Comparison of Temporal Trends (1940s–1990s) of DDT and PCB in Baltic Sediment and Biota in Relation to Eutrophication

Olsson, Mats; Bignert, Anders; Eckhéll, Jan; Jonsson, Per R.

doi:10.1579/0044-7447-29.4.195

Cited by 42 publications

(19 citation statements)

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“…These results do not fit with the prediction that marine biota close to the primary source of PCB contamination have higher proportions of the less volatile and more persistent congeners [12–14]. A possible explanation for this could be the substantial eutrophication of the Baltic Sea [18]. Rather than dissolving into the water column, the most hydrophobic POPs (e.g., highchlorinated PCBs) tend to associate themselves with nutrients and solid particles in the water column of eutrophicated water, resulting in a high sedimentation of these compounds into the seabed.…”

Section: Discussionmentioning

confidence: 79%

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Polychlorinated biphenyls and organochlorine pesticides in baltic and atlantic gray seal (Halichoerus grypus) pups

Sørmo¹,

Skaare²,

Jüssi³

et al. 2003

Enviro Toxic and Chemistry

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Organochlorine pollutants (OCs), such as polychlorinated biphenyls (PCBs), DDT, chlordanes (CHLs), hexachlorobenzene (HCB) and hexachlorocyclohexanes (HCHs) were determined in blubber biopsies from free-ranging Baltic and Atlantic gray seal (Halichoerus grypus) pups. Well-fed pups from the Baltic Sea had concentrations of DDT, PCBs, and HCHs that were 2 to 10 times higher than in corresponding pups from populations in the Atlantic Ocean. The OC pattern in the Baltic seals differed significantly from that of their Atlantic relatives, reflecting the predominance of regional point source inputs into the Baltic Sea and long-range atmospheric inputs into the Atlantic Ocean. The differences in the pattern of the compounds also indicated an enhanced metabolism of the more metabolizable compounds in the more contaminated Baltic seals. Surprisingly, the proportions of the high chlorinated and low-volatile PCB congeners (> 6 Cl atoms) were comparable or lower in the Baltic pups as compared to the Atlantic pups. This difference might be due to Baltic seals occupying a lower trophic level than Atlantic seals and/or to the eutrophication situation in the Baltic Sea, which causes sedimentation of these PCB congeners. Significantly higher OC concentrations were found in starved and/or abandoned Baltic pups as compared to well-fed pups. The most contaminated Baltic seal pups in the present study had PCB concentrations that are comparable or higher than those reported to impair the immune systems and vitamin A dynamics in phocids.

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Section: Discussionmentioning

confidence: 79%

“…Due to industrial and agricultural spillage and surface runoff from applications and dumping sites, the Baltic Sea has a long record of being highly polluted with OCs [18]. This warrants the need for monitoring of OC concentrations and assessment of their possible risk on developing Baltic gray seal pups.…”

Section: Introductionmentioning

confidence: 99%

Polychlorinated biphenyls and organochlorine pesticides in baltic and atlantic gray seal (Halichoerus grypus) pups

Sørmo¹,

Skaare²,

Jüssi³

et al. 2003

Enviro Toxic and Chemistry

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“…During the last 2 decades, decreasing levels of PCBs (Olsson et al 2000) in the prey of seals has led to improved health conditions and reproductive capacity of the Baltic grey seal (Bergman 1999), followed by an increase in population size. The population growth rate has been monitored by annual counts since the mid 1970s in Sweden.…”

Section: Recent Population Size Estimatesmentioning

confidence: 99%

Status of Baltic grey seals: Population assessment and extinction risk

et al. 2007

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The grey seal (Halichoerus grypus) population in the Baltic Sea is recovering after a century of bounty hunting and 3 decades of low fertility rates caused by environmental pollution. A conservative estimate of the population size in 2003 was 19,400 animals, and available data suggest an annual rate of increase of 7.5% since 1990. The growing population has led to increased interactions with the fishery, and demands are being raised for the re-introduction of the hunt. We provide a demographic analysis and a risk assessment of the population, and make recommendations on how to decrease the risk of overexploitation. Although hunting increases the risk of quasi-extinction, the risk can be significantly reduced by the choice of a cautious hunting regime. The least hazardous regimes allow no hunting below a 'security level' in population size. Obviously, to implement such a hunting regime detailed knowledge of the population size and growth rate is required. It is not possible to estimate "true" risks for quasi-extinction, but we used an approach where the relative difference for different scenarios can be compared. With a security level at 5,000 females, the population quasi-extinction risk increases 50 fold at an annual hunt of 500 females compared with a scenario with no hunting. The risk of quasi-extinction is very sensitive to declines in the mean growth rate and to increased variance in growth rate. The variance in the population estimates over the last 14 years imply that it would take 9 years to detect a decline from 1.075 to 1.027 in the rate of population increase. We also show how the age composition of killed animals influences the impact of the hunt. The overall recommendation is that hunting should be kept to a minimum, carefully documented and accompanied by close population monitoring.Harding, K.C., Härkönen, T., Helander, B. and Karlsson, O. 2007. Status of Baltic grey seals: Population assessment and extinction risk. NAMMCO

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“…Indeed, the inference of a trend from a single core should be done cautiously, because such trends may be expected to vary within the fjord. The high levels of PCBs in the layer dating back to the late 1940s may have been caused by one or more spills occurring at that time, and diffusive processes may have transported PCBs to deeper sediment layers [44]. Although the deeper part of Bunnefjorden is occasionally low in oxygen, bioturbation may still be of significance.…”

Section: Resultsmentioning

confidence: 99%

Modeling the fate of polychlorinated biphenyls in the inner Oslofjord, Norway

Breivik

Bjerkeng

Wania

et al. 2004

Enviro Toxic and Chemistry

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A dynamic, segmented, multimedia fate and transport model has been developed, evaluated, and applied to gain insight regarding the behavior of seven polychlorinated biphenyl (PCB) congeners in the Inner Oslofjord (Norway). A comparison with a dated sediment core reveals that the model is not capable of reproducing some key features of the observed, historical, long-term trend in sediments, although better agreement is observed for six of seven PCB congeners over the last two decades. The model also underestimates the concentrations of PCBs in surface sediments in areas adjacent to the city of Oslo (Norway). In general, deviations between modeled and observed concentrations indicate that the historical emissions and discharges of PCBs are not sufficiently characterized and described. Net fluxes predicted by the model suggest that several congeners may have experienced a reversal of air-water and seawater-sediment exchange during the last decade or even earlier. The present study further suggests that the benefit of the proposed removal of the most contaminated sediments of the Inner Oslofjord needs to be assessed, with consideration of the relative contribution of current atmospheric inputs as well as the leaching of PCBs from less contaminated sediments.

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Comparison of Temporal Trends (1940s–1990s) of DDT and PCB in Baltic Sediment and Biota in Relation to Eutrophication

Cited by 42 publications

References 0 publications

Polychlorinated biphenyls and organochlorine pesticides in baltic and atlantic gray seal (Halichoerus grypus) pups

Polychlorinated biphenyls and organochlorine pesticides in baltic and atlantic gray seal (Halichoerus grypus) pups

Status of Baltic grey seals: Population assessment and extinction risk

Modeling the fate of polychlorinated biphenyls in the inner Oslofjord, Norway

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