Perfluoroalkyl Contaminants in an Arctic Marine Food Web: Trophic Magnification and Wildlife Exposure

Abstract

To better understand the bioaccumulation behavior of perfluoroalkyl contaminants (PFCs), we conducted a comparative analysis of PFCs and lipophilic organohalogens in a Canadian Arctic marine food web. Concentrations of perfluorooctane sulfonic acid (PFOS), perfluorooctansulfoamide (PFOSA), and C7-C14 perfluorocarboxylic acids (PFCAs) ranged between 0.01 and 0.1 ng x g(-1) dry wt in sediments and 0.1 and 40 ng x g(-1) wet wt in biota, which was equivalent to or higher than levels of PCBs, PBDEs, and organochlorine pesticides. In beluga whales, PFOS and PFCA concentrations were higher (P < 0.05) in protein-rich compartments (liver and blood), compared to other tissues/fluids (milk, blubber, muscle, and fetus). In the marine mammalian food web, concentrations of PFOSA and lipophilic organochlorines (ng x g(-1) lipid equivalent) and proteinophilic substances (i.e., PFOS and C8-C14 PFCAs, ng x g(-1) protein) increased significantly (P < 0.05) with trophic level. Trophic magnification factors (TMFs) of organochlorines ranged between 5 and 14 and exhibited significant curvilinear relationships (P < 0.05) with octanol-water and octanol-air partition coefficients (KOW, KOA). TMFs of perfluorinated acids (PFAs) ranged between 2 and 11 and exhibited similar correlation (P < 0.05) with protein-water and protein-air partition coefficients (KPW, KPA). PFAs did not biomagnify in the aquatic piscivorous food web (TMF range: 0.3-2). This food web specific biomagnification behavior was attributed to the high aqueous solubility and low volatility of PFAs. Specifically, the anticipated phase-partitioning of these proteinophilic substances, represented by their protein-water (KPW) and protein-air (KPA) partition coefficients, likely results in efficient respiratory elimination in water-respiring organisms but very slow elimination and biomagnification in air-breathing animals. Lastly, the results indicate that PFOS exposure in nursing Hudson Bay beluga whale calves (CI95 range = 2.7 x 10(-5) to 1.8 x 10(-4) mg x kg bw(-1) x d(-1)), exceedsthe oral reference dose for PFOS (7.5 x 10(-5) mg x kg bw(-1) x d(-1)), which raises concern for potential biological effects in these and other sensitive Arctic marine wildlife species.

Bioaccumulation and risk assessment of per- and polyfluoroalkyl substances in wild freshwater fish from rivers in the Pearl River Delta region, South China

“…4) are consistent with some previous studies (Martin et al, 2003;Hart et al, 2008;Kelly et al, 2009;Kwadijk et al, 2010;Labadie and Chevreuil, 2011). PFASs with longer carbon chain exhibit higher protein water partition coefficients (K pw ), thus resulting in higher bioaccumulative ability for the long-chain PFASs (Kelly et al, 2009). …”

Trends of polyfluoroalkyl compounds in marine biota and in humans

“…1.6 20.9 [96] Beluga [98] Polar bear, USA (Alaska), 1990s, n ¼ 17 180-680 [119] Polar bear, USA (Alaska, Beaufort Sea), 1993-2000, n 2.5 [100] (Continued)…”

“…Kidney 11.4 [98] 4. Blood Elephant seal, Antarctica, 2004-05, n ¼ 59 (blood) 0.5 [103] Baikal seal, Russia (Lake Baikal), 2005, n…”

“…16.0-230 [119] Harbour seal, German Bight, 2007, n ¼ 4 (whole blood) in ng g À1 25.9 [126] Tucuxi dolphin, south-eastern Brazil (Rio de Janeiro), 2008, n 11.4 [98] Trends of PFCs in marine biota and in humans were found in some animals in a few nanograms per gram range showing decreasing temporal trends in harbour seal livers from the German Bight. [76] In harbour seals from the Dutch Wadden Sea, PFBS was found only in spleen, but not in liver.…”

Brain region distribution and patterns of bioaccumulative perfluoroalkyl carboxylates and sulfonates in East Greenland polar bears (Ursus maritimus)

“…Several PFCAs and PFSAs, notably perfluorooctane sulfonate (PFOS), have been shown to be globally distributed in biota. Longer-chain (>C 6 ) PFSAs and (>C 8 ) PFCAs have been shown to generally bioaccumulate and biomagnify in aquatic food webs, resulting in top-predator species being most exposed [5].…”