Soil residues and crop accumulation of organophosphorus and pyrethroid pesticides in agricultural fields in Shaanxi, China

Purpose

This study aimed to investigate the residual levels of representative organophosphorus and pyrethroid pesticides (chlorpyrifos, cypermethrin, deltamethrin, and lambda-cyhalothrin) in agricultural soils and crops in Shaanxi Province, and to reveal their accumulation characteristics and regional distribution characteristics in crops.

Materials and methods

The study was conducted using 115 soils and crops samples from typical agricultural areas in Shaanxi Province. The pesticide residues were measured using gas chromatography-mass spectrometry (GC-MS). The crops were analyzed based on the residue characteristics of fruits, vegetables, and field crops. Additionally, the pesticide residues in crops from the Guanzhong area (central part of Shaanxi), northern Shaanxi, and southern Shaanxi regions were analyzed. A correlation analysis was conducted to examine the influencing factors of pesticide residues in soil-crops, considering the physical and chemical properties of the soil in Shaanxi Province.

Results and discussion

The results indicate that there are differences in the detection rates and residual concentrations of different pesticides in soil. In the Guanzhong area, the pesticide residual levels in crops follow the trend of chlorpyrifos > deltamethrin > lambda-cyhalothrin > cypermethrin, with relatively high pesticide residues found in corn. In northern Shaanxi, the overall pesticide residual levels in crops show a trend of chlorpyrifos > deltamethrin > cypermethrin > lambda-cyhalothrin. In southern Shaanxi, all the pesticides were detected to varying degrees in crops, with chlorpyrifos showing the highest residual levels.

Conclusions

All four pesticides were detected in the soils of the study area and the enrichment capacity of different crops varied greatly. Pesticide enrichment is not only affected by temperature and climate conditions in different regions, but soil organic matter, pH, and CEC also have a significant effect on the enrichment of pesticides by crops.