Perfluorinated Compounds (PFCs) in Soil of the Pearl River Delta, China: Spatial Distribution, Sources, and Ecological Risk Assessment

Abstract

This study investigated the levels, spatial distribution, sources, and ecological risks of 16 perfluorinated compounds (PFCs) in 68 surface soil samples (0–20 cm) from 7 cities in the Pearl River Delta (PRD), China. Sixteen target PFCs, including perfluoroalkyl carboxylic acids (PFCAs, C5–C14, C16, and C18) and perfluoroalkyl sulfonic acids (PFSAs, C4, C6, C8, and C10), were analyzed by high-performance liquid chromatography-negative electrospray ionization-tandem mass spectrometry (HPLC/ESI-MS/MS). Concentrations of total PFCs (∑PFCs) ranged from 2.19 to 98.5 μg kg−1 (dry weight, dw), with an average of 5.97 μg kg−1 dw. Perfluorooctane sulfonate (PFOS) was the dominant PFC, accounting for 23.9% of ∑PFCs. The highest ∑PFCs was found in the soil sample collected from Dongguan with a large number of manufacturing industries. There were no significant differences of ∑PFCs among unban, industrial, and agricultural soils, indicating similar pollution sources in soil of the PRD. More than 70% of ∑PFCs in soil of the PRD could be attributed to the four principal components, represented by PFOS and perfluorooctanoic acid (PFOA), perfluoropentanoic acid (PFPeA) and perfluorohexanoic acid (PFHxA), perfluorodecanoic acid (PFDA), and perfluoroundecanoic acid (PFUdA). Ecological risk assessment indicated that PFOA had low risk to soil plants and animals. However, the risk of PFOS to soil plants was relatively high in some studied regions.