Perfluorinated Compounds in the Plasma of Loggerhead and Kemp's Ridley Sea Turtles from the Southeastern Coast of the United States

Abstract

Perfluorinated compounds (PFCs) have been measured in blood of humans and wildlife and are considered globally distributed contaminants. We examined 12 PFCs in the plasma of 73 loggerhead sea turtles (Caretta caretta) and 6 Kemp's ridley sea turtles (Lepidochelys kempii) captured from inshore waters of Core Sound, North Carolina (NC), and offshore waters of South Carolina, Georgia, and Florida (SC-FL). Perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA) were the dominant compounds, with respective mean concentrations of 11.0 ng/mL and 3.20 ng/mL for loggerhead turtles and 39.4 ng/mL and 3.57 ng/mL for Kemp's ridley turtles. Mean PFOS concentrations were 2- to 12-fold higher than typical mean sigmaPCB concentrations (approximately 5 ng/g wet mass) measured previously in sea turtle blood. More than 79% of the samples had detectable levels of perfluorocarboxylates (PFCAs) with 8-12 carbons, whereas only 17% or less of samples had detectable levels of PFCAs with 6 or 7 carbons. No samples had detectable levels of PFCAs with 4 or 5 carbons. In loggerhead turtles, sigmaPFC concentrations were not influenced by sex (p > 0.05), but were higher in turtles captured from inshore waters of NC than in turtles from offshore waters of SC-FL (p = 0.009). A backward stepwise multiple regression model showed that sigmaPFC concentrations were (1) significantly higher in Kemp's ridley turtles than loggerhead turtles (p < 0.0001), (2) higher in larger turtles (p = 0.018; carapace length used as a proxy for age), and (3) higher in turtles captured toward the north (p = 0.006). These findings suggest that bioaccumulation of PFCs in sea turtles is influenced by species, age, and habitat.

Perfluoroalkyl contaminants in plasma of five sea turtle species: Comparisons in concentration and potential health risks

“…Estimated margins of safety values less than 1 indicate that sea turtles are exposed to concentrations above the threshold known to cause toxic effects. The EMOS for the sea turtle exposed to average PFOS in the current study ranged from 35,270 for green sea turtle risk of liver toxicity to [7]), indicating a declining risk of toxicity as the concentrations decline in these populations.…”

“…LOAEL ¼ lowest observed adverse effect level; PFOS ¼ perfluorooctane sulfonate; F ¼ female; M ¼ male; GD ¼ gestational day; PND ¼ postnatal day; hpf ¼ hours post-fertilization; bw ¼ body weight; T4 ¼ thyroxine; T3 ¼ triiodothyronine. [7]. c Estimated margins of safety <100, which is suggestive of potential health risks.…”

“…Perfluorooctanoic acid was below detection limits in loggerhead sea turtles (Caretta caretta) captured at four sites along the Atlantic coast of the United States, but was detected in loggerhead turtles from Florida Bay, Florida [8]. Kemp's ridley sea turtles (Lepidochelys kempii) had higher PFC concentrations than loggerheads, suggesting that they select slightly different prey items found higher on the food web than other marine turtles studied [7]. A robust spatial and temporal trend analysis using loggerhead plasma found that PFOS increased in concentration with capture latitude from Cape Canaveral, Florida, in the south to the Chesapeake Bay (Virginia and Maryland) in the north.…”

“…Two studies have previously reported PFCs in sea turtle samples, with interesting contrasts between species, as well as geographical and temporal differences in PFC concentrations [7,8]. Perfluorooctane sulfonate, the predominant PFC, was shown to be the organic pollutant at the highest concentration measured to date in sea turtle blood, even higher than total polychlorinated biphenyls [7]. Perfluorooctanoic acid was below detection limits in loggerhead sea turtles (Caretta caretta) captured at four sites along the Atlantic coast of the United States, but was detected in loggerhead turtles from Florida Bay, Florida [8].…”

“…These substances have been detected in human and wildlife samples worldwide, including several species of seabirds and marine mammals [3,4] and have been shown to biomagnify in various food webs [4][5][6]. Two studies have previously reported PFCs in sea turtle samples, with interesting contrasts between species, as well as geographical and temporal differences in PFC concentrations [7,8]. Perfluorooctane sulfonate, the predominant PFC, was shown to be the organic pollutant at the highest concentration measured to date in sea turtle blood, even higher than total polychlorinated biphenyls [7].…”