Author(s): Cai S, L Yue, Q Shang, G Nordberg
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 on 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 367-382 micrograms/ day. Smokers had additional exposure from locally grown cadmium-containing tobacco. Cadmium concentrations in samples of urine (11 micrograms/g creatinine), blood (12 micrograms/l) and in the hair (0.11 microgram/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.