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Chemical dispersion is an oil spill response strategy where dispersants are sprayed onto the oil slick to enhance oil dispersion into the water. However, accidental application could expose seabirds to dispersants, thereby negatively affecting their plumage. To understand the possible impacts on seabirds, feathers from common eider (Somateria mollissima) and thick-billed murre (Uria lomvia) were exposed to different dosages of the dispersant Dasic Slickgone NS. For all exposure dosages the feathers increased in weight, and mostly for common eider. Analysing the feather microstructure, e.g., the Amalgamation Index, showed that larger damages were found on thick-billed murre than common eider. A no-sinking limit was established at 0.109 ml/m 2. Relating this value to desktop simulations of potential sea-surface dosages in real-life situations, and to published accounts of response operations, showed that the limit is likely to be exceeded. Thus, our results show that chemical dispersants in realistic dosages could impact seabirds.

In-situ burning is a well-proven technology for combatting oil spills offshore. However, as a coastline oil spill response at rocky shores it is novel and investigated here for the first time. The viability and efficiency of coastline in-situ burning of oil spills and the fate of the resulting burn residue was studied through a field experiment. The experiment included a controlled release of 600 L crude oil and subsequent burn of the oil on a remote coast in Greenland. In line with other documented large-scale offshore burns, a high burn efficiency was estimated. Fate studies and chemical analysis of the burn residue diversely caught in the tidal seaweed vegetation showed varying compositions depending on the specific burn intensity. In general, however, a relative increase in high ring numbered PAHs was observed compared to fresh oil. After 4 days, waves and tidal flushing markedly reduced visible oil and burn residue from the burn area. Elevated concentrations of total hydrocarbons were found from the fresh oil in the seawater, but the impacts on the coastal water was below levels of ecotoxic concern. Overall, coastline in-situ burning proved efficient, with a high operational potential. In addition, when the oil is in place at the coast, with a possible increased operational time window compared to an offshore burn.

The Environmental Protection Agencies (EPAs) of Denmark, Sweden, Norway, Germany and the Netherlands submitted a proposal to the European Chemical Agency (ECHA) in February 2023 calling for a ban in the use of toxic industrial chemicals per- and polyfluoroalkyl substances (PFAS). These chemicals are highly toxic causing elevated cholesterol, immune suppression, reproductive failure, cancer and neuro-endocrine disruption in humans and wildlife being a significant threat to biodiversity and human health. The main reason for the submitted proposal is recent findings of significant flaws in the transition to PFAS replacements that is leading to a widespread pollution. Denmark was the first country banning PFAS, and now other EU countries support the restrictions of these carcinogenic, endocrine disruptive and immunotoxic chemicals. The proposed plan is among the most extensive received by the ECHA for 50 years. Denmark is now the first EU country to initiate the establishment of groundwater parks to try and protect its drinking water. These parks are areas free of agricultural activities and nutritious sewage sludge to secure drinking water free of xenobiotic including PFAS. The PFAS pollution also reflects the lack of comprehensive spatial and temporal environmental monitoring programs in the EU. Such monitoring programs should include key indicator species across ecosystems of livestock, fish and wildlife, to facilitate detection of early ecological warning signals and sustain public health. Simultaneously with inferring a total PFAS ban, the EU should also push for more persistent, bioaccumulative and toxic (PBT) PFAS substances to be listed on the Stockholm Convention (SC) Annex A such as PFOS (perfluorooctane sulfonic acid) that is currently listed on the SCs Annex B. The combination of these regulative restrictions combined with groundwater parks and pan-European biomonitoring programs, would pave the way forward for a cleaner environment to sustain health across the EU.

Environmental science and pollution research : ESPR (2020). doi:10.1007/s11356-020-11729-5, Published by Springer, Berlin

Oil spills from ship traffic or oil production represent a huge threat to the environment. A controlled and thick oil slick is crucial in relation to combatting oil spills, not least for Arctic waters, before introducing the oil spill response method in situ burning. Recently, herding agents have been introduced, with success, as a measure to contain and thicken oil spills, when sprayed to the perimeter of the slick. In this study, we evaluated potential environmental impacts of using herding agents. Toxicity, bioaccumulation and biodegradability of the two herders ThickSlick 6535 (TS6535) and Siltech OP‐40 (OP‐40) were studied in laboratory set-ups with Arctic water and the high Arctic copepod, Calanus hyperboreus. TS6535 was found to biodegrade rapidly within 7 days, and did not seem to bioaccumulate in the copepods or affect their grazing activity. Tests with OP-40 showed bioaccumulation in the copepods, sublethal effects (as reduced grazing activity) and limited biodegradation. The results thus indicate that OP-40 may possibly pose a risk to the Arctic marine environment. The data and knowledge from the tests poses valuable input to assess the potential environmental impacts from using herders in Arctic waters in connection with oil spill response. However, more knowledge is still needed to fully understand the fate and effect of herders in the environment; this also includes possible combined and/or cumulative effects from herders and oil.

The priorities for oil spill response (OSR) are to protect people, prevent or mitigate environmental damages, and minimize the long-term impacts. Several analytic approaches have emerged in the field of spill impact mitigation assessment (SIMA), a science-based framework evolved from net environmental benefits analysis (NEBA), to broaden the focus from consideration of mitigation of ecological impact to also include socioeconomic and cultural impact considerations. In the northern Gulf of Mexico (GOM), a comparative risk assessment (CRA) decision-support tool was developed for identifying and comparing the ecological consequences of different oil spill response technologies in temperate/sub-tropical deep water, including the use of subsea dispersants. Another analytic assessment tool, Environment & Oil Spill Response (EOS), was developed based on offshore western Greenland and the Baltic Sea to assist in selection of oil spill response options that best mitigate the consequences of spilled oil in polar / sub-polar aquatic ecosystems in the Nordic region. In this work, we briefly review the CRA and EOS tools and highlight the shared and unique attributes of both assessment frameworks and how ecological, environmental and oil chemistry characteristics are handled in contrasting climatic and ecosystem conditions.

In-situ burning (ISB) has been an oil combat technique studied since the 1950s. However, burning of the oil on the sea surface along the coastline, coastline ISB (cISB), is novel and was tested for the first time in the Arctic along a rocky coast in the summer 2017. A light crude oil was burned and effects of the cISB operation on the littoral zone communities investigated. The impact on macroalgal vegetation and associated fauna was analysed in three littoral zone levels. The analyses revealed limited effects on the littoral community, and that variation between sample plots and years in macroalgal biomass and coverage, as well as fauna biomass and abundance was higher than the impact from cISB. Therefore, it is concluded that cISB in the Arctic along a rocky shore may be an oil spill response option with relatively low environmental side effects for the specific oil type used.

Facilitated by a receding sea ice extent, new and shorter routes have led to increased maritime traffic in Arctic areas with an inherent risk for oil spills along Arctic rocky shorelines. To estimate natural oil removal under Arctic conditions, a crude oil and a heavy fuel oil were applied to slate tiles, mimicking rocky shore substratum, and placed at four levels within and just above the tidal zone on two rocky shorelines in West Greenland. Tiles were regularly sampled (within 95 days) to determine natural oil removal and chemical composition of the remaining oil. We found that natural oil removal on the rocky shorelines depends on (1) level position on the shoreline, i.e., within and above the tidal zone where ample exposure to water and wave-wash increases oil removal rate and efficiency, and (2) physical and chemical oil properties with the crude oil being removed more readily than the heavy fuel oil. These findings can help improve the risk assessment of oil spills in Arctic areas and facilitate the development of effective oil spill response strategies in Arctic seas.

New economic developments in the Arctic, such as shipping and oil exploitation, bring along unprecedented risks of marine oil spills. Microorganisms have played a central role in degrading and reducing the impact of the spilled oil during past oil disasters. However, in the Arctic, and in particular in its pristine areas, the self-cleaning capacity and biodegradation potential of the natural microbial communities have yet to be uncovered.This review compiles and investigates the current knowledge with respect to environmental parameters and biochemical constraints that control oil biodegradation in the Arctic. Hereby, seawaters off Greenland are considered as a case study. Key factors for biodegradation include the bioavailability of hydrocarbons, the presence of hydrocarbon-degrading bacteria and the availability of nutrients. We show how these key factors may be influenced by the physical oceanographic conditions in seawaters off Greenland and other environmental parameters including low temperature, sea ice, sunlight regime, suspended sediment plumes and phytoplankton blooms that characterize the Arctic.Based on the acquired insights, a first qualitative assessment of the biodegradation potential in seawaters off Greenland is presented. In addition to the most apparent Arctic characteristics, such as low temperature and sea ice, the impact of typical Arctic features such as the oligotrophic environment, poor microbial adaptation to hydrocarbon degradation, mixing of stratified water masses, and massive phytoplankton blooms and suspended sediment plumes merit to be topics of future investigation.

Fourhorn sculpins (Myoxocephalus quadricornis) and shorthorn sculpins (Myoxocephalus scorpius) have been considered suitable local bioindicators for environmental monitoring studies in the Arctic. Because these species share many characteristics, data from the two species have previously been pooled when assessing marine metal contamination. A chemical and histological study was conducted on fourhorn and shorthorn sculpins collected around a contaminated lead-zinc mine at East Greenland to investigate whether there were any differences in the residues of metals, histopathology and parasites in liver and gills between the two sculpin species. The results demonstrated that concentrations of copper (Cu), zinc (Zn), mercury (Hg) and lead (Pb) were significantly higher in the fourhorn sculpins (p

Due to increased sea transport and offshore gas and oil exploration, the Arctic is facing an unprecedented risk of marine oil spills. Although beached oil spills can lead to acute and chronic impacts on intertidal ecosystems, the effects of oil spills on macro-algae in Arctic ecosystems is lacking. Here, we assessed the effect and response of the tidal macro-algae Fucus distichus to oiling, i.e. self-cleaning potential by seawater wash and photosynthetic activity. Oiling with four oil types (ANS, Grane, IFO30 and MGO) was simulated by exposing F. distichus tips to oil. Oil removal half-times ranged between 0.8 - 4.5 days, indicating that oiling of macro-algae with the tested oils was short-term. Further, Grane oil mostly inhibited photosynthetic activity whereas oil from ANS, IFO30 and MGO stimulated it. The photosynthetic activity of F. distichus continued to be affected (inhibited or stimulated), even after oil on the tip surface was washed off.

The EOS is a desktop analysis based on oil spill scenarios and published as well as expert knowledge on the environment in the assessment area. The EOS tool can support decisions of inclusion of mechanical recovery, in situ burning and chemical dispersants in national oil spill contingency plans. In addition, the results obtained through the EOS tool can be used for establishment of cross-border and trans-boundary co-operation and agreements on oil spill response. The EOS tool is based on an Excel spreadsheet, with references to explanatory boxes provided in the EOS Handbook. This EOS tool was developed in Work package 5 of the GRACE project: Strategic Net Environmental Benefit Analysis. During the planning and development phase the tool was known as the sNEBA tool, but the name was changed to EOS tool during the working process. The EOS analysis goes through 5 steps for each of the oil spill response methods and for each season 1. Gathering basic environmental data and information for the assessment area 2. Assessments of basic data and oil spill modelling results 3. Scores and indices calculations 4. Decision trees for each oil spill response technology 5. Interpretation and dissemination of EOS results. European Commission, EU H2020 GRACE grant no. 679266 Published Refereed Current 14.1 Mature Validated (tested by third parties) Method Specification of criteria

Here we review sled dogs as a sentinel monitoring species of ecosystem health across the Arctic focusing on environmental changes including pollution, climate change, and infectious diseases. Studies on environmental contaminants have been carried out mostly in Alaska and Greenland. While the majority of reports focus on mercury exposure and health effects, a major classical case-controlled study of exposure and effects from persistent organic pollutants (POPs) has been carried out on Greenland sled dog bitches and their pups. Altogether, the studies show that mercury and POPs affect multiple health endpoints across physiological systems, including reproductive, endocrine, and immune systems, that ultimately affect systems such as the liver and kidney. Therefore, sled dogs have proved to be a good model for assessing the health effects from contaminant exposure of top predators and Northerners in the Arctic. Furthermore, they are widelydistributed across the Arctic and show similar correlations to important health indicators reported in Northerners and polar bears. With respect to climate change and disease dynamics of zoonosis, most studies have taken place in Canada. However, at present sled dogs are not utilized in monitoring studies of zoonotic diseases. Such an inclusion will increasethe understanding of environmental changes, pollution, and diseases dynamics in Northerners and wildlife. We therefore recommend that ecosystem health assessments in the Arctic including that of Northerners start to include analyses of sleddogs combined with modeling tools. Doing so in a circumpolar perspective will further increase our understanding and monitoring possibilities of ecosystem health and Northerners exposure to contaminants, diseases, and climate change in the Arctic.

Increased economic activity in the Arctic may increase the risk of oil spills. Yet, little is known about the degradation of oil spills by solar radiation and the impact of nutrient limitation on oil biodegradation under Arctic conditions. We deployed adsorbents coated with thin oil films for up to 4 months in a fjord in SW Greenland to simulate and investigate in situ biodegradation and photo-oxidation of dispersed oil droplets. Oil compound depletion by dissolution, biodegradation, and photo-oxidation was untangled by gas chromatography–mass spectrometry-based oil fingerprinting. Biodegradation was limited by low nutrient concentrations, reaching 97% removal of nC13–26-alkanes only after 112 days. Sequencing of bacterial DNA showed the slow development of a bacterial biofilm on the oil films predominated by the known oil degrading bacteria Oleispira, Alkanindiges and Cycloclasticus. These taxa could be related to biodegradation of shorter-chain (≤C26) alkanes, longer-chain (≥C16) and branched alkanes, and polycyclic aromatic compounds (PACs), respectively. The combination of biodegradation, dissolution, and photo-oxidation depleted most PACs at substantially faster rates than the biodegradation of alkanes. In Arctic fjords during summer, nutrient limitation may severely delay oil biodegradation, but in the photic zone, photolytic transformation of PACs may play an important role.

Since the last Arctic Monitoring and Assessment Programme (AMAP) effort to review biological effects of the exposure to organohalogen compounds (OHCs) in Arctic biota, there has been a considerable number of new Arctic effect studies. Here, we provide an update on the state of the knowledge of OHC, and also include mercury, exposure and/or associated effects in key Arctic marine and terrestrial mammal and bird species as well as in fish by reviewing the literature published since the last AMAP assessment in 2010. We aimed at updating the knowledge of how single but also combined health effects are or can be associated to the exposure to single compounds or mixtures of OHCs. We also focussed on assessing both potential individual as well as population health impacts using population-specific exposure data post 2000. We have identified quantifiable effects on vitamin metabolism, immune functioning, thyroid and steroid hormone balances, oxidative stress, tissue pathology, and reproduction. As with the previous assessment, a wealth of documentation is available for biological effects in marine mammals and seabirds, and sentinel species such as the sledge dog and Arctic fox, but information for terrestrial vertebrates and fish remain scarce. While hormones and vitamins are thoroughly studied, oxidative stress, immunotoxic and reproductive effects need further investigation. Depending on the species and population, some OHCs and mercury tissue contaminant burdens post 2000 were observed to be high enough to exceed putative risk threshold levels that have been previously estimated for non-target species or populations outside the Arctic. In this assessment, we made use of risk quotient calculations to summarize the cumulative effects of different OHC classes and mercury for which critical body burdens can be estimated for wildlife across the Arctic. As our ultimate goal is to better predict or estimate the effects of OHCs and mercury in Arctic wildlife at the individual, population and ecosystem level, there remain numerous knowledge gaps on the biological effects of exposure in Arctic biota. These knowledge gaps include the establishment of concentration thresholds for individual compounds as well as for realistic cocktail mixtures that in fact indicate biologically relevant, and not statistically determined, health effects for specific species and subpopulations. Finally, we provide future perspectives on understanding Arctic wildlife health using new in vivo, in vitro, and in silico techniques, and provide case studies on multiple stressors to show that future assessments would benefit from significant efforts to integrate human health, wildlife ecology and retrospective and forecasting aspects into assessing the biological effects of OHC and mercury exposure in Arctic wildlife and fish. © 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

This article introduces the EU Horizon 2020 research project GRACE (Integrated oil spill response actions and environmental effects), which focuses on a holistic approach towards investigating and understanding the hazardous impact of oil spills and the environmental impacts and benefits of a suite of marine oil spill response technologies in the cold climate and ice-infested areas of the North Atlantic and the Baltic Sea. The response methods considered include mechanical collection in water and below ice, in situ burning, use of chemical dispersants, natural biodegradation, and combinations of these. The impacts of naturally and chemically dispersed oil, residues resulting from in situ burning,and non-collected oil on fish, invertebrates (e.g. mussels, crustaceans) and macro-algae are assessed by using highly sensitive biomarker methods, and specific methods for the rapid detection of the effects of oil pollution on biota are developed. By observing, monitoring and predicting oil movements in the sea through the use of novel online sensors on vessels, fixed platforms including gliders and the so-called SmartBuoys together with real-time data transfer into operational systems that help to improve the information on the location of the oil spill, situational awareness of oil spill response can be improved. Methods and findings of the project are integrated into a strategic net environmental benefit analysis tool (environment and oil spill response, EOS) for oil spill response strategy decision making in cold climates and ice-infested areas. © The Author(s) 2019. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/)

Due to a northward shift in off-shore activities, including increased shipping traffic and oil and gas exploration there is a growing focus on the potential effects of oil pollution on Arctic marine ecosystems. Capelin (Mallotus villosus)is a small fish and a member of the smelt family, and is a key species in the marine food chain. Capelin are seasonally abundant in the Northern Atlantic and in coastal Arctic waters, e.g. in western Greenland and in the Barents Sea, where it undertakes aggregated spawning in the intertidal and subtidal zone. To study the possible effects of oil pollution on the physiology and development of early life stages in capelin, freshly fertilised capelin eggs were exposed to a water accommodated fraction of physically (WAF)and chemically (CEWAF)dispersed heavy fuel oil (IFO30)for 72 h. Subsequent mortality, hatching success, larvae malformations, growth and CYP1A/EROD activity was measured over a 4-week period. The nominal exposure concentrations of WAF and CEWAF were between 0.02 and 14.5 mg total hydrocarbon content (THC)L −1 and 0.5–304 mg THC L −1 , respectively. Egg mortality correlated significantly with WAF exposure concentration. The proportions of hatched eggs decreased with increasing CEWAF exposure concentration. Further, the percentage of malformed larvae with craniofacial abnormalities, body axis defects, generally under developed larvae, reduced total body length (dwarfs), correlated significantly with exposure concentrations in both CEWAF and WAF treatments. The four types of the predominant malformations were distributed differently in two parallel experiments. At the biochemical level, we observed a significant relationship between CEWAF exposure concentration and CYP1A/EROD activity in newly hatched larvae and this effect persisted for 3 weeks after the 72 h exposure. We conclude that even short-term exposure to both heavy fuel oil WAF and CEWAF, at environmentally relevant THC concentrations following an oil spill, may induce adverse developmental effects on the vulnerable early life stages of capelin. The mechanisms responsible for the observed effects on mortality, growth and embryo development in capelin eggs and embryos following WAF and CEWAF exposure require further studies.

Shipping activities across the Artic are expected to increase with decreasing sea ice cover, thus increasing the risk of oil spills. Heavy Fuel Oil (HFO, a mixture of residual fuel and distillate d ...

Arctic shipping and oil exploration are expected to increase, as sea ice extent is reduced. This enhances the risk for accidental oil spills throughout the Arctic, which emphasises the need to quantify potential consequences to the marine ecosystem and to evaluate risk and choose appropriate remediation methods. This study investigated the sensitivity of Arctic marine plankton to the water accommodated fraction (WAF) of heavy fuel oil. Arctic marine phytoplankton and copepods (Calanus finmarchicus) were exposed to three WAF concentrations corresponding to total hydrocarbon contents of 0.07 mg l-1, 0.28 mg l-1 and 0.55 mg l-1. Additionally, the potential phototoxic effects of exposing the WAF to sunlight, including the UV spectrum, were tested. The study determined sub-lethal effects of WAF exposure on rates of key ecosystem processes: primary production of phytoplankton and grazing (faecal pellet production) of copepods. Both phytoplankton and copepods responded negatively to WAF exposure. Biomass specific primary production was reduced by 6, 52 and 73% and faecal pellet production by 18, 51 and 86% with increasing WAF concentrations compared to controls. The phototoxic effect reduced primary production in the two highest WAF concentration treatments by 71 and 91%, respectively. This experiment contributes to the limited knowledge of acute sub-lethal effects of potential oil spills to the Arctic pelagic food web.

Polar bears (Ursus maritimus) are among the world's highest trophic level marine predators and as such have some of the highest tissue concentrations of organohalogen contaminants (OHCs) among Arctic biota. In this paper we present the results of a three decade (1983–2013) risk assessment of OHC exposure and effects on reproduction, immunity, and cancer (genotoxicity) in polar bears from Central East Greenland. Risk of adverse effects are evaluated using a risk quotient (RQ) approach with derivation from measured OHC concentrations in polar bear tissue and critical body residues (CBR) extrapolated for polar bears using physiologically-based pharmacokinetic modelling (PBPK). The additive RQs for all OHCs in polar bears were above the threshold for all effect categories (RQ > 1) in every year, suggesting this population has been at significant and continuous risk of contaminant-mediated effects for over three decades. RQs peaked in 1983 (RQ > 58) and again in 2013 (RQ > 50) after a period of decline. These trends follow ΣPCB levels during that time, and contributed almost all of the risk to immune, reproductive, and carcinogenic effects (71–99% of total RQ). The recent spike in RQs suggests a major shift in polar bear contaminant exposure from climate related changes in food composition and hereby the increased risk of adverse health effects. In the context of lifetime exposure ΣPCB and PFOS levels showed the interactive importance of year of birth, age, and emission history. In conclusion, the results indicate that East Greenland polar bears have been exposed to OHC levels over the period of 1983–2013 that potentially and continuously affected individual and theoretically also population health, with a peaking risk in the more recent years. Keywords: Polar bear, Ursus maritimus, Organohalogen contaminants, PBPK modelling, Critical body residue, Immune suppression, Reproductive toxicity, Risk quotient

We used PBPK (physiologically-based pharmacokinetic) modelling to investigate distribution, bioaccumulation and excretion of the seven POPs (persistent organic pollutants) CB-99, CB-153, HCB, oxychlordane, p,p'-DDE, BDE-47 and BDE-99 in 4 adult captive Greenland sledge dog (Canis familiaris) bitches fed minke whale (Balaenoptera acuterostrata) blubber for 500-635 days. The PBPK modelled POP concentrations in adipose tissue, liver, kidney and plasma were mostly within a factor 2 of actual measured tissue levels even for those at the lower concentration end. The excretion route for oxychlordane and CB-153 was modelled to be via faeces while lung alveolar excretion dominated for BDE-47, BDE-99, HCB, p,p'-DDE and CB-99. Furthermore the model suggested the retained mass of POPs after 500 and 635 days of exposure, respectively, to be relatively low despite these POPs being highly recalcitrant. The retention increased in the following order (% of total intake); p,p'-DDE (1%)

Zoonotic infections transmitted from terrestrial and marine mammals to humans in European Arctic are of unknown significance, despite considerable potential for transmission due to local hunt and a rapidly changing environment. As an example, infection with Brucella bacteria may have significant impact on human health due to consumption of raw meat or otherwise contact with tissues and fluids of infected game species such as muskoxen and polar bears. Here, we present serological results for Baffin Bay polar bears (Ursus maritimus) (n = 96) and North East Greenland muskoxen (Ovibos moschatus) (n = 32) for antibodies against Brucella spp. The analysis was a two-step trial initially using the Rose Bengal Test (RBT), followed by confirmative competitive enzyme-linked immunosorbent assays of RBT-positive samples. No muskoxen had antibodies against Brucella spp., while antibodies were detected in six polar bears (6.25%) rendering a seroprevalence in line with previous findings in other Arctic regions. Seropositivity was not related to sex, age or biometrics i.e. size and body condition. Whether Brucella spp. antibodies found in polar bears were due to either prey spill over or true recurrent Brucella spp. infections is unknown. Our results therefore highlight the importance of further research into the zoonotic aspects of Brucella spp. infections, and the impact on wildlife and human health in the Arctic region. Prevalence of antibodies against Brucella spp. in West Greenland polar bears (Ursus maritimus) and East Greenland muskoxen (Ovibos moschatus) © Springer-Verlag GmbH Germany, part of Springer Nature 2018. This is a post-peer-review, pre-copyedit version of an article published in Polar Biology. Locked until 19 March 2019 due to copyright restrictions. The final authenticated version is available online at: https://doi.org/10.1007/s00300-018-2307-4.

The former lead-zinc mine at Mestersvig, Greenland, continues to contaminate the surrounding environment despite its operations ceasing over 50 years ago. Elevated concentrations of heavy metals are found in water, sediment and biota in the terrestrial, freshwater and marine environments. To shed light on the present contamination and its potential effects on local fish we investigated gill and liver histology of sculpins (Myoxocephalus spp.) around the former mining area. Two species of sculpins were caught; shorthorn sculpins (M. scorpius; n = 16) and fourhorn sculpins (M. quadricornis; n = 17) at a contaminated site, Nyhavn, and shorthorn sculpins (M. scorpius; n = 25) at the reference site. In a previous study we found histopathological changes in the tissues of the sculpins, and we suspected this to be related to elevated heavy metal tissue concentrations. Concentrations of Fe, Hg, Mn, Pb, Se and Zn were significantly higher in sculpins at Nyhavn compared to the reference site. Reference NOED and LOEC thresholds for biochemistry, tissue lesions, growth, survival and reproduction for hepatic Hg, As, Cd and Pb from the ERED database were exceeded in both sculpin species. Histopathological investigations of the sculpins gills revealed significant increases in the prevalence of hyperplastic epithelium, inflammation, intensity of neutral and total mucus cells and chloride cells along with an increased infection of colonial Peritricha. At the contaminated Nyhavn site, fourhorn sculpins had a significantly higher prevalence of chondroplastic tissue and intensity of neutral, mixed and total mucus cells in the gills compared to the shorthorn sculpins. The data indicate that both sculpin species could be useful indicator species for environmental monitoring of metal pollution in Arctic areas. However, confounding effects of gender and species should be investigated further. Effects on other biomarkers as well as baseline measurements should be included in future environmental monitoring efforts around mining activities in Greenland.

Oil spills in ice-covered waters pose unique challenges to remediation activities. In-situ burning is a potential remediation technique that has shown promising efficiency in earlier trials. An element of arctic in-situ burning is the feedback between the flame of a burn on oil-infiltrated sea ice and the melting ice beneath. A series of experiments was devised to quantify the impact of this mechanism on burn efficiency. Seven experiments were performed that started with a crude oil pool of 0.2 or 0.3 m diameter on a 1 x 1 m2 freshwater ice block. The pools were ignited and the development of the flame, ice temperatures, and ablation rates was monitored. All burns ended in a vigorous burn phase (boil-over). Burn efficiency was below 65 %. A simple pond spread model was used to derive burn rates of a spreading pond. Burn rates were mostly around 0.9 mm/min. The low burn efficiencies were found to result from significant increase of the pond area during the burn in combination with relatively thin initial oil pools. The measurements provide a starting point to address the feedback effect of pond spread and ablation on burns on an oil-infested sea ice surface layer. Laboratory In-situ Burns of Oil on Ice

Oil and gas exploration in the Arctic will increase the risk for accidental oil spills and thereby have a potential impact on the ecosystem and the organisms inhabiting these areas. Lipid rich copepods are an important food source for higher trophic levels in Arctic marine ecosystems. However, high lipid content and a slower metabolism increase the risk for bioaccumulation in Arctic species. Here we exposed three late development stages of the lipid rich high-Arctic copepod species Calanus hyperboreus to two different 14C-marked crude oil model compounds, the alkane dodecane (log Kow 6.10) and the polycyclic aromatic hydrocarbon (PAH) phenanthrene (log Kow 4.46) on a short-term scale of 4days. Exposure was followed by a depuration phase of 3days. We observed a difference in estimated bioaccumulation of the two model compounds between stages and found a slower depuration of dodecane than of phenanthrene in the two largest and most lipid rich stages. However, depuration of dodecane and phenanthrene was non-significant for all three stages. The results indicate that even short-term exposure may result in long-term bioaccumulation and internal exposure of oil compounds in the lipid rich high-Arctic copepods C. hyperboreus. Slow elimination and depuration of oil components indicate a risk for transfer of oil component up the food web to pelagic fish, seabirds and baleen whales.

It is well known, that in case of oil spill, seabirds are among the groups of animals most vulnerable. Even small amounts of oil can have lethal effects by destroying the waterproofing of their plumage, leading to loss of insulation and buoyancy. In the Arctic these impacts are intensified. To protect seabirds, a rapid removal of oil is crucial and in situ burning could be an efficient method. In the present work exposure effects of oil and burn residue in different doses was studied on seabird feathers from legally hunted Common eider (Somateria mollissima) by examining changes in total weight of the feather and damages on the microstructure (Amalgamation Index) of the feathers before and after exposure. The results of the experiments indicate that burn residues from in situ burning of an oil spill have similar or larger fouling and damaging effects on seabird feathers, as compared to fresh oil.

Polar bears (Ursus maritimus) feed mainly on ringed seal (Phoca hispida) and consume large quantities of blubber and consequently have one of the highest tissue concentrations of organohalogen contaminants (OHCs) worldwide. In East Greenland, studies of OHC time trends and organ system health effects, including reproductive, were conducted during 1990-2006. However, it has been difficult to determine the nature of the effects induced by OHC exposures on wild caught polar bears using body burden data and associated changes in reproductive organs and systems. We therefore conducted a risk quotient (RQ) evaluation to more quantitatively evaluate the effect risk on reproduction (embryotoxicity and teratogenicity) based on the critical body residue (CBR) concept and using a physiologically-based pharmacokinetic (PBPK) model. We applied modelling approaches to PCBs, p,p'-DDE, dieldrin, oxychlordane, HCHs, HCB, PBDEs and PFOS in East Greenland polar bears based on known OHC pharmacokinetics and dynamics in laboratory rats (Rattus rattus). The results showed that subcutaneous adipose tissue concentrations of dieldrin (range: 79-1271 ng g(-1) lw) and PCBs (range: 4128-53,923 ng g(-1) lw) reported in bears in the year 1990 were in the range to elicit possible adverse health effects on reproduction in polar bears in East Greenland (all RQs > or = 1). Similar results were found for PCBs (range: 1928-17,376 ng g(-1) lw) and PFOS (range: 104-2840 ng g(-1) ww) in the year 2000 and for dieldrin (range: 43-640 ng g(-1) lw), PCBs (range: 3491-13,243 ng g(-1) lw) and PFOS (range: 1332-6160 ng g(-1) ww) in the year 2006. The concentrations of oxychlordane, DDTs, HCB and HCHs in polar bears resulted in RQs

Polychlorinated biphenyls (PCBs) can cause endocrine disruption, cancer, immunosuppression, or reproductive failure in animals. We used an individual-based model to explore whether and how PCB-associated reproductive failure could affect the dynamics of a hypothetical polar bear (Ursus maritimus) population exposed to PCBs to the same degree as the East Greenland subpopulation. Dose-response data from experimental studies on a surrogate species, the mink (Mustela vision), were used in the absence of similar data for polar bears. Two alternative types of reproductive failure in relation to maternal sum-PCB concentrations were considered: increased abortion rate and increased cub mortality. We found that the quantitative impact of PCB-induced reproductive failure on population growth rate depended largely on the actual type of reproductive failure involved. Critical potencies of the dose-response relationship for decreasing the population growth rate were established for both modeled types of reproductive failure. Comparing the model predictions of the age-dependent trend of sum-PCBs concentrations in females with actual field measurements from East Greenland indicated that it was unlikely that PCB exposure caused a high incidence of abortions in the subpopulation. However, on the basis of this analysis, it could not be excluded that PCB exposure contributes to higher cub mortality. Our results highlight the necessity for further research on the possible influence of PCBs on polar bear reproduction regarding their physiological pathway. This includes determining the exact cause of reproductive failure, i.e., in utero exposure versus lactational exposure of offspring; the timing of offspring death; and establishing the most relevant reference metrics for the dose-response relationship.

We report the development and application of a prototype tool for integrated assessment of chemical status in aquatic environments based on substance- and matrix-specific environmental assessment criteria (thresholds). The Chemical Status Assessment Tool (CHASE) integrates data on hazardous substances in water, sediments and biota as well as bio-effect indicators and is based on a substance- or bio-effect-specific calculation of a 'contamination ratio' being the ratio between an observed concentration and a threshold value. Values1.0 indicate areas potentially 'unaffected', while values1.0 indicate areas potentially 'affected'. These ratios are combined within matrices, i.e. for water, sediment and biota and for biological effects. The overall assessment used a 'one out, all out principle' with regard to each matrix. The CHASE tool was tested in the Baltic Sea and the North Sea in 376 assessment units. In the former, the chemical status was1.0 in practically all areas indicating that all areas assessed were potentially affected. The North Sea included areas classified as unaffected or affected. The CHASE tool can in combination with temporal trend assessments of individual substances be advantageous for use in remedial action plans and, in particular, for the science-based evaluation of the status and for determining which specific substances are responsible for a status as potentially affected.

Sculpins are widely used as key species for monitoring heavy metal pollution near arctic mine sites. Typically, metal concentrations in liver and muscle tissue have been used as a proxy for metal exposure but such analyses lack temporal information of uptake and accumulation. Otoliths (ear bones) are considered metabolically stable and can potentially contain a complete record of the fish’s metal exposure history. To investigate the otolith chemistry of sculpins and the potential of these as records of metal exposure, common sculpins (Myoxocephalus scorpius) were collected at five sites near a former Pb–Zn mine in West Greenland. Otoliths were analyzed by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) for 12 elements of which Mg, Mn, Sr, Ba, and Pb were detected. The highest Pb concentrations were found within the otoliths from the most Pb-polluted sites near the mine (up to 0.6 ppm), and decreasing concentrations were observed in a gradient away from the mine. Notably, Pb and Sr variations were closely correlated and showed an annual oscillatory pattern with peaks consistently found in the winter zones. It is not clear to what the extent high winter-time accumulation of Pb in the otoliths is due to high winter-time exposure of Pb through diet or water and/or to physiological processes such as growth in the sculpins. The study indicates that LA-ICP-MS analyses of sculpin otoliths have the potential to become a valuable method for assessing time-resolved metal loading near mine sites but also that more studies are required to investigate the links between metal sources, pathways, and processes affecting otolith metal deposition.

In situ burning is a method by which oil is burned at a spill site under controlled conditions, and this method is subject to increased interest due to its applicability in the Arctic. This paper reviews the literature regarding the characterization and environmental effects of burn residues in Arctic waters. The results of a systematic literature search indicate that only a very limited number of studies have arctic pertinence. From the review, it is also indicated that the properties and composition of the residues depend on the efficiency of the burning and the oil type. Furthermore, the studies within the frame of the literature search reach consensus that in situ burning may increase the concentrations of large poly-aromatic hydrocarbons (PAHs; high ring number) while reducing small PAHs (low ring number). There are very few toxicity studies of burn residues on aquatic and arctic organisms, and to enhance the knowledge base, more organisms as well as oil types must be studied. Furthermore, there is a lack of studies investigating the potential effect of sinking burn residues on benthic organism and the smothering effects of the more viscous burn residues on birds and other organisms related to the sea surface. More knowledge regarding environmental fate and effect of residues is crucial to complete a robust net environmental benefit analysis prior to an oil spill response operation in arctic waters.

The risk from POP (persistent organic pollutant) exposure and subsequent reproductive, immunotoxic and liver histopathological effects was evaluated in a classical parallel trial on Greenland sledge dogs (Canis familiaris) fed contaminated minke whale (Balaenoptera acutorostrata) blubber. First the critical body residues (CBRs) were estimated using the physiologically-based pharmacokinetic (PBPK) model for seven POP compounds based on rat critical daily doses (CDDs). These were then compared with the actual daily oral POP doses (DD) and body residues (BR) in the sledge dogs by calculating risk quotients (RQDD: DD/CDD; RQBR: BR/CBR; ≥1 indicates risk). The results showed that risk quotients for reproductive, immunotoxic and liver histopathological effects were significantly lowest in the control group (p

Polar bears (Ursus maritimus) consume large quantities of seal blubber and other high trophic marine mammals and consequently have some of the highest tissue concentrations of organohalogen contaminants (OHCs) among Arctic biota. In the present paper we carried out a risk quotient (RQ) evaluation on OHC-exposed polar bears harvested from 1999 to 2008 and from 11 circumpolar subpopulations spanning from Alaska to Svalbard in order to evaluate the risk of OHC-mediated reproductive effects (embryotoxicity, teratogenicity), immunotoxicity and carcinogenicity (genotoxicity). This RQ evaluation was based on the Critical Body Residue (CBR) concept and a Physiologically-Based Pharmacokinetic Modelling (PBPK) approach using OHC concentrations measured in polar bear adipose or liver tissue. The range of OHC concentrations within polar bear populations were as follows for adipose, sum polychlorinated biphenyls ∑PCBs (1797-10,537ng/g lw), sum methylsulphone-PCB ∑MeSO2-PCBs (110-672ng/g lw), sum chlordanes ∑CHLs (765-3477ng/g lw), α-hexachlorocyclohexane α-HCH (8.5-91.3ng/g lw), β-hexachlorocyclohexane β-HCH (65.5-542ng/g lw), sum chlorbenzenes ∑ClBzs (145-304ng/g lw), dichlorodiphenyltrichloroethane ∑DDTs (31.5-206ng/g lw), dieldrin (69-249ng/g lw), polybrominated diphenyl ethers ∑PBDEs (4.6-78.4ng/g lw). For liver, the perfluorooctanesulfonic acid (PFOS) concentrations ranged from 231-2792ng/g ww. The total additive RQ from all OHCs ranged from 4.3 in Alaska to 28.6 in East Greenland bears for effects on reproduction, immune health and carcinogenicity, highlighting the important result that the toxic effect threshold (i.e. RQ>1) was exceeded for all polar bear populations assessed. PCBs were the main contributors for all three effect categories, contributing from 70.6% to 94.3% of the total risk and a RQ between 3.8-22.5. ∑MeSO2-PCBs were the second highest effect contributor for reproductive and immunological effects (0.17

To improve risk estimates for herbicides in streams, the sensitivity of natural periphyton communities to four herbicides (metribuzin, hexazinone, isoproturon, and pendimethalin) was examined in experiments including varying exposure duration and a recovery phase. Effect parameters included assimilation of 14C and concentration of diagnostic pigments as proxies for photosynthetic activity and algal group composition, respectively. The results indicated that isoproturon, metribuzin, and hexazinone affected the photosynthetic activity of periphyton at distinctly lower concentrations than the effect concentrations published for standard single-species growth-tests with phytoplankton species. Pendimethalin did not show effects on the photosynthetic activity of periphyton at the concentrations tested. The effect concentration (EC50) of isoproturon and metribuzin decreased by one to two orders of magnitude when the duration of exposure increased from 1 h to 24 h, while hexazinone had a stimulating effect on the photosynthetic activity of periphyton after 1 h exposure and inhibiting effect after 24 h exposure. The photosynthetic activity after exposure to metribuzin for 1, 2, 6, 18, 23, or 48 h recovered almost completely after 48 h in herbicide-free water. However, different periphyton groups responded differently to metribuzin exposure: Chlorophytes were severely affected by exposure and did not recover, whereas diatoms and especially cyanobacteria recovered well. Overall the study showed that the effects of herbicides on periphyton are strongly affected by the duration of exposure, and even short-term exposure may have distinct effects on the periphyton community.

Sea-Nine211 has been introduced as a new biocide in antifouling paints with an immediate degradation when it is released from ship hulls. The active component of Sea-Nine211 is 4,5-dichloro-2-n-octyl-isothiazoline-3-one (DCOI). In the present study, the toxicity of DCOI and the occurrence of Pollution Induced Community Tolerance (PICT) were tested in microcosms containing eutrophic coastal water with its natural composition of phytoplankton. The experiment was performed in closed systems with a single addition of the nominal concentrations 0, 3.2, 10, 32 and 100 nM DCOI, for a period of 16 days. Pollution induced community tolerance (PICT) was observed in the phytoplankton communities exposed to the nominal concentrations 32 and 100 nM DCOI. Chemical analysis of DCOI in the coastal water utilised in the toxicity and PICT experiment was performed by GC-MS using a solid- phase extraction method. Half-life was calculated to be 2.5 days for the nominal concentrations 32 and 100 nM DCOI. The results of the present study show that nominal concentrations of 32 and 100 nM DCOI significantly increased the community tolerance already after 2 days of exposure and that the tolerance was maintained for a period of 16 days even when DCOI was degraded during this period. The causes for the persistent tolerance are discussed in relation to the degradation of DCOI and structural changes in the phytoplankton communities.

Due to high lipid content and a slow metabolism, there is a higher risk of bioaccumulation of oil compounds in Arctic than in temperate copepods. There is also a concern that the bioavailability of oil compounds is higher when oil is dispersed with dispersants. The purpose of this project was to increase the knowledge on how the use of dispersants on an oil spill may affect the passive uptake of PAHs in resting high arctic copepods using Calanus hyperboreus as a model organism. To evaluate this, resting high arctic C. hyperboreus were caught in Disko Bay at>250 meters depth, November 2013, and subsequent experimental work was initiated immediately after, at nearby Arctic Station at Disko Island Western Greenland. C. hyperboreus females were incubated in phenanthrene (111, 50 and 10 nM), pyrene (57, 28 and 6 nM) and benzo(a) pyrene (10, 5 and 1 nM) for three days in treatments with and without oil (corn oil) and dispersant (AGMA DR372). After exposure, the highest measured concentrations of respectively phenanthrene, pyrene and benzo(a) pyrene in the copepods were 129, 30 and 6 nmol PAH g female(-1). Results showed that with addition of oil and dispersant to the water, the accumulation of PAH was significantly reduced, due to the deposition of the PAHs in the oil phase, decreasing the available PAHs for copepod uptake. While PAH metabolites and a depuration of the PAHs were observed, the copepods still contained PAHs after 77 days of incubation in clean seawater. Differences of treatments with and without oil and dispersant on the egg production were not statistically conclusive, although it is the most likely an effect of the highly variable day-to-day egg production between individual copepods. Equally, although there was an indication that the addition of dispersant and oil increased the mortality rate, there was no statistical difference.

Industrially produced chemicals have been a major environmental concern across our entire Globe since the onset of rapid industrial development around the early 1900. Many of the substances being used are known to be endocrine disrupting chemicals (EDCs) and are also known to be long-range dispersed and to biomagnify to very high concentrations in the tissues of Arctic apex predators such as polar bears (Ursus maritimus). A major concern relating to EDCs is their effects on vital organ-tissues such as bone and it is possible that EDCs represent a more serious challenge to the species' survival than the more conventionally proposed prey reductions linked to climate change. We therefore analyzed penile bone mineral density (BMD) as a key phenotype for reproductive success in 279 polar bear samples born 1990-2000 representing eight polar bear subpopulations. Since EDC concentrations were not available from the same specimens, we compared BMD with published literature information on EDC concentrations. Latitudinal and longitudinal BMD and EDC gradients were clearly observed, with Western Hudson bears having the highest BMD and lowest EDCs, and North East Greenland polar bears carrying the lowest BMD and highest EDCs. A BMD vs. polychlorinated biphenyls (PCB) regression analysis showed that BMD decreased as a function of the eight subpopulations' PCB concentrations and this relationship was close to being significant (p=0.10, R(2)=0.39). Risk quotient (RQ) estimation demonstrated that PCBs could be in a range that may lead to disruption of normal reproduction and development. It is therefore likely that EDCs directly affect development and bone density in polar bears. Canadian bears had in general the best health and the North East Greenland subpopulation being at the highest risk of having negative health effects. While reductions in BMD is in general unhealthy, reductions in penile BMD could lead to increased risk of species extinction because of mating and subsequent fertilization failure as a result of weak penile bones and risk of fractures. Based on this, future studies should assess how polar bear subpopulations respond upon EDC exposure since information and understanding about their circumpolar reproductive health is vital for future conservation.

The former Black Angel lead-zinc mine in Maarmorilik, West Greenland, is a historic example of how mining activity may result in a significant impact on the surrounding fjord system in terms of elevated concentrations of especially lead (Pb) and zinc (Zn) in seawater, sediments and surrounding biota. In order to shed light on the present contamination and possible effects in the fjord we initiated a range of studies including a pilot study on gill and liver morphology of common sculpins (Myoxocephalus scorpius) around Maarmorilik. Sculpins were caught and sampled at five different stations known to represent a gradient of Pb concentrations. Fish livers from all specimens were analyzed for relevant elements in the area: Fe, Zn, As, Cu, Se, Cd, Pb, Ag, Hg, Co and Ni. Lead, As and Hg showed significant differences among the five stations. For 20% of the sculpins, Hg concentrations were in the range of lowest observed effect dose (LOED) of 0.1-0.5μg/gww for toxic threshold on reproduction and subclinical endpoints. Likewise LOEDs for tissue lesions, LOEDs for biochemistry, growth, survival and reproduction were exceeded for Cd (0.42-1.8μg/gww) and for As (11.6μg/gww) in 28% and 85% of the sculpins, respectively. Similar to this, the no observed effect dose (NOED) for biochemistry was exceeded for Pb (0.32μg/gww) and for growth, mortality and reproduction for Zn (60-68μg/gww) in 33% and 24% of the sculpins, respectively. For all sculpins, females were significantly larger than males and for five of the elements (Fe, Co, Ni, Cu, Se) females had higher concentrations. The chronic lesions observed in liver (mononuclear cell infiltrates, necrosis, vacuolar hepatocytes, portal fibrosis, bile duct hyperplasia, active melanomacrophage centers) and gills (fusion and edema of secondary lamellae, laminar telangiectasis, mononuclear cell infiltrates, blebs) were similar to those in the literature studies for both wild and laboratory exposed sculpins and other fish species carrying similar or higher Hg concentrations. Ignoring sex and size, specimens with hepatic cell infiltrates had the highest concentrations of most elements, a relation that was also found for gill telangiectasis and Hg (all p

Phytoplankton blooms were created in freshwater enclosures to study the functional succession and diversification for attached (>10 µm size fraction) and free-living ( 0.07), whereas 3 glucoside-bond cleaving enzymes were more frequent among the free-living isolates (p < 0.02). These results indicate that attached and free-living bacteria were functionally closely related and that their succession tended to converge during the phytoplankton bloom. Hence, bacteria attached to particulate matter are not necessarily functionally distinct and specialized for polymer hydrolysis relative to the free-living assemblage, though they are often anticipated to be different due to their close association with particulate polymers.

The impact of UV-B radiation (290-315 nm) on bacterial activity and abundance in coastal water was studied in mesocosm experiments in May 1994 and May 1995 at Kristineberg Marine Research Station, Sweden. Mesocosms (6 m3) containing natural pelagic communities were exposed either to ambient irradiation (AMB), ambient irradiation with enhanced UV-B (+UV) (0.7 W m-2 4h every day around noon), or ambient irradiation screened for UV-B (-UV). Bacterial activity in the mesocosms was measured by means of thymidine incorporation in short-term tests during incubations at ambient irradiation, at ambient irradiation with enhanced UV-B, and at ambient irradiation screened for UV-B. In +UV mesocosms, bacterial activity was significantly stimulated when incubated at ambient radiation. The stimulating effect was suggested to be due to an increase in carbon or nutrient supply through a photodegradation of recalcitrant dissolved organic material (DOM). Low attenuation coefficients for UV-B and PAR (400-700 nm) in the +UV mesocosms supported this hypothesis. The bacterial activity in +UV mesocosms, however, was inhibited when incubations were made at enhanced UV-B irradiation, implying that the bacteria had become more sensitive to UV-B radiation. The increased sensitivity to UV-B exposure in bacterial assemblages that already had been exposed and stressed by UV-B radiation is suggested to be due to an overburdening of the energy- consuming DNA repair mechanism. The data suggest that increased UV-B radiation, which might occur with ozone depletion, may both stimulate and suppress bacterial activity in coastal waters, implying that the net outcome of enhanced UV-B radiation could be an unchanged bacterial activity.

In a three-week pelagic estuarine enclosure experiment, no effect concentrations (NEC) for tri-butyl-tin (TBT) were found in phytoplankton in the lower pico molar (pM) range as indicated by increased TBT tolerance, changes in taxonomic composition, decreased primary production and in the chlorophyll a (chl. a) concentration. Decreased primary production and chl.a concentrations were found only three days after addition of TBT. On the other hand, taxonomic changes and increased tolerance were found throughout the experiment, indicating a recovery of the ecosystem caused by adaptation of the phytoplankton in terms of structural changes. Induction of TBT tolerance is assumed to be evident of a direct toxic effect of TBT on the phytoplankton and the observed effects are thus not just attributable to indirect effect caused by direct effects on e.g. zooplankton. TBT concentrations in the lower pM range in coastal waters, such as open bays and estuaries, have been reported, indicating that natural phytoplankton could be affected by TBT in such areas.

Sediments and blue mussels were collected along a transect through the Baltic Sea to the Atlantic Ocean and analysed for a number of specific halogenated organic compounds and sum parameters. Multivariance analysis indicated geographical separation of the sediment data due to high concentrations of EOCl and EPOCl in the Bay of Bothnia and Bothnian Sea, high concentrations of sPCB in the Baltic proper and low concentrations of most of the compounds in the Skagerrak. The separation in mussels was due to high concentrations of sHCH and sDDT in the Danish sounds and the Kattegat, and high concentrations of EOX, EOCl and EOBr in the Baltic Sea. In contrast to the sediments, where no correlation was found between EOCl and EOX, these parameters are well correlated in the mussels. EOCl correlates to EPOCl both in sediments and blue mussels. The share of EPOCl is remarkably similar (ca. 11% of EOCl) in sediments and mussels.

The impact of UV-B radiation on alkaline phosphatase activity (APA) was examined in water samples from a phosphorus-depleted Norwegian fjord, Hylsfjord, in July 1995. APA was regularly measured for 4–7.5 h in water samples from the fjord (Exp. 1) and from a nutrient-manipulated enclosure (Exp. 2) incubated under three different light regimes; ambient radiation (AMB), ambient radiation with enhanced artificial UV-B (+UV), 1.10 W m −2 UV-B, and ambient radiation screened for UV-B (−UV). Water samples exposed to UV-B (+UV; AMB) had significantly lower APA than water samples screened for UV-B (−UV), both in raw water samples as well as in water samples prefiltered through 1 and 0.2 μm filters. The decline could be explained by photodegradation of dissolved and cell-bound APA, with dissolved APA being more affected than APA associated with organisms. The results suggest that UV-B radiation inhibits APA in phosphorus-depleted aquatic environments and has the potential to strengthen the phosphorus limitation of microbial ecosystems.

The toxic effect of copper to coastal phytoplankton communities was studied in 6 m3 enclosures during 15 days using the PICT (Pollution-Induced Community Tolerance) methodology. PICT, primary production, algal biomass, species composition and diversity in phytoplankton communities were measured in control enclosures and enclosures with 1, 3, 6 and 15 μg Cu l-1 added. Increased copper tolerances were induced in the enclosures with added copper and, related to the pooled mean value of the controls, the mean values for copper tolerance were significantly higher in enclosures with 1, 6 and 15 μg Cu l-1. In enclosures with 6 and 15 μg Cu l-1, photosynthetic activity was significantly depressed. Fundamental changes in taxonomic diversity and species composition occurred in enclosures with 15 μg Cu l-1. Algal biomass was not affected by the addition of copper. The distribution and concentration of copper in the enclosures showed that copper exposure was almost constant over time in the enclosures and was proportional to the amount of copper added to them. Our studies indicate that the PICT methodology is sensitive enough to detect even minor effects of copper on phytoplankton communities. The PICT measurements indicate effects from concentrations as low as 1 μg Cu l-1 in highly eutrophic coastal areas, where the bioavailability of copper is assumed to be low. Copper concentration in the fjord and control enclosures was high, about 0.5 μg Cu l-1, only a factor two below the effect concentration measured by PICT. These results are significant in view of the increased release of copper to the coastal marine environment as results of the substitution of copper-based ship paints for tri-n-butyltin (TBT) antifouling paints.

The impact of enhanced and reduced UVB radiation (UVBR) on pelagic ecosystems was studied during two mesocosm experiments in May and June/July 1994. The ambient UVBR exposure was either reduced with mylar foil or artificially enhanced with UVB fluorescent tubes. Developments in the phytoplankton communities were followed during 11 and 8 day periods using several structural and functional parameters. In the May experiment, enhanced UVBR significantly stimulated carbon dioxide fixation, activity of alkaline phosphatase and content of fatty acids. In the June-July experi- ment, the effects induced by changed UVBR were smaller with some indications of decreased algal biomass with enhanced UVBR. Several of the measured parameters indicated that the two experi- ments represented different stages in the plankton community development. In the May experiment, the community was in a development stage, moving from nutrient-replete to nutrient-depleted conditions, while the community in June/July was depleted of nutrients from the start. The stimulating effects of UVBR in May are suggested to be the secondary effects of a photochemically induced breakdown of dissolved organic matter, resulting in an increase in available nutrients.