Study On The Occurrence Status And Environmental Risk Of Organophosphate Esters In Soils Of Beijing Urban Parks

In recent years,emerging pollutants have received widespread attention globally.China also attaches great importance to the governance of emerging pollutants,but currently there are still shortcomings in the evaluation and monitoring of emerging pollutants,as well as relatively weak scientific and technological support.Organophosphate esters(OPEs)are a typical emerging pollutant with high production and usage and various biological toxicities.Although OPEs are widely present in soil,research on OPEs in soil is still in its initial stage.Urban park is an essential component of urban ecosystem,playing a significant role in the ecological environment quality.Park soil serves as an essential "sink" for urban pollutants and is crucial for human health and ecological security.In this study,Beijing was selected as the study area for its typical highly urbanized megacity in China with high green coverage to investigate organophosphate triesters(tri-OPEs)and organophosphate diesters(di-OPEs)in soils from 104 urban parks.Multiple statistical analysis,machine learning,and probabilistic risk assessment models were used to analyze the pollution status and environmental risks of OPEs.This study can provide reference for the soil environmental management of urban parks in China,and have important significance for the prevention and control of soil emerging pollutants in China.The main results obtained are as follows:(1)The median concentrations of tri-OPEs and di-OPEs in Beijing urban park soils were 157 ng/g dw and 17.9 ng/g dw,respectively.Tris(2-chloro-isopropyl)phosphate(TCIPP)was the most important component of OPEs.The major sources of tri-OPEs in park soil were consumer material release,traffic emissions,and reclaimed water irrigation,while di-OPEs were mainly derived from the degradation of parent compounds and industrial applications dominated by chemicals and textiles.(2)Population density and distance from the city center were key factors affecting the accumulation of tri-OPEs in park soil,while the occurrence of di-OPEs was mainly influenced by parent compound concentrations,industrial and commercial activities,and soil organic matter content.The total concentration of OPEs in Beijing urban park soils is expected to exhibit a clear upward trend in the future and OPE concentrations in parks in Xicheng,Chaoyang,and Haidian District may increase rapidly.(3)The ecological risk of OPEs in Beijing urban park soils is at a moderate level.Parks with relatively high ecological risk are concentrated in Xicheng District,and the ecological risk of tris(2-chloroethyl)phosphate(TCEP),TCIPP,and trimethylphenyl phosphate(TMPP)is relatively high.The non-carcinogenic and carcinogenic risk of OPEs can be neglected.Pollutant concentrations,exposure frequency,and soil ingestion rate are important parameters affecting the health risk of OPEs.