Bioaccumulation and human exposure of perfluoroalkyl acids (PFAAs) in vegetables from the largest vegetable production base of China

Abstract

This study investigated perfluoroalkyl acids (PFAAs) in edible parts of vegetables, soils, and irrigation water in greenhouse and open filed, for the first time, in Shouguang city, the largest vegetable production base in China, which is located nearby a fluorochemical industrial park (FIP). The bioaccumulation factors (BAFs) were calculated, and the human exposures of PFAAs via consumption of the vegetables for different age groups assuming the maximum levels detected in each vegetable and average consumption rates were also estimated. The ΣPFAA levels ranged from 1.67 to 33.5 ng/g dry weight (dw) in the edible parts of all the vegetables, with perfluorobutanoic acid (PFBA) being the dominant compound with an average contribution of 49% to the ΣPFAA level. The leafy vegetables showed higher ΣPFAA levels (average 8.76 ng/g dw) than the fruit and root vegetables. For all the vegetables, the log10 BAF values of perfluorinated carboxylic acids showed a decreasing trend with increasing chain length, with PFBA having the highest log10 BAF values (average 0.98). Cabbage had higher bioaccumulation of PFBA (log10 BAF 1.24) than other vegetables. For the greenhouse soils and vegetables, the average contribution of perfluorooctanoic acid (PFOA) to ΣPFAA was lower than that in the open field samples, while the contributions of PFBA, PFHxA, PFPeA to ΣPFAA were higher. Irrigation water may be an important source of PFAAs in greenhouse, while for open field vegetables and soils, atmospheric deposition may be an additional contamination pathway. The estimated maximum exposure to PFOA through vegetable consumption for urban preschool children (aged 2–5 years) was 63% of the reference dose set by the European Food Safety Authority. Suggestions are also provided for mitigating the health risks of human exposure to PFAAs. Keywords: Perfluoroalkyl acids, Vegetable production, Greenhouse planting, Bioaccumulation, Food safety, Health risk evaluation