Excretion of PFOA and PFOS in male rats during a subchronic exposure

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.