Concentrations of worldwide fallout 137Cs were measured in the lichen-caribou-Eskimo food chain of northern Alaska during the period 1962-79. Pronounced inputs of fallout occurred after major nuclear weapons tests in the atmosphere and 137Cs was transmitted through the food chain to Eskimos with about a 2-yr delay due to environmental parameters. Caribou (Rangifer tarandus) meat sampled during spring harvest contained 4 times the 137Cs concentration of lichens obtained from their winter range. Calculated caribou meat ingestion rates of Anaktuvuk Pass Eskimos during winter ranged from approximately 1 kg/day in 1964 to 0.16 kg/day in 1977. Several environmental factors affected seasonal patterns and amounts of 137Cs transferred through the food chain. Maximum 137Cs concentrations of approximately 20 nCi/kg body weight in ESkimos occurred in 1964 and have now decreased to approximately 0.5 nCi/kg, largely because of cultural and political factors. Radiation doses from 137Cs body burdens during the study period ranged from 60 mrad/yr in 1962 to approximately 140 mrad/yr during the 1962-64 maxima and decreased to 8 mrad/yr in 1979.
From: Fortuine, Robert et al. 1993. The Health of the Inuit of North America: A Bibliography from the Earliest Times through 1990. University of Alaska Anchorage. Citation number 832.
The presence of organotin compounds, e.g., tributyltin (TBT) and triphenyltin (TPhT) including the di- and monosubstituted breakdown products, was studied in a representative marine food web in order to assess the accumulation potential at different trophic levels in Danish coastal waters. This included samples of two species of seaweed, four species of invertebrates, four species of fish, five species of birds and two species of mammals. All organisms were sampled away from harbour areas and the organotin concentrations found in this study can therefore be considered to reflect a general level in organisms living in Danish coastal waters. All the samples analysed contained organotin compounds. The highest hepatic concentrations of butyltins were found in flounder (60-259 ng g-1 wet weight [ww], as Sn), eider duck (12-202 ng g-1 ww) and harbour porpoise (134-2283 ng g-1 ww). The lowest concentrations were found in seaweed and a plant-feeding bird. TPhT or its degradation products were also found in most of the samples with the highest concentrations in flounder (9.8-74 ng g-1 ww), cod (23-28 ng g-1 ww) and great black-backed gull (19-24 ng g-1 ww). This indicates an input of TPhT in the region, probably from the use as antifouling agent. A high variance in accumulation potential was found between the species, even between species at the same trophic level, which probably reflects the species-specific differences in exposure routes and the capabilities to metabolise and eliminate the organotin compounds. This study gives evidence of the importance of biomagnification of butyltin in harbour porpoises and, to a lesser extent, in fish and birds.
Accumulation of artificial and natural radionuclides in the chains of food webs leading to non-predatory and piscivorous fish of the Yenisei River was investigated during one year before and three years after the shutdown of a nuclear power plant at the Mining-and-Chemical Combine (2009-2012). The activity of artificial radionuclides in the samples of biota ofthe Yenisei River (aquatic moss, gammarids, dace, grayling, pike) was estimated. The concentration of radionuclides with induced activity (51Cr, 54Mn, 58Co, 60Co, 65Zn, 141, 144Ce, 152, 154Eu, 239Np) decreased in the biomass of biota after the shutdown of the nuclear power plant; the concentration of 137Cs did not. Analysis of the accumulation factors (C(F)) allows us to expect the effective accumulation of 137Cs in the terminal level of the food web of the Yenisei River--pike (C(F) = 2.0-9.4), i.e. biomagnifications of radiocesium. Accumulation of artificial, radionuclides in non-predatory fish from gammarids was not effective (C(F)
Differences in the degree of separate and combined effects of temperature, pH, and heavy metals (zinc, copper) on the trypsin- and chymotrypsin-like proteinase activities have been established in the whole body of some invertebrate animals - potential objects of fish nutrition: pond snail Lymnaeae stagnalis, orb snail Planorbis purpura, zebra mussel Dreissena polymorpha, oligochaetae Tubifex sp. and Lumbriculus sp. in total, chironomid larvae Chironimus sp. and Ch. riparus, as well as crustacean zooplankton. It has been shown that enzymes of the potential victim at a low temperature can compensate low activity of intestinal proteinases of fish bentho- and planktophages.
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.
We studied the relationship between increasing age and blood concentrations of four persistent organochlorines (OCs), hexachlorbenzene (HCB), oxychlordane, p,p'-dichlorodiphenyldichloroethylene (DDE), and 2,2',4,4',5,5'-hexachlorbiphenyl (PCB-153), in arctic-breeding glaucous gulls (Larus hyperboreus). We measured OC concentrations in 31 individuals of known age and took repeated blood samples of 64 individuals in different years, either one year apart or three or four years apart. The age of individuals was not related to the blood concentrations for any of the four compounds, and in birds whose values were measured repeatedly, there was no effect of the length of time (number of years) between sampling events on the relative change in OC concentration. This indicates that steady-state levels were reached before the age of first breeding. However, breeding area significantly influenced the changes in OC concentration between sampling events. In areas in which birds fed on prey from higher trophic levels, the OC concentrations showed large increases between sampling events; in areas in which birds fed at lower trophic levels, OC concentrations increased relatively little or not at all. This indicates that individual birds had different equilibrium concentrations, which are reached at different ages depending on the intake of OCs through the food. It also indicates that some individuals had not reached steady-state concentrations at the onset of reproduction. Changes in body condition and amount of blood lipids were of lesser importance than trophic level and influenced the concentrations of HCB and oxychlordane more strongly than DDE and PCB-153. In conclusion, this study indicates that steady-state concentrations of persistent OCs are reached early in life in most glaucous gulls, considering the long life span of the species.
Polybrominated diphenyl ethers (PBDEs) were analysed in adipose tissue from 92 East Greenland polar bears (Ursus maritimus) sampled during 1999-2001. Mean SigmaPBDE concentrations were 70 ng/g lipid weight (lw) (range: 22-192 ng/g lw) and showed no relationship with age or sex. Of the 32 analysed PBDE congeners; BDE47, BDE153, BDE99 and BDE100 dominated, and comprised 99.6% of the SigmaPBDE concentration. The SigmaPBDE concentration had a highly significant correlation with SigmaPCB, SigmaCHL, dieldrin, HCB and SigmaHCH concentrations. We found a seasonal pattern of median SigmaPBDE concentration with 1.2 to 1.8 times higher concentrations in March to July than the rest of the year. The seasonal variation also provides a clue to the seasonal exposure, bio-availability, toxic exposure and degradation. We suggest that future geographical PBDE data comparisons may not need corrections for sex or age, but such data sets should be corrected for seasonal variability, using the presented correctional trigonometric regression.
1. Leakage of fertilizers from farmland has affected levels of nitrogen and phosphorus in many coastal areas, reducing limitation of primary productivity with consequences for timing and magnitude of the annual peak in phytoplankton and zooplankton. Such changes in nutrient availability may have affected temporal patterns of abundance of marine invertebrates and vertebrates that are the main prey of seabirds. 2. We investigated the extent to which changes in the use of fertilizers by farmers affected timing of breeding, clutch size, recruitment and longevity of a coastal seabird, the Arctic tern Sterna paradisaea Pont., in Denmark. 3. Timing of breeding advanced with the increase in use of fertilizers, with an effect as a consequence of a phenotypic response of individuals exposed to different levels of fertilizers. 4. Annual mean clutch size increased with the amount of fertilizer. While individual Arctic terns increased their clutch size with fertilizer level, there was no evidence of individual Arctic terns in different years changing their clutch size in response to changes in fertilizer use. 5. Annual recruitment rate, estimated as the proportion of young that were subsequently recovered as adults, was related to fertilizer use. 6. Mean longevity, estimated as the maximum age of adult individuals, decreased in response to fertilizer use. 7. These findings provide evidence of fertilizer use in agriculture having significant indirect effects on timing of reproduction, clutch size, recruitment and longevity of a seabird.
The alternative prey hypothesis predicts that the interaction between generalist predators and their main prey is a major driver of population dynamics of alternative prey species. In Fennoscandia, changes in climate and human land use are assumed to alter the dynamics of cyclic small rodents (main prey) and lead to increased densities and range expansion of an important generalist predator, the red fox Vulpes vulpes. In order to better understand the role of these potential changes in community structure on an alternative prey species, willow ptarmigan Lagopus lagopus, we analyzed nine years of population census data from SE Norway to investigate how community interactions affected their population dynamics. The ptarmigan populations showed no declining trend during the study period, and annual variations corresponded with marked periodic small rodent peaks and declines. Population growth and breeding success were highly correlated, and both demographic variables were influenced by an interaction between red fox and small rodents. Red foxes affected ptarmigan negatively only when small rodent abundance was low, which is in accordance with the alternative prey hypothesis. Our results confirm the important role of red fox predation in ptarmigan dynamics, and indicate that if small rodent cycles are disrupted, this may lead to decline in ptarmigan and other alternative prey species due to elevated predation pressure.