Risk Assessment and Source Identification of Arsenic in Surface Sediments from Caohai Lake, China

Urban freshwaters containing arsenic are facing an increasing problem of eutrophication. This study evaluated the spatial distribution, ecological risk, and origin of As in surface sediments obtained from Caohai Lake, a typical hypertrophic urban lake in China. It revealed that the total As concentration in surface sediments decreased gradually from north to south, consisted with the lake eutrophication status. The average As level was 161 mg/kg, dominated by reducible and oxidisable fractions. The analyses of geoaccumulation index and enrichment factor indicated that As ranged between moderately-to-heavily and heavily contamination, was severely influenced by anthropogenic factors, i.e. industrial discharges and agricultural activities. Risk assessment code and potential ecological risk index results showed moderate to high potential ecological risk could be observed although the current As risk was low, supporting by the experimentally quantified As release data.