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Marine pollution has posed a grave challenge to China over the past years.Due toChinas double-figure annual economic growth and the failure of factories,powerplants, sewage systems and other sources to obey environmental regulations,pollution in China has risen sharply.Large amounts of contaminants are filtering fromthe land into the sea,which caused the coastal marine ecosystem to get worse.Inrecent years,global public concern over accumulation of pollutants in marineorganisms has increased because it would not only threaten life themselves,but mayalso lead to adverse health effects to population considering seafood consumption isan important route of human exposure to environmental contaminants. In response to this concern,the present study aimed to determine the currentlevels of various organic and inorganic pollutants in different species of marine fish.At the same time,the potential health risks derived from the exposure to thesecontaminants for the general population were also assessed. As well as the commercial values and human consumption,fish have beenestablished as good bioindicators of environmental pollution because their tissuesoften contain high contaminant concentrations due to their relatively high position inthe food chain and consequent elevated exposure levels in the aquatic environment.Many investigations have reported high concentrations of environmentalcontaminants including a suit of organochlorine compounds,brominated flameretardants and metals in marine fish all over the world,and suggested that they maypose a health risk to human body.
In this work,two species of marine fish, namely large yellow croaker(Pseuclosciaena crocea)and sliver pomfret(Pampus argenteus)collected from ninecoastal cities of eastern China in 2008 were analyzed for a series of organochlorinepesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenylethers(PBDEs),hexabromocyclododecanes(HBCDs)and a number of trace elements.Additional fish samples namely small yellow croaker(Pseuclosciaena polyactis)were also determined for the trace elements. Among the OCPs,dichlorodiphenyltrichloroethane and its metabolites(DDTs),hexachlorocyclohexane isomers(HCHs),hexachlorobenzene(HCB)and chlordanecompounds were the predominant and ubiquitous residues. In particular, theconcentrations of DDTs were one order of magnitude greater than those from othercountries,indicating that the coastal regions of China probably are among the mostDDT-polluted areas in the world,although there was a decreasing trend of DDTs bycomparing the results of previous studies in the past.The composition of DDTsrevealed that the main source of DDTs was possibly due to the heavy historicalagricultural and public health usage.While,the high proportion of γ-HCH in Chinesecoastal environment suggested the continuous use of lindane.Cancer and noncancerrisk assessments suggested a lifetime cancer risk is a possibility,especially from DDTs.The calculated daily and meal consumption limits were 9g/day and 1 meal/month forcroakers,and 67g/day and 9 meals/month for pomfrets,respectively.
Total PCB concentrations were at the low end of the worldwide figures.The levelsof total dioxin-like PCBs were found to be strong positively correlated to total PCBconcentrations,indicating total PCB levels can explain 80% variability in dioxin-likePCBs concentrations.Large yellow croakers have a greater tendency to bioaccumulate PCBs than pomfrets,which may be attributed to their different feeding and livinghabits. No significant difference in total PCB levels among the cities was observed.Risk estimation indicates that PCBs may pose a health risk to heavy seafoodconsumers. PBDEs and HBCDs are widely used as additive brominated flame retardants(BFRs)in electronic equipment,plastics,textiles,building materials and otherapplication to avoid catching fire.Although they were detected in all of the samples,their concentrations were relatively lower than other regions of the world,especiallyNorth America where Penta-BDE was extensively used and Europe,where HBCDswere intensively used.BDE47 and BDE154 were the predominant congeners in bothspecies,accounting for more than 60% of the total PBDE concentrations,which wassome kind of difference from the commonly detected pattern in fish reported by theprevious studies.Among the three individual HBCD isomers,the a-isomer showed aremarkable predominance,reflecting its higher bioaccumulativedaily intakes of PBDEs and HBCDs via fish consumption for thepotential.EstimatedChinese populationwere much lower than the effect levels,suggesting that large yellow croakers andpomfrets were safe to eat according to these chemicals. Methylmercury and trace elements(total mercury,selenium,cadmium,cobalt,chromium,copper,iron,manganese,nickel,lead,strontium and zinc)were alsoexamined.The levels of mercury,iron and nickel were at the low end of the globalrange,while the results of other elements are globally within the same range ofconcentrations.
Except for cadmium levels in 16% of the samples higher than criterionrecommended by the European Commission Regulation,the concentrations of othermetals were well below the international standards.From the human health point ofview,the estimated daily intake of these metals did not exceed the reference doseestablished by US EPA,hence the hazard quotients(HQs)were all less than one,indicating a situation of no risk for the consumer.
Overall,this study expanded current knowledge of various contaminants levels inmarine fish from China and provided a preliminary health risk of these pollutants tohuman consumers via dietary fish consumption in Chinese coastal cities.Although therisks by trace metals and BFRs were not notable,continuous monitoring of these andother pollutants in the coastal marine ecosystem are remarkably advisable.Moreover,some actions need to be taken to reduce the environmental levels of DDTs besidesgiving advisory consumption recommendations.