Determination of soil environment criteria for ecological safety of benzo[a]pyrene in soil based on the species sensitivity distribution approach

Benzo[a]pyrene (BaP) is a highly carcinogenic organic pollutant. Its distinct toxic effects have raised significant concerns among regulators and researchers. However, the absence of established soil environmental criteria for ecological safety of BaP has led to a lack of evidence in the current risk assessment for soil ecological security. To address this gap, we conducted a comprehensive study to investigate the toxicity of BaP using multiple soil organisms, including rice, wheat, lettuce, rape, cucumber, tomato, leonurus, and earthworm. The toxicity data obtained were applied to the species sensitivity distribution (SSD) approach, and the soil environment criteria for ecological safety of BaP under different land use types were derived. The soil environmental criteria for ecological safety of BaP were estimated to be 1.07 (Natural reserve and agricultural land), 1.63 (Parkland), 3.84 (Residential land) and 6.46 (Commercial service and industrial land) mg·kg−1, respectively. This study is the first to conduct toxicity testing and derive soil environmental criteria of BaP in terrestrial ecosystems. These findings are effective supplement for the current soil environmental quality standards and will function as the basis for ecological risk assessment of BaP.