OBJECTIVETo research the impairment of renal function and the combined effects of arsenic and cadmium exposure in population residing in polluted area, and to calculate the benchmark doses of urinary arsenic (UAs) and cadmium (UCd) in renal dysfunction.

METHODSThe concentrations of Uas and UCd were used as as exposure biomarker. Urinary beta(2)-microglobulin (Ubeta(2)-MG), N-acetyl-beta-glucosaminidase (UNAG), and albumin were calculated as biomarkers of renal dysfunction. The benchmark dose (BMD) and the lower confidence limit of the benchmark dose (BMDL) were calculated. Totally 245 patients were enrolled in the study, them, of 122 were from the exposed area, and 123 from the control area.

RESULTSUAs and UCd concentrations in the exposed group were shown significantly higher than those in the control group (P < 0.01). The levels of Ubeta(2)-MG, UNAG and urinary albumin in the exposed group were significantly higher than those of the controls (P < 0.01). There existed positive correlation among the concentrations of UAs, UCd, Ubeta(2)-MG, urinary albumin and UNAG, showing a significant dose-effect relationship. The combination of cadmium and arsenic caused even more renal injury than by chemicals alone in a same dose. The BMD/BMDL of UAs were estimated as 121.91-171.88 microg/g Cr and 102.11-144.44 microg/g Cr. Of UCd, the BMD/BMDL were 1.05-1.48 microg/g Cr and 0.88-1.24 microg/g Cr.

CONCLUSIONSThis study indicates the combination of cadmium and arsenic might cause even more renal injury than by chemicals given alone, and cadmium might cause potential arsenic nephrotoxicity during long-term coexposure to arsenic and cadmium in human beings. It also suggests that UAs and UCd should be kept below 102.11 and 0.88 microg/g creatinine as to preventing renal damage from coexposure to arsenic and cadmium. The BMD method should be used in calculating the BMD of UAs and UCd on renal dysfunction.