Perfluoroalkyl acids (PFAAs) in indoor and outdoor dusts around a mega fluorochemical industrial park in China: implications for human exposure

The manufacture of fluorochemicals can lead to high levels of perfluoroalkyl acids (PFAAs) contaminating the surrounding environment and consequently elevated exposure to the local residents. In this study, measurements of PFAAs associated with indoor and outdoor dusts around a mega fluorochemical industrial park (FIP) were made. Perfluorooctanoic acid (PFOA) and short-chain perfluoroalkyl carboxylic acids (C4-C7 PFCAs) were the predominant forms in all samples. The signature of the PFAAs in dusts in the local area matched that found within the FIP complex. The contamination plume in the local area could be linked to the prevailing wind direction starting from the FIP. The concentrations decreased exponentially with distance from the FIP (noticeably in the first 5 km). PFAAs contamination could be detected at the most distant location, 20 km away from the FIP. The relatively small size of this high contamination zone suggested that the PFAAs were associated with large/dense dust particles with limited ability to be transported far by the air. The concentrations of PFAAs were higher in indoor dust (73-13,500 ng/g, median: 979 ng/g) than those in outdoor dust (5-9,495 ng/g, median: 62 ng/g) at every location. The highest estimated daily intake of PFOA via dust ingestion (26.0 ng/kg.bw/day) was for toddlers (2-5 yrs) living in 2 km away from the FIP, which is posing human health risk, though within the provisional tolerable daily intake values.