.

gravel

Unconsolidated rock fragment > 2mm to < 63mm

fractions

Categories of sediments using grain size.

persistence

feature of organic compounds to resist to environmental degradation through

chemical, biological, and photolytic processes

(i) Evidence that the half-life of the chemical in water is greater than two months,

or that its half-life in soil is greater than six months, or that its half-life in sediment

is greater than six months; or

(ii) Evidence that the chemical is otherwise sufficiently persistent to justify its

consideration within the scope of this Convention (Stockholm POPs Convention);

permitting authority

The official department or agency that has the legal authority to permit or refuse

deposit in the marine environment and to prosecute violations of deposit

regulations.

PIANC

The International Navigation Association.

placement

placement of matter for a purpose other than the mere disposal thereof,

provided that such placement is not contrary to the aims of the present

Convention (Article 2 (4bii) of the 1992 Helsinki Convention)

practicable

Idea that a project, or scheme that can be realized, with the available resources

and within the given constraints of cost and time.

sand

Mineral particles > 63 µm and < 2 mm in size.

sediment

Naturally occurring material that is produced through the processes of

weathering and erosion of rocks, and is subsequently transported by the action of

fluids such as wind, water, or ice, and/or by the force of gravity acting on the

particle itself.

sidecast dredging

most common currently applied method to outfall construction involving

dredging or excavation of a trench, and placing of excavated material on the

seabed to one or both sides of the trench

silt

Mineral particles between 2.0 µm and 63 µm in size;

solid waste

Any persistent, manufactured or processed solid material or items discarded,

deposited of or abandoned in the marine and coastal environment

toxic

Has lethal or debilitating effects when ingested or contacted externally, such as

exposure to gill membranes during respiration or to skin.

treatment

The processing of (contaminated) dredged material to reduce its quantity or to

reduce the contamination.

Page

of 39

Analytical Requirements for Dredged Material Assessment

Technical Annex I

1. This Technical Annex covers the analytical requirements necessary to implement paragraphs

6.4 - 6.10 of the HELCOM Guidelines for the Management of Dredged Material at Sea.

2. A tiered approach to testing is recommended. At each tier it will be necessary to determine

whether sufficient information exists to allow a management decision to be taken or whether further testing

is required.

3. As a preliminary to the tiered testing scheme, information required under section 6.3 of the

Guidelines will be available. In the absence of appreciable pollution sources and if the visual determination of

sediment characteristics leads to the conclusion that the dredged material meets one of the exemption criteria

under paragraph 6.3 of the Guidelines, then the material will not require further testing. However, if all or part

of the dredged material is being considered for beneficial uses, then it will usually be necessary, in order to

evaluate these uses, to determine at least some of the physical properties of the material indicated in Tier I.

4. The sequence of tiers is as follows:

- assessment of physical properties

- assessment of chemical properties

- assessment of biological properties and effects

A pool of supplementary information, determined by local circumstances may be used to augment each tier

(cf. section 6.5 of the Guidelines).

5. At each stage of the assessment procedure account must be taken of the method of analysis.

Analysis should be carried out on the whole sediment (< 2mm) or in a fine-grained fraction. If analysis is carried

out in a fine-grained fraction, the results should be appropriately converted to whole sediment (< 2 mm)

concentrations for establishing total loads of the dredged material. Additional information (e.g. as regards

storage and pre-treatment of samples, analytical procedures, analytical quality assurance) should be included

in relevant HELCOM Monitoring Manual.

6. The physical composition of samples, and therefore the chemical and biological properties,

can be strongly influenced by the choice of sampling sites, the method of sampling and sampling handling.

These possible influences should be taken into account when evaluating data.

Tier I: PHYSICAL PROPERTIES

Physical analyses are important because they help to indicate how the sediment may behave during dredging

and deposit operations and indicate the need for subsequent chemical and/or biological testing. It is strongly

recommended that the following determinations be carried out:

Determinant

Indicating

•

grain size analysis (by laser or sieving

methods)

•

percent solids (dry matter)

•

Cohesiveness, settling velocity/resuspension potential,

contaminant accumulation potential

•

density/specific gravity

•

Consolidation of placed material, volume in situ vs. after

deposit

•

organic matter (as total organic

carbon)

•

Potential accumulation of organic associated

contaminants

Page

of 39

When dredged material is being considered for beneficial uses, it will also usually be necessary to have

available details of the engineering properties of the material e.g. permeability, settling characteristics,

plasticity and mineralogy.

Tier II: CHEMICAL PROPERTIES

Primary List

List of metals, metalloids and organic/organo-metallic compounds to be determined:

•

Cadmium (Cd)

•

Chromium (Cr)

•

Copper (Cu)

•

Lead (Pb)

•

Mercury (Hg)

•

Nickel (Ni)

•

Zinc (Zn)

•

Arsenic

•

Polychlorinated biphenyl (ΣPCB) congeners - IUPAC nos 28, 52, 101, 118, 138, 153 and 180 (ICES

7).

•

Polycyclic aromatic hydrocarbons (PAHs). ΣPAH16 and/or ΣPAH9 as a subgroup of ƩPAH16 (at least

the following, but not limited to: anthracene; benzo[a]anthracene; benzo[ghi]perylene;

benzo[a]pyrene;chrysene; fluoranthene; indeno[1,2,3-cd]pyrene; pyrene; phenanthrene).

•

Tri-butyl tin (TBT) compounds and their degradation products.

As a minimum requirement, national action levels need to be established for the primary list above.

Determination of PCBs, PAHs and Tri-Butyl tin compounds and their degradation products will not be

necessary in circumstances where the sediments are very unlikely to be contaminated with these substances.

The relevant circumstances are:

a) sufficient information from previous investigations indicating the absence of contamination is

available (cf. para 7.5-7.7 in the HELCOM Guidelines for Management of dredged Material at

Sea); or

b) - there are no known significant sources (point or diffuse) of contamination or historic

inputs; and

- the sediments are predominantly coarse; and

- the content of total organic carbon is low.

Secondary List

Based upon local information of sources of contamination (point sources or diffuse sources) or historic inputs,

other determinants may require analysis, for instance:

•

Other chlorobiphenyls

•

Organochlorine pesticides

•

Organophosphorus pesticides

•

Tri-phenyl tin (TPhT)

•

Other anti-fouling agents

•

Petroleum hydrocarbons

•

Polychlorinated dibenzodioxins (PCDDs)/polychlorinated dibenzofurans (PCDFs)

•

Phthalates (DEHP and optionally - DBP/BBP)

Page

of 39

In deciding which additional individual organic contaminants to determine, reference should be made to

existing priority substance lists, such as those prepared by HELCOM

and the EU

(as applicable).

Normalisation

It is recommended that normalised values of contaminants should be used to enable a more reliable

comparison of contaminant concentrations in dredged material with those in sediments at deposit or

reference sites, as well as with action levels. The normalisation procedure (see Technical Annex II) used within a

regulatory authority should be consistent to ensure effective comparisons.

Additionally in order to be in the position to anticipate the effects of contaminants absorbed on sediment

particles on deposit or filter feeders it is important to have information on the contaminant concentration of

the relevant fine fraction (e.g. less than 63 µm or 20 µm).

Analytical Techniques

Reference should be made to the Technical Annexes of the relevant HELCOM Monitoring manual and ISO/EN

methods for recommended analytical techniques.

Tier III: BIOLOGICAL PROPERTIES AND EFFECTS

In a significant number of cases the physical and chemical properties described above do not provide a direct

measure of the biological impact. Moreover, they do not adequately identify all physical disturbances and all

sediment-associated constituents present in the dredged material. If the potential impacts of the dredged

material to be deposited cannot be adequately assessed on the basis of the chemical and physical

characterisation, biological measurements should be carried out.

The selection of an appropriate suite of biological test methods will depend on the particular questions

addressed, the level of contamination at the dredging site and the degree to which the available methods

have been standardised and validated.

To enable the assessment of the test results, an assessment strategy should be developed with regard to

granting a permit authorising deposit at sea. The extrapolation of test results on individual species to a higher

level of biological organisation (population, community) is still very difficult and requires good knowledge of

assemblages that typically occur at the sites of interest.

1. Toxicity bioassays:

The primary purpose of toxicity bioassays is to provide direct measures of the effects of all sediment

constituents acting together, taking into account their bioavailability. For ranking and classifying the

acute toxicity of harbour sediment prior to maintenance dredging, short-term bioassays may often

suffice as screening tools.

•

To evaluate the effects of the dredged material, acute bioassays can be performed with pore water, an

elutriate or the whole sediment In general, a set of 2-4 bioassays is recommended with organisms from

different taxonomic groups and different trophic levels (e.g. crustaceans, molluscs, polychaetes, bacteria,

echinoderms);

•

In most bioassays, survival of the test species is used as an endpoint. Chronic bioassays with sub-

lethal endpoint (growth, reproduction etc) covering a significant portion of the test species life

cycle may provide a more accurate prediction of potential impact of dredging operations.

However, standard test procedures are still under development.

List of Harmful Substances according to Annex I of the HELSINKI Convention and the priority hazardous substances

contained in HELCOM Recommendation 31-E/1

Directive 2013/39/EU of the European Parliament and of the Council of 12 August 2013 amending Directives 2000/60/EC

and 2008/105/EC as regards priority substances in the field of water policy

Page

of 39

The outcome of sediment bioassays can be unduly influenced by factors other than sediment-

associated chemicals. Confounding factors like ammonia, hydrogen sulphide, grain size, oxygen

concentration and pH should therefore be determined during the bioassay.

Guidance on the selection of appropriate test organisms, use and interpretation of sediment bioassays

is given by e.g. USACE/EPA (1991/1994) and CEDA & IADC (2008) while guidance on sampling of

sediments for toxicological testing is given by e.g. ASTM (1994).

2. Biomarkers:

Biomarkers may provide early warning of more subtle (biochemical) effects at low and sustained levels

of contamination. Most biomarkers are still under development but some are already applicable for

routine application on dredged material (e.g. one which measures the presence of dioxin-like

compounds - Murk et al., 1997) or organisms collected in the field (e.g. DNA strand/breaks in flat fish).

3. Microcosm experiments:

There are short-term microcosm tests available to measure the toxicant tolerance of the community

e.g. Pollution Induced Community Tolerance (PICT) (Gustavson and Wangberg, 1995)

4. Mesocosm experiment:

In order to investigate long-term effects, experiments with dredged material in mesocosms can be

performed, for instance to study the effects of PAHs in flatfish pathology. Because of the costs and time

involved these experiments are not applicable in the process of authorising permits but are useful in

cases where the extrapolation of laboratory testing to field condition is complicated r environmental

conditions are very variable and hinder the identification of toxic effects as such. The results of these

experiments would be then available for future permitting decisions.

5. Field observation of benthic communities:

Monitoring in the surrounding of the deposit site of benthic communities e.g. in situ (fish, benthic

invertebrates) can give important clues to the condition of marine sediments and are relevant as a

feed-back or refinement process for authorising permits. Field observations give insight into the

combined impact of physical disturbance and chemical contamination. Guidelines on the monitoring of

benthic communities are provided by e.g. OSPAR, ICES, HELCOM.

6. Other biological properties:

Where appropriate, other biological measurements can be applied in order to determine e.g. the

potential for bioaccumulation and for tainting.

SUPPLEMENTARY INFORMATION

The need for further information will be determined by local circumstance and may form an essential part of

the management decision. Appropriate data might include: redox potential, sediment oxygen demand, total

nitrogen, total phosphorus, iron, manganese, mineralogical information or parameters for normalising

contaminant data (e.g. aluminium, lithium, scandium – cf. Technical Annex II). Consideration should also be

given to chemical or biochemical changes that contaminants may undergo when deposited of at sea.

Page

of 39

Literature References related to Technical Annex I

ASTM, 1994. Standard guide for collection, storage, characterisation and manipulation of sediment for

toxicological testing. American Society for Testing and Material, Annual Book of Standards. Vol. 11.04,

E1391-96.

EPA/CE, 1991. Evaluation of Dredged Material Proposed for Ocean Disposal: Testing Manual

EPA-503/8-91/001. US-EPA Office of Water (WH-556F).

EPA/CE, 1998. Evaluation of Dredged Material Proposed for discharge in Waters of the US. Testing Manual

(Draft): Inland Testing Manual EPA – 823-B-98-004.

EPA, Office of Water, 2001. Methods for Collection, Storage and Manipulation of Sediments for Chemical

and Toxicological Analyses: Technical Manual EPA-823-F-01-023.

International Association of Dredging Companies (IADC)/Central Dredging Association (CEDA), 1997.

Environmental Aspects of Dredging. Guide 3 (Investigation, Interpretation and Impact). ISBN 90-75254-08-

International Maritime Organization (IMO) 2003. Waste Assessment Guidance - Selection and analysis of

physical and chemical parameters for the assessment of dredged material quality, Report of the Scientific

Group of the LONDON Convention.

IOC - UNEP - IMO, 2000. Global Investigation of Pollution in the Marine Environment (GIPME 2000):

Guidance on Assessment of Sediment Quality, Pub. No. 439/00.

Gustavson, K. and Wangberg, S.A.,1995. Tolerance induction and succession in microalgae communities

exposed to copper and atrazine. Aquatic Toxicology. 32: 283-302.

HELCOM, 1997. Manual for Marine Monitoring in the Cooperative Monitoring in the Baltic Marine

Environment (COMBINE Programme) of HELCOM. Part C – Programme for Monitoring of Eutrophication

and its Effects. Annex C-4: Directives for sampling and analysis of hydrographic, chemical and biological

variables. Annex C-8: Soft bottom macrozoobenthos.

Murk et al., 1996. Chemical-activated luciferase gene expression (CALUX): a novel in vitro bioassay for Ah

receptor active compounds in sediments and pore water. Fund. & Applied Tox. 33: 149-160.

OSPAR, 1997 (available from the OSPAR website):

JAMP Eutrophication Monitoring Guidelines: Benthos - Technical Annex 1 (Hard-bottom

macrophytobenthos and hard-bottom macrozoobenthos) - Technical Annex 2 (Soft-bottom

macrozoobenthos)

OSPAR 2002. JAMP Guidelines for Monitoring Contaminants in Sediments

Rees, H.L., C. Heip, M. Vincx and M.M. Parker, 1991. Benthic communities: use in monitoring point-source

discharges. ICES Techniques in Marine Environmental Sciences No. 16.

Rumohr, H.,1990. Soft-bottom macrofauna: collection and treatment of samples. ICES Techniques in

Marine Environmental Sciences No. 8.

Page

of 39

Technical Annex

Normalisation of Contaminants Concentrations in

nts

This Annex provides guidance on the application of methods to normalise contaminant concentrations in

sediments

1. Introduction

Normalisation is defined here as a procedure to correct contaminant concentrations for the influence of the

natural variability in sediment composition (grain size, organic matter and mineralogy). Most natural and

anthropogenic substances (metals and organic contaminants) show a much higher affinity to fine particulate

matter compared to the coarse fraction. Constituents such as organic matter and clay minerals contribute to

the affinity to contaminants in this fine material.

Fine material (inorganic and organic) and associated contaminants are preferentially deposited in areas of low

hydrodynamic energy, while in areas of higher energy, fine particulate matter is mixed with coarser sediment

particles which are generally not able to bind contaminants. This dilution effect will cause lower and variable

contaminant concentrations in the resulting sediment. Obviously, grain size is one of the most important

factors controlling the distribution of natural and anthropogenic components in sediments. It is, therefore,

essential to normalise for the effects of grain size in order to provide a basis for meaningful comparisons of

the occurrence of substances in sediments of variable granulometry and texture within individual areas,

among areas or over time.

When analysing whole sediment (i.e. < 2mm fraction) for spatial distribution surveys, the resulting maps give a

direct reflection of the sea bed sediments. However, in areas with varying grain size distributions, a map of

contaminant concentrations will be closely related to the distribution of fine grained sediments, and any

effects of other sources of contaminants, for example anthropogenic sources, will be at least partly obscured

by grain size differences. Also in temporal trend monitoring, differences in grain size distribution can obscure

trends. If samples used for a spatial survey consist predominantly of fine material, the influence of grain size

distribution is of minor importance and may probably be neglected.

2. Normalisation procedures

Two different approaches to correct for variable sediment compositions are widely used:

a. Normalisation can be performed by relating the contaminant concentration with components

of the sediment that represents its affinity for contaminants, i.e. binding capacity. Such co-

factors are called normalisers (cf. section 4). Normalisation can be performed by simple

contaminant/normaliser ratios or linear regression. Another procedure takes into account that

the coarse sediment fraction contains natural metal concentrations in the crystal structure before

the normalisation is performed (see section 5). Combinations of co-factors, possibly identified

from multiple regression analysis, can be used as normalisers.

b. Isolation of the fine fraction by sieving (e.g. <20 µm, <63 µm) can be regarded as a physical

normalisation to reduce the differences in sediment granulometric compositions and is

applicable to both metals and organic contaminants (Ackermann et al. 1983; Klamer et al. 1990).

Consequently the coarse particles, which usually do not bind anthropogenic contaminants and

dilute their concentrations, are removed from the sample. Then, contaminant concentrations

measured in these fine fractions can be

Technical Annex 5 - Normalisation of contaminant concentrations in sediments - to the JAMP Guidelines for

monitoring contaminants in sediments

Page

of 39

directly compared. Subsequently, the differences in sediment composition due to geochemical

nature remaining after sieving can be further corrected for by the use of co-factors. Thus, sieving

is a first powerful step in normalisation.

3. Limitations of normalisation

Clearly, normalisation procedures may not apply equally well to all elements at all sites; especially

important in this respect are elements that participate in diagenetic reactions. In cases where there is a lack

of full understanding of the geochemical processes operating care should be taken when normalising for

grain size differences. These processes can create important natural enrichment of metals at the sediment

surface, as a result of the surficial recycling of oxihydroxides or deeper in the sediment as the result of co-

precipitation of the metals with sulphides (cf., e.g., Gobeil et al. 1997), which cannot be accounted for by

normalisation.

There is no evidence that normalised data are more appropriate for ecotoxicological interpretation than

non-normalised data. However, the matter deserves further investigation.

4. Normalisation with co-factors

a. The binding capacity of the sediments can be related to the content of fines (primary factor) in

the sediments. Normalisation can be achieved by calculating the concentration of a contaminant

with respect to a specific grain-size fraction such as <2 µm (clay), <20 µm or <63 µm.

b. As the content of fines is represented by the contents of major elements of the clay fraction

such as aluminium (Windom et al. 1989) or an appropriate trace element enriched in that fraction

such as lithium (Loring 1991), these can also be used as co-factor (secondary). Both, aluminium

and lithium behave conservatively, as they are not significantly affected by, for instance, the early

diagenetic processes and strong redox effects frequently observed in sediments. Problems may

occur in when the sediment is derived from glacial erosion of igneous rocks, with significant

amounts of aluminium present in feldspar minerals contributing to the coarse fraction. In such

cases, lithium may be preferable (Loring 1991).

c. Organic matter, usually represented by organic carbon, is the most common co-factor for

organic contaminants due to their strong affinity to this sediment component. Trace metals can

be normalised using the organic carbon content (Cato 1977) but would require further

explanation due to the non-conservative nature of organic matter.

Sand

Slope PL=dC/dN

Co-factor i.e.

normaliser

Figure 1: Relation between the contaminant C and the cofactor N (see text).

Page

of 39

5. Theory

The general model for normalisation taking into account the possible presence of contaminants and cofactors

in the coarse material is given in figure 1 (Smedes et al.1997). C

and N

represent the co-factor and the

contaminant contents, respectively, in pure sand

These “intercepts” can be estimated from samples without

fines and organic material. The line of regression between the contaminant and co-factor will originate from

that point. That means that regression lines of sample sets with a different pollution level and consequently

different slopes will have this point in common (i.e. pivot point). When this pivot point is known only one

sample is required to estimate the slope. This allows determination of the contaminant content for any

agreed

(preselected) co-factor content (N

) by interpolation or extrapolation. The slope for a sample with a

contaminant content C

and a cofactor content of N

can be expressed as follows:

PL =

.................................................................................................(1)

−

The extrapolation to an agreed co-factor content, N

, follows the same slope:

PL =

..............................................................................(2)

−

Rewriting gives the contaminant content, C

, that is normalised to N

(

)

...................................................................................(3)

Results of different samples normalised to the agreed N

can be compared directly.

Normalisation by this model can be applied with different cofactors. Here primary and secondary cofactors

can be distinguished. A primary cofactor like clay or organic carbon is not present in the coarse fraction and

consequently has no intercept (N

=0). Al and Li are present in the coarse fraction and therefore are considered

to be secondary cofactors. Provided N

and C

are known, the model allows recalculation of total

samples to

a co-factor content usually found in sieved fractions, either <20 or <63µm. However such an extrapolation

for a coarse grained sample will be associated with a large error due to the uncertainty of the intercepts and

the analysed parameters. For a more fine grained sample, the uncertainty of the normalised result is much

lower than for normalisation of a sieved fraction to the agreed cofactor content and will result in a more

accurate result. The model presented also applies to the normalisation of organic contaminants

using organic

carbon but in that case the intercepts N

and C

will not differ significantly from zero.

Principally, the result allows comparison of data of total and sieved samples, irrespective the sieving diameter

but the error has to be taken into account. Through propagation of errors the standard error of the result

can

be calculated from the analytical variation and the natural variation of the intercept N

. Results can

therefore always be reported with a standard deviation.

6. Considerations on co-factors

The clay mineral content is the most important cofactor for trace metals. In the model above the N

will be

zero for clay and only the intercept due to the content of the trace metal in the coarse fraction (C

) has to be

taken into account. However, current intercomparison exercises do not include this parameter. Presently

other parameters such as aluminium or lithium are used to represent the clay content.

The aluminium content in the sandy fraction may vary from area to area. For some areas aluminium contents

in the sandy fractions are found at the same level as found in the fines (Loring, 1991) and therefore the

intercept N

becomes very high. In equation (3) this implies that the denominator is the result of subtracting

Page

of 39

two large numbers, that is the normaliser content in the sample (N

) and the normaliser content in only sand

). Consequently, due to their individual uncertainties, the result has an extremely high error. Obviously,

Page

of 39

normalisation with low intercepts is more accurate. Much lower intercepts are found if partial digestion

methods are used that digest the clay minerals, but not the coarse minerals. Using partial digestion, the

spatial variability of the results of aluminium analyses in the sandy fraction has been found to be much smaller

than with total methods. Although normalising concentrations of contaminants in fine grained material will

always give more accurate results, an error calculation will identify whether using coarse samples (and total

methods, e.g. HF, X-ray fluorescence) allows the requirements of the program to be met.

For most areas the lithium content in the sandy fraction is much lower than in the fine fraction. In addition,

results from partial digestion and total methods do not differ significantly. There is only little spatial variability

of the lithium content in the sandy fraction. Generally, compared to aluminium, more accurate normalised

data can be expected using lithium.

As for clay, no intercept (N

) applies for organic matter, which is usually represented by organic carbon.

Organic matter also occurs in the coarse fraction but is even then a cofactor that contributes to the affinity

for contaminants, whereas the aluminium in the coarse fraction does not. Furthermore, organic matter in a

sample is not always well defined as it can be composed of material with different properties. The most

variable properties will be found in the organic matter present in the coarse fraction, i.e. that not associated

with the fines. In fine sediments or in the sieved fine fractions the majority of the organic matter is associated

with the mineral particles and it is assumed to be of more constant composition than in the total sample. In

addition, the nature of the organic matter may show spatial variation. For samples with low organic carbon

content close to the detection limit, normalisation using this cofactor suffers from a large relative error. This

results from the detection limit and the insufficient homogeneity that cannot be improved due to the limited

intake mass for analysis.

For further interpretation of data the proportion of fines determined by sieving can be useful. Provided, there

are no significant amounts of organic matter in coarse fractions, the proportion can be used as normaliser.

The error in the determination of fines has to be taken into account and will be relatively high for coarse

samples.

7. Considerations on contaminants

Almost all trace metals, except mercury and in general also cadmium, are present in the coarse mineral matrix

of samples. The metal concentrations show a spatial variability depending on the origin of the sandy material.

In sandy sediments, partial digestion techniques result in lower values than are obtained from total digestion

techniques. This implies that partial digestion results in lower intercepts (pivot point is closer to the zero).

However, the partial digestion must be strong enough so the clay will be totally digested (as is the case with

HF digestion techniques), and the measured aluminium content remains representative for the clay. It was

demonstrated that analyses of fine material gave similar results for several trace elements using both total

and strong partial methods (Smedes et al. 2000, QUASH/QUASIMEME intercalibrations).

In general, correlations of organic contaminants with organic carbon have no significant intercept. Obviously a

normalised result from a coarse sample will show a large error as due to the dilution by sand the

concentrations are often close or even below the detection limit. Presently, organic carbon is usually applied

for normalisation of PAHs. It should be recognised that due to the possible presence of undefined material,

for example soot or ash, elevated PAH concentrations may occur in specific fractions that might have limited

environmental significance. Although this needs further investigation, existing results indicate that PAH

concentrations in the sieved fractions are not affected significantly.

Page

of 39

8. Isolation of fine fractions for analyses

The Sample preparation

Samples must be sieved at 2 mm as soon as possible after sampling to remove large detritus and benthic

organisms. Otherwise during further sample handling like storage, freezing or ultrasonic treatment, biotic

material will deteriorate and become part of the sediment sample. Until the final sieving procedure that

isolates the fines, the sample can be stored at 4°C for about a week and up to 3 months when frozen at –

20°C, although direct wet sieving is preferred. For prolonged storage freeze-drying of samples can be

considered. In this case contamination and losses of contaminants during freeze-drying have to be checked.

Air-drying is not appropriate due to high contamination risks. Besides, samples may be difficult to be

disaggregate and mineral structures may be affected.

Requirements for Sieving

A wet sieving procedure is required to isolate the fine-grained fractions (<63 µm or <20 µm). Wet sieving re-

suspends fine particles that would otherwise remain attached to coarser particles in the sample. Sediments

should be agitated during sieving to prevent to disaggregate agglomerates of fines and to prevent clogging

of the mesh. Freeze-dried samples need to be re-suspended using ultrasonic treatment. Seawater, preferably

from the sampling site, should be used for sieving as it reduces the risk of physico-chemical changes in the

sample i.e. losses through leaching or contamination. Furthermore seawater assists the settling of fine

particles after the sieving. If water from the sampling site is not available, then seawater of an unpolluted site,

diluted with deionised water to the required salinity, can be used. The amount of water used for sieving should

be kept to a minimum and be reused for sieving subsequent batches.

To minimise or prevent contamination it is recommended to use large sample amounts of sediment for

sieving. No significant contaminant losses or contamination was detected when at least 25 g of fine fraction

is isolated. (QUASH).

Methodology

Both automated and manual methods are available for sieving. A video presentation of these methods can be

provided by the QUASH Project (QUASH 1999).

•

The automatic sieving method pumps seawater over a sieve that is clamped on a vibrating table (Klamer

et al. 1990). The water passing the sieve is lead to a flow-through centrifuge that retains the sieved particles

and the effluent of the centrifuge is returned to the sieve by a peristaltic pump. Large sample amounts, up

to 500 g, can be handled easily.

•

The second method is a manual system sieving small portions 20-60 g using an 8-cm sieve in a glass beaker

placed in an ultrasonic bath (Ackermann et al. 1983). Particles are isolated from the water passing the

sieve by batch wise centrifugation. The water can be reused for a subsequent batch of sediment. In case

of sandy samples, when large amounts of sediments have to be sieved, removal of the coarse material by a

pre-sieving over e.g. 200-µm mesh can facilitate the sieving process.

Isolated fine fractions have to be homogenised thoroughly, preferably by a ball mill, as centrifugation

produces inhomogeneous samples due to differences in settling speed of different grain-size fractions.

9. Recommendations

1. For both temporal trend and spatial monitoring, it would be ideal to analyse samples with equal

composition. This could be confirmed by determination of co-factors Al, Li, OC and parameters of the

grain size distribution (e.g. clay content, proportion <20um, proportion <63um). However, this situation

will not always occur, particularly in the case of spatial surveys.

2. New temporal trend programs should be carried out by the analysis of fine sediments or a fine-grained

fraction, isolated by sieving. Existing temporal trend programs could be continued using existing

procedures, provided that assessment of the data indicates that the statistical power of the programs

Page

of 39

is adequate for the overall objectives.

3. Contaminant concentrations in whole sediments can be subjected to normalisation using co-factors

for organic matter, clay minerals etc., taking into account the presence of both co-factors and target

contaminants in the mineral structure of the sand fraction of the sediment. Taking into account these

non-zero intercepts of regressions of contaminant concentrations with co-factors, normalisation to

preselected co-factor content will reduce the variance arising from different grain sizes. Normalised

values for sandy sediments will have greater uncertainties than for muddy sediments. The propagated

error of the variables used for normalisation may be unacceptable high for sandy sediments, if both

contaminant and co-factor concentrations are low, particularly when approaching detection limits. In

that case, in order to draw reliable maps, alternative procedures, such as sieving, need to be used to

minimise the impact of this error structure.

4. Variance arising from grain size differences can be reduced in a direct way by separation of a fine

fraction from the whole sediment. Spatial distribution surveys of the concentrations of contaminants in

separated fine fractions can be used to prepare maps which will be much less influenced by grain size

differences than maps of whole sediment analyses. There will still be some residual variance arising from

differences in the composition (mineralogy and organic carbon content) of the sediments.

5. The natural variance of sample composition will be smaller in the fraction <20 µm than in the fraction

<63 µm. Therefore, the fraction <20 µm should be preferred over the fraction <63 µm. However,

separation of the fraction <20 µm can be considerably more laborious than the separation of the

fraction <63 µm and might be an obstacle to its wide application. For this practical reason, the fraction

<63 µm is an acceptable compromise for both temporal trend and coordinated large scale spatial

surveys.

6. The preferred approach for preparing maps of the spatial distribution of contaminants in sediment

consists of two steps: analyses of contaminants in fine sediments or in the fraction <63 µm, followed

by normalisation of analytical results using co-factors (see section 4). Current scientific knowledge

indicates that this procedure minimises the variances arising from differences in grain size, mineralogy

and organic matter content. Application of this two-tiered approach to fractions <20 µm gives results

that can be directly compared to results found by normalisation of concentrations measured in fractions

<63 µm. This approach should give consistent and comparable data sets over the ICES/HELSINKI area.

Maps of contaminant levels in fine sediments should be accompanied by maps of the co-factors in the

whole sediments.

7. In order to clarify aspects of data interpretation, analytical data for field samples should be

accompanied by information on limits of detection and long term precision. In order to contribute to

environmental assessment, data for field samples should include the grain size distribution, as a

minimum the proportion of the analysed fraction in the original whole sediment.

10. References:

Ackermann, F., Bergmann, H., and Schleichert, U. (1983) Monitoring of heavy metals in coastal and

estuarine sediments - A question of grain-size: <20 µm versus <60 µm. Environmental Technology Letters,

4: 317-328.

Cato, I. (1977): Recent sedimentological and geochemical conditions and pollution problems in two marine

areas in south-western Sweden. Striae 6, 158 pp. Uppsala.

Gobeil, C., MacDonald, R. W. & Sundby, B. (1997): Diagenetic separation of cadmium and manganese in

suboxic continental margin sediments. Geochim. Cosmochim. Acta 61, 4647-4654.

Klamer, J. C., Hegeman, W. J. M. & Smedes, F. (1990): Comparison of grain size correction procedures for

organic micropollutants and heavy metals in marine sediments. Hydrobiologia 208, 213-220.

Loring, D. H. (1991): Normalization of heavy-metal data from estuarine and coastal sediments. ICES J. mar.

Sci. 48, 101-115.

Page

of 39

QUASH (1999) Sediment Sieving Techniques, QUASH Project Office, FRS Marine Laboratory, PO Box 101,

Victoria Road, Aberdeen, AB11 9DB, Scotland

Smedes, F. (1997) Grainsize Correction Procedures, Report of the ICES Working Group on Marine Sediments

in Relation to Pollution. ICES CM 1997/Env:4, Ref. E, Annex 6.

Smedes, F., Lourens, J., and Wezel, van A. (1997) “Zand, Slib en Zeven, Standardisation of contaminant

contents in marine sediments, Report RIKZ-96.043 (Dutch), ISSN 0927-3980, RIKZ, PO Box 20907, 2500 EX,

The Hague.

Smedes, F. Davies, I.M., Wells, D., Allan, A., Besada, V. (2000): Quality Assurance of Sampling and Sample

Handling (QUASH) - Interlaboratory study on sieving and normalisation of geographically different

sediments; QUASH round 5 (sponsored by the EU Standards, Measurements and Testing Programme)

Windom, H. L., et al. (1989): Natural trace metal concentrations in estuarine and coastal marine sediments

of the southeastern United States. Environ. Sci. Technol. 23, 314-320.

Appendix

Testing normalisation methods

As normalisation should correct for sediment composition, a criterion for an adequate normaliser is that

after normalisation of equally polluted sediment samples with different grain size distributions, the results

should not differ significantly. However, sample sets to test normalisation approaches for this criterion are

scarce. An alternative approach is to take one sample and to produce subsamples with varying grain size

distributions (Smedes 1997, Smedes et al. 1997, Smedes et al. 2000). Both the fine and coarse subsamples

are analysed for contaminants and potential normalisers. In this way a higher variability for the normaliser

concentrations, i.e. a worst case than ever will occur in nature, can be obtained which provides a sensitive

test for the usefulness of potential normalisers.

Page

of 39

Technical Annex

III

Introduction

Best Environmental Practice (BEP)

This Technical Annex was prepared bearing in mind that, although the guidelines strictly only apply to the

deposit of dredged material, Contracting Parties are encouraged also to exercise control over dredging

operations.

This Technical Annex has as its aim to provide guidance to national regulatory authorities, operators of

dredging vessels and port authorities on how to minimise the effects on the environment of dredging and

deposit operations. Careful assessment and planning of dredging operations are necessary to minimise the

impacts on marine species and habitats.

The items given as BEP under the different headings of this Technical Annex are given as examples. Their

applicability will generally vary according to the particular circumstances of each operation and it is clear that

different approaches may then be appropriate. More detailed information on dredging techniques and

processes can be found in Guide 4 of the IADC/CEDA series on Environmental Aspects of Dredging.

BEST ENVIRONMENTAL PRACTICE TO OPTIMISE

THE DEPOSIT OF DREDGED MATERIAL AT SEA

MINIMISE

THE

EFFECTS CAUSED

THE DEPOSIT

DREDGED

MATERIAL

MINIMISE

THE

IMPACTS

DREDGING

OPTIMISE

THE

DEPOSITED

QUANTITIES

IMPROVE

SEDIMENT QUALITY

Point A - Minimisation of the effects caused by the deposit of dredged material - is comprehensively described

in the main body of these guidelines; Point B ‘Optimisation of the deposited quantities’; Point C

‘Improvement of sediment quality’ and Point D ’Minimise the Impacts of Dredging’ are requirements

resulting from Annex V to the HELSINKI Convention (see § 3.5 of the HELCOM Guidelines for the Management

of Dredged Material at Sea), and, in addition, are very relevant to the prevention of pollution of the marine

environment resulting from the deposit of dredged materials. Descriptions of BEP in relation to these activities

are given at Appendices I and II.

Page

of 39

OPTIMISE THE DEPOSITED QUANTITIES

APPENDIX I

KEEP VOLUME OF DREDGED MATERIAL MINIMAL IMPROVE DREDGING PROCESS

MINIMISE NEED FOR DREDGING OPTIMISE DREDGING OPERATIONS MANAGEMENT

In fluid mud areas: introduce the concept of

Navigable depth based on:

- physico-chemical evaluation of the sediment

(including rheometry and densimetry)

- full scale trials

BEP: Dredging only the amount of

material required for maintaining a particular

density level to allow navigation. This may require

e.g. continuous underway measurement of sediment

density by using a nuclear transmission gauge or

measurement of shear forces.

In areas with sandy waves etc.

BEP: - selective dredging of sand waves and

other mobile sand structures

Hydraulic Engineering

BEP: - use of hydraulic structures to

reducesedimentation

Accurate monitoring of dredged depths at an

appropriate frequency

BEP: - accurate positioning systems e.g.:

- microwave systems

- radiowave technology

- DGPS

- apply rapid survey equipment

- continuous measurement systems

- echosounders

- swath/multibeam systems

Accurate survey systems

(see column 1: Accurate monitoring)

Availability of survey data on board

BEP: - on-line visualisation of updated

bathymetric charts, including topographic

data, coastlines, deposit areas, dredge

position, dredge head position

- tidal information

Process evaluation

BEP: - visualisation/evaluation of dredged

tracks/profiles/zones

- dredging intensity chart

- in case of muddy material, sand and

gravel: establish optimum overflow time

by analysis of load diagrams

Effective dredging process control

BEP: - Continuous on-line measurements and

presentation e.g.

- of area, heading, speed of the dredgers

and position of the suction

head/buckets/cutter/backhoe/grab/

wheel/...

- measurement of mixture velocity and

concentration

- measurement of macro production (load

diagram)

- hopper-measurement system monitoring

the filling process

Output improving techniques

BEP: - best suited suction head/cutters wheel/

backhoe/buckets

- submerged dredge-pumps

- degassing installations

- etc.

Selective dredging techniques

BEP: - selective dredging to e.g. separate

contaminated material (e.g. “freeze”

dredging)

See IADC/CEDA report referenced in the Introduction

for further information on this topic

Page

of 39

APPENDIX

IMPROVE SEDIMENT QUALITY

MINIMISE THE IMPACTS OF DREDGING

IN SITU BEFORE DREDGING AND AFTER DEPOSIT IN THE HOPPER

Improve physical aspects (cohesion, consistency,

density) of dredged material

BEP: - increase sediment density by physical

means e.g. vibration

Mechanical separation

BEP: - hydrocyclones for separation of

granulometric fractions

- flotation

- dewatering (under development)

(consider potential problems with process water and

associated contaminants e.g. re-circulation will reduce

problems

Minimise increases in turbidity

BEP: - use excavation tools /dredger heads

appropriate to minimise turbidity

- use silt screens/shields

- minimise overflow by e.g. recirculation

of overflow water

- use specially designed dredgers to

dredge contaminated sediments

- avoid the use of dredgers which

introduce large amounts of suspended

sediments into the water column where

this may lead to problems with oxygen

depletion or contamination e.g.

agitation dredgers

Minimise oxygen depletion

BEP: Avoid periods when dredging

induced turbidity will lead to

unacceptable reductions in oxygen levels

due to high temperatures

Page

of 39

HELCOM Reporting Format for Management of Dredged Material at Sea

Attachment 1

Explanatory notes for 2014 revised reporting format for management of dredged

material at sea

GENERAL

1. HOD 51-2016 adopted this revised reporting format for use from 2017 onwards.

2. National data should be entered in the respective sheets of the accompanying spreadsheet by

following the instructions given below.

3. Deposit site would be described in Sheet 1a. Only one row per deposit site is allowed

4. Material originating from different locations but deposited of at the same deposit site described in

Sheet 1a should be described in separate lines in sheets 2 and 3.

5. Please do not alter the format of the spreadsheet (e.g. by insertion of new columns or rows), but inform

the Secretariat of any problems you may encounter.

6. Please indicate clearly the reference for all additional information by using sheet 7 of the spreadsheet.

7. Each deposit site will be assigned with unique HELCOM ID/code, which must not change from year to

year.

8. The location of deposit sites of each Contracting Party, should be supplied in ArcGIS compatible shape

files (in ETRS89LAEA projection) clearly showing the HELCOM codes (as given in the data tables), the

location and any other relevant information in the attribute table of the shapefile.

GUIDANCE FOR REPORTING

9. The data should be entered by using the continental decimal (with a space as 1000 separator and a

comma as decimal separator) with the maximum number of digits available (i.e. with maximum number

of digits after the comma) and taking into account the unit given in the column header. This will ensure

correct calculations for preparing total amounts. The pre-defined number format in all data cells ensures

that the values will be displayed and printed.

10. Missing information should be indicated as follows:

NI no information

ND not determined

< less than (please state in the “text.doc” file the value of the respective limit)

EX exempted from analyses according to the HELCOM Guidelines for the Management of

Dredged Material at Sea (cf. Section 6.3 of the Guidelines)

11. Please submit your data to the HELCOM Secretariat HELCOM.Secretariat@helcom.fi by 1 October of

the year following the dredging activity. It is intended that HELCOM Secretariat will combine the

information to a database and will make it available online via HELCOM website.

Page

of 39

Instructions for reporting data per sheet:

cf. attached MS-Excel Spreadsheet

Sheet 1 – Permits

Contracting Party

Select correct option from dropdown list provided

Year

Year of deposit activity.

Report ID

Unique ID, Contracting party-Year e.g. PL-2014

Number of permits issued or regulated

under other means

Number of permits issued or regulated under other means in year prior to

reporting year. By ‘other means’ any kind of relevant national regulation

is meant, that is used for

permitting/licensing/allowing

deposit operation

Material licensed or regulated by other

means (tonnes - dry weight)

See sheet 7 in the attached MS Excel Spreadsheet for conversion from

wet weight to dry weight

Dredged material deposited (tonnes -

dry weight)

Amount actually deposited

Notes

Information of relevance

Sheet 1a – Deposit sites (optional)

proposed by HELCOM, based on IMO LC/LP Tabular reporting format

Report ID

Report code: Contracting party-Year, e.g. PL-2014

PL – country of origin

2014 - year

National Deposit site code

Code for a particular location remains the same from year

to year., e.g.

001 – deposit site code

HELCOM Deposit site ID

Unique ID, is generated to differentiate separate deposit

sites, with dash separator e.g.

PL-001

PL – country of origin

001 – deposit site code

Specific national site name

Name should preferably indicate name of water system e.g.

Bay of Gdansk and then type of water system: river,

estuary, harbour, coastal waters, and actual name of the

site etc., e.g. “Baltic Proper, Kolobrzeg Harbour waters”

Shapefile submitted

Yes/No-field indicating whether spatial data is included as

shapefile (this is recommended) with data submission.

Circular Deposit Site Center Point - Latitude

Area should be reported as GIS Shapefile containing

HELCOM Site ID (See instructions for reporting data per

shapefiles)

Reference Note:

Conversion of latitude and longitude coordinates from

degrees, minutes and seconds to decimal degrees can be

accomplished by accessing the U.S. Federal Communications

Commission website at:

Circular Deposit Site Center Point - Longitude

Circular Deposit Site - Radius

Polygonal Deposit Site Coordinate 1 - Latitude

Polygonal Deposit Site Coordinate 1 - Longitude

Polygonal Deposit Site Coordinate 2 - Latitude

Polygonal Deposit Site Coordinate 2 - Longitude

Page

of 39

Polygonal Deposit Site Coordinate 3 - Latitude

http://www.fcc.gov/mb/audio/bickel/DDDMMSS-

decimal.html. It is likely that there are many such sites

available to LC/LP member States.

No need to fill coordinates, if those are reported as shapefile

containing geographic area and HELCOM ID

Polygonal Deposit Site Coordinate 3 - Longitude

Polygonal Deposit Site Coordinate 4 - Latitude

Polygonal Deposit Site Coordinate 4 - Longitude

Activity within deposit site (optional)

Contains latitude and longitude coordinates of a pointwise

deposit operation within a deposit site area/licensed area

(polygon or a circular site)

Type of deposit (dumping or placement)

Select correct option from dropdown list provided

Comments

Sheet 1b – Dredging site coordinates (optional: If available, shapefile or pointwise location of

dredging site, where dredged material is originated)

HELCOM Dredging site ID

Unique ID for a dredging site to differentiate dredging site

Shapefile submitted

Yes/No-field indicating whether spatial data about dredging site is included

as shapefile (this is recommended)

Latitude

Dredging site latitude and longitude coordinates of a pointwise

dredging operation within a dredging site area/licensed area

(polygon or a circular site)

Longitude

Specific national site name

Name of dredging site.

Sheet 2 – Contaminated material (to be filled-in case of depositing contaminated sediments)

HELCOM Deposit site ID

Is used to link to deposit site e.g. PL-001; will be generated automatically

HELCOM Dredging site ID

is generated to differentiate separate deposit operations per deposit site

per year, e.g.

0009 – dredged material origin code (e.g. permit #)

Contaminant

Average concentration in the dredged

material (mg/kg dry wt)

National criteria/upper level (mg/kg dry

weight)

Dredged material deposited (tonnes -

dry weight)

Reasons for allowing deposit

Describe reasoning behind granting of approval.

Additional information

Sheet 3 – Details of activity (refers to reporting of dredging operations)

HELCOM Deposit site ID

Is used to link to deposit site e.g. PL-001; will be generated automatically

HELCOM Dredging site ID

is generated to differentiate separate deposit operations per deposit site

per year, e.g.

0009 – dredged material origin code (e.g. permit #)

Description of dredged material eg silt /

sand / gravel

Describe in general terms, the granulometry of the sediment - % gravel,

sand and silt

Page

of 39

Origin, (name of water system dredged)

River, estuary, etc.,

Type of areas dredged

Select correct option from dropdown list provided

Dredging Activity

Select correct option from dropdown list provided

Amount of dredged material deposited

(tonnes - dry weight)

As indicated

Amount of dredged material placed

Quantity for beneficial use (tonnes - dry

weight)

As indicated

Placement (beneficial use)

Select correct option from dropdown list provided

Material exempted from

characterisation (tonnes - dry weight)

As indicated

Notes (e.g. monitoring reports)

monitoring related to dredging activities

Comments

Page

of 39

Sheet 4 – Contaminant load

HELCOM Deposit site ID

Is used to link to deposit site e.g. PL-001; will be generated automatically

HELCOM Dredging site ID

is generated to differentiate separate deposit operations per deposit site per year,

e.g.

0009 – dredged material origin code (e.g. permit #)

Exemption

Yes/No-field indicating whether dredged material is exempted from physical and

chemical characterization (see Guideline paragraph 6.3)

Cd (tonnes dry wt)

Tonnes of cadmium deposited (dry weight)

Hg (tonnes dry wt)

Tonnes of mercury deposited (dry weight)

As (tonnes dry wt)

Tonnes of arsenic deposited (dry weight)

Cr (tonnes dry wt)

Tonnes of chromium deposited (dry weight)

Cu (tonnes dry wt)

Tonnes of copper deposited (dry weight)

Pb (tonnes dry wt)

Tonnes of lead deposited (dry weight)

Ni (tonnes dry wt)

Tonnes of nickel deposited (dry weight)

Zn (tonnes dry wt)

Tonnes of zinc deposited (dry weight)

ΣPAH16 (tonnes dry wt)

Tonnes of USEPA 16 selected selected polycyclic aromatic hydrocarbons deposited,

(dry weight) if data available (see glossary below)

ΣPAH9 (tonnes dry wt)

and/or as a part of PAH16; Tonnes of nine selected polycyclic aromatic

hydrocarbons deposited (dry weight) (see glossary below)

ΣPCB7 (kg dry wt)

Tonnes of IUPAC nos 28, 52, 101, 118, 138, 153 and 180 (ICES 7) deposited (dry

weight)

TBT (kg dry wt)

Kilograms of tributyl tin deposited (dry weight)

DBT (kg dry wt)

Kilograms of dibutyl tin deposited (dry weight)

MBT (kg dry wt)

Kilograms of monobutyl tin deposited (dry weight)

Other contaminants

Contracting Parties are invited to include substances from the Secondary List as

relevant, deposited (dry weight)

Petroleum HC (tonnes dry wt)

Tonnes of petroleum hydrocarbons/oil deposited (dry weight) (see glossary below)

HCB (kg dry wt)

Kilograms of Hexachlorobenzene deposited (dry weight)

χ-HCH (kg dry wt)*

Kilograms of χ-Hexachlorocyclohexane (Lindane) deposited (dry weight)

Σ DDT** (kg dry wt)

Kilograms of total DDT deposited (dry weight) (see glossary below)

TPhT (kg dry wt)

Kilograms of total TPhT deposited (dry weight) (see glossary below)

Page

of 39

PCDDs/PCDFs (kg dry wt)

Kilograms of total PCDDs/PCDFs deposited (dry weight) (see glossary below)

DEHP (DBP/BBP) (kg dry wt)

Kilograms of total DEHP (DBP/BBP) deposited (dry weight) (see glossary below)

notes

Any additional relevant information (dry weight)

* α-HCH or β-HCH can be optionally reported

** Ʃ DDT refers to Ʃ of o,p'-DDT; p,p'-DDT; o,p'-DDE; p,p'-DDE; o,p'-DDD; p,p'-DDD“ or Ʃ of 4,4'-DDT, 4,4'-

DDE, 4,4'-DDD, 2,4' DDT, 2,4'-DDD, 2,4'-DDE

Sheet 5 – Analyses quality information

•

Purpose of this sheet is to collect relevant information on national quality assurance procedures, which is

relevant if the data to be used e.g. for HELCOM assessments;

•

Information to be provided only once (upon request) if there are substantial changes in labs used for analysis

and/or in case data quality information is needed for assessment purposes

•

Details of limits of detection only required where analysis result is below detection limit.

•

Analytical quality information for other reported contaminants (from Secondary List) should be also provided

in the same manner as for Primary List of substances

•

Reference should be made to Part B of the HELCOM Manual for Marine Monitoring (including relevant

Annexes, e.g. B-13 Technical Note on the determination of heavy metals and persistent organic compounds

in marine sediments) and ISO/EN methods for recommended analytical techniques, e.g.

o The monitoring laboratories should have a QA/QC system that follows the requirements of EN

ISO/IEC 17025 "General requirements for the competence of testing and calibration laboratories"

(formerly EN 45001 and ISO Guide 25)

o Limit of detection, quantification or application are validation parameters which describe the

sensitivity of an analytical methods with regard to the detection and quantification of a certain

analyte. Therefore, a number of publications recently provided different approaches to define and

calculate these measures by

instrumental

mathematical approaches

(DIN 32645, 1994; EURACHEM,

1992; Geiß and Einax, 2000; ICH, 1996; ISO 11843, 1997-2003; ISO/CD 13530, 2003; IUPAC, 1997,

2002).

Sheet 6 – Action levels

•

Action levels should be provided when initially completing new reporting format. Action levels do not need to

be reported again unless they are revised.

•

Action Level information for other reported contaminants (from Secondary List) should be also provided in

the same manner as for Primary List of substances

Sheet 7 - Additional information for CP

•

Calculations for wet weight to dry weight

•

Conversion factors from volume to weight which can be used in the event that density has not been

measured (see Sheet 7 in the attached MS-Excel Spreadsheet for conversion from wet weight to dry weight)

Instructions for reporting data per shapefile:

The areas of deposit sites (Excel sheet 1a, circular / polygonal deposit site coordinates, Excel sheet 3, details of activity,

point coordinates) can be reported using GIS shapefile, which contains the geographic area of the deposit site. The

shapefile should have following information content and format:

- Shapefile should be in ETRS89LAEA projection (EU-INSPIRE compatible projection) (How to define

projection/project shapefile in ArcGIS)

- All circular / polygonal depositsites (Excel sheet 1a) of a contracting party should be reported in one shapefile

- All pointwise activity locations (Excel sheet 3) of a contracting party should be reported in one shapefile

- Each polygon/point in a shapefile should contain the HELCOM Site ID (e.g. PL-2014-001) of the deposit site in the

attribute table column titled

“HELCOM_ID”

Shapefiles should be reported simultaneously with the reporting MS Excel sheets

Page

of 39

Glossary:

Capital dredging

Capital dredging includes geological material dredged from previously unexposed layers

beneath the seabed and surface material from areas not recently dredged.

Σ DDT

Dichlorodiphenyltricholoethane

(DDT) (CAS no. 50-29-3) is an organochlorinated pesticide;

DDT and “related compounds” or sum of DDT refer to p,p’-DDT, o,p’-DDT, p,p’-DDE, o,p’-

DDE, p,p’-DDD and o,p’- DDD

Dredged material

Dredged material is sediment dredged from the sea bed, which could consist of e.g.

boulder, clay, sand, rocks.

Harbour

Harbours include enclosed and semi-enclosed docks, docks entrances, marinas, wharves

and unloading jetties

Maintenance

dredging

Maintenance dredging is the dredging required to maintain berths and navigation

channels

advertised depth. It includes material dredged from recently deposited by sedimentation

processes in harbour or sea areas

Oil

Total petroleum hydrocarbons (total oil and grease)

C10 – C40

Others

This could include e.g. disposals resulting from force majeure or emergency situations or

the disposal of spoiled cargos.

Σ PAH

anthracene; benzo[a]anthracene; benzo[ghi]perylene; benzo[a]pyrene; chrysene;

fluoranthene;

indeno[1,2,3-cd]pyrene;

pyrene; phenanthrene

Σ PAH

acenaphthene, acenaphthylene, anthracene, benzo[a]anthracene, benzo[b]fluoranthene,

benzo[k]flouranthene, benzo[a]pyrene, benzo[ghi]perylene, chrysene,

dibenz(ah)anthracene, fluoranthene, fluorene, indeno(1,2,3-cd)pyrene, naphthalene,

phenanthrene and pyrene,

PCDDs/PCDFs

Polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) are

environmental contaminants detectable in almost all compartments of the global

ecosystem in trace amounts. These compound classes in particular have caused major

environmental concern.

ΣPCB

CB 28; CB 52; CB 101; CB 118; CB 138; CB 153; and CB 180

Total PCB

Total PCB is the extraction of the 209 congeners

Petroleum HC

Petroleum hydrocarbons are the primary constituents in oil, gasoline, diesel, and a variety

of solvents and penetrating oils. The petroleum constituents of primary interest to human

health have been the aromatic hydrocarbons (i.e., benzene, ethylbenzene, toluene, and

xylenes), polynuclear aromatic hydrocarbons (PAHs)

DEHP (DBP/BBP)

Phthalates, or phthalate esters, are esters of phthalic acid and are mainly used

as plasticizers

(substances added to plastics to increase their flexibility,

transparency, durability,

and

longevity). Di(2-ethylhexyl) phthalate (DEHP), Di-n-butyl phthalate (DBP) and

Benzylbutylphthalate (BBP) and one of most widely used and raising most environmental

concerns phthalates.

Sea areas

Areas outside harbours i.e. in open, coastal and offshore sea areas

TPhT

Triphenyltin compounds are organotin compounds with the general formula (C

)

Triphenyltin compounds have been used extensively as algicides and molluscicides in

antifouling products since the 1960s, together with tributyltin compounds and both these

classes of compounds are of local (but not global) environmental concern because they are

persistent organic pollutants

Page

of 39

Attachment 2

Explanatory notes for the reporting template of consolidated reporting to LC/LP, carried out by the HELCOM

Secretariat.

Sheet 1 – summary

Country

Contracting Party of deposit site

Year

Year of activity

Maintenance (Number of activities)

Number of activities, Maintenance dredging

Capital (Number of activities)

Number of activities, Capital dredging

Maintenance (Amount)

Amount material deposited, Maintenance dredging

Capital (Amount)

Amount material deposited, Capital dredging

Total amount

Total amount of material deposited

Unit

Unit of material deposited (e.g. tonnes - dry weight)

Sheet 2 - details of the sites

Country

Contracting Party of deposit site

Code

HELCOM deposit ID

Latitude

Latitude of deposit site (centroid for polygon and line features)

Longitude

Longitude (centroid for polygon and line features)

radius (optional)

Radius of pointwise deposit site

BS sub-basin

HELCOM sub-basin of deposit site

Maintenance (Amount)

Amount material deposited, Maintenance dredging

Capital (Amount)

Amount material deposited, Capital dredging

Total amount

Total amount of material deposited

Unit

Unit of material deposited (e.g. tonnes - dry weight)

Amount (beneficial use)

Amount material deposited for beneficial use

Purpose (beneficial use)

Purpose of beneficial use