Organophosphorus pesticides in greenhouse and open-field soils across China: Distribution characteristic, polluted pathway and health risk

A national-scale survey was conducted to investigate the distribution characteristic, polluted pathway and health risk of organophosphorus pesticides (OPPs) in greenhouse and open-field soils in 20 regions across China. The total concentrations of eight OPPs ranged from 22.1 to 435 ng/g with a mean of 96.2 ng/g in greenhouses, and from 9.93 to 303 ng/g with a mean of 66.6 ng/g in open fields. Due to the intensive agricultural activities, the high residue of OPPs in greenhouse and open-field soils was found in the northeastern, northern and central areas. Furthermore, the effect of environmental factors (i.e. human activities, soil properties, heavy metals and microorganism) on OPPs were evaluated through the partial least squares path modeling. Apart from microorganisms, all the other factors affected the soil contamination of OPPs directly (p < 0.05), where the soil properties occupied the most important position (p < 0.01). In greenhouses, the highest correlation was observed in the relationship between human activities and soil properties, indicating that their combination was more likely to cause the contamination of OPPs in greenhouses indirectly. Moreover, the soil properties had the significant effect on the heavy metals in open fields (p < 0.05), suggesting that the residual OPPs in open fields was sensitive to interaction of these two factors. Although the hazard indexes in all soil samples were less than 1.0, the children were more susceptible to the non-cancer risks of OPPs in greenhouse. This study provided valuable information to understand the pollution status of OPPs in farmlands and protect the agroecological environment.