Environ. Sci. Technol. 2004, 38, 5379-5385
Perfluoroalkyl Contaminants in a Food Web from Lake Ontario J O N A T H A N W . M A R T I N , * ,† D. MICHAEL WHITTLE,‡ DEREK C. G. MUIR,§ AND SCOTT A. MABURY† Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada, Great Lakes Laboratory for Fisheries and Aquatic Sciences, Department of Fisheries and Oceans, 867 Lakeshore Road, Burlington, Ontario L7R 4A6, Canada, and National Water Research Institute, Environment Canada, 867 Lakeshore Road, Burlington, Ontario L7R 4A6, Canada
Perfluorooctane sulfonate (PFOS) is a persistent and bioaccumulative perfluorinated acid detectable in humans and wildlife worldwide that has alerted scientists to examine the environmental fate of other fluorinated organic contaminants. Recently a homologous series of perfluoroalkyl carboxylates (PFCAs) was detected in the Arctic, yet little is known about their sources, breadth of contamination, or environmental distribution. In this study we analyzed for PFOS, the homologous series of PFCAs ranging from 8 to 15 carbons in chain length, and the PFOS-precursor heptadecafluorooctane sulfonamide (FOSA) in various organisms from a food web of Lake Ontario. The sampled organisms included a top predator fish, lake trout (Salvelinus namaycush), three forage fish species including rainbow smelt (Osmerus mordax), slimy sculpin (Cottus cognatus), and alewife (Alosa pseudoharengus), and two invertebrates Diporeia (Diporeia hoyi) and Mysis (Mysis relicta). A striking finding was that the highest mean concentration for each fluorinated contaminant was detected in the benthic macroinvertebrate Diporeia, which occupies the lowest trophic level of all organisms analyzed. Perfluorinated acid concentrations in Diporeia were often 10fold higher than in Mysis, a predominantly pelagic feeder, suggesting that a major source of perfluoroalkyl contaminants to this food web was the sediment, not the water. PFOS was the dominant acid in all samples, but longchain PFCAs, ranging in length from 8 to 15 carbons, were also detected in most samples between 4 years) (10, 20) and the known exposure of humans and wildlife to perfluorinated acids, the toxicological risk associated with this long-term exposure scenario in humans and wildlife is a critical data-gap. VOL. 38, NO. 20, 2004 / ENVIRONMENTAL SCIENCE & TECHNOLOGY
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TABLE 1. Mean Concentration (Wet Weight ( 1 SD) of Contaminants in Whole Body Homogenates of Invertebrates and Fish Collected from Lake Ontario in 2001 mean concentration (ng/g) ( 1 RSD analyte PFOS FOSA ∑PFOS PFOA PFNA PFDA PFUnA PFDoA PFTrA PFTA PFPA ∑PFCA ∑PFOS/∑PFCA
chemical formula -
CF3(CF2)7SO3 CF3(CF2)7SO2NH2 CF3(CF2)6CO2CF3(CF2)7CO2CF3(CF2)8CO2CF3(CF2)9CO2CF3(CF2)10CO2CF3(CF2)11CO2CF3(CF2)12CO2CF3(CF2)13CO2-
Mysis
Diporeia
alewife
smelt
sculpin
trout
13 ( 1.8 130 ( 4.2 143 2.5 ( 0.4 2.7 ( 0.1 1.3 ( 0.1 1.3 ( 0.1 1.8 ( 0.2 1.5 ( 0.2
