A Deep Dive into Sediments
Exploring approaches to assess environmental risks and achieving
environmental goals in management of contaminated sediments in
Sweden
Peter Bruce
Peter Bruce A Deep Di ve into Sed imentsDoctoral Thesis in Marine Ecotoxicology at Stockholm University, Sweden 2021
Department of Ecology, Environment and
Plant Sciences
ISBN 978-91-7911-562-3
Peter Bruce
Stockholm, Sweden
Based on my original research, this thesis highlights some of the potential and limitations in the Swedish practice of assessing and evaluating environmental risks from contaminated sediments. I address approaches for assessing risks and effects on the environment from contaminated sediments with a focus on Sweden. I assess the ecological basis and relevance for the knowledge that is produced and how that knowledge aligns with the goals of environmental management. I identify a potential to make considerable improvements in how risks from contaminated sediments are assessed and managed in a Swedish context.
A Deep Dive into Sediments
Exploring approaches to assess environmental risks and achieving
environmental goals in management of contaminated sediments in
Sweden
Peter Bruce
Academic dissertation for the Degree of Doctor of Philosophy in Marine Ecotoxicology at Stockholm University to be publicly defended on Thursday 16 September 2021 at 09.30 in Vivi Täckholmsalen (Q-salen), NPQ-huset, Svante Arrhenius väg 20. Also online via Zoom, public link will be available at the department website prior to the defense.
Abstract
Contaminated sediments are common, especially near urban and industrialized areas, and they can have negative ecological effects. In three studies, I explore the challenges for environmental management of contaminated sediments, focusing on environmental risk assessment (ERA) in Sweden. I investigate the scientific basis and ecological relevance of the knowledge that is produced in, and evaluated from, assessments. I then relate that knowledge to environmental goals set for general management, but also within individual assessments.
Study I identified environmental goals set by society that ERA of contaminated sediment sites should address through a survey conducted among governmental agencies working with contaminated sediment. To investigate to what extent the practice of ERA addressed the goals which had been identified in the survey, the study also analyzed seven cases of ERA, from 2008-2015. Study II reviewed established strategies for assessing risks from contaminated sediments, from four countries. Then, with the ERAs included in study I, the Swedish ERA practice was characterized and contrasted to the review. Study III investigated to what extent dumping dredged sediment at sea was used as an alternative to manage dredged sediments. The study further investigated how courts, in 14 cases from 2015-2020, evaluated environmental risk when considering to allow dumping.
The five environmental goals identified as most relevant focused on ecosystem services and management of environmental resources. While the ERAs occasionally addressed these goals, their priorities were not well aligned with that of the agencies (I). In studies II-III, the case-specific goals were not clearly addressed with the methods used. The results indicate that there is a focus on contaminant concentrations and sediment mobility. Four out of the seven ERAs in study II, and none in study III, measured potential effects from contaminants. The ERAs in study II surveyed benthic species and one conducted a toxicity test. When characterizing risk, there was also a frequent use of references not related to toxicity (II-III). Furthermore, uncertainties were not quantified and rarely discussed. Transparency was lacking regarding what weight individual types of measurements had in characterizing risk (II). In study III, sediment accumulation and contaminant concentrations were the decisive factors. However, in evaluating concentrations, the courts’ reasoning was inconsistent. The ERA practice in Sweden does not clearly produce the information needed to effectively characterize or evaluate risk in line with case specific or societal goals and risk underestimating the risks from contaminated sediments.
Additional development and research could improve the capability to produce information for efficient management. Issues that should be addressed are, for example, requirements and guidance for designing case specific ERAs, including setting measurement and assessment endpoints in line with the ERA goals; additional types of measurement of contaminant effects; a system for criteria when characterizing risk; and requirements and guidance for how to consider future changes of site-specific conditions, such as climate change.
This thesis highlights some of the potential and limitations in the Swedish practice to inspire management in how to incorporate existing best available methods as well as point to additional research needs.
Keywords: Sediment, risk assessment, risk evaluation, risk management, contaminants, regulations, weight of evidence,
line of evidence, environmental goals, environmental management, guidelines. Stockholm 2021
http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-195040 ISBN 978-91-7911-562-3
ISBN 978-91-7911-563-0
Department of Ecology, Environment and Plant Sciences
A DEEP DIVE INTO SEDIMENTS
A Deep Dive into Sediments
Exploring approaches to assess environmental risks and achieving environmental goals in management of contaminated sediments in Sweden
©Peter Bruce, Stockholm University 2021
ISBN print 978-91-7911-562-3 ISBN PDF 978-91-7911-563-0
Cover: Sediment at the Swedish West coast. Photo by Benjamin Jones Back cover image by Carly Evaeus
Contents
List of studies ... 1
Abbreviations ... 2
Svensk sammanfattning ... 3
Preface ... 4
Scope of the thesis ... 5
Aims ... 5
Introduction to contaminated sediments and the approach to manage them . 8 Sediment contamination ... 8
Environmental risk assessment ... 13
International and Swedish regulatory conventions for sediment assessment and management ... 14
Regulations regarding sediment management ... 16
The goals of environmental management ... 17
Sediment management at Swedish governmental agencies ... 18
Methods ... 19
Study I ... 19
Study II ... 20
Study III ... 21
Reflection of limitations and possibilities ... 21
Synthesis of results and discussion ... 23
Environmental goals and ERA ... 24
Case-specific methods and goals in ERA ... 27
Characterizing risk in ERA ... 33
Multiple types of measurement in ERA ... 35
Integrating measurements in ERA... 36
Concluding remarks... 38
Dissemination ... 41
Acknowledgement ... 42
References ... 43 Papers I-III
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List of studies
This thesis is based on the following studies, referred to in the text by roman numerals I-III:
I. Bruce P, Ohlsson Y. 2020. Environmental Goals Addressed in Assessments of Contaminated Sediments. Integrated Environ-mental Assessment and Management. 16(1):128–139. DOI:10.1002/ieam.4223.
II. Bruce P, Sobek S, Ohlsson Y & Bradshaw C. 2020. Risk assess-ments of contaminated sediassess-ments from the perspective of weight of evidence strategies – a Swedish case study, Human and Eco-logical Risk Assessment: An International Journal, DOI: 10.1080/10807039.2020.1848414
III. Bruce P, Bradshaw C, Ohlsson Y, Sobek A, Christiernsson A. Inconsistencies in how environmental risk is assessed when dredged sediment is dumped at sea (submitted manuscript) My contribution to above studies:
I had the main responsibility for planning and designing the studies from start but with valuable input from my co-authors. I performed the method de-velopment, data acquisition and analysis. I also had the main responsibility in writing the studies and steering I-II through the submission and review process.
Additional relevant publications relevant to the thesis:
Syberg, K, Backhaus, T, Banta, G, Bruce, P, Gustavsson, M, Munns, W, Rämö, R, Selck, H and Gunnarsson, J. 2017. Toward a conceptual approach for assessing risks from chemical mixtures and other stressors to coastal eco-system services. Integrated Environmental Assessment and Management, 13: 376-386. DOI.10.1002/ieam.1849
Selck H, Adamsen P, Backhaus T, Banta G, Bruce P, Burton G, Butts M, Boegh E, … Chapman P. 2017. Assessing and managing multiple risks in a changing world—The Roskilde recommendations. Environmental Toxicol-ogy and Chemistry, 36: 7-16. DOI/10.1002/etc.3513
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Abbreviations
Environmental Risk Assessment (ERA) Swedish Environmental Code (EC)
United Nation’s Sustainable Development Goals (SDGs) Helsinki Commission (HELCOM)
HELCOM Baltic Sea Action Plan (BSAP) Water Framework Directive (WFD) Oslo – Paris commission (OSPAR) Environmental Quality Standards (EQS) Marine Strategy Framework Directive (MSFD) Tributyltin (TBT)
Swedish Environmental Protection Agency (SEEPA)
Swedish Agency for Marine and Water Management (SwAM)
The following are environmental goals:
A balanced marine environment, flourishing coastal areas and archipelagos (Marine balance)
Life below water (Life in water)
Flourishing lakes and streams (Flourishing lakes) Clean water and sanitation (Clean water)
Life on land (Life on land)
Good health and well-being (Good health)
A rich diversity of plant and animal life (Biodiversity) Sustainable cities and communities (Sustainable cities) Good-quality groundwater (Quality groundwater) Reduce climate impact (Climate impact)
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Svensk sammanfattning
Förorenade sediment är vanliga, särskilt nära bebyggelse och industrier, och de kan ha negativa ekologiska effekter. Med de tre studierna i denna avhand-ling utforskar jag utmaningarna för att bedöma riskerna av förorenade sedi-ment i Sverige. Jag undersöker den vetenskapliga grunden och ekologiska re-levansen av den kunskap som produceras och utvärderas för att sedan relatera till de miljömål som satts.
Studie I identifierade miljömål som satts av samhället som borde beaktas i miljöriskbedömningar. Detta gjordes bland annat med en enkät riktad till myn-digheter som arbetar med förorenade sediment. För att undersöka i vilken ut-sträckning som miljöriskbedömningar i praktiken beaktar de identifierade må-len analyserades sju miljöriskbedömningar från 2018-2015. Studie II grans-kade etablerade strategier, från fyra länder, för miljöriskbedömning av förore-nade sediment. För att karaktärisera den svenska praktiken jämfördes strategierna mot de sju miljöriskbedömningar från studie I. Studie III under-sökte utbredningen av dumpning av muddrade sediment till havs, relativt andra kvittblivningsmetoder. Vidare undersöktes hur domstolar utvärderade miljörisker när de bedömde huruvida dumpning skulle tillåtas, i 14 ärenden från 2015-2020. De fem miljömål som identifierades som högst relevanta fo-kuserade på ekosystemtjänster samt förvaltning av naturresurser. Miljöriskbe-dömningarna beaktade i viss utsträckning de mål som pekats ut som relevanta men bedömningarnas prioriteringar var inte i linje med myndigheternas (I). Studierna II-III visade hur kopplingen mellan ärendespecifika mål och meto-der var otydlig med ett fokus på föroreningskoncentrationer och sedimentmo-bilitet. Fyra av de sju ärendena i studie II och inget från studie III undersökte potentiella föroreningseffekter, därutöver användes mätvärden som inte rela-terade till toxicitet återkommande när risk bedömdes. Miljöriskbedömning-arna kvantifierade aldrig, och diskuterade bara undantagsvis, osäkerheterna i bedömningarna. De redovisade heller ej vikten olika faktorer gavs då de väg-des samman. I studie III var sedimentackumulation och föroreningskoncent-rationer de avgörande faktorerna. Domstolarna skilde sig dock i hur de be-dömde huruvida koncentrationerna utgjorde en risk.
Det finns risk att sannolikheter och effekter undervärderas i Sverige. Det är inte tydligt att information konsekvent producera eller hanteras på lämpligt vis för att nå samhällets eller de enskilda ärendenas miljömål. För att förbättra förmågan att bedöma och utvärdera risk behöver flera frågor beaktas. Till ex-empel, krav och stöd för hur och vad som ska mätas i relation till lämpliga mål. Vidare behövs metoder för att bedöma risken för föroreningseffekter samt ett system för hur risk ska karaktäriseras. För framtiden behövs också krav och vägledning för hur, till exempel, klimatförändringar, kan komma att påverka risk.
Den här avhandlingen belyser en del av potentialen och begränsningarna i svensk praxis. Särskilt betonas möjligheten till ett utökat användande av exi-sterande tillvägagångssätt samt utvecklingsbehoven.
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Preface
My interest in how environmental risks are managed stems from my master thesis for which I conducted a study that characterized environmental risk among aqua-cultures in the Vietnamese archipelago. Later, I was fortunate to interact with a several international seniors within the field, such as Peter Chapman who came up with the original method that I used for my master thesis. I was exposed to various ideals for how ERA of contaminated sites should be conducted and what the chal-lenges were, for example how to achieve good communication among stakehold-ers, how to account for environmental values and for future changes that might affect risk. This work led to my first two publications were I, as a coauthor, mainly contributed with content on communication and ecosystem services in relation to ERA. However, my experience from this period were at odds with experiences I had on the subject in Sweden.
In Sweden, I meet assessors with strong opinions on what approaches were most suitable for ERA and I was struck by the differences both among different Swedish actors and in relation to my previous experiences. A geochemist would argue for one approach and a geoengineer for a very different one, and none seemed to ad-vocate the approaches I had been exposed to previously or put much consideration into aspects that I had come to think of as important challenges for ERA. Then I got the opportunity to start my PhD.
I was spurred by what to me seemed as a lack of inclusion of an ecological per-spective and a focus on technical aspects of contaminants. I questioned how ERA was to be conducted in theory and how it compared to in the field and what was supposed to be the point of the process.
During the first half of the PhD, I posed many such questions and spent a large portion of the time on how to address them. In the end, it boiled down to the three studies that form this thesis, that I hope you will find both engaging and enlight-ening.
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Scope of the thesis
Contaminated sediments are common, especially close to historic and current urban and industrialized areas (Cundy et al. 2003; Taylor et al. 2004; HEL-COM 2010) and the contaminants can have a negative effect on the environ-ment (Förstner et al. 2004; Gerbersdorf et al., 2011; Hollert et al. 2005; Keiter et al. 2008; Knott et al. 2009). As societal demands on the marine environment increase, contaminated sediments are receiving more attention (USEPA et al. 2005; NAS 2007; Bridges et al. 2012; OECD 2016; Severin et al. 2018; Brils 2020). However, the risk of ecological effects from contaminated sediments are complex to assess and the outcome of such an assessment and following management is highly dependent on the approach and goals (Dale et al. 2008; Keiter et al. 2008; Kennedy et al. 2009; Pheiffer et al. 2019). The approaches in use for risk assessment of sediments are not necessarily well suited for pro-ducing the information needed for effective and sustainable management of contaminated sediments (Apitz, 2008; Chapman et al. 2002; Gerbersdorf et al. 2011; Ländell, Vestin, Ohlsson, & Göransson, 2014; Selck et al. 2017).
My general hypothesis has been that there are gaps in the connections be-tween the scientific underpinning of environmental risk assessment (ERA), the practical implementation, and the goals of ERA. By identifying these gaps, there is a potential to make considerable improvements in ERA and manage-ment of contaminated sedimanage-ments.
Aims
This thesis aims to improve our understanding of potential challenges and potential for improvement in the environmental management of sediments. More specifically, I address approaches for assessing risks and effects on the environment from contaminated sediments with a focus on Swedish practice. I assess the ecological basis and relevance for the knowledge we produce and how that knowledge aligns with general and case-specific environmental ob-jectives (Fig. 1).
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In study I, the aim was to investigate which societal sustainability goals should be addressed when managing sites with contaminated sediment, and to what extent different parts of the process of ERA addressed these goals in practice.
The objective of study II was to provide an increased understanding of how the risk at sites with contaminated sediment was assessed in comparison to established strategies. Using Sweden as a case study, we specifically ad-dressed what evidence of environmental risk and impairment had been col-lected and how the evidence had been used in order to characterize risk in ERA cases. We contrasted this with established approaches and the literature. When dumping dredged sediments at sea, new risks may arise and the aim of study III was to investigate the environmental implications of how envi-ronmental risks are evaluated when considering dumping dredged sediments at sea. We explored on what environmental conditions dumping at sea is al-lowed and how the governing regulations are implemented to ensure that dumping does not lead to environmental detriment. We further looked for po-tential gaps in the implementation, or regulations themselves, in relation to safeguarding that dumping does not cause environmental harm.
The three studies are complementary in attempting to add to the picture of how and why environmental risks from contaminated sediments are assessed and evaluated in Sweden. The studies aim to illustrate what measurements of risk are used as well as their basis and relevance in relation to the general and case-specific environmental objectives important for ERA of contaminated sediments.
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Figure 1. The focus of the thesis is on environmental risk assessment (ERA), a process of determining the need for environmental management, from con-taminated sediments. The scope covers the scientific underpinning and prac-tice in relation to the general and case-specific environmental goals in two types of ERA. Addressing the two types. The two types of ERA are: 1) Retro-spective assessments of the need for management of already contaminated sediment sites, and 2) Predictive assessments of the risk from proposed dumping of dredged sediment at a marine site.
Study II –
Retrospective
ERA
Describing how the risks at
sites with contaminated sediment were assessed in comparison to established strategies.
Study I – ERA goals
Determining what societal environ-mental goals, ERA of sites with contaminated sedimentshould, and are, addressing.
Study III –
Predictive ERA
Investigating the en-vironmental implica-tions of how envi-ronmental risks are evaluated when con-sidering dumping dredged sediments at sea.
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Introduction to contaminated sediments and the
approach to manage them
The following chapter gives an overview of the scientific and regulatory back-ground relevant for the scope of this thesis. The first section introduces sedi-ment contamination and potential risks and effects as well as the need to un-derstand those risks in order to manage the marine environment effectively. The second section introduces ERA, the process of assessing the risks and effects of sediment contamination and the need for management. The third section gives an overview of policies, management processes and frameworks that affect sediment management in Sweden.
Sediment contamination
Historically, harmful substances have been released directly into the aquatic environment. During the 1900s, dumping of waste ranging from dredged sed-iment to radioactive waste and chemicals became large scale (Elmgren, 2001; Nihoul, 1991; USEPA, 2020). In addition to direct discharge, contaminants can reach the sediment from a number of sources, such as the atmosphere, leaching from agriculture, waste water treatment plans, waste deposits or household products (Förstner et al. 2004; Armitage et al. 2009; Sundqvist and Wiberg 2013; Tornero and Hanke 2016; HELCOM 2018) (Fig. 2).
Today, there are high levels of historical contaminants in the sediment in many areas, especially around urban areas and places that historically have had in-dustrial activity (Sundqvist and Wiberg 2013; Taylor et al. 2004; Cundy et al. 2003). In the Baltic Sea, the input from local sources of for example persistent organic pollutants have been limited, thanks to an increased awareness and regulations, but the levels of some contaminants, such as, PCB and HCB are still increasing in some sediment areas (Assefa et al. 2014; Sobek et al. 2015). Today, areas with a good chemical status in the Baltic Sea are the exception (Fig. 3) (HELCOM 2018).
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Figure 2. Examples of the different forms of transport by which contaminants move to and from sediment, both from direct and indirect sources.
Over time, contaminants can be buried with cleaner sediments, if left undis-turbed (Jonsson, 2000; Wang et al. 2004). However, several factors affect whether sediment store contaminants or become sources (Fig. 2). One factor is the interplay of sediment and contaminant chemistry. For example, contam-inants can move with diffusive exchange when the ratio of contaminant con-centrations in the sediment and bottom water changes. Thus, if the contami-nant concentrations in the water decreases, contamicontami-nants can move from the sediment into the water. Other factors are also at play. For example, the sedi-ment capacity to store metals is affected by pH and organic contaminants, such as PAHs and dioxins, are hydrophobic and can be strongly bound by organic material ( Di Toro et al. 1990; Chapman et al. 1998; Wania and Daly 2002; Eek et al. 2010). Physical and biological factors, such as storms, dredging and bioturbation, i.e. the activities of sediment-living organisms, can also resus-pend or incorporate contaminants in the sediment (Davis 1993; Erickson et al. 2005; Knott et al. 2009; Sobek et al. 2014; Mustajärvi et al. 2019).
Sediment contaminants are important, as they can be harmful to exposed organisms. They can lead to tissue damage, endocrine disruption, lower abun-dance in the benthic community and disturb the ecological functions of a sys-tem (Förstner et al. 2004; Hollert et al. 2005; Keiter et al. 2008; Knott et al. 2009; Gerbersdorf et al. 2011; Raymond et al. 2021).
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Figure 3. The Baltic Sea exhibits hazardous substances above threshold limits at all assessed sites. The map is based on indicators integrating concentra-tions-to-threshold derived values for the listed individual hazardous sub-stances or substance groups. The colors in the pie charts indicate how many out of the assessed substances achieved (green) or failed (red) their threshold value in each of the assessment areas. The Danish waters were assessed sep-arately. The map is adapted from HELCOM (2018).
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The potential effects of sediment contaminants also depend on the sensitivity of the local ecosystem. In the Baltic Sea, brackish water and frequent hypoxic conditions (Meier et al. 2006) create physiologically stressful conditions that result in there being relatively few species in the Baltic Sea (Laine, 2003; Weaver, 2003). The low biodiversity makes the system sensitive as different species fill various functional roles important for sediment functions and re-lated ecosystem services (Waldbusser et al. 2004). With low functional redun-dancy, a decrease, or loss, of a few species can have substantial negative ef-fects on ecosystem functions (Cardinale et al. 2002; Duffy 2009; Sandifer et al. 2015).
There is also a need to consider sediment contamination from a human per-spective (Fig. 4). As a society, we aim to prevent contaminants affecting the environment and our health. To do so we have to understand the risks and effects caused by the contaminants. However, there are different perspectives on the need for a healthy sediment environment, for example legal require-ments, economic gain through blue growth and intrinsic environmental values. It is also a challenge for our food supply as sediment contaminants can end up in the seafood we consume (USEPA et al. 2005; Bridges et al. 2012; Sobek et al. 2014; Severin et al. 2018).
There are also different perspectives as to what risks entail and how to as-sess them, both in general and specifically in Sweden (Ländell et al. 2014; Selck et al. 2017). Therefore, to ensure that management is effective, there is a need to have goals in ERA in line with how risks are perceived and an as-sessment process providing a comprehensive and pluralistic evidence base that is evaluated with a high degree of transparency and participation.
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Figure 4. There are many challenges in managing sediment, such as economic blue growth, several laws and goals and the ecological functions by which sediment contributes to society’s needs and require a healthy sediment envi-ronment. Adapted from Severin et al. (2018).
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Environmental risk assessment
In this thesis, I focus on ERA, a process for collecting and analyzing scientific information to characterize the exposure, hazard and risk of contaminants to an environmental endpoint (as described in e.g. Stahl et al. 2001; Jensen et al. 2006). For example, an ERA might collect and analyze information describing the state, or set of possible states of a benthic community suspected to be af-fected by industrial effluents, and the probability that these states will occur. In general, an ERA should be a systematic process that structures scientific information to characterize risk and effects to support environmental risk gov-ernance.
A common ERA framework begins with formulating the problem, initial planning, defining the objectives and planning the data collection and analy-sis, followed by implementing the plan. These steps can be iterated until suf-ficient results have been gathered. The results are used to characterize the risks, followed by evaluation where the results are considered in conjunction with other factors, such as regulations and the vulnerability of socio-economic values, to determine the need for management or additional investigations (Fig. 5)
Figure 5. Risk governance framework adapted from study II, USEPA (1998) and the International risk governance council’s framework for risk govern-ance.
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The risk that an ERA of contaminated sediment addresses can be described as the combination of exposure and adverse effects of the contaminants. A high exposure and severe effects would then imply a high risk. An ERA can be predictive, as when assessing the potential exposure and effects that will arise from dumping dredged sediment at a marine dumpsite. ERA can also be ret-rospective, as when assessing the exposure and effects of already existing sed-iment contamination.
To quantify risk or to characterize the significance of risk, measured indices of risk can be compared to different criteria. For example, sediment contami-nant concentrations can be compared to predetermined limit values (as in Breedveld et al. 2015) or the benthic community at the assessment site can be compared to the community at a reference site (as in Anderson et al. 2008). However, in comparing to a reference site or general concentration limits there is a risk of over or under estimating risk due to specific local environmental factors. Therefore, a more site-specific approach to determine acceptable con-ditions can be used. For example, to account for the influence of the individual factors, contaminant concentrations or ecological effects together with envi-ronmental variables can be measured along a gradient from the assessment site (Ellis and Schneider 1997; Preston 2002; Landis et al. 2011; Clements et al. 2012; CSWG 2020).
Multiple approaches and frameworks have been developed for how to as-sess the environmental risks from potentially contaminated sediment. Both from moving potentially contaminated sediment from one location to another (predictive assessment) (Munns et al. 2002; OSPAR 2009; HELCOM 2020); as well assessing sediment sites already contaminated (retrospective assess-ment) (Linkov et al. 2009; Chapman et al. 2010; Breedveld et al. 2015; Simp-son and Batley 2016; CSWG 2020).
International and Swedish regulatory conventions for
sediment assessment and management
Multiple societal conventions are relevant for management of contaminated sediments, from an international to national level. This is important as many waterbodies border more than one country and management of aquatic pollu-tion often requires internapollu-tional communicapollu-tion and cooperapollu-tion (Heise & Apitz, 2007). When the awareness of environmental problems rose, much thanks to efforts such as the publication of Silent Spring by Rachel Carson (1962), several international conventions followed that have an effect on sed-iment contamination. For example the London Protocol (1972) limits the types of waste that can be dumped at sea around the globe (London Convention, 2006). A more recent convention is the UN Agenda 2030 resolution (UN 2015). The agenda sets global Sustainable Development Goals (SDGs) for
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creating a more sustainable society in three dimensions – economically, so-cially and ecologically.
Regional conventions more specific for the seas and sediments bordering Sweden are the Oslo-Paris Convention for the Protection of the Marine Envi-ronment of the North-East Atlantic (OSPAR 1992) and the Helsinki Conven-tion on the ProtecConven-tion of the Marine Environment of the Baltic Sea Area (1992). The signatory countries dictate their joint agreements to limit the re-lease of new contaminants and improve the environmental status. The Baltic countries also agreed on the Baltic Sea Action Plan (BSAP) (HELCOM 2007) which, based on an Ecosystem Approach, is the basis for HELCOM policy implementation for a good environmental status.
As part of the EU, Sweden has also implemented several EU directives relevant for sediment contaminants. Contrary to the conventions, the direc-tives are legally binding. The EU Water Framework Directive (WFD)1 sets common goals to reach “good” chemical and ecological status for the envi-ronmental management of all coastal and inland water bodies in the EU. The chemical status is determined in relation to Environmental Quality Standards (EQS) for metals and organic pollutants. There are EQS values mandatory for surface water and some countries, such as Sweden, have also implemented EQS values for some sediment contaminants (SwAM 2019; Lehoux et al. 2020). The focus on sediment in the WFD is to be strengthened with additional guidance in the WFD Common Implementation Strategy (Brils, 2020). Im-portant to note though is that while the EQS values are used to specify status as part of the fulfillment of a good aquatic environment of larger water bodies, the values are not specifically intended for assessing site-specific environmen-tal risk or determining the need for risk reducing management. Other relevant EU directives are the Marine Strategy Framework Directive (MSFD)2 that for example requests the implementation of monitoring programs of sediment contamination, and the Waste Framework Directive3 that dictates that reuse should be prioritized over disposal and regulates what is considered waste and its management.
1 Directive 2000/60/EC of the European Parliament and of the Council establishing a
frame-work for the Community action in the field of water policy
2 Directive 2008/56/EC of the European Parliament and of the Council of 17 June 2008
estab-lishing a framework for community action in the field of marine environmental policy
3 Directive 2008/98/EC of the European Parliament and of the Council of 19 November 2008
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Regulations regarding sediment management
In Sweden, EU directives are either directly implemented or included in na-tional law. The Swedish Environmental Code (EC) (1998:808) explicitly pro-motes sustainable development and declares that nature is worthy of protec-tion and should be managed responsibly. Several paragraphs in the code are relevant for the management of contaminated sediments. For example, the precautionary principle states that whenever there is cause to assume that an activity may cause damage or detriment to the environment all precautionary measurements have to be taken (2:3 EC). Another example is the polluter pays principle that states that a person or organization that has caused pollution or environmental detriment is responsible for managing the contamination (10:2 EC). There is also a direct ban on dumping waste at sea (15:27 EC). However, exemption can be granted on the condition that the waste can be dumped with-out detriment to human health or the environment (15:29 EC). When for ex-ample dumping dredged sediment the waste hierarchy is important and dic-tates that one should consider reuse or recycling of any waste and that the method that best safeguards environmental and human health should have pri-ority (15:10 EC). The regulations are implemented through, for example, ad-ministration and monitoring, which in turn are realized through various activ-ities such as granting exemptions, remedial programs and plans for construc-tion (Fig. 6).
Figure 6. The implementation of regulations and goals in Swedish manage-ment in relation to sedimanage-ment. Adapted from Severin (2018).
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The goals of environmental management
In addition to the legal requirements, environmental management in Sweden also has a set of national objectives (SEEPA 2012). These objectives imple-ment the ecological dimension of the SDGs, guide public actions at national, regional and local level and also offer guidance for private companies.
The environmental objectives aim at achieving an environment without adverse effects from manmade pol-lution as well as thriving aquatic eco-systems. Societal and international objectives are especially important for the management of the aquatic and sediment environment that often crosses borders and require interna-tional collaboration (Heise & Apitz, 2007).
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Sediment management at Swedish governmental agencies
Several agencies are responsible for various aspects of managing contami-nated sediments. The Swedish Environmental Protection Agency coordinates (SEEPA), prioritizes and monitors general environmental management. The Swedish Agency for Marine and Water Management (SwAM) is responsible for marine and aquatic issues, for example fulfilling the WFD. The twenty-one County Administrative Boards are regionally responsible for, for exam-ple, monitoring. The Swedish Geotechnical Institute, Swedish Chemicals Agency and the Geological Survey of Sweden have advisory and knowledge building responsibilities for assessment and management of contaminated sites (Fig. 7).
Figure 7. Overview of Swedish agencies and their connections and responsi-bilities in relation to contaminated sediments. Adapted from Severin (2018).
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Methods
The thesis combines three individual studies, providing an understanding of the linkage between different pieces of scientific knowledge, practical imple-mentation and management objectives. Subsequently it also points to where there are discords.
To support the research for the studies, a variety of methods and infor-mation sources were used. The data stems from written accounts such as re-ports of environmental risk assessments, court cases, rere-ports and policy doc-uments from organizations such as HELCOM, governmental agencies and others. We also gathered data from semi-structured interviews, a survey and a workshop. For the three studies, over 2000 pages from more than 30 docu-ments, describing conducted risk assessments were initially included and thor-oughly analyzed with content analysis to find information connected to the study aims. For an increasingly in-depth analysis and to address different questions we repeatedly revisited large parts of the content.
In the following section, I give an overview of the data collection and the analysis for the individual studies. I also describe some of the implications of the methods used and additional ideas, questions and challenges that arose during the work for each study that could have added to or otherwise improved the studies.
Study I
To identify which environmental goals were considered relevant when as-sessing risks from contaminated sediments, and to understand why, we used a combination of methods.
First, we conducted a survey, designed mainly according to a structured format (Bryman 2008a, 2008b and 2008c). We addressed staff working at agencies with roles related to management of contaminated sediment such as guidance, policy and regulations, research and environmental monitoring. We chose respondents from governmental agencies as they are to advocate the goals in their practice and are in positions where they can make requirements and guide assessors in how to conduct ERA. The survey requested respond-ents to rank the relevance of goals in relation to management of contaminated sediment. The goals were a subset from the Sustainable Development Goals
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(United Nations General Assembly, 2015) and the Swedish national Environ-mental Objectives (SEEPA, 2012). In addition to the set of goals, the respond-ents were also encouraged to suggest additional goals that they perceived as relevant. To verify the results and gain an in-depth understanding of the un-derlying perspectives we conducted a workshop with the respondents and semi-structured interviews with three of them, as per Bryman (2008d) and Al-vesson (2010). During the workshop and interviews, we discussed the addi-tional goals suggested in the survey responses to determine what goals were relevant.
To investigate the practice of ERA, we gathered seven reports that included ERA of contaminated sediments from 2008-2015. The reports were produced for the party responsible for management of the potentially contaminated site in question and environmental monitoring agencies. We focused on reports that covered the procedure from retroactive assessments of sites with contam-inated sediments, as opposed to the more common predictive assessments where one plans to move sediment and has to assess the risk at the site of disposal.
We then conducted the analysis in two steps. First, we used the information characterizing the environmental goals to create an analytical framework to analyze to what extent the cases of ERA addressed the identified objectives (Julien, 2008). Then, to determine to what extent the ERA cases addressed each of the identified objectives, we used content analysis, based on the works of Bryman (2008c), Julien (2008), Duriau et al. (2007a), Neuendorf (2002) and Krippendorff (2004). In doing so, we could quantitatively determine the where and how often the goals were mentioned as well as qualitatively identify latent content in the ERA cases corresponding to the previously established analytical framework and thus to what extent the goals were addressed.
Study II
To explore the process of ERA of contaminated sediment for study II, we returned to the ERA cases addressed in study I. We again created an analytical framework as a reference point for a content analysis of the ERA cases. This time, however, the aim was to investigate what evidence of environmental risk and effects the ERAs collected, and how that information was used to charac-terize risk. For the analytical framework, we defined themes describing meth-ods and procedures for decision making in ERA, based on reviewing estab-lished strategy documents for ERA of contaminated sediments from Canada, the Netherlands, Norway and the USA. Similar to study I, we then used con-tent analysis to categorize the concon-tent of the ERA cases followed by a com-parative analysis to describe the practical implementation of ERA and identify differences compared to the framework.
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Study III
To investigate the environmental implications of the application of the ban on dumping dredged sediment at sea we looked at two sources of information. First, we investigated how common dumping is as an alternative for disposal of dredged sediment, and how common it is in relation to other options. Through the SwAM we got access to information on all granted exemptions to dump waste at sea during 2015 – 2019. We acquired data such as the grant-ing authority, volume and type of the dredged sediment, dumpsite, dredggrant-ing permits and other methods used for disposal. We could then assess the extent of dumping and describe the frequency and volume in relation to other alter-natives of disposal.
To assess the environmental grounds for granting exemption and the im-plementation of the regulations, we looked at how environmental courts con-sidered applications for exemption. Such cases are publically available and we gathered all cases, from January 2015- June 2020. We included 14 cases. The Land and Environmental Court of Appeal, the highest instance, tried five out of those. We did not include the preceding cases as separate cases. The cases provide information such as the final verdict, on which conditions exemption is granted and cover detailed descriptions of the arguments the court base their decision upon as well as detailed accounts of the courts’ reasoning.
The reason for including cases from 2015-2020 was in part due to that the availability of data from SwAM was limited prior to 2015. Another factor was that a case at the Land and Environment Court of Appeal in 20154 was de-scribed as having set a norm for how applications for exemption were consid-ered by representatives from county administrative boards at a workshop on challenges for sediment management in Sweden (December 2019).
When analyzing the court cases we used the explorative approach used when establishing the analytical frameworks for studies I-II (e.g. Julien 2008). We could then identify content connected to the aims of the study to describe and scrutinize the process of considering applications on the ban on dumping.
Reflection of limitations and possibilities
With more time and resources, it would have been interesting to expand on the studies with additional sources to further triangulate the results and add a broader understanding of the issues.
For study I, additional stakeholders could have been interviewed on their perspectives on environmental goals, for example, the assessors, recreational fishermen and people living in proximity to contaminated sediments. In the survey, we chose to ask the respondents to rank a number of pre-set goals and
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then suggest other goals in an open format. It would have been interesting to let the respondents instead describe which goals were relevant and why, with-out the list. However, the semi-closed format was chosen to increase the re-sponse rate as suggested in (Bryman, 2008b). It would also have been illumi-nating to have a better grasp on how well the seven analyzed ERAs covered the practice. Both for study I and II, additional interaction with the assessors could have added by contradicting or supporting the analysis of the written accounts of ERA and insights into why the practice appears as it does. There is also the question of how large a proportion of contemporary ERAs we were able to include. ERA of contaminated sediments in Sweden are rare compared to terrestrial ERAs and while they are reported and filed at regulatory agen-cies, locating them is not straight forward. Similarly, for study III, a more extensive investigation could have broadened the results and strengthened the conclusions. It would have been particularly interesting to have discussions with members of court regarding their perspective on risk and why particular aspects were considered and why others were not. In contrast to studies I-II, I am reasonably certain that I in study III was able to locate all court cases that fit the criteria. However, the scope of the study could have been expanded with more input from the County Administrative boards. While the court de-cisions carry weight in how future cases are considered, addressing the county boards could have provided additional insight into standard practice as the county boards’ exemptions make up the majority of cases. These cases would also have allowed for a more extensive quantitative analysis, of for example contaminant limits and types. Unfortunately, these cases are not readily avail-able in a standardized format. For all of the studies, it would have been inter-esting to expand the scope even further and address the practice in neighboring countries or globally as well.
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Synthesis of results and discussion
The following chapter presents and discusses the main results from the studies conducted for the thesis
Main findings
The environmental goals considered most relevant by staff at rel-evant agencies, in relation to contaminated sediment, focus on ecological values and sustainable use of the environment (study I).
ERAs of contaminated sediments are currently capable of ad-dressing society’s most relevant environmental goals, but could do so more frequently (study I).
The alignment between methods and objectives was not always clear and the role of individual indicators or reference values in-dicative of risk was not transparent in analyzed ERAs (studies II-III).
There is a lack of use and availability of suitable reference val-ues for characterizing risk from contaminated sediments in Swe-den (studies II-III).
ERA in Sweden favored indicators that could be used to estimate potential exposure to sediment contaminants, such as sediment contaminant concentrations. Environmental risk was only occa-sionally addressed with measurements of contaminant effects (studies II-III).
Exemption to dump dredged sediment at sea appears to be granted based on practical considerations rather than environ-mental risk, in contrast to current legislation and international conventions. The current practice risks allowing dumping caus-ing negative environmental effects (study III).
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Environmental goals and ERA
In study I, we identified a set of environmental goals of high relevance in relation to risks from contaminated sediments, as perceived by the informants, i.e. staff working with contaminated sediments at Swedish environmental agencies (Table 1). The five goals ranked as most relevant were Swedish na-tional environmental objectives and UN SDGs.
In addition to the set of goals the respondents were asked to consider in the survey, the respondents were also encouraged to suggest additional goals that they perceived as relevant. The suggested goals were then discussed in the following workshop and interviews. Out of the suggested goals, the partici-pants concluded that the national environmental objective “A Non-Toxic En-vironment” (“No toxins” for short) and the EU WFD were clearly relevant and they were subsequently included in the analytical framework.
The majority of the goals described as relevant were addressed in the ana-lyzed ERA cases, albeit to varying degrees. All of the ERAs addressed the national environmental objective “No toxins” by addressing risks to the envi-ronment or human health from harmful substances. Moreover, all ERAs also addressed “No toxins” in all the steps of the ERA processes. However, most goals were only addressed by some of the ERAs and at some steps in the pro-cess. The goal “Sustainable cities and communities” (“Sustainable cities” for short) was only addressed by case A, and then only in the case’s analysis. The two goals “Good-quality groundwater” and “Reduce climate impact” (“Qual-ity groundwater” and “Climate impact” for short) were not addressed at any step in any ERA (Table 2 and 3). The three least addressed goals were also those perceived as the least relevant by the informants.
While all of the ERAs addressed goals with an ecosystem focus, none of them specifically addressed two ecological aspects that the five most relevant goals had in common, namely, environmental resources or ecosystem ser-vices. Furthermore, the goals specific for freshwater systems, which the in-formants perceived as most relevant, were not among the goals addressed most frequently by the ERAs focusing on freshwater sediments (Table 2).
As most of the goals were addressed at least occasionally, it appears that the ERAs already are capable of addressing the goals, at least in part of their process. However, the difference in what goals were perceived as most rele-vant and the ones that were addressed most frequently in the ERAs indicates a discrepancy in priorities. In study I, we therefore argue that there is a poten-tial for ERA of contaminated sediment sites to contribute further to the achievement of the societal environmental goals. However, as earlier works show, for ERA to effectively support management, it is important that the goals of the ERA are clear and well aligned with the assessment methods (e.g. Dale et al. 2008). To effectively promote additional implementation of the goals in ERA in practice, facilitation in combination with enforcement might be needed (Victor, Raustiala, & Skolnikoff, 1998; Weiss & Jacobson, 1998),
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for example, with new guidelines, that provides necessary knowledge but also standardizing implementation of the goals.
Table 1. Goals for environmental management in relation to ERA, ranked by number of positive responses in a survey of 12 respondents at eight Swedish agencies closely involved with contaminated sediments. The results from the survey were subsequently discussed in a workshop with the respondents and interviews with three of them,there-after, the two last goals in the table were added as relevant (study I).
Environmental goals Condensation of goal titles Directly relevant A balanced marine environment,
flourish-ing coastal areas and archipelagos*1 Marine balance 12
Life below water**1 Life in water 11
Flourishing lakes and streams*2 Flourishing lakes 11
Clean water and sanitation**2 Clean water 10
Life on land**2 Life on land 9
Good health and well-being** Good health 6
A rich diversity of plant and animal life* Biodiversity 6 Sustainable cities and communities** Sustainable cities 4
Good-quality groundwater* Quality ground-water 4
Reduce climate impact* Climate impact 4
A Non-Toxic Environment No toxins
EU Water Framework Directive WFD
*Denotes Swedish National Environment Objectives (SEEPA, 2012). **Denotes Sustainable Development Goals (UN 2015b). 1Goal only relevant for marine
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Table 2. The frequency at which analyzed ERAs met criteria for some of the environ-mental goals identified as relevant in four phases of assessment. The goals are shown in abbreviated form; see Table 1 for the full names. The goals listed first were relevant for all seven cases of ERA. The goals listed later were relevant for six or one ERA depending on whether they addressed freshwater (6) or marine environments (1), re-spectively. Goals in bold are the five identified as most relevant for their respective environment. Table adapted from study I.
Goals ERAs Nr. Problem, formula-tion
Analysis Risk characteri-zation: descrip-tion of risk Risk characteri-zation: reduction needs No toxins 7 7 7 7 7 Good health 7 5 5 6 0 Biodiversity 7 4 4 6 4 WFD 7 0 1 2 1 Sustainable cities 7 0 1 0 0 Quality ground-water 7 0 0 0 0 Climate impact 7 0 0 0 0 Life on land 6 3 4 5 4 Flourishing lakes 6 0 1 1 0 Clean water 6 1 2 4 0 Marine balance 1 1 1 1 1 Life in water 1 1 0 1 1
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Case-specific methods and goals in ERA
While study I indicates that the role of environmental goals could be imple-mented and developed further in ERA, studies II-III indicate that there is also a need to further develop the implementation of case-specific goals in ERA. In studies II-III, the goals set in several of the analyzed ERAs are not clearly achieved with the described methods and criteria used for assessing risk.
In some of the cases addressed in study II, the objectives are seemingly well aligned with the choice of methods and criteria (e.g. case A and G in Table 3), in others the alignment is arguably less clear (e.g. case B or C in Table 3). For example, in case C, sediment contaminant concentrations were measured and compared to national guidelines for soils, guidelines intended for classifying a terrestrial site as low/highly contaminated. The goal was to assess the extent of contamination the marine site could withstand and the as-sessors reached the conclusion that there was no risk. However, measuring the concentrations of contaminants and comparing to criteria for soil does not clearly fulfill the goal.
In study III, the goal of the assessments by courts was to determine if ex-emption to the ban on dumping dredged sediment at sea could be granted with no risk of environmental detriment. However, the definition of what consti-tutes environmental detriment is vague. Environmental detriment in relation to sediment is defined as a level of contamination that causes a risk of negative effects on plants and animals in the ecosystem, or as considerable contamina-tion of the bottom at and surrounding the dumpsite (free translacontamina-tion from guid-ance documents by SwAM (2018)).
To assess the risk of environmental detriment, the courts in study III mainly addressed measurements of the contaminant concentrations in the dredged sediments that were to be dumped and assessed the conditions for sediment to remain at the dumpsites. To characterize the risk of environmental detriment, the courts used a variety of criteria and reasoning. For example, in case A, the court reasoned that the concentration of tributyltin (TBT) in the dredged masses that were to be dumped should not exceed the concentration at the dumpsite. In another case, D, the court reasoned that it was necessary to cover the dumped sediment with a cap of cleaner sediment even though the preceding concentrations at the dumpsite were higher than in the dredged sed-iments that were to be dumped (Table 4). The majority of the cases in study III used a system to classify the contaminant levels in sediment based on ranges of background concentrations and developed by the SEEPA in 1999 (SEEPA 1999). The system defined five concentration ranges for several met-als and organic compounds, indicating relative low (class 1) to very high (class 5) levels of contamination. The cases reasoned differently as to at what class there was a risk of environmental detriment. The allowed maximum limits ranged from the lower limit of class 3 (medium contamination) in case B and
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C, to class 4 (high contamination) in case F and G and even above the lower limit of class 5 (very high contamination) in case H (Table 4).
We argue in study III that the two main indices addressed are not clearly in line with the goal of ensuring no environmental detriment. First, the poten-tial for the dredged sediment to remain at the dumpsite in itself is not a meas-urement of the risk at the dumpsite. It is also not a guarantee that the contam-inants do not reach the food-web as sediment contamcontam-inants can spread via, for example, bioturbation, diffusion or resuspension (Davis, 1993; Eek et al., 2010; Mustajärvi et al., 2019; Roberts, 2012). Secondly, comparing the con-centrations of contaminants in the sediments that are to be dumped to back-ground concentrations is not an indication of the risk for plants and animals in the ecosystem. Neither can it be said that the risk for considerable contamina-tion of the bottom at, and surrounding, the dumpsite is properly accounted for in all cases. For example, the courts in case F, G and H granted exemption to dump sediment with high to very high levels of contaminants (class 4-5), as classified by the classification system the courts used from SEPA (1999) (Ta-ble 4).
We further ague in study III that the cases that grant exemption for sedi-ments containing certain contaminants at class 3, and others at class 4, risk hazardous environmental effects as these classes coincide with concentrations where effects have been observed in the field (Raymond et al., 2021) or are estimated to occur (Breedveld et al., 2015) (Table 4). For activities with po-tentially negative environmental impact that require permits rather than ex-emption the applicant is required to conduct an environmental impact assess-ment considering alternative manageassess-ment solutions and sites and assess the environmental impact of the activity. However, as exemption should not be granted if there is a risk of environmental detriment (15:29 EC), environmen-tal impact assessments are not required. By virtue of being banned and in need of exemption rather than a permit, dumping might thus be allowed even though there are alternatives that are more suitable. By requiring environmen-tal impact assessments, or similar requirements as stipulated in the process, the potential negative environmental impacts from dredged sediments could be further reduced by obliging the applicants to reuse or recycle the sediments if possible. In cases where dumping is shown to be the most suitable manage-ment method, the applicant would have to show that the suggested dumpsite is the most suitable.
29 T abl e 3. P re se nt ed be low are t he ER A c ase s anal yze d in s tudi es I -II w it h the ir i ndi vi dua l case -spe ci fi c goa ls a nd t he soc ie tal env ironme nt al go al s the y addre ss ed ( in abbre vi at ed for m , se e T abl e 1 for the fu ll nam es ) fol low ed by the m et ho ds and c ri te ri a eac h case use d to ass ess ri sk . Adapt ed from st ud ie s I-II . E R As E R A spe ci fi c go al s envi ron -S oc ie ta l m ent al go al s add re ss ed Me asur em en ts / est im a-tion s of r isk C ri te ri a use d to a ss ess ri sk A D et er m ine t he e xt en t of c on -ta m in at ion in a m ar ine h ar bo r to de ve lo p m an age m ent st ra te gy to l im it e nvi ronm en ta l ef fe ct s an d re m ove t he o ut fl ow of c on -ta m in an ts fr om the h ar bo r. G ood he al th , W F D L if e in w at er Ma ri ne ba la nc e B iodi ve rsi ty N o to xi ns S ust ai na bl e ci ti es 1. Ma ri ne se di m ent con -ta m in an t c on ce nt ra tion s 2. W at er c on ta m in an t con -ce nt ra tio ns an d m ode lli ng of tr an spo rt r at e. 3. T iss ue c on ta m in an t c on -ce nt ra tio ns in bi va lve s. 1. Fr eshw at er se di -m ent ba ck gr ound con -ce nt ra tio ns 1 2. C om pa ri son to ba ck gr ound con ce nt ra -tion s 1 a nd t ra nspo rt f ro m ot he r w at er w ay s in to t he B al tic S ea 3. B ac kg ro und con -ce nt ra tio ns 1 B P ro vi de inf or m at ion to en -sur e th at c on ta m in an ts in l ake se di m en ts w oul d no t po se a con si de ra bl e en vi ronm ent al ri sk . G ood he al th L if e on la nd B iodi ve rsi ty N o to xi ns 1. S edi m ent con ta m in an t conc en tr at io ns 1. B ac kg ro und con -ce nt ra tio ns 1 C D et er m ine t he e xt en t of c on -ta m in at ion t he a re a co ul d w it h-st an d, to de te rm ine t he ne ed fo r po te nt ia l m it ig at in g m an ag e-m ent . G ood he al th L if e on la nd B iodi ve rsi ty N o to xi ns 1. S edi m ent con ta m in an t conc en tr at io ns 1. G ui de line va lu es fo r so il 5
30 D A ss ess the r is k of e ff ec ts an d po te nt ia l spr ea d of P A H s fr om con ta m in at ed la ke s edi m ent . L if e on la nd B iodi ve rsi ty N o to xi ns 1. P as si ve sa m pl er s in t he w at er c ol um n 1. D ut ch ta rge t a nd in -te rve nt ion v al ue s 6 E A ss ess the ne ed of m iti ga ti on of e nvi ronm en ta l ri sk s in r ive r ba y se di m ent a nd t he spr ea d of con ta m in an ts to sur ro un di ng w at er bo di es. G ood he al th C le an w at er L if e on la nd B io di ve rsi ty N o to xi ns 1. S edi m ent con ta m in an t conc en tr at io ns 2. W at er c on ta m in an t con -ce nt ra tio ns an d m ode lli ng of tr an spo rt r at e. 3. F ish a nd g ast ro po d tis-sue c on ce nt ra tion s 4. B en th ic c om m uni ty sur -ve y 1. B ac kg ro und con -ce nt ra tio ns 3 2. C om pa ri son to tr an spo rt f rom o the r w a-te rw ay s in to the B al ti c S ea 3. B ac kg ro und con -ce nt ra tio ns 3 4. R ef er en ce a re a F A ss ess the ri sk s to hu m an he al th and the envi ronm ent fr om c on ta m in at ed se di m en t in a st re am ; an d pr ov ide inf or -m at ion t o ac hi eve ba ckg ro und le ve ls of m et al s in the w at er c ol -um n; a nd t he c ol on iz at ion of a ga st ro pod com m un it y in the ar ea . G ood he al th C le an w at er L if e on la nd B iodi ve rsi ty N o to xi ns 1. S edi m ent con ta m in an t conc en tr at io ns 2. W at er c on ta m in an t con -ce nt ra tio ns 3. S ur ve y of ga st ro pod abun da nc e 4. F ish tiss ue conc en tr a-tion s 1. G ui de li ne va lu es fo r so il 7 2. B ac kg ro und con -ce nt ra tio ns 1 3. R ef er en ce a re a 4. B ac kg ro und con -ce nt ra tio ns (No r ef er en ce )
31 R efe re nc es us ed by t he E R A s: 1 SE E PA 2007 ; 2 R ef er en ce no l on ge r av ai la bl e; 3 N o re fe re nc es g iv en ; 4 C CM E 2002 ; 5 SE E PA 2009 ; 6 V R O M 2000 (de sc ri be d in th e E R A a s no t i nt en de d spe ci fi ca ll y fo r pa ss iv e sa m pl ing); 7N o re fe re nc e st at ed but li ke ly S E E PA 20 09 . *M ea su re m en t o f ac ti va ti on o f en zy m e et ho xy re so ruf in -O -de et hy la se (E R O D ), in di ca tiv e of o rga ni c po ll ut io n. G P ro vi de inf or m at ion to de te r-m ine the ne ed and sc op e of m it-ig at ing m an age m ent of la ke se di m en ts, f oc us ing on b iol ogi -ca l r isk s. G ood he al th , W F D C le an w at er L if e on la nd F lo ur is hi ng la ke s B iodi ve rsi ty N o to xi ns 1. S edi m ent con ta m in an t conc en tr at io ns 2. S edi m en ta ti on ra te to de te rm ini ng r at e of bur ia l 3. B en th ic c om m uni ty sur -ve y 4. P A H m et abol it es and E R O D * in f is h 5. Mi cr ot ox bi ol um ine s-ce nc e te st w ith s ed im ent sa m -pl e se di m ent C an ad ia n qua lit y gui de li ne s. 4 3. H ist or ic al r ef er enc e fr om t he a ss ess m en t si te , inde x of st re ss tol er an ce 4. R ef er enc e ar ea 5. R ef er enc e ar ea
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Table 4. Presented below are fourteen court cases that tried applications for exemption to dump dredged sediment at marine dumpsites. The respective contaminant concentrations set as limits in the dredged sediment are shown next to the concentrations measured at the proposed dumpsites prior to dump-ing. Last, the conditions at the dumpsites considered by the courts when as-sessing whether the proposed dumpsites were suitable. The contaminant con-centrations and levels were not available for some cases.
Case Maximum
con-taminant levels in ex-emptions Contaminants at the dumpsites Considered dumpsite con-ditions A 50 µg/kg dw TBT, for other contami-nants the limit was set at class 4*
> class 3, class 4 for some PAHs, 47µg/kg dry weight for TBT
Sediment sink
B Class 3
Good chemical status as per the EQS (as de-fined by SWAM 2012) Sediment sink, Hypoxia C Class 3 Na Contami-nants D 100 µg/kg dw
TBT, for other con-taminants the limit was set at class 5
123-534 µg/kg dw TBT Sediment sink, Contami-nants E Not available
The dumpsite is de-scribed as contaminated without additional detail on the types or levels of contaminants. Sediment sink, Contami-nants, Sur-rounding envi-ronmental val-ues
F Not available** Not available
Sediment sink, local envi-ronmental val-ues, filling ca-pacity, previous use
G Class 4
Class 1-2 for metals, 4 for some organic pollu-tants.
Sediment sink
H
Class 4 with the exception of Cu at class 5
Class 1-2 for metals, 4 for some organic pollu-tants.
Sediment sink
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I Class 3 Not available
Previous use, Reduced sediment,
Ben-thic
commu-nity, Depth
J Not available Not available
Sediment sink, Previous use, Depth K 200 µg/kg dw TBT. PAH-11 and PCB-7 are allowed to exceed the lower limit for class 5. TBT 3.4 – 163 µg/kg dry weight Sediment sink L
Class 3, except for TBT (50 µg/kg dw) & Cr (90 mg/kg dw) Not available Sediment sink, Previous use
M Not available Not available
Hydrology, Previous use, Ecosystem
N Not available Not available Previous use
*Classification of the contaminant concentrations in sediment based on ranges of background concentrations, ranging from 1-5, low to very high contamination (SEEPA 1999). **The dredged sediments are described to contain contaminant con-centrations lower than set as a limit in case A.
Characterizing risk in ERA
In study II, we show how the analyzed ERAs, except for case D, measured contaminant concentrations and compared to various reference values to char-acterize risk. In case G, the risk characterization was in part based on compar-ing the contaminant concentrations to reference values derived from sediment contaminant concentrations in relation to ecological effects. However, this was the only case in study II to do so. Instead, values such as background concentrations were used, as in case A, B and E. Similarly, case A and E used background values to characterize the risk based on contaminant concentra-tions in tissue samples (Table 3).
When characterizing risk in study III, none of the analyzed cases compared sediment contaminant concentrations to reference values relating concentra-tions to negative ecological effects. Rather, we show how background con-centrations were used in court to characterize the risk from sediment. For ex-ample, in case A, the risk was characterized as acceptable by limiting the TBT
