Original research articleSeasonal variation and exposure risk assessment of pesticide residues in vegetables from Xinjiang Uygur Autonomous Region of China during 2010-2014

- Residues of 48 types of pesticides in 19,786 vegetable samples were analyzed.
- High pesticide contamination levels were most prevalent during winter (Jan-Mar).
- The most frequently detected pesticide residue was procymidone.
- Pesticide residues in vegetables are not a serious public health threat in Xinjiang.

In the present study, 48 pesticide residues in 19,786 vegetable samples collected from Xinjiang Uygur Autonomous Region (Xinjiang) of China over four seasons during 2010-2014 were quantitatively analyzed by gas chromatography tandem mass spectrometer (GC-MS/MS) or liquid chromatograph tandem mass spectrometer (LC-MS/MS). The potential exposure risks were then evaluated. Overall, pesticide contamination is the most serious risk in the first three months of the calendar year (Jan-Mar); thereafter the levels of contamination tend to decrease. There were 6325 samples (31.97%) that contained pesticide residues, and 768 samples (3.88%) that exceeded the maximum residue limits (MRLs). The highest residue rates and those exceeding MRLs rate were found in celery. Leafy vegetables and legume vegetables were more contaminated than other vegetable groups. The most frequently detected pesticide was procymidone (6.43%). Some banned or restricted pesticides such as HCB, DDT and carbofuran were detected. The highest detected concentration was in cypermethrin (7.40 mg/kg). The target hazard quotient (THQ) of all pesticides was <1, and the hazard index (HI) was 0.0872. The results supported that pesticide residues in vegetables may not pose a serious threat to public health in Xinjiang, despite a high detection rate. More importantly, continuous monitoring and tighter regulation of pesticide residues are highly suggested to promote food safety.