A comprehensive investigation of the occurrence and speciation of arsenic in the water, sediments and aquatic products in Dongping Lake, an important drinking water source in East China

The total arsenic (TAs), inorganic arsenic (iAs) including arsenate (As(V)) and arsenite (As(III)) distribution in water, surface/core sediments and aquatic products in Dongping Lake was investigated. The pollution levels and associated risks were evaluated using the methods of geoaccumulation index, single factor index, health risk model and potential ecological risk index. The results showed that As(V) dominated across all environmental matrices. TAs concentrations in water (1.36–3.90 μg/L) were all below the threshold set by the World Health Organization (10 μg/L). The average concentrations of As(V) and As(III) in water were 0.82 ± 0.48 μg/L and 0.28 ± 0.31 μg/L, respectively, while those in surface sediments were 7.30 ± 2.58 mg/kg and 1.16 ± 0.38 mg/kg. Laohu Wharf, the Dawen River inlet and the northern outlet area were identified as hot spots for elevated arsenic levels in water and surface sediments. In core sediments, the maximums were detected at a depth of 1–2 cm or 2–3 cm. As(V) and As(III) in water were significantly correlated with dissolved organic carbon, Chla, dissolved inorganic nitrogen and pH. As(V) in sediments were closely associated with oxidation–reduction potential, organic carbon and total nitrogen. Shellfish had significantly higher TAs and iAs levels compared to fish and shrimp. Collectively, shellfish and fish had been polluted with iAs. The average carcinogenic risks caused by iAs through daily intake of shellfish (3.72 × 10^–4/a) exceeded the acceptable level (10^–4/a). The TAs pollution in sediments was at a slight to moderate contamination level and posed a considerable ecological risk.