Abstract: To assess food contamination levels of organic (MeHg) and inorganic mercury associated with mining and urban environments in Guizhou, we analyzed 503 samples from Hezhang County (lead-zinc mining area) and Guiyang. The health risk associated with dietary consumption was assessed using Monte Carlo simulations. The highest levels of total mercury were 39 and 18 ng·g^-1 in the samples from the mining area and the urban residential area, respectively. The corresponding highest measurement values for MeHg were 1.7 and 7.7 ng·g^-1, respectively. The investigated foodstuffs such as rice, potatoes, chicken eggs, fish, pork did not contain significant levels of mercury contamination, with the exception of certain vegetables that frequently showed levels above the current limit standard of 10 ng·g^-1. 14.7% (lead/zinc mining area) and 17.7% (residential area) of vegetable samples exceeded the limit specified in China’s National Food Safety Standard (GB 2672-2017). Dietary inorganic mercury exposure was similar for food with different origins (residential area: 0.031 μg·kg^-1·d^-1, lead-zinc mining area: 0.032 μg·kg^-1·d^-1), while exposure to organic mercury was nearly twice greater in the urban environment (6.0 vs. 3.2 ng·kg^-1·d^-1). In general, the average daily exposure to inorganic mercury and MeHg was lower than the provisional weekly tolerable intake (PTWI) of 4 μg·kg^-1·week^-1 for IHg by WHO/JECFA and the reference dose (RfD) of 0.1 μg·kg^-1·d^-1 for MeHg established by USEPA, respectively. Hazard index in both regions was much less than unity, suggesting no obvious non-carcinogenic health risks.

Key words: lead-zinc mining area, Guiyang city, inorganic mercury, methylmercury, risk assessment