Biomarkers of arsenic exposure in arsenic-affected areas of the Hetao Basin, Inner Mongolia

Abstract

Seventy saliva samples, seventy urine samples, seventy nail samples, seventy hair samples, eight drinking water samples and ninety-three crop samples were collected from four villages of the Hetao Basin in Inner Mongolia to determine arsenic (As) exposure biomarkers and evaluate relationship between As uptake and human health risk. Trivalent As (As(III)), pentavalent As (As(V)), dimethylarsinic acid (DMA), arsenobetaine (AsB) and monomethylarsonic acid (MMA) were found in all urine samples. Only As(III) and As(V) were detected in saliva samples. In nail and hair samples, DMA, MMA, As(III) and As(V) were observed. Based on total As contents in crops and drinking water, the local residents' daily intake of total arsenic (TDIAs), the hazard quotient (HQ), and the cancer risk (R) were assessed. Male, older and cases of skin lesion participants generally had higher As contents in saliva, urine, nail and hair samples in relative to others. Salivary, urinary, nail and hair As were not significantly affected by body mass index (BMI) and smoking. Good correlations were observed between TDIAs and salivary, urinary, nail and hair As, showing that saliva, urine, nail and hair samples can be used as biomarkers of As exposure. Individually, levels of arsenicosis were positively correlated with TDIAs. The relationship between TDIAs and prevalence of arsenicosis concluded that, although As levels in crops and drinking water did not exceed national standards, they still pose a potential threat to human health. It was suggested that the maximum permissible levels of crop As and drinking water As should be re-evaluated for protecting human health.