Research on Urinary Arsenic Metabolites of Population Exposed to Different Concentrations of Arsenic by Drinking Water

Objective Based on the health standards for arsenic in drinking water recommended by WHO (0.01 mg/L) and adopted by decentralized rural water supply in China (0.05 mg/L), to explore the conditions of arsenic metabolism and levels of methylation in population consuming drinking water with different concentrations of arsenic. Methods Three hundred and forty-eight adults in Shanxi exposed to different concentrations of arsenic(≥0.05 mg/L, ≥0.01-0.05 mg/L, 0.01 mg/L) in drinking water were chosen as the objects for study in Oct.2008, which were divided into higher (n=124, ≥0.05 mg/L ) ,lower (n=154,≥ 0.01-0.05 mg/L) exposure group, control group(n=70, 0.01 mg/L) ,and the arsenic species and TAs in the urine samples were detected with hydride generation atomic absorption spectroscopy. Results With the concentrations of arsenic in drinking water increasing, the concentrations of arsenic species and TAs in the urine increased (P0.05). DMA, TAs and secondary methylation ratio (SMR) of female were significantly higher than those of male (P0.05) in higher exposure group, while no gender differences were found (P0.05) in arsenic species , TAs , first methylation ratio (FMR) and SMR in lower exposure group and the control group. In higher exposure group, the FMR of adults aged over 60 years was significantly higher than that in groups of 18-39 years old and 40-49 years old (P0.05), while no differences of the FMR and SMR were found among each age group in lower exposure group and control group (P0.05). Conclusion In higher exposure group, the 2nd reaction of the metabolic pathway is more active in female than that in male, and arsenic methylation capacity of the higher age group arise. No significant effects of gender and age on arsenic methylation capacity is found among population exposed to drinking water with lower level of arsenic.