Levels and congener profiles of PBDEs in edible Baltic, freshwater, and farmed fish in Finland.

Fish is the major source of polybrominated diphenyl ethers (PBDEs) for Finnish consumers. To estimate the PBDE contamination in fish that Finns regularly consume as food, a large-scale sampling was undertaken in 2009-2010. Altogether 207 samples of 17 edible fish species were collected from commercially and recreationally important fishing areas in the Baltic Sea, freshwater lakes, and farming facilities. The analysis of 15 PBDE congeners was performed in an accredited testing laboratory with high-resolution gas chromatography mass spectrometry. In all of the samples, the Σ15PBDE varied between 0.029 and 73 ng/g fw. The most abundant congeners were BDE-47 (average proportion 42%), -99 (8.4%), -100 (11%), -154 (5.6%), and -209 (27%). High levels of BDE-209 were observed in the Baltic Sea, off the coast of Pori, in Baltic herring, perch, pike, and pike-perch. Overall, the PBDE levels in Baltic and freshwater fish were low. The levels in farmed whitefish were slightly higher than in wild whitefish. The reasons for the high BDE-209 levels in Baltic herring in Pori and the elevated levels of PBDEs in farmed whitefish should be investigated more thoroughly.

High Lipid Content of Prey Fish and n-3 PUFA Peroxidation Impair the Thiamine Status of Feeding-Migrating Atlantic Salmon (Salmo salar) and Is Reflected in Hepatic Biochemical Indices.

Signs of impaired thiamine (vitamin B1) status in feeding-migrating Atlantic salmon (Salmo salar) were studied in three Baltic Sea areas, which differ in the proportion and nutritional composition of prey fish sprat (Sprattus sprattus) and herring (Clupea harengus). The concentration of n-3 polyunsaturated fatty acids (n-3 PUFAs) increased in salmon with dietary lipids and n-3 PUFAs, and the hepatic peroxidation product malondialdehyde (MDA) concentration increased exponentially with increasing n-3 PUFA and docosahexaenoic acid (DHA, 22:6n-3) concentration, whereas hepatic total thiamine concentration, a sensitive indicator of thiamine status, decreased with the increase in both body lipid and n-3 PUFA or DHA concentration. The hepatic glucose 6-phosphate dehydrogenase activity was suppressed by high dietary lipids. In salmon muscle and in prey fish, the proportion of thiamine pyrophosphate increased, and that of free thiamine decreased, with increasing body lipid content or PUFAs, or merely DHA. The thiamine status of salmon was impaired mainly due to the peroxidation of n-3 PUFAs, whereas lipids as a source of metabolic energy had less effect. Organochlorines or general oxidative stress did not affect the thiamine status. The amount of lipids, and, specifically, their long-chain n-3 PUFAs, are thus responsible for generating thiamine deficiency, and not a prey fish species per se.

Distribution of perfluoroalkyl acids in fish species from the Baltic Sea and freshwaters in Finland.

Occurrence and distribution of perfluoroalkyl acids (PFAAs), a sub-category of per- and polyfluoroalkyl substances (PFASs), is widespread in the environment. Food, especially fish meat, is a major pathway via which humans are exposed to PFAAs. As fish is an integral part of Nordic diet, therefore, in this study, several fish species, caught in selected Baltic Sea basins and freshwater bodies of Finland, were analysed for PFAAs. Perfluorooctane sulfonate (PFOS) was detected in all Baltic Sea fish samples and in >80% fish samples from freshwaters. PFOS contributed between 46 and 100% to the total PFAA concentration in Baltic Sea fish samples and between 19 and 28% in fish samples from freshwaters. Geographically, concentration ratios of PFOS to other PFAAs differed between fish from the Baltic Sea and Finnish lakes suggesting that distribution of PFAAs differ in these environments. Results were compared with current safety thresholds - environmental quality standard for biota (EQSbiota) set by the European Commission and a group tolerable weekly intake (TWI) for the sum of four PFASs (∑PFAS-4) i.e. perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorohexane sulfonate (PFHxS) and PFOS, recommended by the European Food Authority (EFSA). EQSbiota compliance was observed for PFOS in all species except smelt caught in the Baltic Sea and also in the River Aurajoki, where smelt had migrated from the Baltic Sea for spawning. Moderate consumption of most Baltic fishes (200 g week-1) results in an exceedance of the new TWI (4.4 ng kg-1 body weight week-1) for ∑PFAS-4.

Organotin intake through fish consumption in Finland.

BACKGROUND: Organotin compounds (OTCs) are a large class of synthetic chemicals with widely varying properties. Due to their potential adverse health effects, their use has been restricted in many countries. Humans are exposed to OTCs mostly through fish consumption. OBJECTIVES: The aim of this study was to describe OTC exposure through fish consumption and to assess the associated potential health risks in a Finnish population. METHODS: An extensive sampling of Finnish domestic fish was carried out in the Baltic Sea and freshwater areas in 2005-2007. In addition, samples of imported seafood were collected in 2008. The chemical analysis was performed in an accredited testing laboratory during 2005-2008. Average daily intake of the sum of dibutyltin (DBT), tributyltin (TBT), triphenyltin (TPhT) and dioctyltin (DOT) (SigmaOTCs) for the Finnish population was calculated on the basis of the measured concentrations and fish consumption rates. RESULTS: The average daily intake of SigmaOTCs through fish consumption was 3.2ng/kgbwday(-1), which is 1.3% from the Tolerable Daily Intake (TDI) of 250ng/kgbwday(-1) set by the European Food Safety Authority. In total, domestic wild fish accounted for 61% of the SigmaOTC intake, while the intake through domestic farmed fish was 4.0% and the intake through imported fish was 35%. The most important species were domestic perch and imported salmon and rainbow trout. CONCLUSIONS: The Finnish consumers are not likely to exceed the threshold level for adverse health effects due to OTC intake through fish consumption.

Accumulation and effects of nodularin from a single and repeated oral doses of cyanobacterium Nodularia spumigena on flounder (Platichthys flesus L.).

Nodularin (NODLN) is a cyclic pentapeptide hepatotoxin produced by the cyanobacterium Nodularia spumigena, which occurs regularly in the Baltic Sea during the summer season. In this study flounder (Platichthys flesus L.) was orally exposed to NODLN either as a single dose or as three repeated doses 3 days apart. Liver and bile samples of the fish were taken 4 days after the last dose. Liver glutathione-S-transferase (GST) activity was also measured and the histopathology of the liver was investigated. The liver of the exposed fish was analyzed by liquid chromatography-mass spectrometry for NODLN concentration. The content of NODLN-like compounds in the bile was analyzed by enzyme-linked immunosorbent assay. NODLN exposure caused slightly incoherent liver architecture and degenerative cell changes in both groups. The mean liver GST activity was significantly higher in the repeatedly dosed flounders than in the singly dosed flounders or in the control. In conclusion, the significantly lower NODLN concentration and the increased GST activity in the liver of the repeatedly dosed flounders compared to the singly dosed flounders suggest that NODLN is rapidly detoxificated. The absence of NODLN glutathione conjugates and the low concentrations of NODLN-like compounds in the bile indicate that detoxification products disintegrate or they are rapidly excreted.

How to preserve and handle fish liver samples to conserve RNA integrity.

As transcriptomic studies are becoming more and more common, it is important to ensure that the RNA used in the analyses is of good quality. The RNA integrity may be compromised by storage temperature or freeze-thaw cycles, but these have not been well studied in poikilothermic fishes. This work studied the effects of tissue storage time and temperature, and freeze-thaw cycles of tissue and extracted RNA on RNA integrity in brown trout (Salmo trutta L.) liver. The storage time and temperature had an effect on RNA integrity, but RNA suitable for quantitative reverse transcription PCR (RT-qPCR) (RIN > 7) was still obtained from samples preserved at - 20 °C for 6 months. Freeze-thaw cycles of tissue or RNA did not compromise the integrity of RNA. RNA degradation had an effect on RT-qPCR results, and the effect depended on gene. The RT-qPCR analysis of historical samples from a bleached kraft pulp mill effluent exposure in 1984 revealed no significant cyp1a induction. Recommendations are given for the preservation and handling procedures of samples designated for transcriptomic analyses.

Fatty acid signatures connect thiamine deficiency with the diet of the Atlantic salmon (Salmo salar) feeding in the Baltic Sea.

Thiamine (vitamin B1) deficiency in salmonids related to a lipid-rich fish diet causes offspring mortality in the yolk-sac fry phase. A low free thiamine (THIAM) concentration in eggs is an indication of this syndrome. Thiamine deficiency of salmon (Salmo salar) feeding in the Baltic Sea, called M74, was connected to the principal prey fish and feeding area using fatty acid (FA) signature analysis. The FAs of feeding salmon from two areas of the Baltic Sea, the Baltic Proper (57°10' 19°30') and the Bothnian Sea (61°30' 20°00') in 2004, reflected the principal prey species in these areas, sprat (Sprattus sprattus) and herring (Clupea harengus), respectively. Arachidonic acid (ARA, 20:4n-6) and 18:1n-7 indicated dietary herring, 18:1n-9 dietary sprat and 14:0 feeding in the Baltic Proper. The muscle FA profile of non-M74 female spawners of the River Simojoki in a year (1998) with a moderate M74 incidence and salmon of a non-M74 year (2004) reflected herring FAs, whereas the FAs in the M74 year and specifically in M74 females displayed characteristics of sprat. In the M74 year, the THIAM concentration had the strongest positive correlation with the proportion of muscle ARA, and the strongest negative correlations with 14:0 and the ratios 18:1n-9/ARA and 14:0/ARA. Thus, ARA along with 14:0 and these ratios were the most sensitive FA indicators of the dietary species and origin of the M74 syndrome. Despite the pre-spawning fasting, tissue FA signatures were consequently able to connect dietary sprat in the Baltic Proper with thiamine deficiency in Baltic salmon.

Human dietary intake of organochlorines from Baltic herring: implications of individual fish variability and fisheries management.

This study examines the extent to which Finnish human dietary intake of organochlorines (PCDD/Fs and PCBs) originating from Northern Baltic herring can be influenced by fisheries management. This was investigated by estimation of human intake using versatile modeling tools (e.g., a herring population model and a bioenergetics model). We used a probabilistic approach to account for the variation in human intake of organochlorines originating from the variation among herring individuals. Our estimates were compared with present precautionary limits and recommendation for use. The results show that present consumption levels and frequencies of herring give a high probability of exceeding recommended intake limits of PCDD/Fs and PCBs. Furthermore, our results clearly demonstrate that in the risk management of dioxinlike organochlorines, regulating fishing (in this case increasing fishing pressure) is a far less effective way to decrease the risk than regulating the consumption of herring. Increased fishing would only slightly decrease organochlorine concentrations of herring in the Finnish fish market.

Oxygen and carbon isoscapes for the Baltic Sea: Testing their applicability in fish migration studies.

Conventional tags applied to individuals have been used to investigate animal movement, but these methods require tagged individuals be recaptured. Maps of regional isotopic variability known as "isoscapes" offer potential for various applications in migration research without tagging wherein isotope values of tissues are compared to environmental isotope values. In this study, we present the spatial variability in oxygen (δ18OH2O) and dissolved inorganic carbon (δ13 CDIC) isotope values of Baltic Sea water. We also provide an example of how these isoscapes can reveal locations of individual animal via spatial probability surface maps, using the high-resolution salmon otolith isotope data from salmon during their sea-feeding phase in the Baltic Sea. A clear latitudinal and vertical gradient was found for both δ18OH2O and δ13 CDIC values. The difference between summer and winter in the Baltic Sea δ18OH2O values was only slight, whereas δ13 CDIC values exhibited substantial seasonal variability related to algal productivity. Salmon otolith δ18Ooto and δ13Coto values showed clear differences between feeding areas and seasons. Our example demonstrates that dual isotope approach offers great potential for estimating probable fish habitats once issues in model parameterization have been resolved.

Developmental disturbances in early life stage mortality (M74) of Baltic salmon fry as studied by changes in gene expression.

BACKGROUND: We have studied alterations of gene expression associated with naturally-occurring early life stage mortality (M74) in Baltic salmon using a cDNA microarray and real time PCR. M74-affected fry have several typical neurological, cardiovascular and pathological symptoms. They are also characterized by low thiamine content and show signs of oxidative stress. RESULTS: Affected fry can be divided into three major groups with early, intermediate or late onset of mortality. If mortality starts during the first third of the yolk-sac stage, virtually all the responses are compatible with stress, which rapidly leads to the common terminal responses. If death occurs during the second third of the yolk sac stage, the terminal stage is preceded by a decrease in globin gene expression, which leads to internal hypoxia when the animals grow and shift from skin- to gill-breathing. Fry will eventually proceed to the terminal responses. The group developing M74 most slowly appears to compensate for reduced oxygen delivery by downregulation of metabolism, and hence some fry can escape death. CONCLUSION: Our study is the first demonstration of diverse transcriptional responses to a naturally-occurring developmental disturbance. Since many of the genes differentially expressed in M74-fry are evolutionarily conserved, the M74 of Baltic salmon can serve as a model for developmental disturbances and environmental stress responses in vertebrates in general.

Polychlorinated dibenzo-p-dioxins, dibenzofurans, biphenyls, naphthalenes and polybrominated diphenyl ethers in the edible fish caught from the Baltic Sea and lakes in Finland.

A total of 156 fish composite samples were collected from five areas of the Baltic Sea and from three lakes and analysed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs) and polybrominated diphenyl ethers (PBDEs). The European Union's maximum permissible level for PCDD/Fs, 4 pg WHO-TEQ/g fresh weight (fw), was exceeded in salmon, river lamprey and Baltic herring. In other species from the Baltic Sea, the 90th percentile was 3.42 pg WHO(PCDD/F)-TEQ/g fw. In the lake fish, the concentrations of PCDD/Fs, PCBs and PCNs were only 29-46% of those in the same species caught from the Baltic Sea, whereas the concentrations of PBDEs in the lake fish were as high as in the Baltic Sea fish. Dioxin-like PCBs contributed to the total dioxin-like toxicity of PCBs and PCDD/Fs by 49+/-12% in all the analysed samples.

Measurements of biomarker levels in flounder (Platichthys flesus) and blue mussel (Mytilus trossulus) from the Gulf of Gdansk (southern Baltic).

In the framework of the EU funded BEEP project a set of biomarkers, gross morphometric indices and tissue concentrations of selected organic pollutants were measured in flounder (Platichthys flesus) and mussels (Mytilus trossulus) collected twice a year (April and October) from three sites in the inner Gulf of Gdansk between autumn 2001 and spring 2003. In flounder, seasonal differences in most biomarkers were observed, but no correlations with tissue pollutant levels could be found. In mussels, highly variable levels in biomarker responses were seen, but no clear seasonal or spatial trends, directly related to tissue concentrations, could be established. The observed biomarkers distribution the study sites are probably mostly caused by interannual, seasonal and individual variability and, in case of flounder, possibly by exchange of stocks between the sampling sites.

The dependence of organohalogen compound concentrations on herring age and size in the Bothnian Sea, northern Baltic.

The concentrations and composition profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans, polychlorinated biphenyls, polybrominated diphenyl ethers and polychlorinated naphthalenes were determined in herring individuals collected from the commercial catches of the Bothnian Sea, northern Baltic. The median age of herring was 5.0 years and in the muscle the median toxic equivalent concentration of PCDD/Fs was 5.6 WHO(PCDD/F)-TEQ pg/g fresh weight (fw) and that of PCBs 2.7 WHO(PCB)-TEQ pg/g fw. The median sum concentration of PBDEs was 1.4 ng/g fw and that of PCNs 0.1 ng/g fw. Differences in age-dependent accumulation between the organohalogen groups and individual congeners were major. In the Bothnian Sea the content of organohalogen compounds in herring is obviously elevated due to the availability and large proportion of Mysis crustaceans in their diet. More intensive fishing could reduce the concentrations of organohalogens, including the abundant, accumulative and toxic 2,3,4,7,8-PeCDF congener in the Baltic herring catch.

Biomarker responses as indication of contaminant effects in blue mussel (Mytilus edulis) and female eelpout (Zoarces viviparus) from the southwestern Baltic Sea.

During a field study performed in spring and autumn 2001 and 2002, blue mussels (Mytilus edulis) and female eelpout (Zoarces viviparus) were collected at three locations in the Wismar Bay (Baltic Sea), and several biomarkers of contaminant effects were analysed. Besides seasonal and inter-annual variations, biomarker signals were most pronounced at the location closest to Wismar Harbour (Wendorf) in both species. Lysosomal membrane stability (LMS) was lowest and acetylcholinesterase activity (AChE) was significantly reduced. Frequency of micronuclei (MN) was significantly higher (in blue mussels), indicating mutagenic effects. In eelpout elevated levels of DNA adducts, EROD induction and PAH-metabolites were measured. Metallothionein (MT), biomarker for trace metal exposure, showed a gradient only in spring. Organochlorine contaminant analyses (PCBs, DDTs) corresponded to the observed biomarker levels. The results obtained clearly demonstrate pollution effects in the southwestern Baltic Sea. Moreover, they show that a multibiomarker approach is also applicable in a brackish water environment.

Use of biliary PAH metabolites as a biomarker of pollution in fish from the Baltic Sea.

During field campaigns of the BEEP project (Biological Effects of Environmental Pollution in Marine Coastal Ecosystems) in 2001-2002, metabolites of polycyclic aromatic hydrocarbons (PAHs) were determined in bile samples from three fish species, flounder (Platichthys flesus), perch (Perca fluviatilis) and eelpout (Zoarces viviparus), from four separate areas in the Baltic Sea. Two determination methods were applied: fixed wavelength fluorescence (FF) for pyrene-type metabolites and high-performance liquid chromatography with fluorescence detection (HPLC). There was a good correlation between the FF method and 1-OH pyrene determined by HPLC. Normalisation of the FF data for absorbance at 380 nm or bile protein concentrations greatly increased variance in one third and decreased it in two thirds of the cases and resulted in a loss of significant differences (protein normalisation) between the sampling stations, but normalisation of the HPLC data had little effect on the results. The biliary PAH metabolite content was usually higher in males than in females. In perch and eelpout the biliary PAH contents were at similar levels, whereas in flounder the levels were lower. The sampling areas arranged in decreasing order of biliary PAH contents were: Wismar Bay > Gulf of Gdansk > Lithuanian coast > Kvadofjärden (reference area). It is concluded that FF with un-normalised data is a reliable and simple method for monitoring purposes and only one sex of a selected species should be used.

The BEEP project in the Baltic Sea: overview of results and outline for a regional biological effects monitoring strategy.

Field studies in the framework of the EU funded BEEP project (Biological Effects of Environmental Pollution in Marine Coastal Ecosystems, 2001-2004) aimed at validating and intercalibrating a battery of biomarkers of contaminant exposure and effects in selected indicator species in the Mediterranean, the North Atlantic and the Baltic Seas. Major strategic goals of the BEEP project were the development of a sensitive and cost-efficient biological effects monitoring approach, delivery of information and advice to end-user groups, and the implementation of a network of biomarker researchers around Europe. Based on the main results obtained in the Baltic Sea component of the BEEP the present paper summarises and assesses the applicability of biomarkers for different regions and species in this sea area. Moreover, a general strategy and some practical considerations for the monitoring of biological effects in the Baltic Sea are outlined.

Biochemical biomarkers in adult female perch (Perca fluviatilis) in a chronically polluted gradient in the Stockholm recipient (Sweden).

A battery of biochemical biomarkers and the SigmaPCB concentration in adult female perch (Perca fluviatilis) verified an aquatic pollution gradient with the city of Stockholm (Sweden) as a point source of anthropogenic substances. The investigation included both an upstream gradient, 46 km westwards through Lake Mälaren, and a downstream gradient, 84 km eastwards through the Stockholm archipelago. Besides the main gradient from Stockholm, there were strong indications of pollution coming from the Baltic Sea. The results indicated a severe pollution situation in central Stockholm, with poor health status of the perch, characterised by increased specific EROD activity in the liver, increased liver EROD somatic index, decreased AChE activity in the muscle, increased amount of DNA adducts in the liver, and a high concentration of biliary 1-pyrenol. In addition, laboratory exposure to common EROD inducers elicited an abnormal response, suggestive of chronic intoxication.

Biomarker responses in flounder (Platichthys flesus) and mussel (Mytilus edulis) in the Klaipeda-Butinge area (Baltic Sea).

During the EU project BEEP a battery of biomarkers was applied in flounder (Platichthys flesus) and the blue mussel (Mytilus edulis) collected at three locations off the Lithuanian coast (Baltic Sea) in June and September 2001 and 2002. The elevated biomarker responses in specimens sampled in September 2001 were apparently related to the extensive dredging activities in the Klaipeda port area and subsequent dumping of contaminated sediments. High concentrations of organic pollutants (organochlorines and PBDEs) were also measured in the tissues of both indicator species. In addition, response levels of genotoxicity, cytotoxicity, immunotoxicity as well as concentrations of PAH metabolites in the bile of flounder showed elevations in 2002 after an oil spill in the Butinge oil terminal in November 2001. In flounder, biomarker measurements 10 months after the spill indicated recovery processes but in mussels a high level of genotoxicity could still be observed 22 months later. The present study illustrates the usefulness of the multi-biomarker approach in the detection of biological effects of pollution in this region of the Baltic Sea.

Perfluoroalkyl acids in various edible Baltic, freshwater, and farmed fish in Finland.

In this study, the concentration of perfluoroalkyl acids (PFAAs) in various edible Finnish Baltic Sea, freshwater, and farmed fish species were analysed. PFAAs were present in all the Baltic and freshwater species, but were not observed in any farmed fish. The most abundant compound in each species was perfluorooctane sulfonate (PFOS), comprising 41-100% of the total concentration. The total PFAA concentration varied considerably from 0.31 to 46ngg(-1) fresh weight. A notable variation in the PFAA concentrations implies that a single fish species alone is not suitable for monitoring PFAA contamination in a certain area. Our results confirm that wild domestic fish is one of the PFAA source in the Finnish diet.

Effects of furazolidone, PCB77, PCB126, Aroclor 1248, paraquat and p,p'-DDE on transketolase activity in embryonal chicken brain.

The effect of in ovo exposure to PCBs, DDE and paraquat on transketolase activity was measured in 19-day-old chicken embryos. Furazolidone was used as a positive control for decreased activity of the enzyme. The potency of contaminants to interact with transketolase was also tested in an in vitro system, using control brain 7000xg supernatants containing the enzyme. No effects were found on transketolase activity after in ovo or in vitro exposure to PCB126, Aroclor, DDE or paraquat. PCB77 decreased transketolase activity in vitro, but only at concentrations that, extrapolated to in ovo exposure, would be lethal to the embryo. Furazolidone decreased transketolase activity both in ovo and in vitro. For this contaminant, thiamine residues were analysed in the yolk sacs, but no differences were found between exposed and non-exposed eggs. Transketolase is dependent on thiamine pyrophosphate as a cofactor, and therefore, the decreased enzyme activity could be the result of an interaction between furazolidone and thiamine metabolism. Since thiamine residues were not affected by furazolidone and transketolase inhibition in vitro was similar to the inhibition after in ovo exposure, it was concluded that furazolidone interacted with transketolase on the enzymatic level rather than by a depletion of thiamine.