Bioaccessibility and health risk assessment of arsenic in soil and indoor dust in rural and urban areas of Hubei province, China.

Incidental oral ingestion is the main exposure pathway by which human intake contaminants in both soil and indoor dust, and this is especially true for children as they frequently exhibit hand-to-mouth behaviour. Research on comprehensive health risk caused by incidental ingestion of both soil and indoor dust is limited. The aims of this study were to investigate the arsenic concentration and to characterize the health risks due to arsenic (As) exposure via soil and indoor dust in rural and urban areas of Hubei province within central China. Soil and indoor dust samples were collected from schools and residential locations and bioaccessibility of arsenic in these samples was determined by a simplified bioaccessibility extraction test (SBET). The total arsenic content in indoor dust samples was 1.78-2.60 times that measured in soil samples. The mean As bioaccessibility ranged from 75.4% to 83.2% in indoor dust samples and from 13.8% to 20.2% in soil samples. A Pearson's analysis showed that As bioaccessibility was significantly correlated with Fe and Al in soil and indoor dust, respectively, and activity patterns of children were utilised in the assessment of health risk via incidental ingestion of soil and indoor dust. The results suggest no non-carcinogenic health risks (HQ<1) or acceptable carcinogenic health risks (1×10(-6)<CR<1×10(-4)) in all studied locations. Indoor activities comprised between 64.0% and 92.7% of the total health risk incurred during daily indoor and outdoor activities. The HQ and CR values for children in urban areas were 1.59-1.95 times those for children in rural areas. The HQ and CR values for children three to five years of age were 1.40-1.47 times those for children six to nine years of age. The health risk accounting for bioaccessibility was only 50.8-59.8% of that obtained without consideration of bioaccessibility.