Rapid Response of Arctic Ringed Seals to Changes in Perfluoroalkyl Production

Abstract

Temporal trends in perfluoroalkyl compounds (PFCs) were investigated in liver samples from two ringed seal (Phoca hispida) populations in the Canadian Arctic, Arviat (Western Hudson Bay) (1992, 1998, 2004, 2005) and Resolute Bay (Lancaster Sound) (1972, 1993, 2000, 2004, 2005). PFCs analyzed included C7-C15 perfluorinated carboxylates (PFCAs) and their suspected precursors, the 8:2 and 10:2 fluorotelomer saturated and unsaturated carboxylates (FTCAs, FTUCAs), C4, C6, C8, C10 sulfonates, and perfluorooctane sulfonamide (PFOSA). Liver samples were homogenized, liquid-liquid extracted with methyl tert-butyl ether, cleaned up using hexafluoropropanol, and analyzed by liquid chromatography with negative electrospray tandem mass spectrometry (LC-MS/MS). C9-C15 PFCAs showed statistically significant increasing concentrations during 1992-2005 and during 1993-2005 at Arviat and Resolute Bay, respectively. Doubling times ranged from 19.4 to 15.8 years for perfluorododecanoate (PFDoA) to 10.0-7.7 years for perfluorononanoate (PFNA) at Arviat and Resolute Bay but were shorter when excluding the 2005 samples. Conversely, perfluorooctane sulfonate (PFOS) and PFOSA concentrations showed maximum concentrations during 1998 and 2000 at Arviat and Resolute Bay, with statistically significant decreases from 2000 to 2005. In the case of Arviat, two consecutive decreases were measured from 1998 to 2003 and from 2003 to 2005. PFOS disappearance half-lives for seals at Arviat and Resolute Bay were 3.2 and 4.6 years. These results indicate that the ringed seals and their food web are rapidly responding to the phase out of perfluorooctane sulfonyl fluoride based compounds by 3M in 2001. Further, the relatively short doubling times of the PFCAs and PFOS disappearance half-lives support the hypothesis of atmospheric transport as the main transport mechanism of PFCs to the arctic environment.

Trends of polyfluoroalkyl compounds in marine biota and in humans

“…[70] Ringed seal livers were also collected in the Canadian Arctic from Resolute Bay and Arviat (1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005). [71] In agreement with the results from Greenland, at both Canadian locations PFOS was the major PFC compound followed by PFUnDA 4 PFNA ! PFTriDA.…”

“…[69,71,77,78,87,88] This specific odd-even PFCA pattern supports the hypothesis of atmospheric fluorotelomer alcohol (FTOH) degradation as a source of PFCAs. For example, 8 : 2 FTOH degrades to equal amounts of PFOA and PFNA, but PFNA has been shown to be more bioaccumulative than PFOA, resulting in higher PFNA levels in organs of biota compared to PFOA.…”

“…[79] As most of the polar bears' diet consists of ringed and bearded seals it might be possible that similar trends exist for their prey. Indeed, similar increasing temporal trends were found between 1970s and 2000-02 in livers of ringed seals to those of polar bears from the same locations in Canada [71,78] and eastern Greenland. [69,79] [71] However, the changes of the PFC concentrations in polar bears should be investigated in the future.…”

“…In contrast to decreasing PFC concentrations in harbour seals from the German Bight, no significant temporal trend was observed in grey seals (Halichoerus grypus) from the Baltic Sea between 1999 and 2008. However, significantly increasing concentrations were found for C 6 -C 8 PFSAs, PFOSi and C 7 -C 14 PFCAs Melon-headed whales, Japan Northern sea otters, Alaska Temporal trends of PFOS (logarithmic scale) in livers of polar bears from eastern Greenland, [79] harbour seals from Germany, [76] ringed seals from eastern and western Greenland, [69] ringed seals from Canada (Arviat and Resolute Bay), [71] Baikal seals from Russia, [72] melon-headed whales from Japan [73] and northern sea otters from Alaska [74] ; data adapted from references in brackets.…”

“…[17] Polar bears showed the highest amounts of PFHxS among mammals, but PFBS was not analysed (Table 1). Fluorotelomer saturated and unsaturated carboxylates (FTCAs and FTUCAs) were found in very low concentrations in several marine mammal species such as ringed seals (o4.6 ng g À1 ww) [71] and dolphins from the US Atlantic Ocean coast (o1.4 ng g À1 ww), [92] but they were not detected in polar bears from the Canadian Arctic [78] and in dolphins and porpoises from South China and India. [84,88] The presence of those precursor compounds supports the hypothesis that atmospheric FTOHs are a source of PFCAs as FTOH can degrade via atmospheric oxidation to FTCAs and FTUCAs.…”