Monitoring and risk assessment of pesticide residue in plant-soil-groundwater systxem about medlar planting in Golmud.

Farm worker and consumers are vulnerable to the potentially toxic pesticides accumulated in the environment and food. Nonetheless, few studies have investigated the pesticide pollution and risk in the medlar planting site at a large scale. Hereupon, this study focused on the pesticide contamination distribution, their potential risk assessment of contaminated sites and dietary. The 11 pesticide pollution sources were collected from the five systems of fruit, leaf, soil, groundwater, and honey based on a systematic review in medlar planting site. Seventy-six samples were analyzed by chromatography technique. Residues of 4 (36.7%) compounds were found in the samples. The most distributed pesticides were imidacloprid for all samples, followed by avermectin for leaf, soil, groundwater, and honey, and carbendazim for leaf, glyphosate for soil, and those with the highest average concentrations were carbendazim (3.8-8.4 mg/kg of leaf) and glyphosate (0.21-1.3 mg/kg of soil). The vertical migration characteristic of imidacloprid was relatively stable, and the residual concentration gradually declined with the increase of burial depth. However, glyphosate tended to accumulate gradually or was close to the surface concentration with the increase of burial depth. The distribution of abamectin had no obvious regularity. Imidacloprid was lower than the MRL in fruit and honey. Imidacloprid, avermectin, and glyphosate no MRL in soil and groundwater are set. Using the monitoring data, potential health risk come from fruit, soil, and groundwater was evaluated. The HI and HQ could be considered safe for pesticide residues in fruit, soil, and groundwater. Even if these results are in general safe to eat, the effects of insecticide on human health, especially on genetic toxicity, have gradually aroused more attention. To minimize the increasing human health risk, this study suggests that authorities must regulate the usage of agrochemicals, to strengthen the controls for effective implementation of the pesticide bans.