Bioaccumulation of sediment-bound dichlorodiphenyltrichloroethane and heavy metals in benthic polychaete, Nereis succinea from a typical mariculture zone in South China.

Bioaccumulation potential and associated ecological risk of sediment-bound DDT and its metabolites (DDXs) and heavy metals in Hailing Bay, a typical mariculture zone along the southern coast of China, were evaluated. The estuarine sediments were co-polluted by DDXs (120-4882ng/g dry wt.) and heavy metals (292-409mg/kg dry wt.). Both DDXs and metals in sediment were bioavailable to Nereis succinea, although the biota-sediment accumulation factors were less than 1 except for DDE. Significant transformation of DDT in organism was observed and DDE was the main metabolite. Ecological risk assessment showed that sediment-bound p,p'-DDT and p,p'-DDD frequently exhibited adverse effects on benthic community in the aquaculture zone, and heavy metals would cause moderate to considerable ecological risk, with Cd dominating the risk. The highest risk occurred in the shipyard area, indicating severe pollution and urgent need to control the source of DDT and heavy metals from aquafarming activities. CAPSULE: Estuarine sediments in South China was co-polluted by DDT and its metabolites and heavy metals due to aquafarming activities, which resulted in bioaccumulation of the contaminants in benthic invertebrates and posed potential risk to species at higher trophic levels.