Food chains and POPs - Project title
	Persistent organic contaminants in the food-web of the Barents Sea.
Co-ordinating institution
	Institute of Marine Research
Final report
	Jarle Klungsøyr:  Persistent organochlorines (OCs) in the pelagic foodweb in the Barents Sea
Summary and results
	Concentrations of persistent organochlorines (OCs) and biomagnification from zooplankton to fish in the pelagic food web of the Barents Sea have been investigated. Sampling took place during 1998-2000. Cod (Gadus morhua), polar cod (Boreogadus saida), haddock (Melanogrammus aeglefinus), long rough dab (Hippoglossoides platessoides), redfish (Sebastes marinus), herring (Clupea harengus) and capelin (Mallotus villosus) were collected. Zooplankton sampling included copepods (Calanus finmarchicus, Metridia longa), krill (Thysanoessa inermis, Meganyctiphanes norvegica) and amphipods (Themisto abyssorum, Themisto libellula). Pools of fish livers and zooplankton whole organisms from a minimum of two stations for each species were analysed by gas chromatography (GC-ECD): ∑PCB (IUPAC congeners 28, 52, 101, 105, 118, 128, 138, 149, 153, 156, 170, 180 and 194), ∑DDT (p,p´-DDD, p,p´-DDE, p,p´-DDT), ∑HCH (a-HCH, b-HCH, g-HCH), trans-nonachlor, HCB and toxaphene (CHB) congeners 26, 50 and 62 (only fish). Cod was analysed as individual fish (2 stations, 25+25 cod). Concentrations of OCs in copepods (C. finmarchicus and M. longa) were very low: ∑PCB 0.4-1.7 ng/g ww, ∑DDT  0.2-3.2 ng/g ww and ∑HCH 0.3-0.4 ng/g ww. In krill (T. inermis) the concentrations detected were: ∑PCB 1.2-1.7 ng/g ww, ∑DDT 1.6-1.7 ng/g ww and ∑HCH 1.6-2.3 ng/g ww. In the other krill species M. norvegica concentrations were: ∑PCB 1.6-2.0 ng/g ww, ∑DDT  2.0-2.1 ng/g ww and ∑HCH 0.8-1.3 ng/g ww. In the amphipod T. libellula the following concentrations were found: ∑PCB 1.9-2.3 ng/g ww, ∑DDT 2.0-3.0 ng/g ww and ∑HCH 0.3-0.8 ng/g ww. The amphipod T. abyssorum had approximately similar or slightly lower concentrations: ∑PCB 0.6-0.8 ng/g ww, ∑DDT 0.8-1.1 ng/g ww and ∑HCH 0.2-1.1 ng/g ww. Trans-nonachlor and HCB were detected at very low concentrations in all zooplankton samples analysed (<0.01-0.8 ng/g ww). Capelin liver contained low concentrations of OCs. The dominant compounds were ∑CHB (3.2-5.9 ng/g ww) followed by approximately similar or slightly lower concentrations of ∑PCB (2.3-5.5 ng/g ww), ∑DDT (1.9-4.0 ng/g ww) and ∑HCH (1.0-1.9 ng/g ww). Trans-nonachlor (0.5-1.0 ng/g ww) and HCB (1.0-1.2 ng/g ww) were detected at low concentrations. Polar cod contained slightly higher concentrations of OCs than capelin possibly due to a higher liver lipid content: ∑CHB 26-29 ng/g ww, ∑PCB 20-21 ng/g ww, ∑DDT 17-18 ng/g ww and ∑HCH 8-13 ng/g ww. Normalised to lipid weight the concentrations of OCs in the two species and herring were approximately similar. Herring contained approximately similar concentrations of OCs as found in capelin: ∑PCB 3.0-3.3 ng/g ww, ∑DDT 1.7-3.0 ng/g ww, ∑CHB 1.5-1.9 ng/g ww and ∑HCH 1.2-1.8 ng/g ww. Low levels of trans-nonachlor (0.3-0.4 ng/g ww) and HCB (0.4-0.7 ng/g ww) were also present. The highest concentrations of OCs in long rough dab were found of ∑PCB (9.2-26 ng/g ww) with only slightly lower concentrations of ∑DDT (6.6-15 ng/g ww) and ∑CHB (9.6-10 ng/g ww).  The concentrations of ∑HCH were only 1.0-1.2 ng/g ww, which is lower than for trans-nonachlor (3.1-5.7 ng/g ww) and HCB (1.2-2.5 ng/g ww). Individual cod livers contained the highest concentrations of OCs: ∑PCB (72-325 ng/g ww), ∑DDT (26-206 ng/g ww) and ∑CHB (24-144 ng/g ww). Trans-nonachlor (12-81 ng/g ww), HCB (1.1-25 ng/g ww) and ∑HCH (0.5-20 ng/g ww) were also detected. Haddock liver contained slightly lower concentrations than cod for ∑PCB (78-95 ng/g ww), ∑DDT (34-35 ng/g ww) and ∑CHB (36 ng/g ww). Average concentrations of ∑HCH (4.6-5.9 ng/g ww) were about the same as for cod, while trans-nonachlor (11-12 ng/g ww) and HCB (6 ng/g ww) were lower. Redfish liver contained low and approximately equal concentrations of ∑PCB (12-29 ng/g ww), ∑DDT (10-18 ng/g ww) and ∑CHB (17-26 ng/g ww). Trans-nonachlor, HCB (3.4-3.9 ng/g ww) and ∑HCH (2.1-2.4 ng/g ww) were also detected. Biomagnification factors from copepods (M. longa) containing the lowest concentrations of OC to other zooplankton and fish were calculated, based on average concentration on a lipid weight basis. Biomagnification factors for different zooplankton species varied between 1.8 and 5.2 for ∑PCB, ∑DDT and ∑HCH. Biomagnification factors for ∑PCB showed a general increase from zooplankton (1.8-5.2), to plankton feeding fish (5.8-9.2) and to fish further up in the food chain like cod and haddock (23-58). For ∑DDT the biomagnification factors for krill, amphipods and plankton feeding fish were quite similar (2.7-5.8) with an increase in factors for long rough dab (11), redfish (13), haddock (14) and cod (33). The biomagnification factors for ∑HCH from zooplankton (1.5-5.6) to fish (19-38) showed approximately a tenfold increase. Relevance for monitoring The project has provided new information about occurence and magnification of POPs in the pelagic food chain in the Barets Sea from zooplankton to fish. The information can be utilized for reporting state of the environment in the region and in future monitoring.
Original project description
	The ubiquitous presence of persistent organic contaminants (POPs) like PCBs, toxaphene and DDTs in the Barents Sea has been well documented. It is assumed that POPs to a great extent enters the Barents Sea by long range transport from more temperate regions. To be able to do an assessment of the effects of POPs on the Barents Sea food web there is a need for more information about uptake and transfer of compounds between different trophic levels. The total amounts of POPs taken up and transported through the food web can be estimated by linking the above information to general knowledge about the production of phytoplankton, zooplankton and fish in different areas of the Barents Sea. Information on the exposure at different trophic levels and general knowledge about biological effects is essential for risk assessment on the influence of POPs on the Barents Sea ecosystem. Arctic marine food webs are characterised by large seasonal variations in production which probably plays an important role both for the uptake, transfer and fate of POPs in the Barents Sea. POPs are often bound to lipids in marine organisms and great seasonal fluctuations in lipids play an important role for the effects and fate. Institute of Marine Research (IMR) intend to use the results from the proposed study to improve our time trend monitoring programme of contaminants in the Barents Sea. In connection with the field work, samples will also be collected for analysis of trace metals (cadmium, mercury and lead) and radionuclides. The plans for analysis of radiunuclides will be sent in as a separate proposal by Statens strålevern as a joint project with IMR. Analysis of trace metals will be carried out in cooperation with Fiskeridirekoratets ernæringsinstitutt if external funding is obtained. Objectives Increased knowledge of present levels of POPs in key species of the food web in the Barents Sea. Calculations will be performed to estimate the total amounts of POPs at different trophic levels from phytoplankton to fish. Increased knowledge about important processes for uptake and transport of POPs in the pelagic food web of the Barents Sea, with special focus on the role of lipids. Better basis for assessment of environmental impacts of POPs and for improving the monitoring of the Barents Sea. Methods Field sampling The pelagic food web in the Barents Sea is relatively simple, with a restricted number of dominant species in the food chains supporting fish and other higher trophic level species. The food web involving benthos and demersal fish is less studied than the pelagic part of the Barents Sea ecosystem. The analyses of POPs will be done on the following selected species in the food web: Phytoplankton - Samples of the mixed phytoplankton community will be taking by filtering large water samples onto filters with pore size of approximately 1 m m. The water samples will be prescreened through 30 or 60 m m mesh to remove zooplankton. Samples of phytoplankton will be taken during and after the spring bloom in water influenced by ice and ice melt and in Atlantic water in the central Barents Sea. Calanus spp. - Calanus finmarchicus and C. glacialis are two key herbivore species in respectively the Atlantic and Arctic water masses in the Barents Sea (Melle 1998, Melle and Skjoldal 1998). Samples of the two Calanus spp. will be taken in early summer as the new generations of copepodites are developing (June), in autumn (September) at the start of the overwintering period, and in winter (February-March) towards the end of the overwintering period. The overwintering stage CV will be used for C. finmarchicus. C. glacialis overwinters both as stage CIV and CVI. Stages CIV-CVI will be sampled and used according to their availability at the times of sampling. Krill - Thysanoessa inermis is the main krill species in the western and central Barents Sea. It is distributed mainly in the Atlantic water mass and is rare in the Arctic water (Dalpadado and Skjoldal 1996). T. inermis has a life span of 3-4 years, and the majority of individuals mature in the Barents Sea as two-years old. We assume that this species is predominantly herbivore. Samples of T. inermis will be taken in Atlantic water in the central Barents Sea early (June) and late (September) in the growth season and during overwintering (February). Amphipods - Themisto abyssorum and T. libellula are two important pelagic amphipods in respectively the Atlantic and Arctic water masses in the Barents Sea (Dalpadado et al. 1994). The Themisto spp. are carnivores, and they constitute an important component of the diet of capelin and cod. Samples of the two Themisto spp. will be taken in autumn (September) and winter (February). Individuals will be sorted into "small" and "large" categories prior to contaminant analyses. Capelin (Mallotus villosus) is a key corner stone species in the Barents Sea ecosystem (Skjoldal and Rey 1989, Sakshaug et al. 1994, Bogstad and Mehl 1998). It feeds mainly on Calanus spp., krill, and amphipods, and it constitutes a major food item for cod, seabirds, and sea mammals. Capelin has a large scale feeding migration from Atlantic water in the central Barents Sea into the Arctic water during summer. Samples of juvenile and immature capelin (0-, 1-, and/or 2-group) will be collected early (June) and late (September) in the seasonal growth period, and during winter (February). Maturing capelin will be sampled in winter (February-March). Polar cod (Boreogadus saida) lives mainly in the Arctic water north of the Polar front. It is like capelin a plankton feeder, and constitute a major food item for seals and seabirds in the ice covered waters of the Barents Sea. Samples of polar cod will be taken early (June) and late (September) in the growth season. If possible samples will also be taken during winter (February-March). Herring - Juveniles of the Norwegian spring spawning herring stock (Clupea harengus) have the southern and eastern Barents Sea as their nursery grounds. This is particularly the case for strong yearclasses of herring. The juvenile herring leave the Barents Sea to join the adult stock in the Norwegian Sea at an age of 3-4 years (Holst 1996). Juvenile herring is an important but variable component in the Barents Sea ecosystem. Herring is a plankton feeder and preys particularly on Calanus finmarchicus in the Barents Sea. Samples of juvenile herring will be taken early (June) and late (September) during the growth season. Shrimp (Pandalus borealis) lives and feeds mainly at the bottom. It can also swim up in the water column and feed on zooplankton, particularly during the dark winter period. P. borealis is an important food item for cod. Samples of shrimp from the central Barents Sea will be taken in autum (September) and winter (February-March). Long rough dab (Hippoglossoides platessoides) form a large stock in the Barents Sea. They feed at the bottom and are being preyed upon by cod. Samples of long rough dab will be taken from the central Barents Sea in autum (September) and winter (February-March). Cod (Gadus morhua) is a major species in the Barents Sea ecosystem of large economic and ecological importance. Capelin is the most important food item for cod. Krill and amphipods are also important, particularly for young age groups of cod and in periods when the capelin stock is low (Bogstad and Mehl 1998). Shrimp and herring may also contribute significantly to the diet of cod. Samples of cod will be taken in winter (February), early summer (June), and autumn (September). Samples will be taken from different size groups according to the guidelines of ICES and OSPAR. Haddock (Melanogrammus aeglefinus) has a major stock in the Barents Sea. Its feeding habit is more associated with the bottom than for cod, and it feeds to a large extent on benthic organisms. Samples of haddock will be taken in winter (February), early summer (June), and autumn (September). Chemical analysis GC-ECD and HRGC/MS will be used for the analysis of: PCBs (IUPAC Nos. 28, 31, 52, 101, 105, 128, 138, 149, 153, 156, 170, 180) DDTs (p,p´-DDT, p,p´-DDE, p,p´-DDD) HCHs (a -HCH, b -HCH, g -HCH) Toxaphenes (Parlar Nos, 26, 50, 62) HCB Trans-nonachlor Wet and dry weight relationship and total lipid will be determined using gravimetric methods. Biological analysis Identification and description of the biological material will be done according to well documented methods at IMR. Method validation Institute of Marine Research (IMR) has participated in a number of intercomparison exercises for the methods used in this project: 1989-1993: ICES/IOC/JMG intercalibration exercises on PCBs in marine media 1993-present: Quality Assurance of Information for Marine Environmental Monitoring in Europe, QUASIMEME. PCBs and organochlorine pesticides in standard solutions, fish oil, lean and fatty fish tissue, and mussels. 1997-present: Intercalibration exercises in the EU-Fair project "Investigations into the Monitoring, Analysis and Toxicity of Toxaphene in marine foodstuffs (MATT)". Since 1984 IMR has regularly contributed to the European Commision´s Measurement and Testing Programme for Certification of Reference Materials (BCR). These contributions include: certification of PCB in fish oil, sewage sludge, mineral oil, milk powder, soil, mussel tissue (ongoing) and certification of organochlorine pesticides in fish oil.   Principal investigators This project will be carried out by IMR, section for Marine Chemistry. Jarle Klungsøyr and Asbjørn Svardal will be the principal scientists responsible for the project.   Time schedule May 1999-Feb. 2000: Sample collection at IMR´s routine cruises in the Barents Sea. June1999-April 2000: Completion of chemical analysis. January 2000: Preparation of technical report for work carried out 1999. Spring 2000: Final publication of results   Costs The project expences will be linked to field work, salary costs and costs for chemical analysis and reporting. Total budget: NOK 1 398 000,- IMR will cover the costs for field work and salary to the scientists involved. IMR has been funded by the programme "Miljøgifter i marine næringskjeder i nordlige havområder" to cover costs for the chemical analysis.   Deliverables The project will result in a detailed description of the concentration of POPs in the food web in the Barents Sea from plankton to fish. Linked to IMR´s extensive database on plankton and fish in the Barents Sea it will be possible to estimate the total burden of POPs in the pelagic food chain of the area. The results from the project will give new information for optimalization of future monitoring of POPs in the Barents Sea.   References Bogstad, B. and Mehl, S. 1998. Interactions between cod and its prey species in the Barents Sea. International Symposium on the Role of Forage Fish in Marine Ecosystems. Anchorage, Alaska 13-16 November 1996. Dalpadado, P., Borkner, N. and Skjoldal, H.R. 1994. Distribution and life history of Thiemisto (Amphipoda) spp., north of 73 0N in the Barents Sea. Fisken og havet 1994:12, ISSN 0071-5638. Dalpadado, P. and Skjoldal, H.R. 1996. Abundance, maturity and growth of the krill species Thysanoessa inermis and T. longicaudata in the Barents Sea. Mar. Ecol. Prog. Ser. 144: 175-183 Melle, W. 1998. Reproduction, life cycles, and distribution of Calanus finmarchicus, Calanus glacialis and Calanus hyperboreus in relation to environmental conditions in the Barents Sea. Thesis for the partial fulfilment of the Dr. scient. degree. Department of Fisheries and Marine Biology, University of Bergen, Norway, 1998. Melle W. and Skjoldal H.R. 1998. Reproduction and development of Calanus finmarchicus, C. glacialis and C. hyperboreus in the Barents Sea. Mar. Ecol. Prog. Ser. 169: 211-228. Holst, J.C. 1996. Long term trends in the growth and recruitment pattern of the Norwegian spring-spawning herring (Clupea harengus, Linnaeus 1758). Thesis for the partial fulfilment of the Dr. scient. degree. Department of Fisheries and Marine Biology, Univeristy of Bergen, Norway, 1996. Sakshaug, E., Bjørge, A., Gulliksen, B., Loeng, H. and Mehlum, F. 1994. Structure, biomass distribution, and energetics of the pelagic ecosystem in the Barents Sea: A synopsis. Polar Biol. 14: 405-411 Skjoldal, H.R. and Rey, F. 1989. Pelagic production and variability in the Barents Sea ecosystem. In: Sherman, K. and Alexander, L.M. (eds.). Biomass yields and geography of large marine ecosystems. AAAS Selected symposium 111. American Assosiation for the Advancement of Science, Washington, USA, Pp. 241-286