Uptake of perfluorooctane sulfonate (PFOS) by common home-grown vegetable plants and potential risks to human health
By Monika Shobhna Lal, Mallavarapu Megharaj, Ravi Naidu, and Md Mezbaul Bahar
May 11, 2020
Per- and poly-fluoroalkyl substances (PFAS) are emerging contaminants of concern in Australia and the world. The two most studied compounds of PFAS are perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). PFOS is toxic, highly persistent, carcinogenic and bioaccumulative in the environment. PFOS has been widely used as an active ingredient in the firefighting foams, stain repellent in leather apparel, for paper and packaging, which has imposed a concern for the environment and the human health. To reduce the human health risks from PFOS, it is important to investigate the fate and transfer of PFOS in the food chain. In this study, a glasshouse pot experiment was conducted for 119 days to evaluate the uptake and accumulation of PFOS in three selected home-grown vegetables. The results showed that there was considerable accumulation of PFOS in different parts of the vegetables. The calculated bioconcentration factors (BCF) suggested that the uptake of PFOS increased with an increase in the soil PFOS concentration in lettuce roots and hearts. Whereas the BCF increased for carrot shoots and roots at PFOS concentrations of 0.23 and 4 mg/kg soil but decreased at the highest concentration of PFOS (40 mg/kg soil) used in this study. The daily intake rates of PFOS via vegetable consumption were found higher than the tolerable daily intake for children of age 2-6 years as per Food Standards Australia New Zealand (FSANZ). Besides, it can be suggested that if the vegetables were planted in the similar contaminated soils, the BCF would be high resulting an increase in the concentration of PFOS in the plant components. This study demonstrates the potential risk of PFOS to humans/animals via food chain.