[Bioaccessibility and Health Risks of the Heavy Metals in Soil-Rice System of Southwest Fujian Province].

Abstract

The bioaccessibility and health risks of heavy metals in soil-rice system of southwestern Fujian province were studied by combining a simple bioavailability extraction method (SBET) with a health risk assessment model. The results showed that some heavy metals in the agricultural soils and rice of southwestern Fujian province were enriched. The contents of Cd, Zn, Pb, and Cu were greater than the screening value of soil pollution risk for agricultural land (GB 15618-2018) by 32.4%, 15.5%, 14.1%, and 12.7% in the study areas, respectively. The accumulation ability of heavy metals was different and followed the approximately decreasing order of Cd > Zn > Cu > Ni > Hg > As > Cr > Pb. The bioaccessibility of heavy metals in soils and rice were quite different. The bioaccessibility of each heavy metal in rice was greater than the bioaccessibility of the heavy metals in soil, which indicated that the heavy metals in rice were more easily absorbed by the human body. The comprehensive non-carcinogenic risk index (HI) of heavy metals to adults and children was 2.71 and 4.06, respectively, indicating that there were non-carcinogenic risks. The comprehensive carcinogenic risk index (TCR) of heavy metals to adults and children was 1.42×10-3 and 5.28×10-4, respectively, indicating that there was a carcinogenic risk present. The non-carcinogenic risks were mainly due to As, while the carcinogenic risks were mainly contributed by Cd. The non-carcinogenic risk of children was higher than that of adults, while the carcinogenic risk of children was lower than that of adults. This result may be related to physiological characteristics, exposure period, and dietary intake. The dietary intake route may be the main pathway for heavy metals in the soil-rice system of southwest Fujian province to cause health risks. Therefore, more attention should be paid to the risks of dietary exposure in the risk management of heavy metals.