Interest and concern about polyfluorinated compounds (PFCs), such as perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), and an increasing number of other related compounds is growing as more is learned about these ubiquitous anthropogenic substances. Many of these compounds can be toxic, and they are regularly found in the blood of animals and humans worldwide. A great deal of research has been conducted in this area, but a surprising amount remains unknown about their distribution in the environment and how people ultimately become exposed. The utility of these compounds seems to ensure their continued use in one form or another for the foreseeable future, presenting a long-term challenge to scientists, industry leaders, and public health officials worldwide.

Sources of human exposure to perfluorinated carboxylic acids (PFCAs) are not well-characterized. Polyfluoroalkyl phosphoric acids (PAPs) are fluorinated surfactants used in human food contact paper products. PAPs can migrate into food and food simulants, and their bioavailability and biotransformation into PFCAs has been demonstrated using a rat model. To characterize human exposure to PAP materials, we analyzed pooled human sera samples collected in 2004 and 2005 (n = 10) and 2008 (n = 10) from the midwestern United States for the 4:2 through 10:2 PAP diesters (diPAPs). The 2004 and 2005 sera samples contained 4.5 microg/L total diPAPs, with the 6:2 diPAP dominating the congener profile at 1.9 +/- 0.4 microg/L DiPAP concentrations observed in the 2004 and 2005 human sera samples were similar to those of the C8 to C11 PFCAs (0.13 +/- 0.01 to 4.2 +/- 0.3 microg/L) monitored in the same samples. 6:2 diPAP was also consistently observed in the 2008 human sera samples at a mean concentration of 0.63 +/- 0.13 microg/L As diPAPs have been shown to degrade to PFCAs in vivo, our observation of diPAPs in human sera may be a direct connection between the legacy of human PFCA contamination and PAPs commercial applications. Wastewater treatment plant (WWTP) sludge and paper fibers were analyzed for diPAPs as a proxy for human use and potential exposure to diPAPs. DiPAPs were observed in WWTP sludge at concentrations ranging from 47 +/- 22 to 200 +/- 130 ng/g, a range similar to perfluorooctane sulfonic acid (PFOS) (100 +/- 70 ng/g) and greater than the C8 to C11 PFCAs (1.6 +/- 0.6 to 0.17 +/- 0.10 ng/g) observed in the same samples. DiPAPs were observed in paper fiber extracts at concentrations ranging from 34 +/- 30 to 2200 +/- 400 ng/g. The high diPAP concentrations in WWTP sludge suggest PAP materials may be prevalent in our daily lives.

Sludges generated at a wastewater treatment plant (WWTP) in Decatur, Alabama have been applied to agricultural fields for more than a decade. Waste-stream sources to this WWTP during this period included industries that work with fluorotelomer compounds, and sludges from this facility have been found to be elevated in perfluoroalkylates (PFAs). With this knowledge, the U.S. Environmental Protection Agency collected soil samples from sludge-applied fields as well as nearby "background" fields for PFA analysis. Samples from the sludge-applied fields had PFAs at much higher concentrations than in the background fields; generally the highest concentrations were perfluorodecanoic acid (≤ 990 ng/g), perfluorododecanoic acid (≤ 530 ng/g), perfluorooctanoic acid (≤ 320 ng/g), and perfluorooctane sulfonate (≤ 410 ng/g). Contrasts in PFA concentration between surface and deeper soil samples tended to be more pronounced in long-chain congeners than shorter chains, perhaps reflecting relatively lower environmental mobilities for longer chains. Several PFAs were correlated with secondary fluorotelomer alcohols (sec-FTOHs) suggesting that PFAs are being formed by degradation of sec-FTOHs. Calculated PFA disappearance half-lives for C6 through C11 alkylates ranged from about 1 to 3 years and increase with increasing chain-length, again perhaps reflecting lower mobility of the longer-chained compounds.