Cyanobacteria are known to produce a variety of toxic compounds. β-N-methylamino-L-alanine (BMAA) is one of the neurotoxins produced by most cyanobacteria. BMAA has been implicated in amyotrophic lateral sclerosis / Parkinsonism dementia complex (ALS / PDC) and was suggested to contribute to this pathology after biomagnification and slow release of BMAA from a protein associated form. The uptake and accumulation of BMAA by the aquatic macrophyte Ceratophyllum demersum has recently been shown, but the consumption of aquatic macrophytes by humans is not typical. The uptake by, and accumulation in, crop plants (Nasturtium officinale and Daucus carota) was therefore investigated so as to establish the existence of any risk to humans from the consumption of plants irrigated with water from dams with high cyanobacterial biomass and therefore high BMAA levels. After the exposure to the BMAA through the growth medium, BMAA had no effect on growth and development of N. officinale and D. carota. The uptake and bioaccumulation of BMAA was observed in N. officinale and D. carota, and was found to be concentration-dependent. Both free and bound cellular BMAA was detected following BMAA exposure through the growth medium. The photosynthetic apparatus of N. officinale was not significantly damaged. The uptake and accumulation of BMAA in edible terrestrial plants may constitute another route of human exposure to BMAA; it may now be prudent to avoid spray irrigation of edible plants with waters from dams with high cyanobacterial biomass and therefore high BMAA levels. After uptake by plants, the cyanotoxins may induce oxidative stress. A recent study showed that BMAA has a significant inhibitory effect on the oxidative stress enzymes in C. demersum. Therefore, the toxicological effects on selected plants were investigated by a range of biochemical enzyme assays in order to establish the plant stress response to exogenous BMAA. The inhibition of antioxidant enzymes upon exposure of N. officinale to BMAA through the growth medium was observed. The inhibition of antioxidant defence enzymes by BMAA correlated with the BMAA bioaccumulation in N. officinale. Further investigations are needed to analyze the uptake, accumulation, and ecotoxicology of BMAA in other crop plants, and to examine the fate of BMAA in these plants particularly its distribution and metabolism.

Increasing oil activities from the gas and oil industry may constitute a hazard towards the marine environment due to potential risks for accidents, such as oil spills. This study examine acute eects on mortality (LC50) and stress gene expressions in two closely related copepod species, Calanus finmarchicus(temperate-boreal species) and Calanus glacialis (Arctic species), adapted to dierent temperatures 10 C and 2 C, respectively. The copepod species were exposed to water soluble hydrocarbon fractions (WSFs)of fresh crude oil. In addition, an experiment was conducted in order to investigate if lipid rich specimen survived a longer exposure of WSFs than lipid poor specimen. The results from the acute toxicity tests indicated that the Arctic species is more tolerated to WSF exposure than the temperate species. Gene expression analysis revealed that both species induced glutathione S-transferase (GST) mRNA levels in a concentration- and time related manner. Calanus glacialis showed a greater and faster induction of the GST transcription compared to Calanus nmarchicus. The results of gene expression analysis of superoxide dismutase (SOD), cytochrome 330A1 (CYP330A1) and gamma-glutmylcystein synthase (gGCS) did not show any concentration- and time related trends following WSF exposure. Biometric measurements of the specimen, and analyzing by a linear multi variable regression model showed that neither of the variables, including the lipid content, explained the dierences in surviving a WSFs exposure. The study support the use of the cultured Calanus species as a model species when testing for acute eects in themarine environment.

Increased anthropogenic release of potentially toxic trace elements such as arsenic (As), cadmium (Cd), mercury (Hg), lead (Pb) and selenium (Se) into freshwater ecosystems over the past century has caused much concern. These elements are well known toxicants in aquatic ecosystems and may exert toxic effects even if present at relatively low concentrations in organisms. In this study, bioaccumulation of As, Cd, Hg, Pb and Se in the pelagic and benthic food chain of Lake Baikal have been investigated, with focus on the benthic and pelagic fish species. Concentrations of the selected trace elements have been analyzed in samples of water, plankton, benthic invertebrates and fish by High Resolution Inductively Coupled Plasma Mass Spectrometry (HR-ICP-MS). Concentration differences in the benthic and pelagic food chain of Lake Baikal have been investigated, with focus on benthic and pelagic fish species. In addition, spatial differences in the concentration of these potentially toxic elements between Selenga Shallows (possibly polluted site) and Listvyanka Bay (reference site) were included in the analysis to reveal potential anthropogenic impact on the lake.The comparative study revealed some concentration differences in water and biotic components at the two sampling locations. The concentration of Pb was significantly higher in water from the Selenga Shallows. However, several of the biota samples had highest concentrations of trace elements at Listvyanka Bay. This can be related to higher bioavailability of trace elements at Listvyanka Bay, possibly caused by lower abundance of natural ligands at this location. In both the pelagic and benthic food chain of Lake Baikal, Hg showed indication of biomagnification while As, Cd and Pb seemed to be biodiluted. When comparing fish inhabiting the pelagic and benthic food chain, differences in concentrations of As and Hg were identified. The As concentrations were twice as high in pelagic fish, while the benthic fish had seven times higher Hg content compared to pelagic fish. The observed concentration differences of As and Hg may be related to such as different complexity of the two food chains, different feeding strategies and habitat. Based on the tissue Se:Hg molar ratio there is no risk of Hg induced toxicity in the endemic fish species of Lake Baikal at the present. In general, the present study confirms low concentrations of potentially toxic chemical elements (As, Cd, Hg, Pb and Se) in Lake Baikal in comparison to other freshwater ecosystems.

Black-legged kittiwakes (Rissa tridactyla) breeding in the Arctic, are exposed to annual fluctuating environmental conditions. The impact of inter-year variations in environmental conditions on the blood concentrations of persistent organic pollutants (POPs) was examined in black-legged kittiwakes breeding in Kongsfjorden, Svalbard. In addition, it was examined if inter-year variations in concentration of POPs were affecting circulating thyroid hormone (TH) levels. Blood samples were collected from breeding kittiwakes during the incubation period in 2008 (n=46) and 2009 (n=31), two different years in respect of environmental conditions. The whole blood samples were analyzed for POPs: polychlorinated biphenyls (PCBs; PCB-28, -52, -99, -118, -101, -138, -153, 180, -183, -187, -194), hexachlorobezene (HCB), hexachlorocyclohexan (HCH), dichlorodiphenyltrichloroethane (p,p’-DDT), dichlorodiphenyldichloroethylene (p,p’-DDE) oxychlordane, cis-chlordane, trans-chlordane, cis-nonachlor, trans-nonachlor, heptachlor, heptachloroepoxid, and mirex, using gas chromatography mass spectrometry. Plasma was analysed for concentrations of total triiodothyronine (T3), using radioimmunoassay. Associations between variables of POPs and T3 were analysed using univariate statistics. Biometric measurements of the kittiwakes; body mass, skull length, and wing length where included in the statistical analysis, together with calculated BC (BC; body mass controlled for body size). Associations between the variables were analysed using multivariate statistics. The PCBs were the dominant contaminants in both 2008 and 2009. The three major constituents in the kittiwakes were PCB-153, followed by PCB-138 and PCB-180. Even though the body condition of the kittiwakes was significant poorer in 2009 compared to 2008, the concentrations of PCBs and DDE did not differ between 2008 and 2009. The concentration (ng/g wet weight [w.w.]) of HCB and oxychlordane were significant higher in 2009 compared to 2008. There was a strong negative association between HCB and body condition of the kittiwakes. Also the concentration of oxychlordane was negative correlated to body condition. Thus, kittiwakes with poor body condition had higher levels of HCB and oxychlordane. Additionally, HCB, oxychlordane and PCB-183 were positively associated with egg-laying date, while body condition was negatively correlated to egg-laying date. The results showed that kittiwakes with a poor body condition and thus, high levels of HCB and oxychlordane, were associated with late breeding. The low body condition in 2009 indicated poor food availability and unfavourable conditions for the kittiwakes that year.

Concentrations of Ag, As, B, Ba, Bi, Ca, Cd, Ce, Co, Cs, Cu, Dy, Er, Fe, Ga, Ge, Hg, Ho, K, La, Li, Lu, Mg, Mn, Mo, Na, Nd, Ni, P, Pb, Pr, Rb, S, Sb, Se, Si, Sm, Sn, Sr, Tb, Th, Tl, V, W, Y, Yb and Zn in the livers of grey seals obtained from stranded, hunted and by-caught animals from the Swedish and Polish Baltic coasts were determined by ICP-MS. Stable isotope analysis of δ13C and δ15N was applied to link chemical element concentrations to feeding preferences (pelagic vs. benthic) and trophic position of the seals, respectively. Isotopic ratios in the seals increased in seals from the north towards the southern Baltic Sea, with markedly higher isotopic signatures in seals inhabiting the Polish coast . Analysis of covariance revealed differences in chemical element concentrations between areas for As, B, Cu, Ni, Rb, Sr, Tl with most of these elements exhibiting higher concentrations in seals from the southern Baltic Sea. Additionally age related differences in concentrations of several trace elements were found. Silver, B, Bi, Cd, Co, Hg, Mo, Sb, Se, Sn, V and Zn and the rare earth elements (REE) were found to increase with age. The role of Se in detoxification of Hg was confirmed by high correlation between these two elements (r = 0.99, p < 0.0001). Significantly higher Se:Hg molar ratio were observed in yearlings compared to juvenile and adult seals . Several other elements also revealed statistically significant interrelationships, especially pronounced for the REEs.

The ringed seal (Phoca hispida) is a circumpolar Arctic species, with several subspecies and –populations. One subspecies, Phoca hispida botnica, is found in the Baltic Sea. Large ecological differences between these regions may cause variations of trophic positioning and chemical composition in tissues among the inhabiting ringed seal populations. The Baltic Sea is one of the worlds’ most polluted seas, and the metal pollution in this area may be problematic for Baltic ringed seals. Liver samples from juvenile ringed seals (1-3 years) from three distinct populations, in northwest Greenland, East Greenland and the Baltic Sea were collected during 2008-09. Concentrations of 42 chemical elements, including As, Cd, Hg, Pb and Se, were determined using HR-ICP-MS. Stable isotope analysis (IRMS) of δ13C and δ15N were conducted in order to reveal population differences in feeding preferences (pelagic versus benthic species) and trophic positioning, respectively. Significant differences for δ13C and δ15N were found between all three populations, and the Greenland populations showed benthic preferences and higher trophic positioning relative to the Baltic Sea. The chemical element analysis revealed spatial differences between the Baltic Sea population and either one or both of the Greenland populations for several elements. However, none of the elements of concern in the Baltic Sea were present at significantly higher concentrations in the Baltic Sea population compared to the two Greenland populations. The lower trophic positioning and preferred pelagic foraging of Baltic ringed seals contribute to protect them from impacts of their polluted habitat.

Contaminants in the Arctic environment are mainly transported from lower latitude areas by atmospheric transport. However, the Russian settlements (Barentsburg and Pyramiden) in Svalbard have shown to be heavily influenced by local pollution of polychlorinated biphenyls (PCB), as high concentrations have been found in vegetation, soil and sediments. The Norwegian settlements (Longyearbyen and Ny-Ålesund) are to a lesser extent influenced by local pollution of PCB. Birds have been utilized as sentinels for environmental pollution in several studies, as the use of bird-eggs is considered as a non-invasive method. The aim of this study was to investigate whether the snow bunting (Plectrophenax nivalis) is influenced by local pollution of PCB in the Russian settlements. During the 2010 field season and the 2011 field season, 32 eggs of snow buntings were collected in Longyearbyen (n=8), Ny-Ålesund (n=8), Barentsburg (n=9) and Pyramiden (n=7). The analysis was conducted at the Norwegian Institute of Air Research (NILU) in Tromsø. The eggs were analyzed for PCBs, organochlorinated pesticides (OCPs), brominated diphenyl ethers (PBDE) and perfluoroalkylated compounds (PFASs). The results showed that PCBs were the most abundant contaminant group in the Russian settlements, while PFASs was the most abundant contaminant group in the Norwegian settlements. Significant higher concentrations (ng/g wet weigth) of ∑7PCB (sum of the seven most common PCBs) were found in the eggs from the Russian settlements (Barentsburg and Pyramiden) than in the eggs from the Norwegian (Longyearbyen and Ny-Ålesund). Further on, the PCB congener composition in the eggs was comparable with the technical PCB-mixtures previous used in the Russian settlements. The results thus indicate influence of local pollution of PCB in eggs of snow buntings in the Russian settlements. Further on, local influence of dichlorodiphenyldichloroethylene (p,p’-DDE) and PFASs cannot be excluded. However, the contaminant burden of hexachlorobenzen (HCB), trans-nonachlor, p,p’-DDE and PFASs in the eggs of snow buntings in Svalbard are mainly explained by; I: atmospheric transport of contaminants to the Arctic environment, II: transport of contaminants by sea birds, III: exposure during migration, IV: exposure in overwintering areas. The concentration of organohalogenated compounds (OHCs) in eggs of snow buntings in this study is considerable lower than concentrations in previously studies that have reported to cause adverse effect in other bird species. Further are the concentrations of OHCs in this study in general lower when compared with other studies on Svalbard seabirds. However, it should be noted that the concentration of ∑PCB in eggs of snow buntings is comparable with previous studies on Svalbard seabirds. The results in this study indicate that the snow bunting may be utilized as a sentinel of local pollution in Svalbard in the future.

DNA lesions are introduced in all living organisms every day, both via endogenous processes and by exposure to an array of DNA damaging agents. DNA lesions require repair for the sustenance of life. Base excision repair (BER) and nucleotide excision repair (NER) are DNA repair pathways involved in removal of oxidative DNA lesions and helix-distorting DNA lesions, respectively. Several studies suggest interactions or crosstalk between these pathways, involving overlapping activities for removal of the same types of DNA lesions but also interference between repair pathways.Non-repaired DNA lesions are regarded as an important risk factor in the pathogenesis of certain conditions and diseases. It is important to gain insight in the interplay between DNA damaging agents, DNA lesions and their DNA repair pathways, since this may be related to the overall sensitivity of cells to combined exposure to endogenous or exogenous agents.In the present study, we aimed at studying combined exposures to environmental genotoxicants at low doses, and potential interactions between DNA repair pathways. The two genotoxicants lead to DNA lesions that are processed via two different DNA repair pathways. We studied the impact of low levels of oxidative stress on the repair of low levels of helix-distorting DNA lesions; and – vice versa - the impact of low levels of helix-distorting DNA lesions, on the repair of low levels of oxidative DNA lesions. We induced the different types of lesions in cells of different genetic background, to study whether a lack of repair of oxidative DNA lesions could also affect the repair of helix-distorting lesions. For this purpose, we utilised wild type mouse embryonic fibroblasts (Ogg1+/+ MEFs), and a MEF cell line deficient in the repair protein 8-oxoguanine DNA glycosylase (Ogg1) (Ogg1-/- MEFs). The Ogg1 gene is involved in the removal of certain oxidized DNA lesions via BER. Ogg1+/+ MEFs exposed to a DNA helix-distorting agent did not show perturbed repair of induced oxidative DNA lesions, suggesting that low levels of NER-sensitive DNA damage do not influence BER. Furthermore, the repair of helix-distorting DNA lesions in wild type MEFs (Ogg1+/+) or Ogg1-/- MEFs was not perturbed by a (single) low level exposure to oxidative stress, suggesting that reactive oxygen species (ROS) or BER-sensitive DNA damage do not influence the repair of low levels of helix-distorting DNA lesions. However, Ogg1+/+ MEFs showed more efficient repair of helix-distorting DNA lesions compared to Ogg1-/- MEFs, regardless of the level of oxidative lesions present in the DNA. This finding suggests that the BER-related repair protein Ogg1 may play a role also in the repair of NER-sensitive helix-distorting DNA lesions.In conclusion, low levels of oxidative stress or helix-distorting DNA lesions did not seem to perturb cellular repair of low levels of helix-distorting DNA lesions or oxidized DNA lesions, respectively, in wild type or Ogg1-deficient MEFs. A crosstalk between Ogg1 and repair of helix-distorting DNA lesions was however observed, suggesting an interplay between BER and NER with respect to the repair of NER-sensitive DNA damage.

PCBs and other environmental contaminants have been found to have an effect on steroid hormones in polar bears (Ursus maritimus). The purpose of this study was to investigate the effect of persistent organic pollutants (POPs) on the steroidogenesis in male polar bears from Svalbard. Blood samples from male polar bears (n=23) were collected at Svalbard, Norway in April 2008 as a part of the International Polar Year-project, BearHealth. The sampled individuals were between 3-21 years, where individuals under 5 years (n=6) were categorized as subadults. Serum and plasma samples were analysed for steroid hormones (pregnenolone (Pre), progesterone (Pro), androstenedione (AN), dehydroepiandrosterone (DEA), testosterone (TS), dihydrotestosterone (DHT), estrone (E1), estradiol-17α (E2-α) and estradiol-17β (E2-β)) with a recently developed gas chromatography-tandem mass spectrometry (GC-MS/MS) determination method, whereas cholesterol concentrations were measured by Reflotron. The environmental contaminants (HCB, α‐HCH, β‐HCH, oxychlordane, trans‐nonachlor, mirex, p,p'-DDE, p,p'‐DDT, PCB‐47, PCB‐74, PCB‐99, PCB‐101, PCB‐128, PCB‐137, PCB-138, PCB‐153, PCB‐170, PCB‐180, PCB‐183, PCB‐187, PCB‐194, PCB‐206, PCB-105, PCB-114, PCB-118, PCB-156, PCB-157, PCB-167, PCB-189, 4'-OH-CB107, 4'-OH-CB130, 3'-OH - CB138, 4‐OH‐CB146, 4'-OH‐CB159, 4'-OH-CB172, 3'-OH-CB180, 4-OH‐CB187, BDE-47, BDE-154) included in this study were analysed by gas chromatography-electron capture detection (GC-ECD) or GC/MS. Multivariate regression analysis, principal component analysis (PCA) and orthogonal partial least squares (OPLS) regression, were performed to investigate the influence of the contaminants on the steroid hormones in the adult individuals. Only the OPLS model with DHT as the response variable was significant. Most of the environmental contaminants had a significantly negative contribution on the variation in dihydrotestosterone concentrations. Based on the statistical analyses, the poly-ortho PCBs and HCB might be more central in explaining the variation in DHT concentrations, while PBDEs and OH-PCBs seems to be less important. Androstenedione were found to be the androgen with highest concentration in circulating blood from male polar bears, unlike other studies on mammals where testosterone has been found to be the most abundant androgen. The high level of AN might be connected to the negative effect of contaminants on DEA levels. The GC-MS/MS method applied in the current study can successfully compete with other frequently used determinations methods, such as RIA. The method is appropriate for the study several steroid hormones and their precursors in male polar bears and can be recommended for studies investigating the effect of persistent organic pollutants on the on the steroidogenesis.

The effects of ammonia to Cd toxicity on marine phytoplankton have been studied. The phytoplankton biomass was significantly increased at higher ammonia flux after high Cd level exposure, which indicated high ammonia decreased Cd toxicity on phytoplankton. In addition, DGT labile Cd concentration was linear decreased with increasing ammonia flux in day 8, while DGT labile Cd concentration was increased at higher ammonia flux in day 12. Cd complexation capacity in seawater of Cd treatment was higher over 100 times than Cd complexation capacity in seawater of without Cd treatment. And high ammonia increased Cd complexation capacity in seawater after high Cd exposure in day 8, while Cd complexation capacity in seawater of Cd treatment was decreased due to high ammonia in day 12. Therefore, ammonia influences the amount of DOM released by phytoplankton and the Cd complexation with organic ligands, and finally leads to affect Cd bioavailability and toxicity on phytoplankton.