Is Teflon (PFOS) another significant global toxic threat to marine mammals?
Wittnich, Carin 2,3,4 ; MacNeil, Joanna E 1,4 ; Belanger, Michael P 3,4 ; Askin, Nesime 2,4
(2) Department of Physiology, University of Toronto, Rm 7256 MSB, 1 King’s College Circle, Toronto, Ont M5S 1A8, Canada
(3) Department of Surgery, University of Toronto, Rm 7256 MSB, 1 King’s College Circle, Toronto, Ont M5S 1A8, Canada
(4) Oceanographic Environmental Research Society, 12 Burton Ave, Barrie, Ont, L4N 2R2, Canada
Teflon (active ingredient perflurooctanesulfonate; PFOS) has seen increased industrial and consumer applications in ways that increase potential contamination of our oceans, putting marine mammals at risk. PFOS is well absorbed, yet poorly metabolized with a reported half life of over 8 years. Its long term toxic effects in marine mammals are unclear but reported effects with experimental exposure in land mammals include reduced perinatal survival, hepatotoxicity, thyroid and neurologic impairment.
This work reviews levels of PFOS reported in various marine mammal species around the world from liver (ng/g) or blood (ng/ml) samples garnered from 1990 onward. PFOS levels above 10 for liver or 6 for blood are considered significant. Despite varying geographic locations and species studied, such levels were consistently achieved or even exceeded with liver levels of 1100 found in Phoca hispida in the Baltic Sea.
In this region species variations were also seen – e.g. blood levels of Halichoerus grypus (14-76) versus Phoca hispida (86-180). Similarly, in the southern North Sea region, Stenella coeruleoalba and Lagenorthynchus acutus showed markedly lower liver levels (10-26) compared to Lagenorhynchus albirostris (14-443). Differing geographic locations also affected values even within a species.
Mediterranean Tursiops truncates had liver levels 170-430 versus those in the Gulf of Mexico at 824. Baltic Sea Halichoerus grypus had liver levels 140-360 versus those in the southern North Sea 11-233. Ursus maritimus in the Canadian arctic had liver levels as high as 678. Finally there is evidence that levels are increasing over time. A dramatic example of this is in the Baltic Sea, where even within one species, Phoca hispida, blood levels in 1996 were at 86-180 and two years later, reached 100-384.
Teflon is clearly another significant contaminant to be considered as a contributor to population declines in marine species, which will worsen with its escalating use.