Health risk evaluation for the inhabitants of a typical mining town in a mountain area, South China.

ABSTRACT

A previous study investigated metal contamination in farmland and the air in a typical mining town of Guangxi, South China. In this study, the health risks associated with exposure to this contamination that were evaluated for the following routes of exposure are reported inhalation, dermal contact, ingestion of dust, and ingestion of homegrown vegetables. The findings demonstrated that the inhabitants were at high risk for noncancer effects posed by some of the metals. The total hazard index (THI) of all the pathways was 145 for adults and 560 for children, which were far higher than the normative level 1. The noncancer risk mainly came from air PM(10) pollution through inhalation and ingestion routes of exposure. However, vegetable ingestion also made a noticeable contribution to HI of about 7 for adults and 22 for children. The metals that posed the greatest noncancer risks were Mn for inhalation, and ingestion of dust and vegetables. The total cancer risks of the inhabitants were 1 x 10(-1) (adult) and 3 x 10(-1) (child), which far exceeded the acceptable carcinogen risk of 10(-4) approximately 10(-6) for regulatory purposes. The cancer risk in the village is mainly (97%) associated with As exposure by inhalation and ingestion of dust. However, consumption of vegetables is also associated with a significant cancer risk of up to 2 x 10(-3) for adults and 8 x 10(-3) for children. The cancers associated with this exposure are estimated to be lung cancer and skin cancer. Air particulate-matter pollution was the main source of noncancer risk and cancer risk and originated from vehicular transport of ore through the community. The risk could be tested by a specifically designed epidemiological study.