Seasonal variations of mercury levels and human health risk in vegetables from Arid Oasis (Shihezi city), Xinjiang,Northwest China

The purpose of this study was to investigate the seasonal variations of mercury levels and human health risk in vegetables that were collected from farmland, home garden, and plastic greenhouse in summer and winter 2016 in Arid Oasis (Shihezi city), Xinjiang, Northwest China. The results showed that the levels of mercury in fresh vegetables were lower in winter (0.003–0.025 mg·kg^?1) than in summer (0.001–0.035 mg·kg^?1). Single factor pollution (P) in vegetables indicated that all vegetables were polluted in diverse levels. The exceeding rate in different vegetables was 0.00% to 88.89% in summer and 0.00% to 100% in winter compared with limits of pollutants in vegetables. The value of bio-concentration factor (BCF) revealed that the mercury absorption capacity of 10 species vegetables decreased in the following order: pea seedling > spinage > caraway > lettuces > pakchoi > celery > crowndaisy chrysanthemum > chives > spinach > shallot. The daily intake (DI) and target hazard quotient (THQ) of mercury for children (2–12 years), young adults (18–45 years), and quinquagenarian (>45 years) indicated that non-carcinogenic values were below the threshold values except one sampling sit from farmland around the industrial parks. Furthermore, the THQ of open field in summer was higher than plastic greenhouse in winter. Under the same pollution level, children had more non-carcinogenic risk than young adults and quinquagenarian.