Abstract
Artisanal small-scale gold mining (ASGM) is the largest single source of mercury (Hg) emissions globally. In this study, Hg contamination was investigated in rice, vegetables, soil, drinking water and groundwater near ASGM sites in Mandailing Natal District, North Sumatra, Indonesia to assess the human health risk of Hg to the residents. The mean Hg concentrations in the rice and vegetables were 50±33 μg/kg dw (n=20) and 2,100±2,500 μg/kg dw (n=12), respectively, and that in the paddy soil and farm soil were 5,600±12,000 μg/kg dw (n=20) and 19,000±33,000 μg/kg dw (n=12), respectively. Hg concentrations in the food, soil and drinking water samples decreased significantly with increasing distance from the amalgam burning facility to the sampling site, suggesting that the burning facility is a major source of Hg in this area. All drinking water samples were below the WHO safe value of Hg, whereas 96% of the vegetable and 82% of rice samples exceeded the safe value from the Indonesian National Standard or the FAO/WHO. The non-cancer risk calculated from the hazard quotients for the rice and vegetables exceeded 1 for children and adults. This paper provides information on Hg contamination in food and the environment in an understudied area, employing health risk assessment to evaluate long-term impacts on human health and offering insights for government decision-making regarding food quality.
