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Perfluorooctane sulfonate (PFOS) and Perfluorooctanoic acid (PFOA) are recognized as emerging environmental pollutants because of their high persistence in various environmental matrices and toxic effects on humans and animals. In Vietnam, PFOA and PFOS have been detected in surface water and sediment in recent studies. The objectives of this study were to evaluate the occurrence of PFOS and PFOA in the sediment of the Cau river, Thai Nguyen city to determine the partition coefficient between water and sediment, and to elucidate the environmental factors affecting the sorption of PFOS and PFOA to sediment. The concentration of PFOS and PFOA in surface sediment ranged from 1.19 ng/g to 4.73 ng/g and 0.17 ng/g to 1.78 ng/g, respectively, with the highest concentrations, are recorded in the areas that receiving wastewater from domestic and industrial activities. Depending on the depth, the total concentrations of PFOS and PFOA ranged from 8.41 to 19.25 ng/g and tended to decrease with increasing sediment depth. The concentrations in the surface sediments are lower than the second layer, indicating a downward trend in the use and consumption of these compounds in recent years. The water-sediment distribution coefficient (Kd) is relatively different for PFOS and PFOA, with log Kd values ranged from 1.31–1.86 and 0.08–1.31 for PFOS and PFOA, respectively. This study also confirms that the total organic carbon content is the physiochemical property that significantly affected the adsorption to sediments of PFOS and PFOA. No apparent relation was found between PFOS, PFOA concentration in sediment and clay content nor sediment particle size. |
