Heavy metal pollution is one of the most serious environmental problems in China and a large number of people are threatened by heavy metal pollution.Extensive damage to human organs,such as liver,kidney,digestion system,and nervous system can be caused by uptake of excess heavy metals.Heavy metals in the environment can originate from both natural and anthropogenic sources.Although contamination of heavy metals has been known to be a severe environmental problem for decades,it is still getting worse in recent years and there are few feasible approaches to resolve this problem.Due to their high toxicity,prevalent existence and persistence in the environment,lead(Pb),mercury(Hg),cadmium(Cd),chromium(Cr) and arsenic(As) are commonly considered as the priority heavy metals which should be concerned and their emission should be controlled in China.This paper reviewed the pollution of heavy metals in China,focusing on the following four aspects:current status of heavy metal pollution in China,sources of heavy metals in China,toxicity and potential risk,and possible reduction strategies.
The concentrations and species of organotin compounds(OTCs) in 52 surface sediment samples from nine fishing ports along the Chinese coast were studied.Butyltins(BTs) and phenyltins(PhTs) were derivatized using sodium tetraethylborate(NaBEt 4) and determined by head-space solid-phase microextraction(HS-SPME) gas chromatography coupled with a flame photometric detector(GC-FPD).The concentrations of OTCs ranged from <3.6 to 194 ng(Sn) g-1 dry weight(dw) for monobutyltin(MBT),<2.3 to 41.5 ng(Sn) g-1 dw for dibutyltin(DBT),<0.7 to 86.0 ng(Sn) g-1 dw for tributyltin(TBT) and <5.1 to 66.1 ng(Sn) g-1 dw for monophenyltin(MPhT),respectively.The concentrations of diphenyltin(DPhT) and triphenyltin(TPhT) were below the limit of detection(LOD).BTs were the main species in the sediments except for the samples collected from Shazikou fishing port in Qingdao.The concentrations of MBT were higher than DBT and TBT.The concentrations of OTCs in the sediments varied widely among different sampling locations.The concentrations of BTs were much higher in the samples collected from fishing ports close to the South China Sea than those in coast of the East China Sea and the Yellow Sea.MPhT was prevalent in most sampling stations except for those in coast of the East China Sea.The environmental and ecotoxicological risks of TBT in most sediment samples were low.
