Phytotoxicity of PFOS and PFOA to Brassica chinensis in different Chinese soils

PFOS and PFOA are potential persistent organic pollutants that have raised many concerns in recent years. Research focusing on phytotoxicity of PFOS and PFOA to higher plants is necessary for their risk assessments. However, few toxicity data exist for PFOS or PFOA and higher plants. Here we investigated phytotoxicity of PFOS and PFOA to Brassica chinensis root growth in six different Chinese soils varying widely in soil properties using a standardized root length assay. The effective concentrations of added PFOS and PFOA causing 50% inhibition (EC₅₀) ranged from 95 to >200 mg kg⁻¹ for PFOS and from 107 to 246 mg kg⁻¹ for PFOA, respectively, representing more than 2.1- and 2.3-fold variation among the tested soils. Regressions of soil PFOS and PFOA toxicity threshold values (EC_x and NOECs) with various soil properties showed that the amount of organic matter was the most significant factor affecting their toxicity to B. chinensis.