Health risks for human intake of aquacultural fish: Arsenic bioaccumulation and contamination

Aquacultural tilapia (Oreochromis mossambicus L.) and shrimp (Penaeus monodon L.) from groundwater-cultured ponds in southwestern Taiwan were analyzed to estimate arsenic (As) bioaccumulation and the potential health risk to human intake. Most of aquacultural ponds exhibited higher arsenic than maximum allowed concentrations (50 μg L ^-1) in pond water of Taiwan. Arsenic levels in tilapia in Budai, Yichu and Beimen were 0.92±0.52 μg g ^-1, 0.93±0.19 μg g ^-1 and 0.76±0.03 μg g ^-1, respectively and in shrimp was 0.36±0.01 μg g ^-1 in Beimen. Total arsenic in tilapia is highly correlated (R ² = 0.80) with total arsenic concentration of pond water. Total arsenic in fish showed high correlation with that in bone (R ² = 0.98), head (R ² = 0.97) and tissue (R ² = 0.96). Organic arsenic species (DMA) was found higher relative to inorganic species of As(III) and As(V). The average percent contribution of inorganic arsenic to total arsenic in fish samples was 12.5% and ranged between 11.7 to 14.2%. Bioaccumulation factors (BAFs) for total arsenic in fish ranged from 10.3 to 22.1, whereas BAF for inorganic arsenic ranged from 1.33 to 2.82. The mean human health cancer risk associated with the ingestion of inorganic arsenic in the fish was estimated at 2.36×10 ^-4±0.99×10 ^-4, which is over 200 times greater than a de Minimus cancer risk of 1×10 ^-6. The mean human health hazard quotient associated with ingesting inorganic arsenic in the fish was 1.22±0.52, indicating that expected human exposure exceeds the reference dose for non-cancer health effects by 22%. These results suggest that the inhabitants in this region are being subjected to moderately elevated arsenic exposure through the consumption of tilapia and shrimp raised in aquaculture ponds.