Occurrence, phase distribution, and bioaccumulation of organophosphate esters (OPEs) in mariculture farms of the Beibu Gulf, China: A health risk assessment through seafood consumption

Abstract

As emerging pollutants, the occurrence and risks of organophosphate esters (OPEs) in mariculture farms should be concerned; however, information is limited. Beibu Gulf is one of the essential mariculture zones in China. This study aimed to investigate the occurrence of OPEs in mariculture farms of the Beibu Gulf, their phase distribution and bioaccumulation among sediment, organisms (shrimp, crab, and oyster), water, and feed. Human exposure to OPEs through seafood consumption was also assessed. The total concentrations of the 11 target OPEs (∑11OPEs) in the water samples ranged 32.9–227 ng L−1. It was significantly higher in water from the culture ponds (mean 122 ng L−1) than in water from the estuaries and nearshore areas (mean 51.1 ng L−1) (nonparametric test, p < 0.05). ∑11OPEs in the feeds averaged 46.0 (range 21.7–84.5) ng g−1 dw, which is similar to the level in the organism samples (mean 55.5, range 21.3–138 ng g−1 dw) and 4.4 times higher than that in the sediment (mean 10.9, range 35–22.1 ng g−1 dw). The ∑11OPEs released from the feeds to the culture ponds was estimated to be 49 μg m−2 per three-month period. In the aquaculture ponds, the sediment-water distribution coefficient (log KOC), and the bioaccumulation factors from the water (log BWAFs) or the feed (log BFAFs) to the organisms, depend linearly on the hydrophobicity (log KOW) of OPEs. The log BWAFs and log BFAFs increased with increasing log KOW within the log KOW range of 1–7. The human exposure to OPEs through consumption of shrimp, crab, and oysters from the mariculture farms does not pose a health risk at present.