Abstract
The Antarctic ecosystem represents a remote region far from point sources of pollution. Still, Antarctic marine predators, such as seabirds, are exposed to organohalogen contaminants (OHCs) which may induce adverse health effects. With increasing restrictions and regulations on OHCs, the levels and exposure are expected to decrease over time. We studied south polar skua (Catharacta maccormiciki), a top predator seabird, to compare OHC concentrations measured in whole blood from 2001/2002 and 2013/2014 in Dronning Maud Land. As a previous study found increasing organochlorine concentrations with sampling day during the 2001/2002 breeding season, suggesting dietary changes, we investigated if this increase was repeated in the 2013/2014 breeding season. In addition to organochlorines, we analyzed hydroxy-metabolites, brominated contaminants and per- and polyfluoroalkyl substances (PFAS) in 2013/2014, as well as dietary descriptors of stable isotopes of carbon and nitrogen, to assess potential changes in diet during breeding. Lipid normalized concentrations of individual OHCs were 63%, 87% and 105% higher for hexachlorobenzene (HCB), 1,1-dichloro-2,2-bis (p-chlorophenyl)ethylene (p,p'-DDE), and ∑Polychlorinated biphenyls (PCBs), respectively, in 2013/2014 compared to 2001/2002. South polar skuas males in 2013/2014 were in poorer body condition than in 2001/2002, and with higher pollutant levels. Poorer body condition may cause the remobilization of contaminants from stored body reserves, and continued exposure to legacy contaminants at overwintering areas may explain the unexpected higher OHC concentrations in 2013/2014 than 2001/2002. Concentrations of protein-associated PFAS increased with sampling day during the 2013/2014 breeding season, whereas the lipid-soluble chlorinated pesticides, PCBs and polybrominated diphenyl ether (PBDEs) showed no change. OHC occurrence was not correlated with stable isotopes. The PFAS biomagnification through the local food web at the colony should be investigated further.
Highlights
Antarctica is located far from point sources of pollution making it one of the least pollutant-affected and most pristine continents on earth (Corsolini, 2009)
Of the 87 individual organohalogen contaminants (OHCs) analyzed in the south polar skua whole blood from 2013/2014, 41 were quantified above the limits of detection (LOD) in more than 75% of the samples (Table S4)
The concentrations of several individual OHCs increased from the 2001/2002 study to the 2013/2014 breeding season, which was con trary to our expectations
Summary
Antarctica is located far from point sources of pollution making it one of the least pollutant-affected and most pristine continents on earth (Corsolini, 2009). OHCs were recorded in Antarctica for the first time in the 1960s, when the chlorinated pesticide dichlorodiphenyltrichloroethane (DDT) was found in Adelie penguins (Pygoscelis adeliae), Weddell seals (Lep tonychotes weddellii) and south polar skuas (Catharacta maccormicki) (George and Frear, 1966). OHCs are found in all compartments of the Antarctic ecosystems including atmosphere, water, sea ice, seawater, sediments, ice, snow and biota (Corsolini, 2009). As a top predator seabird, the south polar skua has among the highest contaminant concentrations recorded in Antarctic species (Bustnes et al, 2006, 2007). Concentrations of the chlorinated pesticides HCB and Mirex increased in south polar skuas during their breeding season at Svarthamaren, Dronning Maud Land (Bustnes et al, 2006). The increase in OHC concentrations suggests increasing exposure from the diet during the breeding season (Bustnes et al, 2006, 2007)
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