ArticlePDF Available

Inconsistencies in How Environmental Risk Is Evaluated in Sweden for Dumping Dredged Sediment at Sea

Abstract and Figures

Millions of tons of dredged sediment are dumped at sea annually. International conventions limit dumping when there is a risk of adverse ecological effects, for example if the sediment is contaminated. However, the perception of risk differs substantially among stakeholders and in Sweden there is a lack of guidelines for how to address such risk. In the current study, we examined exemptions to the Swedish ban on dumping at sea, to explore the extent of dumping and how ecological aspects were considered in the evaluation of risks. We analyzed data from all cases granted exemption by county administrative boards and all court cases considering exemption to the ban from the beginning of 2015 to June 2020. We found that while dumping is the least common alternative management method for dredged sediment in total number of cases (98/792), dumping is the main method in terms of volume (30.8/38.2 million m3). When considering exemptions, the courts mainly evaluated the risk of exposure to contaminants and resuspended sediment for the environment adjacent to the dumpsite. The risks from contaminants were characterized based on various lines of reasoning, mainly relying on reference values not based on a scientific correlation to environmental risk. We argue that the evaluations were not in line with current regulations and international conventions as they insufficiently accounted for the ecotoxicological risk of the dumped sediment. These issues are potentially similar in other Baltic Sea countries, where there is a similar dependency on binary chemical limit values.
fmars-08-755443 October 13, 2021 Time: 16:7 # 1
ORIGINAL RESEARCH
published: 20 October 2021
doi: 10.3389/fmars.2021.755443
Edited by:
Tieyu Wang,
Shantou University, China
Reviewed by:
Periyadan K. Krishnakumar,
King Fahd University of Petroleum
and Minerals, Saudi Arabia
Kari Lehtonen,
Finnish Environment Institute (SYKE),
Finland
*Correspondence:
Peter Bruce
pkhbruce@gmail.com
Specialty section:
This article was submitted to
Marine Pollution,
a section of the journal
Frontiers in Marine Science
Received: 08 August 2021
Accepted: 30 September 2021
Published: 20 October 2021
Citation:
Bruce P, Bradshaw C, Ohlsson Y,
Sobek A and Christiernsson A (2021)
Inconsistencies in How Environmental
Risk Is Evaluated in Sweden
for Dumping Dredged Sediment
at Sea. Front. Mar. Sci. 8:755443.
doi: 10.3389/fmars.2021.755443
Inconsistencies in How
Environmental Risk Is Evaluated in
Sweden for Dumping Dredged
Sediment at Sea
Peter Bruce1*, Clare Bradshaw1, Yvonne Ohlsson2, Anna Sobek3and
Anna Christiernsson4
1Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden, 2Department
for Management of Contaminated Sites, Swedish Geotechnical Institute, Stockholm, Sweden, 3Department of Environmental
Science, Stockholm University, Stockholm, Sweden, 4Department of Law, Stockholm University, Stockholm, Sweden
Millions of tons of dredged sediment are dumped at sea annually. International
conventions limit dumping when there is a risk of adverse ecological effects, for example
if the sediment is contaminated. However, the perception of risk differs substantially
among stakeholders and in Sweden there is a lack of guidelines for how to address such
risk. In the current study, we examined exemptions to the Swedish ban on dumping at
sea, to explore the extent of dumping and how ecological aspects were considered
in the evaluation of risks. We analyzed data from all cases granted exemption by
county administrative boards and all court cases considering exemption to the ban
from the beginning of 2015 to June 2020. We found that while dumping is the least
common alternative management method for dredged sediment in total number of
cases (98/792), dumping is the main method in terms of volume (30.8/38.2 million
m3). When considering exemptions, the courts mainly evaluated the risk of exposure to
contaminants and resuspended sediment for the environment adjacent to the dumpsite.
The risks from contaminants were characterized based on various lines of reasoning,
mainly relying on reference values not based on a scientific correlation to environmental
risk. We argue that the evaluations were not in line with current regulations and
international conventions as they insufficiently accounted for the ecotoxicological risk of
the dumped sediment. These issues are potentially similar in other Baltic Sea countries,
where there is a similar dependency on binary chemical limit values.
Keywords: sediment, contaminant, risk assessment, risk evaluation, risk management, regulation, sea dumping
INTRODUCTION
Sediments play an important role for the functions and processes of the marine environment.
They contribute to our food supply and recreational values as well as providing services such as
filtering and storage of excess nutrients (Troell et al., 2005;Schmidt et al., 2011). However, sediment
ecosystems and their functions are threatened by the historical and ongoing input of contaminants
Frontiers in Marine Science | www.frontiersin.org 1October 2021 | Volume 8 | Article 755443
fmars-08-755443 October 13, 2021 Time: 16:7 # 2
Bruce et al. Inconsistently Evaluating Dumping at Sea
(Elmgren, 2001;Sundqvist and Wiberg, 2013). One source of
contaminants to sediment comes from disposing, or dumping, of
waste at sea. Large scale dumping at sea started in the late 19th
century (Nihoul, 1991). The most common waste that is dumped
today consists of sediment dredged in close proximity to urban
or industrial areas, such as harbors and river outlets, where the
sediment can be highly contaminated (Cundy et al., 2003;Taylor
et al., 2004;Helsinki Commission [HELCOM], 2010;Sundqvist
and Wiberg, 2013;Staniszewska and Boniecka, 2017).
Dumping dredged sediments can increase water turbidity and
cause structural changes to the sea floor habitat, disturbing,
for example, reproduction, and availability of light and food
(Shackle et al., 1999;Stelzenmüller et al., 2010;Kemp et al.,
2011;Kraufvelin et al., 2018;Virtasalo et al., 2018;Dias et al.,
2019;Mossa and Chen, 2021). Contaminants bound to dumped
sediment particles may spread through a range of processes.
Storms, trawling and bioturbation can cause contaminants
dissolved in water or adsorbed to sediment particles to move
through the water column and food web causing adverse effects
to the ecosystem (Malins et al., 1985;Varanasi et al., 1985;
Davis, 1993;Eggleton and Thomas, 2004;Knott et al., 2009;
Roberts, 2012;Donázar-Aramendíaa et al., 2020). The potential
effects from dumping dredged sediment are the result of a
combination of the chemical and physical characteristics of
the dumped sediment and the characteristics of the dumpsite,
such as habitat type and ecological conditions. The rate and
outcome of ecological recovery differs substantially due to these
characteristics. Opportunistic species can recolonize quickly
given the right circumstances and ecological functions can be
regained after a few years. However, the species composition can
be slow in recovering (Pearson and Rosenberg, 1978;Blomqvist,
1982;Hill et al., 1999;Bolam et al., 2006;Guerra-García and
García-Gómez, 2006;Larson and Sundbäck, 2012).
After 1972, dumping at sea was limited on a global scale
through the London Convention on the Prevention of Marine
Pollution by Dumping of Wastes and other Matter, with
exemptions for waste originating at sea, such as dredged sediment
from maintenance of thoroughfares and harbors. The initiative
was soon followed by additional conventions, including the
Barcelona Protocol for the Prevention of Pollution of the
Mediterranean Sea by Dumping from Ships and Aircraft, 1976;
the Marine Protection, Research and Sanctuaries Act, 1972; the
Convention for the Protection of the Marine Environment of the
North-East Atlantic, i.e., the OSPAR Convention (1992); and the
Convention on the Protection of the Marine Environment of the
Baltic Sea Area, i.e., the citeBR670.
Prior to 1972, the annual dumping of sediment from land-
based activities in the United States alone exceeded 100 million
tons, including petroleum products, heavy metals, chemicals, and
radioactive waste (USEPA, 2020). Similar statistics for Europe
are not available, but given the region’s industrialized societies,
a similar situation can be expected to have occurred in Europe
(Nihoul, 1991). Even though there are restrictions in place,
large amounts of dredged sediment, with various levels of
contaminants, are still dumped annually. There are no reports
providing a complete overview, but OSPAR reports that over
a 1,000 million tons of sediment were dumped annually in
the OSPAR maritime area alone during 2008–2014 (OSPAR
Commission, 2021). Similarly, for the EU, over 200 million tons
have earlier been reported to be dumped (Mink et al., 2006).
In Sweden, dumping is a common practice in comparison to
the neighboring HELCOM member states (Helsinki Commission
[HELCOM], 2020b). This is in spite of a national ban on
dumping in the territorial and exclusive economic zone [15:27
Environmental Code (EC), SFS 1998:808, EC]. Exemptions from
the national ban on dumping should only be authorized if there
is no detriment to human health or the environment (15:29 EC).
The EC also prohibits activities jeopardizing the achievement
of a good ecological status of water bodies as part of the EU
Water Framework Directive1(WFD) (5:4 EC) and includes an
obligation to only dispose of waste as a last alternative after reuse
has been ruled out as an option (2:5, 15:10 EC).
Under such strict regulations, it is especially important
that the risk of environmental detriment from dumping is
properly assessed and addressed when exemptions to the ban of
dumping are considered. Recently, a lack of national sediment
risk assessment guidance, resulting in a variation in assessment
approaches, has been reported. It has further been shown that
the current practice of assessing contaminated sediment sites
frequently relies on arguably too narrow sets of indices of risk
and ecological impairment (Severin et al., 2018;Bruce et al.,
2020). In the light of this, it is relevant to investigate both how
common exemptions to the ban are and also on what grounds it
has been ruled that there is no risk of environmental detriment.
Hence, we aim to provide an improved understanding of the
exemption process, focusing on: (1) The environmental aspects
assessed when dumping is considered in practice, and (2) How
the regulations are implemented in relation to ensuring that there
will be no environmental detriment.
Restrictions on dumping are laid down in both the global
London Convention and the regional OSPAR and HELCOM
conventions, to which Sweden is a party (SÖ 2000:48; SÖ
1974:8; SÖ 1992:9). Sweden is moreover a member of the
European Union (EU) and thus bound by inter alia the
WFD and the Waste Framework Directive2. The obligations
laid down in the conventions and the directives have been
implemented into national law, mainly in the EC. While
dumping waste at sea is forbidden (15:27 EC), exemptions can
be granted on the condition that the waste can be dumped
without detriment to human health or the environment (15:29
EC). The condition is to be interpreted restrictively. Moreover,
the burden of proof lies on the applicant (2:1 EC) and the
risk of detrimental effects to the environment is sufficient
for requiring protective measures (2:3 EC). According to the
preparatory works, the room to apply for exemption is limited
to dredged sediments.
The condition “without detriment to human health or
the environment” must moreover be interpreted in the light
of other obligations laid down in the EC and in EU-law,
1Directive 2000/60/EC of the European Parliament and of the Council establishing
a framework for the Community action in the field of water policy.
2Directive 2008/98/EC of the European Parliament and of the Council of 19
November 2008 on waste and repealing certain Directives.
Frontiers in Marine Science | www.frontiersin.org 2October 2021 | Volume 8 | Article 755443
fmars-08-755443 October 13, 2021 Time: 16:7 # 3
Bruce et al. Inconsistently Evaluating Dumping at Sea
such as the obligation to achieve a good water status under
the WFD and a favorable conservation status of species
and natural habitats protected by the Habitat Directive3. The
European Court of Justice has clarified that member states
are required to refuse authorization of individual projects
that risk causing a deterioration of the environmental status
of a water body or jeopardizing the attainment of good
surface water status (in case C-461/13). As a result of the
case, deterioration or jeopardizing the achievement of a good
ecological status of water bodies [as defined by Environmental
Quality Standards (EQS) set for the respective water body
to fulfill the WFD (Swedish Agency for Marine and Water
Management [SwAM], 2019)] is prohibited since January 2019
EC (5:4 EC). Under certain restrictive conditions, derogation
may nevertheless be authorized (5:6 EC, 4:11–12 Water
Management Ordinance).
A balancing of costs and benefits in the particular case,
according to 2:7 EC, is not possible given that exemptions can
only be permitted if the dumping will not cause detriment
to human health or the environment. In extension, as
exemption only can be granted if there is no detriment
to the environment, the regulation for Environmental
Impact Assessment4(EIA) is not necessarily applicable.
Moreover, exemptions on dumping are the last resort and
should not be granted if reuse or recycling of the waste
is possible (2:5, 15:10 EC). An exemption to dump at
sea may be granted with conditions. If dumping causes
adverse effects, the operator can be held responsible for
remediation (15:33 EC).
The regulatory authority with the main responsibility for
marine environmental management is the Swedish Agency
for Marine and Water Management (SwAM). In a guidance
document adopted by SwAM, environmental detriment is
defined as a level of contamination so high that it causes risk
of negative effects to plants and animals in the ecosystem, or
considerable contamination of the bottom at and surrounding the
dumpsite [free translation from Swedish Agency for Marine and
Water Management [SwAM] (2018)].
Exemptions are most commonly authorized by the regional
County Administrative Boards. In the rare case that the sites for
dredging and dumping are situated in different counties, SwAM
is the authorizing body. The decisions, or part thereof, can under
certain circumstances be appealed to the Land and Environment
Courts (District Courts). Moreover, when the dumping is part of
other related water activities that require a permit from the Land
and Environment Court, the room to authorize exemptions to
dump waste in the sea will be tried by the District Court as a first
instance. A concerned party, such as landowners that are at risk of
being affected by the activity and environmental governmental or
non-governmental organizations, can also appeal decisions under
certain circumstances. Cases from the District Courts can be
appealed to the Swedish Land and Environment Court of Appeal
3Directive 92/43/EEC of 21 May 1992 on the conservation of natural habitats and
of wild fauna and flora.
4Directive 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.
(here abbreviated LECA), the highest national environmental
court and a court of precedent, given that the court grants a
leave to appeal. To grant exemption, the ruling authority decides
whether the condition of no environmental detriment is fulfilled.
See Figure 1 for a map of involved parties and their roles in
exemption from the ban on dumping waste at sea.
MATERIALS AND METHODS
Data Collection
We compiled data from SwAM on the frequency and extent of
dredging, dumping and other methods for disposal of dredged
sediments in Sweden. SwAM is the national intermediary for
reporting all national marine dumping activities to HELCOM
and OSPAR and has data on all national granted dumping
exemptions from 2015 to 2019.
The data compiled by SwAM includes the granting authority,
county, dumpsite, identification number, volume and type
of the masses that are to be dumped and dates for when
the exemption was given and its duration. However, the
data only includes information on granted exemptions.
Attempting to find information on non-granted applications,
we contacted the County Administrative Boards that have
granted the highest number of exemptions during 2015–
2019. However, only the county of Skåne could provide
data on the number of non-granted applications, i.e., 1
out of 21 counties of which 11 have granted exemptions
during 2015–2019.
To investigate how the regulations are implemented in
practice and the implication thereof, we assessed court cases
(Table 1) with applications or appeals to exemptions to the
ban on dumping determined by District Courts, or by the
LECA if appealed from the District Courts. We searched for
all relevant court cases from January 2015 to June 2020.
We did not look further back in time as we wanted the
cases to illustrate the current practice and since SwAM’s
register was less structured before 2015. The court cases
were all publicly available and a majority of them could
be found on the online platforms of e.g., the Supreme
Environmental Court and jpinfonet.se5. Some cases were only
available on request from the individual courts. In those
cases where a verdict was appealed, we focused on the
latest case. The cases include the courts’ and other involved
parties’ arguments and reasoning for why exemption should or
should not be granted.
We excluded cases that dealt with dumping at other locations
than the sea as well as one case where the details were classified
as confidential. We also later excluded four cases from the
District Courts where the courts did not consider the potential
environmental detriment as other requirements were not met. In
total 14 cases were included, nine from District Courts and five
from the LECA (Table 1 and Supplementary Appendix 1). Two
5jpinfonet.se is a website serving as a repository for judiciary information such as
court cases.
Frontiers in Marine Science | www.frontiersin.org 3October 2021 | Volume 8 | Article 755443
fmars-08-755443 October 13, 2021 Time: 16:7 # 4
Bruce et al. Inconsistently Evaluating Dumping at Sea
FIGURE 1 | Involved actors in Sweden and their engagement in relation to applications for exemption to dumping dredged sediment at sea.
TABLE 1 | Cases by land and environmental District Courts (DC) or the Land and Environmental Court of Appeal (LECA), processing applications or appeals to
exemption from the ban on dumping waste at sea.
Instance Case Reg. no Year Decision Disposal volume
m3
LECAAA M 1260-14 2015 Granted 4,000,000
LECAAB M 9616 2015 Granted 900,000
Växjö DCAC M 3089-15 2015 Rejected 85,000
LECAAD M 1732-16 2016 Granted 220,000
LECAAE M 837-16 2016 Rejected Not available
Vänersborg DC F M 108-15 2016 Granted/Rejected* 5,000
Vänersborg DC G M 4016-15 2016 Granted 4,000
Vänersborg DC H M 4017-15 2016 Granted 12,000
Östersund DC I M 1697-15 2017 Granted 60,000
Vänersborg DC J M 2553-15 2017 Granted 4,200
LECAAK M 4685-17 2018 Granted 21,100,000
Växjö DC L M 3021-17 2018 Granted 2,500,000
Vänersborg DC M M 3522-17 2018 Rejected Not available
Vänersborg DCAN M 5122-19 2020 Rejected Not available
Cases marked with “A” were appealed from a lower instance. See Supplementary Appendix 1 for a more extensive description of the cases.
*In case F, the application was denied for one proposed dumpsite and granted for another.
of the cases in the District Courts were appealed from County
Administrative Boards.
Method of Analysis
We analyzed the full court cases to find content connected
to our aims. To do so we used content analysis, a method
commonly used to scrutinize large sets of text-based information
in order to identify and divide it into categories (Neuendorf, 2002;
Krippendorff, 2004;Bryman, 2008;Julien, 2008). We conducted
the analysis manually by systematically reading and categorizing
the documents’ content in the analysis with the software NVivo
(QSR International, 2020).
To find the information needed, we organized the content
of the court cases into categories describing the grounds
on which the courts based their decisions, as well as the
factors and reasoning that were considered in relation to
Frontiers in Marine Science | www.frontiersin.org 4October 2021 | Volume 8 | Article 755443
fmars-08-755443 October 13, 2021 Time: 16:7 # 5
Bruce et al. Inconsistently Evaluating Dumping at Sea
evaluating environmental detriment from the requested dumping
exemption. From this content, we focused on the verdict and set
conditions for exemption and the grounds for the decision where
the courts expressed their reasoning. In appealed cases, only part
of the previous judgments were contested. For example, in case A
(Table 1) the conditions for the maximum limit concentrations of
TBT were appealed, whereas limit values for other contaminants
were not. The court therefore only considered the limit value for
TBT. In such cases we included content from the preceding cases
pertaining to the parts that were not appealed. Moreover, when
the courts in their reasoning referred to content from a preceding
appealed case or to content in the same case expressed in the
opinions by the applicants, consultant bodies or other parties,
we also included such content. The appealed cases were added
as appendices to the case material.
We organized the content of the cases into the following
categories:
Clean sediment – content describing the courts’ reasoning
when determining whether the dredged sediments
were safe to dump from the perspective of risk of
environmental detriment.
Suitable dumpsite – content where the courts described
their reasoning when determining if a proposed
dumpsite was suitable.
Ecology – content describing ecological factors in
the courts’ reasoning when characterizing risk of
environmental detriment. Only content directly relating to
ecological risks or conditions was included in this category.
We only included content that dealt with potential
spreading of sediment off-site or contaminant levels
on-site if the content related those factors to ecological
risks or conditions.
Climate change – content describing the courts’ arguments
and reasoning when relating to changes in conditions due
to climate change.
Rejection – content describing the courts’ arguments and
reasoning for rejecting exemption.
A benefit of this approach is that the documents provide the
explicit reasoning and conclusions expressed by the courts when
considering appeals or applications for exemption to the ban on
dumping. The documents are intended to offer a full account
of the grounds for the courts’ decisions. However, the level of
detail differed between the cases providing a varying level of
transparency and insight to the underlying data provided to the
courts and the courts’ reasoning.
RESULTS
Dumping as an Alternative for
Management of Dredged Sediments in
Sweden
In Sweden, dumping at sea was the least common management
alternative for dredged marine sediment in terms of number of
cases. However, dumping constituted a majority of the volume
disposed from dredging of sediments, exceeding any of the
other alternatives by a factor of ten. In 79%, corresponding
to 762 of the cases, the dredged sediments were disposed on
land, e.g., in landfills. In 11%, corresponding to 109 cases, the
sediments were used for “beneficial use,” which can include,
but is not limited to, bolstering of shorelines, filling during
construction in water or on land and recycling of metals and
nutrients. In 10%, corresponding to 98 cases, exemption was
granted to dump approximately 30,847,424 m3of sediment at
sea (Figure 2). The exemptions were unevenly distributed among
the counties bordering the sea (Figure 3). SwAM and some
counties did not keep readily available records on cases that were
rejected. However, the southernmost County Board of Skåne
stated that they had rejected roughly one application per year
compared to granting 3–13 per year during 2015–2019 (Table 2)
(Personal communication with the Skåne County Administrative
Board, 2020-08-11).
The requirements for reporting data to SwAM on alternative
methods for managing dredged sediment were less strict than
those for dumping at sea. Therefore, it was not always clear for
each individual case what beneficial method or type of disposition
on land that had been used. The less restrictive requirements were
also the reason for a number of disposal activities marked as not
registered. The unregistered cases were supposedly distributed
among the different alternatives for beneficial use and storage on
land (Personal communication with SwAM, 2020-08-26).
Clean Sediment
When determining if dumping could be conducted without
detriment to the environment, the courts had to address both
the dredged sediments and the dumpsite. When evaluating the
risk from the dredged sediments the courts considered the
contaminant concentrations in the sediments to determine if they
were “clean,” as phrased by the courts in some cases. Common for
all cases was that when maximum limit concentrations were set
for the contaminants in the dredged sediments, they were defined
in the conditions for the exemption. However, the courts used
different reasoning to conclude what constituted clean sediments
in different cases. The conclusions reached by the courts can
be seen in Table 3 and we illustrate the variability among the
conclusions with two sets of examples below.
The first set covers three examples of reasoning where the
court considered sediments contaminated by TBT. In case A
(2015), the LECA decided that the level of TBT in the dumped
sediments should not exceed the already occurring concentrations
of TBT in the sediment at the sampling site adjacent to the
dumpsite, thus setting a limit at 50 µg TBT/kg dry weight (dw).
The court also stated that they perceived that level to be harmful.
The court explains their reasoning stating that: “An assessment
must be conducted based on the circumstances at hand in each
individual case” (case A, p. 8). This could be interpreted to
mean that limit values should be based on the contaminant
levels, or other conditions, at the dumpsite and that if the TBT
concentrations at the dumpsite were lower than 50 µg TBT/kg
dw, the limit value should also be set lower.
Case A was interpreted in different ways by later cases. The
limit values for TBT and a range of other contaminants set in case
Frontiers in Marine Science | www.frontiersin.org 5October 2021 | Volume 8 | Article 755443
fmars-08-755443 October 13, 2021 Time: 16:7 # 6
Bruce et al. Inconsistently Evaluating Dumping at Sea
FIGURE 2 | Granted permits and exemptions for the disposal of dredged marine sediments in number of cases and volume between the start of 2015 and end of
2019. For some dredging projects several methods of disposal were registered, however, the distribution of volume was in general not reported. Therefore, the figure
shows volume per method as if the respective method was used for 100% of the dredged sediment, thus showing the potential maximum volume. Since the
requirements are strict for reporting dumping exemptions, the volume specifically for dumping ought to be accurate.
A, were used as a precedent in some cases. In case L (2018), the
District courts set the limit values for TBT to 50 µg/kg dw with
referral to case A, without making an argument for the limit based
on the site-specific conditions at the dumpsite.
In other cases during the same time period, higher
levels of TBT were allowed. In case D (2016), the LECA
set a limit concentration for TBT at 100 µg/kg dw for
the sediments to be dumped. Compared to case A, the
circumstances differed in case D. The concentrations of TBT at
the dumpsite prior to dumping, 123–534 µg/kg dw, exceeded
the set limit concentrations of 100 µg/kg dw. A condition
for the exemption was that the contaminated masses had
to be covered with clean sediments, without further defining
the characteristics of the cover. A higher concentration of
TBT was thus allowed in a case where the background
concentration at the dumpsite was higher and the dumped
sediment would be covered with cleaner sediment, although
“clean” was not defined.
In case K (2018), the LECA set a limit value for TBT at
200 µg/kg dw in sediments that were to be dumped. As in case
D, a condition was set to cover the contaminated sediment with
3 m of cleaner sediments (with a maximum concentration of
50 µg/kg dw TBT), but with the difference that the concentration
for TBT, set as a condition, in the dredged sediment (200 µg/kg
dw) exceeded the concentrations at the dumpsite (3.4–163 µg/kg
dw). The LECA thus concluded that sediment with a higher
concentration of TBT was allowed to be dumped at a site with
lower concentrations, if the dumped sediment would be covered
with cleaner sediment.
The second set of examples demonstrate the variability in
conclusions regarding organic and metal contaminants. Nine
of the cases describe the concentrations of contamination in
sediments using a system where the contamination degree
is classified in relation to the occurrence of contaminants
in marine sediment along the Swedish coast. The degree
of contamination is divided into the classes 1–5 (very low
contamination to very high contamination, at the 5th, 25th,
75th, and 95th percentiles, respectively) (Swedish Environmental
Protection Agency [SEEPA], 1999). The system was updated
2017 based on data from 1986 to 2014 (Josefsson, 2017;
Frontiers in Marine Science | www.frontiersin.org 6October 2021 | Volume 8 | Article 755443
fmars-08-755443 October 13, 2021 Time: 16:7 # 7
Bruce et al. Inconsistently Evaluating Dumping at Sea
FIGURE 3 | Number of exemptions to the ban on dumping waste at sea
granted in Sweden by county, 2015–2019.
TABLE 2 | Exemption applications granted and rejected, in Skåne county.
Year Granted exemptions Rejected exemptions
2015 11 1
2016 3 1
2017 6 2*
2018 13
2019 10
Based on personal communication with Mats Lindén, County Administrative Board
of Skåne (2020-08-11).
*During 2017–2019 two applications were rejected but it is not clear at what
individual year the rejections occurred.
Swedish Environmental Protection Agency [SEEPA], 2020) but
all cases used the version from 1999.
Starting again with case A (2015), the LECA did not
change the maximum contaminant limit concentration for
contaminants other than TBT set by the District Court. The
limit was the lower threshold of class 4, corresponding to
high concentrations of contaminants according to the used
classification system (Swedish Environmental Protection Agency
[SEEPA], 1999). Class 4 was in general considerably higher than
the concentrations of metals and similar to the concentrations
of organic contaminants adjacent to the dumpsite. In contrast to
the LECAs condition for TBT in the same case, the contaminant
concentration limits were set considerably higher than the
background concentrations at the dumpsite.
Shortly after case A, a District Court did not authorize
an exemption to dump dredged sediments that contained
contaminant levels exceeding class 3, corresponding to medium
high concentrations, in case C (2015). The District Court
considered such concentrations incompatible with the demand
of no environmental detriment, even though the suggested
dumpsite exhibited higher concentrations of contaminants. In
case B (2015), the LECA also set the limit to class 3, based on
the assessment that it would not infringe on the EQS for the
general waterbody.
In case D (2016), the LECA set the maximum limit to class
5, corresponding to very high levels, without relating to the
concentrations at the dumpsite and with the condition that
the dumpsite had to be covered with cleaner sediment (clean
was not defined).
In case H (2016), the District court authorized an exemption
for sediments with contaminants up to class 4 in general but
with levels of copper at class 5, justified by the dumpsite being
an accumulation bottom from which the sediment was unlikely
to spread. In one of the latest cases (case K 2018) where the
classification system of the degree of contamination was used,
the LECA granted exemption for sediments with concentrations
of specific groups of PCBs and PAHs exceeding the lower limit
for class 5, with the condition that they had to be covered
with sediments with a maximum contaminant concentration
corresponding to class 5 for PAH-11 and PCB-7, and 50 µg/kg
dw for TBT (Table 3).
There are general limit values produced as part of the WFD for
some of the substances that are relevant in the court cases, such as
mercury and PAHs. These limit values were available for all of the
court cases included in the study (Swedish Agency for Marine and
Water Management [SwAM], 2013, updated in Swedish Agency
for Marine and Water Management [SwAM], 2019). However,
they were not used in any of the analyzed cases.
Suitable Dumpsite
We identified several key factors addressed by the courts when
determining if a proposed dumpsite was suitable in relation to the
dredged sediments to be dumped (Table 4). The most prevalent
factor was the capacity of the dumpsite to act as a sediment
sink where the dumped sediments could accumulate with little
or no risk of being spread to the surroundings. This was explicitly
highlighted in 10 out of the 14 cases. As an example, the LECA
stated that:
“The (proposed) site for planned dumping is a sediment
sink, which means that there are good conditions for sediment
transport not to occur. With that, the site can be considered
to be suitable for dumping of dredged sediment” (Case A, p. 8,
translated from Swedish).
In a case where the application was denied, the LECA also
stated that:
“According to the judgment of the LECA, the performed
seabed characterization does not provide sufficient support to
suggest that this is an accumulation bottom suitable for dumping
of dredged material” (Case E, p. 7, translated from Swedish).
In cases M and N, the applications were rejected based
on inadequate information on the hydrological conditions at
the dumpsites. The courts did not specify what hydrological
information was missing. However, based on previous reasoning
by the courts on accumulating properties of the dumpsites, it is
likely that such information was, at least in part, what was missing
in cases M and N.
Frontiers in Marine Science | www.frontiersin.org 7October 2021 | Volume 8 | Article 755443
fmars-08-755443 October 13, 2021 Time: 16:7 # 8
Bruce et al. Inconsistently Evaluating Dumping at Sea
TABLE 3 | Maximum contaminant level accepted for dumping with summaries of reasoning by the courts when determining whether the dredged sediments were safe
to dump without risk of environmental detriment.
Case Year Maximum contaminant
level in sediment granted
exemption
Summary of the courts’ motivation for the maximum allowed contaminant levels in sediments to
be dumped
A 2015 50 µg/kg dw TBT, class 4*
for other contaminants
The court set the limit value to 50 µg/kg dw for TBT, with the motivation that the concentration of TBT in the
dredged masses that were to be dumped at the dumpsite could not exceed the existing concentrations in
the sediment at the dumpsite, as those levels were already at a level of ecological risk. The limit values for
other contaminants were set, without additional discussion provided by the court, to class 4, “highly
contaminated” (page 8, preceding case M 2684-13 page 25)
B 2015 Class 3 No motivation was given for the limit value: the court set the limit to class 3 (specified in the preceding case
M 2414-12, page 6), as suggested by the parties in their opinions
C 2015 Class 3 The application was rejected with the motivation that the court considered dredged sediments exceeding
contaminant class 3 to be too contaminated to be dumped at sea without detriment to the environment or
human health (page 8)
D 2016 100 µg/kg dw TBT, class 5
for other contaminants
The court increased the limit value set by the district court in the previous case, from 50 to 100 µg/kg dw
TBT. The motivation was that the limit should be based on case-specific conditions (referring to case A) and
the dumpsite exhibited sediment accumulating properties reducing the risk of sediment transportation.
Furthermore, the site exhibited high levels of TBT, and a condition for the exemption was to cover the
dumped sediments with cleaner sediment (without defining the characteristics of the cover) (page 10,
appealed case M 2587-14 page 5)
E 2016 Not available The application was rejected
F 2016 Not available The court considered the dredged sediments as clean since they contained lower contaminant
concentrations than the limit values set in case A. The type of contaminants were not defined (pages 20, 56)
G 2016 Class 4 The court considered the dredged sediments to exhibit low concentrations of contaminants, class 4 or
below. No concentration limits were set (pages 11, 27)
H 2016 Class 4 with the exception of
Cu at class 5
The court stated that the reported levels of contaminants were low enough to be safely dumped due to
sediment sink conditions at the dumpsite. No limit value was set. The dredged sediments contained
contaminants up to class 4, and class 5 for copper (pages 22–23)
I 2017 Class 3 No limits were set but the concentrations were described to not exceed class 3 (page 204)
J 2017 Not available The court allowed the dredged sediments to be dumped as they were considered clean. No maximum
contaminant limit was set (page 52)**
K 2018 200 µg/kg dw TBT, PAH-11
and PCB-7 are allowed to
exceed the lower limit for
class 5
The LECA raised the limit value set by the District Court in the appealed case, from 50 to 200 µg/kg dw
TBT. The motivation was that the limit value should be based on case specific conditions (referring to case
A) and the dumpsite exhibited sediment accumulating conditions, making transport of the sediment and
contaminants from the site unlikely. The condition was that the dumped sediment had to be covered with
1 m of sandy masses followed by 2 m of moraine masses all of which were within set contaminant limits,
50 µg/kg dw for TBT and for PAH-11 and PCB-7 at the lower limit of class 5 (pages 21–23, preceding case
M2415-15 pages 4–6)
L 2018 Class 3, except for TBT
(50 µg/kg dw) and chromium
(90 mg/kg dw)
The court set the maximum limit value for chromium to 90 mg/kg dw, with the motivation that the limit had
grounds in guidelines for specific contaminating substances (Swedish EPA report NV5799). For TBT, the
court set the limit to 50 µg/kg dw TBT, with the motivation that the dredged sediments exhibited levels
below 4.7 µg/kg dw and that the Environmental Court of Appeal had set limits between 50 and 200 µg/kg
dw in cases A and K. For other contaminants the limit value was set to class 3 without further motivation by
the court (page 82)
M 2018 Not available The application were rejected
N 2020 Not available The application were rejected
For each case, the specific page intervals indicate where the content connected to the suitability of the dumpsite can be found.
*For a description of the classification system see the first paragraph in the section “Clean Sediment” in the results or Swedish Environmental Protection Agency [SEEPA]
(1999).
**In case J, neither of the involved parties or the court defines clean sediments. One definition could be that sediments are clean if they are of class 3 or below, as the
County Administrative Board (Västra Götaland) in their opinion describes that contaminants at class 4 would have warranted additional discussion, page 22.
A second factor addressed in out of the 14 cases, was if
the proposed dumpsite had been used for dumping previously.
In the four cases F, I, J, and K, the courts describe that
the dumpsites had been used previously as part of their
reasoning for why the site was suitable for dumping. In
cases M and O, the proposed dumpsites had been used
previously but the courts stated that previous use in itself
was not sufficient justification that the site was suitable
for new dumping.
A third factor was the ecological situation at the dumpsite
prior to dumping, addressed by out of 14 cases when considering
the suitability of the dumpsite. In case I, the court described the
site as suitable partially due to a lack of benthic flora and fauna.
In cases F and M, the courts stated that a lack of information
about the ecological implications of dumping at the dumpsites
was part of the reason for rejecting the exemption applications
(Table 5). Ecological aspects are further covered in the next
section of the results.
Frontiers in Marine Science | www.frontiersin.org 8October 2021 | Volume 8 | Article 755443
fmars-08-755443 October 13, 2021 Time: 16:7 # 9
Bruce et al. Inconsistently Evaluating Dumping at Sea
TABLE 4 | Key factors considered by the courts when determining the suitability of proposed dumpsites, with summaries of the reasoning by the courts and
contaminant levels at the dumpsite previous to the planned dumping.
Case Year Key factors Summary of the courts’ reasoning Contaminants at the
dumpsite
A 2015 Sediment sink The court stated that the site was a sediment sink, exhibiting conditions under
which sediment were likely not to spread (page 8)
Measured adjacent to the
dumpsite. Multiple below class
3, class 4 for some PAHs,
47 µg/kg dry weight for TBT
B 2015 Sediment sink, Hypoxia The court described that the general waterbody, of which the dumpsite was
part, exhibited a moderate ecological status and a good chemical status, as per
the WFD (Pages 25–26). The suitability of the site for dumping was not
considered in more detail by the court. The applicant described the site as a
hypoxic sediment sink at a 100 m depth (preceding case M2414-12 pages
15–16)
Good chemical status as per
the WFD EQS
C 2015 Contaminants While the court denied the application for exemption the court also stated that
the proposed site was well situated and that there would be an environmental
benefit to dump and cover the proposed site with cleaner sediment due to the
contaminants on site (page 8)
Not available
D 2016 Sediment sink,
Contaminants
The court stated that the site was a sediment sink, exhibiting conditions under
which sediment was likely not to spread, making the site suitable for dumping
of dredged sediments. A condition was set to cap the contaminated dumped
sediments with cleaner sediment, without a definition of clean. The court further
described that the dumpsite was suitable as it was contaminated with TBT,
anoxic and void of life (page 10, preceding case M-2587-14 pages 83–85)
123–534 µg/kg dw TBT
E 2016 Sediment sink,
Contaminants, Surrounding
environmental values
The court stated that the information offered by the applicant did not
adequately show that the dumpsite exhibited conditions under which dumped
sediments would accumulate without considerable spread, a necessity as the
site was adjacent to areas of high environmental value. The court further stated
that the proposed dumpsite’s sediment exhibited elevated levels of
contaminants and that it was not adequately shown that dumping would not
cause the contaminants to spread (pages 6–8)
The dumpsite is described as
contaminated without
additional detail on the types or
levels of contaminants
F 2016 Sediment sink, Local
environmental values, filling
capacity, previous use
The court stated that one of the proposed sites was suitable for dumping as the
applicant adequately verified that the site had been used previously, the
capacity at the dumpsite was sufficient and that the site was a sediment sink.
The court further stated that another proposed site was unsuitable as it was not
adequately verified that there were no environmental values worthy of protection
or conditions for sediment accumulation. The court considered the site to be
too small to ensure that dumped sediment would not spread during the
dumping and that it was preferable to choose a site that had been previously
disturbed by dumping (pages 56–57)
Not available
G 2016 Sediment sink The court stated that it had been verified that dumped sediment could
accumulate at the dumpsite without considerable risk of being spread and that
the court considered this to be of particular importance for dumping (page 26)
Class 1–2 for metals, 4 for
some organic pollutants
H 2016 Sediment sink The court stated that it had been verified that dumped sediments could
accumulate at the dumpsite without considerable risk of being spread and that
the court considered this to be of particular importance for dumping (page 22)
Class 1–2 for metals, 4 for
some organic pollutants
I 2017 Previous use, Reduced
sediment, Benthic
community, Depth
The court stated that the site was suitable for dumping in relation to the water
depth (50–60 m), that it had been used previously for dumping and that the
sediment was reduced without flora or fauna (page 204)
Not available
J 2017 Sediment sink, Previous
use, Depth
The court stated that the dumpsite was acceptable as it was adequately verified
that it was a sediment sink, at a depth down to 60 m, and that the site had
been used for dumping previously (page 54)
Not available
K 2018 Sediment sink The court stated that the site is a sediment sink, exhibiting conditions under
which sediment are likely not to spread; this, in conjunction with a condition to
cover the contaminated dumped sediments with clean sediments (clean was
defined as below 50 µg/kg dw TBT and below class 5 for PAH-11 and PCB-7),
made the site suitable. The fact that the area was used for shipping did not
affect the assessment (pages 22–23)
TBT 3.4–163 µg/kg Dry weight
L 2018 Sediment sink, Previous
use
The court stated that the site was suitable for dumping as it was adequately
verified that the dumpsite was a sediment sink and that it had been used
previously (pages 80–81)
Not available
M 2018 Hydrology, Previous use,
Ecosystem
The court stated that the fact that the site had been considered suitable
previously was not adequate verification that the conditions had not changed
over time and that the current hydrological, benthic and ecological conditions
were not adequately assessed (page 8)
Not available
N 2020 Previous use The court stated that the fact that the site had been considered suitable
previously was not adequate verification that the conditions had not changed
over time (page 6)
Not available
For each case, the specific page intervals indicate where the content connected to the suitability of the dumpsite can be found.
Frontiers in Marine Science | www.frontiersin.org 9October 2021 | Volume 8 | Article 755443
fmars-08-755443 October 13, 2021 Time: 16:7 # 10
Bruce et al. Inconsistently Evaluating Dumping at Sea
TABLE 5 | Ecological factors considered by the courts when evaluating if exemption could be granted without environmental detriment, followed by summaries of the
courts’ reasoning considering ecological factors.
Case Year Ecological factors Summary of the courts consideration of ecological factors
A 2015 Ecological effects of
contaminants
The court set the condition that the concentration of TBT in the dredged sediments that were to be dumped at the
dumpsite could not exceed the concentration of TBT in the sediment at the dumpsite, and that the concentrations
at the site already posed an ecological risk (page 8, preceding case M 2684-13 page 4)
B 2015 EQS The court considered it adequately verified that dumping would not infringe on the ecological status set for the
entire water body of which the dumpsite was part (pages 24–28)
C 2015 Not available The court did not directly consider ecological factors
D 2016 Not available The court stated that the site was degraded to such an extent that the site could be used for dumping without
environmental detriment (preceding case M-2587-14 pages 83–85)
E 2016 Areas of ecological value close
to the dumpsite
The court stated that there were areas of very high ecological value adjacent to the dumpsite and that it had to be
shown that the dumping would not cause negative environmental effects via turbidity during the dumping and
subsequent erosion and transport of the dumped sediment as well as of the already contaminated sediments at the
dumpsite (pages 6–7)
F 2016 Inadequate evidence to
determine ecological values at
dumpsite
The court stated that it was not adequately shown that no valuable benthic environments would be affected by
dumping. The court further stated that it was preferable to dump at sites that had been used previously rather than
to dump at pristine sites (pages 56–57)
G-H 2016 Not available The court did not directly consider ecological factors
I 2017 Degraded ecological conditions
at dumpsite
The court considered the level of contaminants in the dredged sediments and the ecological conditions at the
dumpsite, and stated that the site was degraded to such an extent that the site could be used for dumping without
environmental detriment (pages 203–204)
J 2017 Not available The courts did not directly consider ecological factors
K 2018 Not available
L 2018 Not available
M 2018 Inadequate evidence to
determine potential effects on
marine ecosystem
The court stated that the accounts on potential effects on the marine ecosystem were lacking (page 8). The court
did not describe what such accounts should have covered
N 2020 Not available The court did not directly consider ecological factors
For each case, the specific page intervals indicate where the content connected to the suitability of the dumpsite can be found.
Ecology
The seven cases, A, B, D, E, F, I, and M, considered ecological
factors as defined by our methods (Table 5). In the two cases
F and M, applications for exemption were denied partially due
to a lack of account of the effects dumping would have on the
local ecosystem. The courts did not further describe how or what
ecological effects should be accounted for.
In the majority of the cases, the courts did not discuss the
ecological effects of dumping, such as local effects of added
contaminants, changes in topography or burial. However, in
cases D and I, the courts considered poor ecological conditions
to make the proposed site suitable for dumping. Case I stated:
“The bottom in Draget (the waterbody) is composed of black
reduced sediments without other life than sulfate-reducing
microorganisms. The Land and Environmental Court considers
the site to be suitable for dumping of the dredged masses as long
as it can be conducted without aforementioned inconvenience”
(Case I, p. 204, translated from Swedish).
In case E, the court stated that it is important that the dumping
would not cause excessive turbidity during the dumping and
that the dumped masses would not spread from the dumpsite
as there were areas of high ecological value adjacent to the
dumpsite (Table 5).
In addition, to limit the potential effect of dumping, the courts
routinely included conditions restraining dumping activities to
months when biological activity was reduced at the dumpsites.
Otherwise, ecological effects were not included in any of the
conditions set for exemption (See Supplementary Appendix 1
for a list of conditions).
Climate Change
Changes in future conditions due to climate change in relation
to risk of environmental detriment due to the dumped sediments
was raised occasionally by the applicants or consultation bodies.
However, the issue was not raised by the courts in any of the cases.
Future changes in conditions due to climate change were not
mentioned or accounted for in the conditions set for exemption
in any of the cases.
Rejection
Five cases, C, E, F, M, and N, did not authorize exemption, neither
in part nor fully (Tables 1,6). In all of those cases the applications
were rejected as the applicants have not adequately verified that
the dumping would not cause detriment to the environment or
human health. However, the applications were considered to be
lacking on different accounts. In case C (2015), the contaminant
levels were considered too high. The District Court stated that
dredged sediment with contaminant levels exceeding class 3 were
not suitable to be dumped at sea. The court further stated that
they considered the proposed dumpsite to be well suited for
dumping with cleaner sediment.
In case E, the LECA stated that it was not adequately verified
that the dumped sediments would not spread from the proposed
dumpsite. Hence, it was not verified that dumping could be
Frontiers in Marine Science | www.frontiersin.org 10 October 2021 | Volume 8 | Article 755443
fmars-08-755443 October 13, 2021 Time: 16:7 # 11
Bruce et al. Inconsistently Evaluating Dumping at Sea
TABLE 6 | A comparison between concentrations used in Norwegian guidelines
for sediment risk assessment indicating when ecological risk cannot be excluded;
and concentrations in sediment corresponding to highly contaminated Swedish
background levels from 1999 (updated values from 2014 in parentheses); and
EQS for chemical status as per the WFD.
Substance Concentrations
indicative of ecological
risk1µg/kg dw
Class 42µg/kg dw EQS3µg/kg
dw
Arsenic 18,000 28,000–45,000
Cadmium 25,000 1,200–3,000 2,300
Mercury 520 40–1,000
Nickel 42,000 66,000–99,000
Lead 150,000 65,000 120,000
Fluoranthene 400 80–270 (140–390) 2,000
Anthracene 4.6 8–30 (11–45) 24
TBT 35* Not available (19–55) 1.6
1Norwegian Environment Agency guideline 02:2013 used in Breedveld et al. (2015).
2Swedish Environmental Protection Agency [SEEPA] (1999) and Josefsson (2017).
3Swedish Agency for Marine and Water Management [SwAM] (2019).
*The limit for TBT is based on a compromise between ecological effects and
background levels.
conducted without environmental detriment (Table 4). In case
F, the applicant proposed two dumpsites. The court rejected one
based on a lack of information regarding the sites capacity to act
as a sediment sink and the potential ecological values at the site
(Tables 4–6). The court further stated that it was preferable to use
a site that previously had been used for dumping. In cases M and
N, the courts stated that the previous exemption to dump at the
proposed dumpsites was not an adequate basis to evaluate if the
dumpsites were still suitable and that the contaminant levels in the
sediments that were to be dredged were not adequately measured
(Tables 3–6).
DISCUSSION
Many factors, both environmental, scientific and societal, affect
the perception of risk, which in turn controls the outcome of
an assessment (Slovic, 1999). When considering applications for
exemption, the courts exhibited quite different perceptions of
risk and the exemptions were given with varying conditions that
had to be met. While the case-specific assessments of risk were
potentially reasonable from an environmental risk perspective,
the overall procedure appears to have been arbitrary when
comparing the cases. The consequence is, as shown in this study,
that the courts arrived at seemingly contradictory conclusions.
It is common among the cases that the risk to the local benthic
community is not an environmental aspect that is considered
(Tables 4–6). This leads to a risk of a long-term loss of the benthic
community. A full recovery back to the community found before
dumping can be a slow process and is not guaranteed (Pearson
and Rosenberg, 1978;Blomqvist, 1982;Bolam et al., 2006;
Guerra-García and García-Gómez, 2006;Larson and Sundbäck,
2012). The risk to the local benthic community was accepted
without comment by the courts that authorized exemptions, with
the exception of cases D and I, where the courts considered that
the degraded state of the local benthic ecosystems made the sites
more suitable for dumping. In the cases where the applications
were rejected, the courts did not specifically state that the risk
for the local benthic community was a concern. However, since
part of the reason for rejection in cases F and M was a lack of
information of the local ecosystem, there appears to be at least
a possibility of rejecting an application based on the risk for the
local ecosystem.
The long term effects stemming from geophysical changes
from dumping, as well as the differences between the sediment
texture at the dumpsite and the dredged sediment, do not appear
to have been addressed in the court cases (recommended in
e.g., Munns et al., 2002;OSPAR Commission, 2009;Helsinki
Commission [HELCOM], 2020a). In areas that are sediment
sinks, dumping can cause long-lasting mounds of deposited
material, changing the benthic habitat and increasing the risk of
erosion (Blomqvist, 1982;Stockmann et al., 2009;Virtasalo et al.,
2018;Mossa and Chen, 2021). Changing the morphology of the
bottom can cause barriers for migration for fish and crustaceans
and should be considered when considering dumping according
to the OSPAR guidelines (OSPAR Commission, 2009;Kraufvelin
et al., 2018).
In short, a degraded local ecosystem has been used as an
argument for granting exemption, but the risk of burying
a local ecosystem is not used as an argument for rejecting
exemption. Therefore, there appears to be an acceptance of loss
of the local ecosystem potentially hindering the achievement
of the UN Global Sustainable Development Goals (SDGs)
“Life under water” and the Swedish national objectives,
e.g., “A Balanced Marine Environment, Flourishing Coastal
Areas and Archipelagos,” according to which Sweden aims
to recover lost and degraded marine ecosystems (Swedish
Environmental Protection Agency [SEEPA], 2012;UN, 2015;
Swedish Government Offices, 2018).
Another perspective on risk is presented in case A, where
the LECA argued that exemptions should be considered based
on case-specific conditions. In that case, exemption was granted
to dump dredged sediments with concentrations of TBT that
the court perceived as harmful, as long as those concentrations
did not clearly exceed the concentrations at the dumpsite. That
is, exemption was granted since the dumping did not result in
additional environmental detriment (Table 3).
The reasoning in case A later gave cause for two other
perspectives. In cases D and K, the LECA referred to the
argument made in case A that applications for exemption should
be considered on a case-specific basis and concluded that there
was no risk of environmental detriment if sediments with high
levels of TBT were isolated with a cap of cleaner sediments. A
condition for a cap to be effective is that it is not eroded, and
sediment sink conditions are a prerequisite for exemption in the
majority of cases (Table 4). However, it is noteworthy that the
courts in none of the cases expressed consideration for potentially
increased resuspension due to climate change, future or current
boat traffic or fishing.
In contrast to cases D and K in the previous paragraph,
the District Court in case L referred to the specific maximum
contaminant concentrations limits set in case A without relating
to case-specific conditions. The court concluded that if the
Frontiers in Marine Science | www.frontiersin.org 11 October 2021 | Volume 8 | Article 755443
fmars-08-755443 October 13, 2021 Time: 16:7 # 12
Bruce et al. Inconsistently Evaluating Dumping at Sea
limits set in case A were not exceeded there would be no risk of
contamination, without relating to the conditions at the dumpsite
(Tables 3–5). The use of predetermined limit values not based
on site-specific background concentrations, as in case L and
in several Baltic countries (Staniszewska and Boniecka, 2017),
could prolong the prevalence of high contaminant levels at a
site. If combined with the reasoning in case A, the contaminant
concentrations at a site could then be used as an argument
to continuously authorize exemption to dump sediments with
contaminant concentrations as high as at the dumpsite. This
is in contrast to the intention to achieve a good ecological
status according to the WFD, and restore deteriorated marine
ecosystems as per the SDG “Life below Water” and the Swedish
objective – “A Balanced Marine Environment, Flourishing
Coastal Areas and Archipelagos.”
The contaminant limit concentrations set as conditions for
exemption by the courts add a measure of uncertainty to their
evaluations from an ecotoxicological perspective. In Sweden,
there are no scientifically based criteria or limit concentrations
for the contaminant levels that dumped sediments can contain.
However, as seen in cases F and L, the limits set by the LECA
can be used as precedents. In guidelines for managing dredged
sediment (Table 3), SwAM also refers to the lowest and highest
concentration limits set by the LECA as reference points (Swedish
Agency for Marine and Water Management [SwAM], 2018).
The limits the courts have set are based on other factors than
the contaminant toxicity. For example, case G set the limits
at class 4 (highly contaminated) as defined in the report from
SEEPA classifying background concentrations, based on data
from before 1999. There seems to be a practical reliance in
considering exemption on the version from 1999 as it was used
even in cases K and L conducted after 2017 when the updated
version was published (Josefsson, 2017). It was also used in
spite of SwAM already in 2015, in case A, recommending that
their guidelines should be used when applicable. The SwAM
guidelines were produced taking ecological effects into account
and prescribe intervention values that for some substances were
lower than for class 4 (in Swedish Environmental Protection
Agency [SEEPA], 1999), for example for several PAHs, but
higher for e.g., lead (Swedish Agency for Marine and Water
Management [SwAM], 2013, updated in Swedish Agency for
Marine and Water Management [SwAM], 2019).
To put the use of the classification system for contaminated
sediments in another perspective, class 3 is the lowest
concentration limit set by any of the cases (Table 3), but already
at those concentrations PAHs correlate to adverse effects on
benthic communities in the Baltic Sea (Raymond et al., 2021).
There are also examples of individual PAHs such as fluoranthene
in class 4, set as the limit in cases A, G, and H, that are
above limits where ecological effects are estimated to be able
to occur compared to Norwegian guidelines (Breedveld et al.,
2015). The Norwegian guidelines are relevant to compare with
as Norway shares a coastline with the west of Sweden where
cases F-H are located. However, several contaminants at class
4, such as arsenic, exceed the expected effect limits used by the
Norwegian guidelines. The concentrations can also be compared
to the Swedish general limit values set for the fulfillment of the
WFD, with higher limits for e.g., fluoranthene but lower limits
for TBT than in the Norwegian guidelines and class 4 values
(Swedish Agency for Marine and Water Management [SwAM],
2019;Table 6). There are also limits set by the other HELCOM
signatories for when dredged sediment can be considered as
contaminated. In Denmark, Finland, Germany, and Latvia the
limit for sediment to be considered contaminated in relation to
TBT ranges between 3 and 20 µg/kg dw. Those countries, except
Germany, also distinguish between concentrations of TBT that
can be considered safe for less and more contaminated areas.
The range for more contaminated areas range between 60 and
200 µg/kg dw (Staniszewska and Boniecka, 2017).
As described earlier, the concentration limit in case A for TBT
(50 µg/kg dw) was based on the concentrations at the dumpsite, a
concentration above the limit for potential environmental effects
(according to e.g., Sahlin and Ågerstrand, 2018;Swedish Agency
for Marine and Water Management [SwAM], 2019;Table 6).
The highest allowed concentration of TBT, set in case K at
200 µg/kg dw, was based on the condition that the sediments
would be isolated with cleaner sediment (Tables 3–5). The basis
for the allowed concentrations of contaminants and evaluation
of risk of toxicity from the dredged sediments in all the court
cases was connected with an unknown level of uncertainty.
Even if the assessments had used concentration levels that
were derived from toxic effects in relation to contaminant
concentrations, they would have some level of uncertainty as
other factors such as bioavailability, unknown contaminants and
additive or synergistic effects can impact the observed effects
caused by contaminants (Swartz et al., 1994;Keiter et al., 2008;
Mustajärvi et al., 2019;Pheiffer et al., 2019;Vogt et al., 2019).
It is therefore important to include measures that account for
these effects (Munns et al., 2002;OSPAR Commission, 2009;
Gerbersdorf et al., 2011;Chapman and Maher, 2014;Helsinki
Commission [HELCOM], 2020a). Furthermore, none of the
courts requested or laid down conditions for the exemptions
demanding measurements directly related to ecological effects,
such as recolonization of the benthic community, to monitor
potential effects after dumping. However, the courts routinely left
the responsibility of establishing a monitoring program to the
applicant together with the local County Administrative Board
(Supplementary Appendix 1).
A common recommendation for better understanding the
potential of environmental detriment is to address both the
potential effects of the dredged sediments and the concentrations
of contaminants. Such an approach can reduce uncertainty and
provide information for management (e.g., Gerbersdorf et al.,
2011;Chapman and Maher, 2014;Brack et al., 2019). Several
guidelines argue that biological testing should be a standard
part of assessing risks from contaminated sediments (Munns
et al., 2002;Algar et al., 2014;Simpson and Batley, 2016).
OSPAR and HELCOM also recommend in their guidelines for
managing dredged sediment that when chemical characterization
is not enough to determine the risk, biological tests of e.g.,
bioaccumulation and toxicity should be conducted (OSPAR
Commission, 2009;Helsinki Commission [HELCOM], 2020a).
However, with the precedents set by the courts, the definition on
what constitutes environmental detriment is unclear. Therefore,
Frontiers in Marine Science | www.frontiersin.org 12 October 2021 | Volume 8 | Article 755443
fmars-08-755443 October 13, 2021 Time: 16:7 # 13
Bruce et al. Inconsistently Evaluating Dumping at Sea
before advocating for specific assessment methods the definition
of environmental detriment and the objective of considering an
application for exemption needs to be better defined.
The focus on chemical and physical measurements in the
court cases corresponds to earlier observations of how sediments
are evaluated in European and Baltic nations. Several HELCOM
members around the Baltic Sea have action list levels for
contaminant concentrations that are used to determine if dredged
sediments can be dumped. Some countries distinguish between
sensitive and less sensitive areas with different concentrations for
each type of area, adding some flexibility. Nevertheless, they also
appear to focus on the risk from single contaminants and do
not include ecological effects in their evaluations (Apitz, 2008;
Staniszewska and Boniecka, 2017).
There might be a historical background for the focus on
chemistry rather than ecology in risk assessments. Environmental
quality standards are a relatively new legal instrument. They
were not implemented into Swedish law until Sweden entered
the EU in 1995 and the EU has only specified limit values on
chemical substances for surface water status. In Sweden, quality
standards for chemical status have therefore been implemented
as legally binding values in individual cases, whereas quality
standards for ecological status have been implemented only as
guiding values, until recently. The difference in legal status results
in different possibilities to reject or require protective measures
in the individual case. Not until 2019, after a clarification by the
European Court of Justice, was the Swedish legislation changed.
However, what this change might entail is too early to tell. The
only case after the clarification by the European Court of Justice,
case N, did not indicate a change in practice.
Based on the perspectives and criteria used by the courts
when considering applications for dumping, it appears that
rather than evaluating if dumping would cause environmental
detriment the courts evaluate if the detriment from dumping
would be acceptable. While this practice might be warranted
from a practical point of view, it is not in line with
relevant environmental obligations. For example, as local benthic
communities are buried and potentially harmful levels of
contaminants are allowed, it can be said that the law is not
respected as it stipulates that exemption only can be granted
if it has been shown that there will be no environmental
detriment (15, 27:29 EC). The practice also appears to deviate
from the commitment to the OSPAR Convention (1992) that
stipulates that only lightly contaminated sediments can be
dumped; exemption is granted for sediments defined as medium
to very highly contaminated [Table 3;Swedish Environmental
Protection Agency [SEEPA] (1999)]. The application of the law is
neither in line with the precautionary principle as future changes
in local conditions, such as changes in anthropogenic use or
climate change, are not well accounted for.
If the practice is to grant exemption based on some measure
of acceptable detriment rather than when detriment is absent,
there is arguably a need for the party applying for exemption
to thoroughly consider alternative management methods and
dumpsites. That practice is already required, in the form of
EIA, for other activities that risk causing environmental effects,
according to the EU Directive 2011/92/EU. As exemption should
not be granted for cases where there is a detriment to the
environment, according to 15:29 EC, applicants for exemption
to the ban on dumping are not required to conduct an EIA.
However, as indicated by the results of this study, there is
a risk that exemption is granted even though the risk of
environmental detriment has not been adequately evaluated
and there might be more sound alternatives than dumping,
or more suitable dumpsites. There is therefore a need to
further consider alternatives in the practice of applying for and
considering exemption.
CONCLUSION AND
RECOMMENDATIONS
It is not clear that current regulations are applied to ensure
that no environmental detriment will be caused by dumping
of sediment. The process in the court cases was characterized
by different, and sometimes contradictory, perspectives on
acceptable risk. None of the expressed perspectives included site-
specific assessments of ecological effects. Too strict guidelines
or regulations for how to assess risk and evaluate applications
could hinder case-specific considerations (as discussed in Dale
et al., 2008). However, the results of this study indicate that
the current practice in Sweden does not lead to well informed
and rigorous site-specific evaluations and that a more structured
process is needed.
The study highlights a gap in the practical definition of what
a risk of environmental detriment entails. That gap needs to
be addressed, followed by the implementation of scientifically
sound and practical criteria well connected to the definition of
risk determining the assessment objectives. These challenges are
likely similar among the HELCOM members around the Baltic
Sea, where there is a similar dependency on binary chemical limit
concentrations (Staniszewska and Boniecka, 2017). However, the
majority of the HELCOM members have set such limits while the
Swedish practice is supposed to rely on case-specific evaluation.
To improve the process of assessing and evaluating the
risk of environmental detriment and the ability of the process
to fulfill relevant obligations, the objective of considering an
application for exemption and the definition of environmental
detriment needs to be better defined and appropriate tools for
assessment and evaluation developed or adapted accordingly.
The evaluations should require a scientifically sound basis and
move away from the use of reference concentrations not related
to environmental risk. As discussed above, there are already
guidelines relating contaminant concentrations to ecological risk
(Breedveld et al., 2015;Swedish Agency for Marine and Water
Management [SwAM], 2019). However, additional research
might be needed to implement the already existing guidelines
to ensure that they align with the specific purpose of evaluating
risks from dumping dredged sediment, for example adapting
them to provide a range of risk estimates and accounting for
site-specific conditions.
Moreover, if chemical and physical measurements are not
enough to evaluate risk with certainty, as this study indicates
is the situation in the Swedish cases, the guidelines from
Frontiers in Marine Science | www.frontiersin.org 13 October 2021 | Volume 8 | Article 755443
fmars-08-755443 October 13, 2021 Time: 16:7 # 14
Bruce et al. Inconsistently Evaluating Dumping at Sea
both OSPAR Commission (2009) and Helsinki Commission
[HELCOM] (2020a) recommend that biological testing should
be conducted [as has been done in e.g., United States (Munns
et al., 2002) and in Greece (Kapsimalis et al., 2013)]. However,
biological testing is not frequently used when assessing risk from
contaminated sediment in Sweden (Bruce et al., 2020). Additional
development and implementation of biological testing, with
the specific purpose of assessing risk from dumping dredged
sediment, would provide the courts with more comprehensive
and pluralistic grounds for evaluation.
It is important to address the gaps highlighted in this study as
the current practice is not in compliance with current legislation
and risk hindering the achievement of environmental objectives
on all levels. Furthermore, there is a risk that current inconsistent
evaluations reach unequal decisions or are too lax in relation to
risk of marine environmental detriment as defined by law.
DATA AVAILABILITY STATEMENT
Publicly available datasets were analyzed in this study. This
data can be found here: Public data regarding the frequency
and extent of dumping dredged sediment in Sweden was
provided by the Swedish Agency for Marine and Water
Management. The data can be requested via following
link: https://www.havochvatten.se/en/our-organization/contact-
us.html. All cases from the Land and Environment Court
of Appeal can be found in the data base accessible
with the following link: https://www.domstol.se/mark–och-
miljooverdomstolen/mark–och-miljooverdomstolens-avgoran
den/. The cases from District Land and Environment Courts
can be requested from the individual courts via the following
link: https://www.domstol.se/domar-och-beslut/bestall-domar-
beslut-eller-handlingar/. Please note that the Swedish courts joint
webpage is currently being updated and that some parts are not
yet available in English. Please contact the corresponding author
if you have any questions regarding the material.
AUTHOR CONTRIBUTIONS
PB had the main responsibility for planning, design, data
gathering, analysis, and writing. AC guided the process in relation
to the juridical aspects and made considerable contributions to
the introduction to relevant regulations. All authors contributed
to the development of the main objective of the study, provided
input on the layout and content of the text as well as proofreading.
FUNDING
This publication and preceding work has been made possible
by Stockholm University and the Swedish Geotechnical Institute
that funded the authors time.
ACKNOWLEDGMENTS
The authors gratefully acknowledge the support from Michael
Pohl and Karin Wall from SwAM and Rasmus Parsmo from the
Swedish Environmental Research Institute who provided us with
data and constructive advice.
SUPPLEMENTARY MATERIAL
The Supplementary Material for this article can be found
online at: https://www.frontiersin.org/articles/10.3389/fmars.
2021.755443/full#supplementary-material
REFERENCES
Algar, C. K., Barry, M., Bell, K. S., Boudreau, B. P., Bridges, T. S., Burton, G. A.,
et al. (2014). Processes, Assessment and Remediation of Contaminated Sediments.
New York, NY: Springer-Verlag.
Apitz, S. E. (2008). Is risk-based, sustainable sediment management consistent
with European policy? J. Soils Sediments 8:461. doi: 10.1007/s11368-008-
0039-8
Blomqvist, S. (1982). Ekologiska Bedömningsgrunder för Muddring Och
Muddertippning. Stockholm: Naturvårdsverket.
Bolam, S. G., Rees, H. L., Somerfield, P., Smith, R., Clarke, K. R., Warwick,
R. M., et al. (2006). Ecological consequences of dredged material disposal in
the marine environment: a holistic assessment of activities around the England
and Wales coastline. Mar. Pollut. Bull. 52, 415–426. doi: 10.1016/j.marpolbul.
2005.09.028
Brack, W., Aissa, S. A., Backhaus, T., Dulio, V., Escher, B. I., Faust, M., et al.
(2019). Effect-based methods are key. The European Collaborative Project
SOLUTIONS recommends integrating effect-based methods for diagnosis and
monitoring of water quality. Environ. Sci. Eur. 31:10. doi: 10.1186/s12302-019-
0192-2
Breedveld, G., Ruus, A., Bakke, T., Kibsgaard, A., and Arp, H. P. (2015). Guidelines
for Risk Assessment of Contaminated Sediments. Oslo, NO: Miljødirektoratet.
Bruce, P., Sobek, A., Ohlsson, Y., and Bradshaw, C. (2020). Risk assessments of
contaminated sediments from the perspective of weight of evidence strategies –
a Swedish case study. Hum. Ecol. Risk Assess. An. Int. J. 27, 1366–1387. doi:
10.1080/10807039.2020.1848414
Bryman, A. (2008). Structured Interviewing In Social Research Methods, 3rd Edn.
New York, NY: Oxford University Press Inc, 190–214.
Chapman, P. M., and Maher, B. (2014). The need for truly integrated
environmental assessments. Integr. Environ. Assess. Manag. 10:151. doi: 10.
1002/ieam.1532
Cundy, A. B., Croudace, I. W., Cearreta, A., and Irabien, M. J. (2003).
Reconstructing historical trends in metal input in heavily-disturbed,
contaminated estuaries: studies from Bilbao, Southampton Water and
Sicily. Appl. Geochem. 18, 311–325.
Dale, V. H., Biddinger, G. R., Newman, M. C., Oris, J. T., Suter, G. W., Thompson,
T., et al. (2008). Enhancing the ecological risk assessment process. Integr.
Environ. Assess. Manag. 4:306. doi: 10.1897/IEAM_2007-066.1
Davis, W. R. (1993). The role of bioturbation in sediment resuspension and its
interaction with physical shearing. J. Exp. Mar. Biol. Ecol. 171, 187–200. doi:
10.1016/0022-0981(93)90003-7
Dias, G. T. D. M., Fontana, L. H. P., Silva, C. G., de Silva, R. C. O., Oliveira,
U. C., Lima, L. D. S., et al. (2019). Geomorphic and Sedimentary Impacts on
the Continental Shelf after Accumulated Dredge Disposal from Rio de Janeiro
Harbor, Brazil. Brazil. J. Geophys. 37, 1–14.
Donázar-Aramendíaa, I., Sánchez-Moyano, J. E., García-Asencio, I., Miró, J. M.,
Megina, C., and García-Gómez, J. C. (2020). Environmental consequences
of dredged-material disposal in a recurrent marine dumping area near to
Frontiers in Marine Science | www.frontiersin.org 14 October 2021 | Volume 8 | Article 755443
fmars-08-755443 October 13, 2021 Time: 16:7 # 15
Bruce et al. Inconsistently Evaluating Dumping at Sea
Guadalquivir estuary, Spain. Mar. Pollut. Bull. 161:111736. doi: 10.1016/j.
marpolbul.2020.111736
Eggleton, J., and Thomas, K. V. (2004). A review of factors affecting the release and
bioavailability of contaminants during sediment disturbance events. Environ.
Int. 30, 973–980. doi: 10.1016/j.envint.2004.03.001
Elmgren, R. (2001). Understanding human impact on the baltic ecosystem:
changing views in recent decades. AMBIO J. Hum. Environ. 30, 222–231. doi:
10.1579/0044-7447-30.4.222
Gerbersdorf, S. U., Hollert, H., Brinkmann, M., Wieprecht, S., Schüttrumpf, H.,
and Manz, W. (2011). Anthropogenic pollutants affect ecosystem services of
freshwater sediments: the need for a “triad plus x” approach. J. Soils Sediments
11, 1099–1114. doi: 10.1007/s11368-011- 0373-0
Guerra-García, J. M., and García-Gómez, J. C. (2006). Recolonization of
defaunated sediments: fine versus gross sand and dredging versus experimental
trays. Estuar. Coast. Shelf Sci. 68, 328–342. doi: 10.1016/j.ecss.2006.01.021
HELCOM Convention (1992). Convention on the Protection of the Marine
Environment of the Baltic Sea Area, 1992. Helsinki Commission.
Helsinki Commission [HELCOM] (2010). Hazardous substances in the Baltic Sea
- An integrated thematic assessment of hazardous substances in the Baltic Sea.
Washington, DC: Helsinki Commission.
Helsinki Commission [HELCOM] (2020b). Map and Data Service. Helsinki:
Helsinki Commission.
Helsinki Commission [HELCOM] (2020a). HELCOM Guidelines for Management
of Dredged Material at Sea and HELCOM Reporting Format for Management of
Dredged Material at Sea. Helsinki: Helsinki Commission.
Hill, A. S., Veale, L. O., Pennington, D., Whyte, S. G., Brand, A. R., and Hartnoll,
R. G. (1999). Changes in Irish sea benthos: possible effects of 40 years of
dredging. Estuar. Coast. Shelf Sci. 48:739.
Josefsson, S. (2017). Klassning av Halter Av Organiska Föroreningar i Sediment TT
- Classification of Levels of Organic Contaminants in Sediment. Sweden: Swedish
Environmental Protection Agency Swedish Geological Survey.
Julien, H. (2008). “The SAGE encyclopedia of qualitative research methods,” in The
SAGE Encyclopedia of Qualitative Research Methods, ed. L. Given (Thousand
Oaks, CA: SAGE Publications, Inc. ), 121–122.
Kapsimalis, V., Panagiotopoulos, I. P., Hatzianestis, I., Kanellopoulos, T. D.,
Tsangaris, C., Kaberi, E., et al. (2013). A screening procedure for selecting
the most suitable dredged material placement site at the sea. The case of the
South Euboean Gulf, Greece. Environ. Monit. Assess. 185, 10049–10072. doi:
10.1007/s10661-013-3312-2
Keiter, S., Grund, S., Van Bavel, B., Hagberg, J., Engwall, M., Kammann, U., et al.
(2008). Activities and identification of aryl hydrocarbon receptor agonists in
sediments from the Danube river. Anal. Bioanal. Chem. 390, 2009–2019. doi:
10.1007/s00216-007-1652-x
Kemp, P., Sear, D., Collins, A., Naden, P., and Jones, I. (2011). The impacts of
fine sediment on riverine fish. Hydrol. Process. 25, 1800–1821. doi: 10.1002/hyp.
7940
Knott, N. A., Aulbury, J. P., Brown, T. H., and Johnston, E. L. (2009).
Contemporary ecological threats from historical pollution sources: impacts
of large-scale resuspension of contaminated sediments on sessile invertebrate
recruitment. J. Appl. Ecol. 46, 770–781. doi: 10.1111/j.1365-2664.2009.01679.x
Kraufvelin, P., Pekcan-Hekim, Z., Bergström, U., Florin, A.-B., Lehikoinen, A.,
Mattila, J., et al. (2018). Essential coastal habitats for fish in the Baltic Sea.
Estuar. Coast. Shelf Sci. 204, 14–30.
Krippendorff, K. (2004). Content Analysis: An Introduction to its Methodology.
Thousand Oaks, CA: Sage.
Larson, F., and Sundbäck, K. (2012). Recovery of microphytobenthos and benthic
functions after sediment deposition. Mar. Ecol. Prog. Ser. 446, 31–44. doi: 10.
3354/meps09488
Malins, D. C., Krahn, M. M., Myers, M. S., Rhodes, L. D., Brown, D. W., Krone,
C. A., et al. (1985). Toxic chemicals in sediments and biota from a creosote-
polluted harbor: relationships with hepatic neoplasms and other hepatic lesions
in English sole (Parophrys vetulus). Carcinogenesis 6, 1463–1469. doi: 10.1093/
carcin/6.10.1463
Marine Protection, Research and Sanctuaries Act. (1972). Marine Protection,
Research and Sanctuaries Act. 33 USC §1401 Et Seq. Washington, DC: US
Congress of the United States.
Mink, F., Dirks, W., van Raalte, G., de Vlieger, H., and Russell, M. (2006). Impact
of European Union environmental law on dredging. Terra Aqua. 104, 3–10.
Mossa, J., and Chen, Y.-H. (2021). Geomorphic insights from eroding dredge
spoil mounds impacting channel morphology. Geomorphology 376:107571. doi:
10.1016/j.geomorph.2020.107571
Munns, W., Berry, W., and Dewit, T. (2002). Toxicity testing, risk assessment, and
options for dredged material management. Mar. Pollut. Bull. 44, 294–302.
Mustajärvi, L., Nybom, I., Eriksson-Wiklund, A.-K., Eek, E., Cornelissen, G., and
Sobek, A. (2019). How important is bioturbation for sediment-to-water flux of
polycyclic aromatic hydrocarbons in the Baltic Sea? Environ. Toxicol. Chem. 38,
1803–1810. doi: 10.1002/etc.4459
Neuendorf, K. A. (2002). The Content Analysis Guidebook. Thousand Oaks, CA:
Sage Publications.
Nihoul, C. (1991). Dumping at sea. Ocean Shorel Manag. 16, 313–326. doi: 10.1016/
0951-8312(91)90010-Y
OSPAR Commission (2009). Guidelines for the Management of Dredged Material.
Sintra: OSPAR Commission.
OSPAR Commission (2021). Trends in Dumping and Dredging. Available online at:
https://www.ospar.org/work-areas/eiha/dredging- dumping (accessed February
2, 2021).
OSPAR Convention (1992). The Convention for the Protection of the Marine
Environment of the North-East Atlantic. Sintra: OSPAR.
Pearson, T. H., and Rosenberg, R. (1978). Macrobenthic succession in relation to
organic enrichment and pollution of the marine environment. Oceanogr. Mar.
Biol. Annu. Rev. 16, 229–311.
Pheiffer, W., Horn, S., Vogt, T., Giesy, J. P., and Pieters, R. (2019). Receptor-
mediated potencies of polycyclic aromatic hydrocarbons in urban sediments:
comparisons of toxic equivalency risk assessment. Int. J. Environ. Sci. Technol.
16, 6405–6418. doi: 10.1007/s13762-019- 02465-6
QSR International (2020). NVivo 1.3. Doncaster: QSR International.
Raymond, C., Gorokhova, E., and Karlson, A. M. L. (2021). Polycyclic aromatic
hydrocarbons have adverse effects on benthic communities in the Baltic Sea:
implications for environmental status assessment. Front. Environ. Sci. 9:624658.
doi: 10.3389/fenvs.2021.624658
Roberts, D. A. (2012). Causes and ecological effects of resuspended contaminated
sediments (RCS) in marine environments. Environ. Int. 40, 230–243. doi: 10.
1016/j.envint.2011.11.013
Sahlin, S., and Ågerstrand, M. (2018). Tributyltin - TBT Sediment Eqs Derivation.
Stockholm: Stockholm University.
Schmidt, A. L., Coll, M., Romanuk, T., and Lotze, H. K. (2011). Ecosystem
structure and services in eelgrass Zostera marina and rockweed Ascophyllum
nodosum habitats. Mar. Ecol. Prog. Ser. 437, 51–68. doi: 10.3354/meps0
9276
Severin, M., Josefsson, S., Nilsson, P., Ohlsson, Y., Stjärne, A., and Wernersson, A.-
S. (2018). Förorenade Sediment-Behov Och Färdplan för en Renare Vattenmiljö.
Uppsala, SE: Taylor & Francis Online.
Shackle, V. J., Hughes, S., and Lewis, V. T. (1999). The influence of three methods
of gravel cleaning on brown trout, salmo trutta, egg survival. Hydrol. Process.
13:477.
Simpson, S., and Batley, G. (2016). Sediment Quality Assessment A Practical Guide
Second Edition, 2nd Edn. Clayton South, AU: Csiro publishing.
Slovic, P. (1999). Trust, emotion, sex, politics, and science: surveying the risk-
assessment battlefield. Risk Anal. 19, 689–701. doi: 10.1111/j.1539-6924.1999.
tb00439.x
Staniszewska, M., and Boniecka, H. (2017). Managing dredged material in the
coastal zone of the Baltic Sea. Environ. Monit. Assess. 189, 1–17. doi: 10.1007/
s10661-016-5734-0
Stelzenmüller, V., Ellis, J. R., and Rogers, S. I. (2010). Towards a spatially explicit
risk assessment for marine management: assessing the vulnerability of fish to
aggregate extraction. Biol. Conserv. 143, 230–238.
Stockmann, K., Riethmüller, R., Heineke, M., and Gayer, G. (2009). On
the morphological long-term development of dumped material in a low-
energetic environment close to the German Baltic coast. J. Mar. Syst. 75,
409–420.
Sundqvist, K. L., and Wiberg, K. (2013). Karakterisering av PCB och PCDD/F i
Östersjöns Ytsediment. Beijing: National Bureau of Statistics of China Statistical.
Swartz, R. C., Cole, F. A., Lamberson, J. O., Ferraro, S. P., Schults, D. W.,
Deben, W. A., et al. (1994). Sediment toxicity, contamination and amphipod
abundance at a DDT-and dieldrin-contaminated site in San Francisco Bay.
Environ. Toxicol. Chem. 13, 949–962.
Frontiers in Marine Science | www.frontiersin.org 15 October 2021 | Volume 8 | Article 755443
fmars-08-755443 October 13, 2021 Time: 16:7 # 16
Bruce et al. Inconsistently Evaluating Dumping at Sea
Swedish Agency for Marine and Water Management [SwAM] (2013). Havs- Och
Vattenmyndighetens Föreskrifter om Klassificering Och Miljökvalitetsnormer
Avseende Ytvatten. Sweden: Swedish Agency for Marine and Water
Management [SwAM].
Swedish Agency for Marine and Water Management [SwAM] (2018). Muddring
Och Hantering av Muddermassor. Havs- Och Vattenmyndighetens Rapport
2018:19. Gothenburg: Swedish Agency for Marine and Water Management
[SwAM].
Swedish Agency for Marine and Water Management [SwAM] (2019). Havs- Och
Vattenmyndighetens Föreskrifter Om Klassificering Och Miljökvalitetsnormer
Avseende Ytvatten; HVMFS 2019:25. Sweden: Swedish Agency for Marine and
Water Management [SwAM].
Swedish Environmental Protection Agency [SEEPA] (1999). Bedömningsgrunder
för Miljökvalitet – Kust Och Hav Rapport 4914. Stockholm: Swedish
Environmental Protection Agency [SEEPA].
Swedish Environmental Protection Agency [SEEPA] (2012). Sweden’s
Environmental Objectives–An Introduction. Stockholm (SE): ISBN 978-
91-620-8620-6. Stockholm: Swedish Environmental Protection Agency
[SEEPA].
Swedish Environmental Protection Agency [SEEPA] (2020). Organiska Miljögifter
I Sediment. Stockholm: Swedish Environmental Protection Agency [SEEPA].
Swedish Government Offices (2018). Agenda 2030 - Action Plan - Handlingsplan.
Sweden: Swedish Government Offices.
Taylor, S. E., Birch, G. F., and Links, F. (2004). Historical catchment changes
and temporal impact on sediment of the receiving basin, Port Jackson, New
South Wales. Aust. J. Earth Sci. 51, 233–246. doi: 10.1111/j.1400-0952.2004.
01054.x
Troell, M., Pihl, L., and Rönnbäck, P. (2005). Regime shifts and ecosystem services
in Swedish coastal soft bottom habitats: when resilience is undesirable. Ecol. Soc.
10:30.
UN (2015). Transforming Our World: The 2030 Agenda for Sustainable
Development - A/RES/70/1. New York, NY: UN.
USEPA (2020). What Was Dumped Into The Ocean Before 1972?. Available
online at: https://www.epa.gov/ocean-dumping/learn- about-ocean-dumping
(accessed February 2, 2021).
Varanasi, U., Reichert, W. L., Stein, J. E., Brown, D. W., and Sanborn, H. R. (1985).
Bioavailability and biotransformation of aromatic hydrocarbons in benthic
organisms exposed to sediment from an urban estuary. Environ. Sci. Technol.
19, 836–841. doi: 10.1021/es00139a012
Virtasalo, J. J., Korpinen, S., and Kotilainen, A. T. (2018). Assessment of the
influence of dredge spoil dumping on the seafloor geological integrity. Front.
Mar. Sci. 5:131. doi: 10.3389/fmars.2018.00131
Vogt, T., Pieters, R., Giesy, J., and Newman, B. (2019). Biological toxicity estimates
show involvement of a wider range of toxic compounds in sediments from
Durban, South Africa than indicated from instrumental analyses. Mar. Pollut.
Bull. 138, 49–57. doi: 10.1016/j.marpolbul.2018.11.019
Conflict of Interest: The authors declare that the research was conducted in the
absence of any commercial or financial relationships that could be construed as a
potential conflict of interest.
Publisher’s Note: All claims expressed in this article are solely those of the authors
and do not necessarily represent those of their affiliated organizations, or those of
the publisher, the editors and the reviewers. Any product that may be evaluated in
this article, or claim that may be made by its manufacturer, is not guaranteed or
endorsed by the publisher.
Copyright © 2021 Bruce, Bradshaw, Ohlsson, Sobek and Christiernsson. This is an
open-access article distributed under the terms of the Creative Commons Attribution
License (CC BY). The use, distribution or reproduction in other forums is permitted,
provided the original author(s) and the copyright owner(s) are credited and that the
original publication in this journal is cited, in accordance with accepted academic
practice. No use, distribution or reproduction is permitted which does not comply
with these terms.
Frontiers in Marine Science | www.frontiersin.org 16 October 2021 | Volume 8 | Article 755443
ResearchGate has not been able to resolve any citations for this publication.
Article
Full-text available
Changes in benthic macrofaunal communities are indicative of environmental stressors, including eutrophication and hypoxia. However, some species are sensitive not only to hypoxia but also to various environmental contaminants. We tested which of the environmental predictors (sediment organic carbon, sediment concentrations of metals and polyaromatic hydrocarbons [PAHs], bottom water oxygen, salinity, temperature, and surface chlorophyll- a concentration) that best explained the following response variables: (1) macrofauna community composition, (2) abundance of a benthic sentinel species, the amphipod Monoporeia affinis ; and (3) the Benthic Quality Index (BQI). All data originated from 29 reference monitoring stations in the Baltic Sea and the statistical tests included both uni- and multivariate analyses. The community composition and BQI were best explained by the same combination of salinity, depth, temperature and PAH concentrations. The abundance of M. affinis , which is sensitive to hypoxia and chemical exposure, was best explained by PAHs as a single predictor. Our findings suggest that benthic communities in the Baltic Sea are influenced by anthropogenic contaminants, which should be taken into account when benthos is used for eutrophication status assessment.
Article
Full-text available
Several countries currently lack common recommendations specific to Ecological Risk Assessment (ERA) of contaminated sediments and stakeholders report inconsistencies between currently used approaches. The objective of this study was to provide an increased understanding of how ERAs of contaminated sediments are conducted in comparison to established guidelines. For this, we use Sweden as a case study and compare seven ERAs with four internationally established strategies. Our results indicate that contaminant concentrations receive a comparatively high weight, despite a lack of appropriate benchmarks; toxicity measurements are uncommon, while routine in established strategies; and the integration and interpretation of results lack transparency. We identify three areas that may help improve the practice of ERAs: a common approach to benchmarks, recommendations for how to assess toxic effects, and a common approach for integrating and interpreting results.
Article
Full-text available
Marine dredging is a sub-aquatic excavation activity executed around the globe for various purposes by many industries. The negative impacts of dredged material discharge on benthic ecosystems are diverse. Researches on the results of dredging on estuarine geomorphology and its sedimentary regime are usual. Still, the results of dumping dredged material off the coast, in the Brazilian continental shelf, are not easily found in the literature. The present research evaluated the geomorphic disturbance resulted from discharging dredged material from Rio de Janeiro Harbor in the inner Rio de Janeiro continental shelf. Grain size analysis of the dredged and dumped sediments was compared to the inner shelf original seabed sediments. The geomorphological impact was evaluated through bathymetric and high resolution seismic and side scan sonar imagery methods. Obtained data revealed significant geomorphologic changes on the offshore bottom caused by the accumulation of compacted mud from the dredge site underlying the recent soft mud bottom of the harbor area. Besides the morphological sea bottom disturbance, sediment accumulation, and local grain size characteristics exhibited significant change, potentially impacting the surrounding benthic environment. RESUMO. A dragagem marinha é uma atividade de escavação subaquática executada em todo o mundo por muitas indústrias para diferentes fins. Os impactos negativos do descarte de material dragado nos ecossistemas bentônicos são diversos. Pesquisas sobre os resultados da dragagem na geomorfologia estuarina e o seu regime sedimentar são frequentes. Ainda assim, os resultados do despejo de material dragado ao longo da costa, na plataforma continental brasileira, não são facilmente encontrados na literatura. A presente pesquisa avaliou o distúrbio geomórfico resultante do descarte de material dragado do Porto do Rio de Janeiro na plataforma continental interna do Rio de Janeiro. A granulometria dos sedimentos dragados e descartados foi comparada com os sedimentos originais do fundo marinho na plataforma interna. O impacto geomorfológico foi avaliado através de métodos batimétricos, sísmica de alta resolução e imageamento por sonar de varredura lateral. Os dados obtidos revelaram mudanças geomorfológicas significativas no fundo causadas pelo acúmulo de lama compactada do local dragado, subjacente ao fundo de lama mole recente da área do porto. Além do distúrbio morfológico do fundo marinho, o acúmulo de sedimentos e as características locais de tamanho de grão apresentaram mudança significativa, potencialmente impactando o ambiente bentônico circundante.
Article
Full-text available
The Klip River, flowing through South Africa’s most populated urban area—Soweto and Lenasia—is subject to various pollution and anthropogenic influences, including great concentrations of polycyclic aromatic hydrocarbons. The aims were to determine the aryl-hydrocarbon receptor-mediated potencies of the 16 priority polycyclic aromatic hydrocarbons in sediments of the Klip River, using chemical- and bio-analytical assessments of hazard, and to compare these results with international sediment quality guidelines. Sediment samples were collected from nine sites during the dry seasons of 2013 and 2014. Two sets of toxic equivalents were calculated from analytically obtained polycyclic aromatic hydrocarbon concentrations using: (1) 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalency factors and (2) relative potency factors for fish. The fraction of the sediment extracts containing polycyclic aromatic hydrocarbons was assayed with the H4IIE-luc reporter gene bio-assay, and the aryl-hydrocarbon receptor potency expressed as bio-assay equivalents. The bio-assay equivalents and tetrachlorodibenzo-p-dioxin equivalency factors were compared to Canadian sediment quality guidelines and of the three approaches, the bio-assay equivalents and the relative potency factors for fish proved the most protective. Results of this study are proof of the utility of combining biological analysis with instrumental analysis when predicting hazard. Even though there were instances where the bio-assay equivalents were orders of magnitude greater than the tetrachlorodibenzo-p-dioxin equivalency factors, the results still showed similar trends. It was concluded that hazard from aryl-hydrocarbon receptor-mediated potency to adversely affect aquatic organisms in the Klip River was relatively great, which indicated the need for further investigation into possible mitigations.
Article
Full-text available
Abstract The present monitoring and assessment of the chemical status of water bodies fail to characterize the likelihood that complex mixtures of chemicals affect water quality. The European Collaborative Project SOLUTIONS suggests that this likelihood can be estimated with effect-based methods (EBMs) complemented by chemical screening and/or impact modeling. These methods should be used to identify the causes of impacted water quality and to develop programs of measures to improve water quality. Along this line of reasoning, effect-based methods are recommended for Water Framework Directive (WFD) monitoring to cover the major modes of action in the universe of environmentally relevant chemicals so as to evaluate improvements of water quality upon implementing the measures. To this end, a minimum battery of bioassays has been recommended including short-term toxicity to algae, Daphnia and fish embryos complemented with in vitro and short-term in vivo tests on mode-of-action specific effects as proxies for long-term toxicity. The likelihood of adverse impacts can be established with effect-based trigger values, which differentiate good from poor water quality in close alignment with Environmental Quality Standards for individual chemicals, while taking into account mixture toxicity. The use of EBMs is suggested in the WFD as one avenue to establish the likelihood of adverse effects due to chemical pollution in European water systems. The present paper has been written as one component of a series of policy briefs to support decisions on water quality monitoring and management under the WFD.
Article
Full-text available
The European Marine Strategy Framework Directive requires the development of suitable indicators for regular reporting on the environmental state and achievement of a good environmental status of EU's marine waters by 2020. The development of indicators for determining seafloor integrity and its possible disturbance by human activities have so far largely ignored the geological properties of seafloor. This paper presents a study of Vuosaari and Uusikaupunki-D offshore dumping sites in Finland, the northern Baltic Sea. Full coverage multibeam bathymetry and relative backscatter data, and a number of sediment cores were collected over the sites. The areas covered by dumped dredge spoil stand out in the multibeam images because of their irregular surface and elevated backscatter. The short gravity cores were studied for lithology, and in 1-cm slices for 137Cs activity, organic content, and grain size distribution. The dumped material is represented in the cores by the gravelly mud lithofacies with massive texture and angular coarse particles. The dumped material is coarser, less sorted and has higher kurtosis compared to natural sediment due to the admixing of blasted rock during the dredging activities, and limited sorting during fall through the water column upon dumping. Dispersed dredge spoil, which was suspended in the water column during the dumping activities or reworked from the dumped material mounds and redistributed along the seafloor soon thereafter, was deposited over a wide area as a thin layer that is not necessarily readily identifiable by visual inspection in the cores. Cesium activity helped distinguish the dumped material from the 137Cs-enriched natural sediments deposited after the 1986 Chernobyl disaster. Considering that the dumped material at many of the coring sites in the Vuosaari dumping area is covered by natural sediment, it probably is largely stable. In contrast, dumped material at the shallower Uusikaupunki-D site has slumped down to an adjacent channel and is likely being redistributed by near-bottom currents. Based on the findings of the study, a protocol for the assessment of the geological integrity of seafloor, its anthropogenic change due to dumping, and its potential recovery is proposed, as required by the Marine Strategy Framework Directive.
Article
A number of large rivers across the world are dredged for navigation. Dredging removes sediment from the channel, creates spoil mounds in the adjoining floodplain, and disposes sediment along the channel margin on a bar, or in open water. Retrospective studies that examine the placement and fate of this disposed material can provide guidance for other localities where dredging is practiced, and better elucidate the impacts associated with disposal at different types of sites. Many studies exist for impacts and benefits of dredging in the coastal environment, particularly to ecosystems and water quality. Few studies have examined disposal site selection and the fate of dredge spoil placed along a river corridor from a geomorphic and retrospective perspective. The Apalachicola River in Florida was dredged from the 1950s for several decades, with disposal on sand bars, in open water on the channel margins, and on the floodplain. Numerous large and small floodplain dredge-spoil mounds are a legacy from this navigation project. One of the larger mounds, disposal site 40 (DS 40), which locals call “Sand Mountain,” stands ~22 m high and extends ~10 ha in area. This disposal site originated in an artificial cutoff created in 1968–69 and grew to hold >625,000 m³ of sediment. Because this section of river was a problem for navigation when dredging was being conducted, detailed historical survey sheets with topographic and bathymetric data exist. The purpose of this paper was to analyze the local floodplain and channel geospatially, coupled with dredging and disposal data, to interpret the geomorphic changes of DS 40 and the adjoining river. Poor placement has resulted in this and other dredge spoil mounds returning sediment to the river through lateral erosion and mass wasting. Intermittent sediment pulses have altered channel morphology adjacent to the spoil mound with the channel becoming wider and shallower than originally, mean bed and thalweg elevations increasing by ~1.5 to 2 m, and width-depth ratio increasing three-fold. Although dredging of this river has not been conducted for nearly two decades, study of historical dredge spoil mounds in this reach suggest poor placement of spoil can continue to stress and alter a river in the decades that follow. Based on our findings, dredging downstream of distributaries will have poor outcomes. Dredge spoil placement in cut-off channels close to the river can be problematic because the river will regain sinuosity. Further, sites on the outer bend of meanders are more subject to erosion, and sites immediately upstream of problem or shallow areas will feed sediment to the problem reach. Findings of this study have implications to other settings, such as intensively mined rivers where unused unconsolidated material is often left on floodplains.
Article
In this study we assessed the effects of the recurrent disposal of dredged material from the Guadalquivir estuary (south-western Spain) in a marine disposal area. We analysed shifts in sediment characteristics as well as bioaccumulation and biomagnification of heavy metals through the benthic food web. Results showed that the significant increase in concentration of some heavy metals observed in the marine disposal area after the latest disposal event could be attributed to the deposition of river-dredged sediments. This increase could also explain the decreased amphipod survival in the ecotoxicology analysis. Heavy metal concentrations in organisms indicated some bioaccumulation in deposit feeders and predators but with no clear patterns nor biomagnification through the food web. Hence, combining studies that monitor shifts in sediment characteristics and their possible consequences for the food web seems to be an interesting approach that should be assessed further in this type of studies.
Article
In this study a recently developed benthic flow‐through chamber was used to assess the sediment‐to‐water flux of PAHs at four sites on the Swedish Baltic Sea coast. The flow‐through chamber allows for assessment of the potential effect of bioturbation on the sediment‐to‐water flux of HOCs. The sediments at the four investigated sites have varying contamination degree and varying densities of bioturbating organisms. The flux of individual PAHs measured with the flow‐through chamber ranged between 21‐510, 11‐370, 3‐9700 and 62‐2300 ng m‐2 d‐1, respectively. In order to assess the potential effect of bioturbation on the sediment‐to‐water flux, three flow‐through and closed chambers were deployed in parallel at each site. The activity of benthic organisms is attenuated or halted due to depletion of oxygen in closed benthic chambers. Therefore, the discrepancy in flux measured with the two different chamber designs was used as an indication of a possible effect of bioturbation. A potential effect of bioturbation on the sediment‐to‐water flux by a factor of 3 to 55 was observed at sites with a high density of bioturbating organisms (e.g. Marenzelleria spp, Monoporeia affinis and Macoma baltica of approximately 860 to 1200 ind. m‐2), but not at the site with much lower organism density (< 200 ind. m‐2). One site had a high organism density and a low potential effect of bioturbation, which we hypothesize to be caused by the dominance of oligochates/polychates at this sites, as worms (Marenzelleria spp.) reach deeper into the sediment than native crustaceans and molluscs. This article is protected by copyright. All rights reserved.