Cadmium exposure among residents in an area

River water used to irrigate arable land in Dayu County, Jiangxi Province, China, is polluted with cadmium from tailings and the wastewater of tungsten ore dressing plants. From information about the date of construction of ore dressing plants and an analysis of the annual growth rings of trees, we deduced that local residents have been exposed to cadmium for at least 25 years. Cadmium exposure was estimated based on a meal survey, which indicated that 99.5% of the oral cadmium intake came from rice and vegetables grown locally. The average oral intake of cadmium was calculated to be 367382 pg/day. Smokers had additional exposure from locally grown cadmium-containing tobacco. Cadmium concentrations in samples of urine (11 pg/g creatinine), blood (12 pg/I) and in the hair (0.11 pg/g) of persons in the exposed area were high. The cadmium exposure lies in a range that can be considered to cause adverse renal effects in the long term.