Empirical estimation of pollution load and contamination levels of phthalate esters in agricultural soils from plastic film mulching in China

Pollution load and contamination levels of phthalate esters (PAEs) in agricultural soils throughout China were studied in this work. The usage amount and residual rates of plastic film were the main factors explaining the variation among regions and leading to higher pollution load and contamination levels in agricultural big provinces. However, higher pollution loads and contamination levels frequently occurred under non-recycling than recycling scenarios during calculation. Extremely high loads (more than 10 kg/ha/year) of PAEs were estimated in five areas including Beijing city, Tibet, Liaoning Province, Jilin Province and Fujian Province and the high contamination levels in agricultural soil were presented in these places with more than 4.0 mg/kg under non-recycling scenarios. The predicted concentrations of PAEs in soils exceed the target value for soils from Netherlands (ΣPAEs = 0.1 mg/kg), indicating very high contamination of most Chinese agricultural soils. Significant differences in estimation results after plastic film utilization suggest that decreasing plastic film residue after application is an effective measure to control PAE pollution in soils. However, the comparison between contamination levels of PAEs estimated by the model and the previous detections of PAEs pollution levels in agricultural soils showed that there were presented wide range of PAE sources indicated to agricultural soils.