Arsenic source analysis of rice from different growing environments and health risk assessment in Hunan Province, China

Rice is an important pathway for arsenic dietary intake. Hunan Province is the major rice-producing region in China and is rich in mineral resources. To evaluate the sources of arsenic contamination in rice and health risks associated with rice consumption, the arsenic content in rice, paddy soils, and irrigation water in Hunan Province was analyzed. The results showed that the mean values of total arsenic (tAs) were 132 +/- 42, 198 +/- 95, 521 +/- 390, and 2050 +/- 3300 mu g/kg in milled rice, brown rice, rice bran, and rice husk, respectively. Inorganic arsenic (iAs) was the dominant species in rice, accounting for 78.1% and 85.9% of tAs in milled rice and brown rice, respectively. Moreover, the contents of iAs in rice husk, bran, and brown rice were 19.7, 4.81, and 1.65 times higher than that in milled rice. Arsenic accumulation rice was mainly from irrigation water, and high tAs in soil may not necessarily cause increased concentrations in rice. Based on the target hazard quotient (THQ) and margin of exposure (MOE) values, residents will not encounter a significant noncarcinogenic risk (THQ < 1) through rice consumption; however, contaminated rice poses a potential carcinogenic risk in Hunan Province (MOE < 100).