Spatial-temporal trends of Cadmium in oyster along Guangdong coastal waters from 1989 to 2010 and their risks on human health

The quality of oysters is crucial to the sustainable development of coastal oysters culturing industry and human health. This paper analyzed the spatial-temporal trends of Cd content in oyster soft tissues from 17 main Guandong coastal bays/estuaries from 1989 to 2010 and assessed their health risks on groups of consumers by their dietary compositions and ages. Results of total 268 samples showed that the concentration of Cd varied between not detected (nd) and 10.80 mg/kg wet weight with average of 1.14 mg/kg wet weight; and among of which, 98.64% of the concentrations of Cd in oyster tissues did not exceed the upper levels（4mg/Kg） which established by Ministry of Agriculture, China and EPA, USA. The Pearl River estuary should be the top of Mussel Watch and environmental management considering its highest Cd content in oysters there. Although the risks of health to the younger (aged 5 to 17) was the highest, and then was to the elder (aged 60 or more) and the adults(aged 18 to 59) in sequence, the Hazard quotient (HQ) was less than 1 for oysters from Guangdong coastal waters, indicating that the oyster consuming had not exceeded the oral Reference Dose .