Excretion of PFOA and PFOS in Male Rats During a Subchronic Exposure

Abstract

Perfluorinated compounds (PFCs), a class of synthetic surfactants that are widely used, have become global environmental contaminants because of their high persistence and bioaccumulation. An increasing number of studies have described the pharmacokinetics of PFCs following in vivo exposure, however, few papers have focused on the excretion of these compounds during a period of consecutive exposure. In this study, the excretions of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) in male Sprague-Dawley rats gavaged consecutively for 28 days were investigated and compared. The faster elimination rate in urine compared to feces indicated that urinary excretion is the primary clearance route in rats for either PFOA or PFOS. During the first 24 h after administration of PFOA (5 and 20 mg/ kg body weight/day), about 24.7-29.6% of the oral dose was excreted through urine and feces, while for PFOS, the excretion amounts were only 2.6-2.8% of the total gavaged doses (5 and 20 mg/kg body weight/day). The excretion rates of both PFCs increased with increasing exposure doses. The higher elimination rate of PFOA through excretion indicated its lower accumulation in rats, thus inducing possible lower toxicities compared to PFOS.

Transfer of Perfluorooctanoic Acid (PFOA) and Perfluorooctane Sulfonate (PFOS) From Contaminated Feed Into Milk and Meat of Sheep: Pilot Study

“…The crude nutrients of PFAA-contaminated corn silage were comparable with those of PFAA-free corn silage (Table 1). Crude ash content of PFAA-contaminated corn silage was not increased (\8 %); therefore, adhesion of soil causing high PFAA In the present study, sheep exposure to PFOA and PFOS by way of ''natural'' contaminated feed was 10-to 100-fold less than those used for kinetic studies with chicken NA not analysed (Yeung et al 2009;Yoo et al 2007) and rats (Vanden Heuvel et al 1991;Cui et al 2010). Comparison of plasma concentrations in wildlife found similar mean concentrations of PFOA and PFOS, ranging from 0.3 to 8 lg/L PFOA and from 0.8 to 74 lg/L PFOS, in panda from China (Dai et al 2006).…”

“…The stronger protein binding of PFOS and its high accumulation potential might explain the slower elimination rate compared with PFOA (Luebker et al 2002;Weiss et al 2009;Tan et al 2008). Numerous studies in rats have demonstrated that PFOA is primarily excreted by way of urine (Cui et al 2010;Kudo and Kawashima 2003;Vanden Heuvel et al 1991). In addition, for sheep in the present study, excretion of PFOA was highest by way of urine, and PFOA excretion by way of other routes of elimination (milk, faeces) were marginal (\1 %, \2 %).…”

Uptake and elimination of perfluorinated phosphonic acids in the rat

“…Gender differences have previously been observed in the excretion of fluorinated acids [16,17]. No statistical differences were observed between male and female serum half-lives for the mono-PFPAs.…”

“…Both male and female animals were included in the elimination study because gender differences in elimination kinetics have been observed for the PFCAs [16,17]. To limit the number of animals used, only male animals were included in the oral absorption study, because any gender differences in oral absorption are not expected to be as pronounced as those observed for the excretion phase.…”

Endocrine, biotransformation, and oxidative stress responses in salmon hepatocytes exposed to chemically induced hypoxia and perfluorooctane sulfonamide (PFOSA), given singly or in combination

“…These compounds are considered relatively persistent to degradation (Cui et al 2010), and the environmental implications of this is apparent when global monitoring shows relatively high levels of PFASs in biota and no decreasing trend in levels (Houde et al 2011;Prevedouros et al 2006) even though phasing out production started in 1997 (Giesy and Kannan 2001;Kannan et al 2004). …”