| As a kind of typical environmental pollutants, heavy metals enter into theaquatic environment continuously via industrial/agricultural/domestic sewagedischarging, polluted sediments releasing and atmosphere depositing. Heavy metalshave potential adverse effects on aquatic ecosystems, including water, aquatic plantsand animals, which may pose a risk to human health due to drinking water and foodfrom aquatic environments.A total of170wild fish samples, including50kinds, were collected from TaihuLake, Xiangjiang River, Dianshan Lake, Liaohe River and Three Gorges reservoirarea, as well as4kinds of crustaceans and shelfish are from Dianshan Lake. Heavymetal concentrations were determinated by graphite oven atomic absorptionphotometry analytical method. The spatial and species variation were analyzed, andheavy metals exposure levels and their health risks were also estimated.The concentrations of cadmium(Cd), lead(Pb), chromium(Cr), mercury(Hg),arsenic(As), copper(Cu) and zinc(Zn) in fish from Xiangjiang Rvier ranged from2.0to2061.1ng/g wet weight(ww), from <LOD to118.3ng/g ww, from <LOD to142.7ng/g ww, from5.4to140.7ng/g ww, from nd to182.3ng/g ww, from221.2to1144.5ng/g ww、from4.5to25.2μg/g ww, respectively. The concentration ranges inLiaohe River were from1.5to22.7ng/g ww, from <LOD to136.3ng/g ww, from36.4to106.8ng/g ww, from8.765to120.4ng/g ww, from9.9to54.4ng/g ww,from333.2to647.3ng/g ww, from9.1to24.3μg/g ww, respectively. Theconcentration ranges in Three Gorges reservoir area were from <LOD to171.2ng/gww, from <LOD to205.9ng/g ww, from <LOD to164.3ng/g ww, from3.7to187.6, from <LOD to106.9ng/g ww, from <LOD to23724.0ng/g ww, from2.8~62.0μg/g ww, respectively. The concentration ranges in Dianshan Lake were from3.7to111.4ng/g ww, from nd to202.4ng/g ww, from35.2to241.6ng/g ww, from3.4to54.5ng/g ww, from8.5to260.6ng/g ww, from250.0to8157.9ng/g ww, from5.2to79.5μg/g ww, respectively. The concentration ranges in Taihu Lake werefrom <LOD to8.6ng/g ww, from <LOD to103.2ng/g ww, from <LOD to238.6ng/g ww, from8.1to97.0ng/g ww, from9.5to41.8ng/g ww, from230.1to539.4ng/g ww, from6.6to30.3μg/g ww, respectively. The concentrations of nutrientelement Zn and Cu were highest and Cr levels were relatively higher amongpollution elements. The levels of Cd, Pb and Hg changed with regions and As levelswere on close level in five regions. Compared with data in other countries andregions, fish in Xiangjiang River were seriously polluted by Cd, and other heavymetal concentrations were at lower level.The concentrations of Cd, Pb, Cr, Hg, As and Zn from five regions showedsignificant difference (p <0.01). The average concentration of Cd was highest inXiangjiang River. The highest Pb average level was in Three Gorges, the highest Hgand Zn levels were in Liaohe River and the highest Cr and As levels were inDianshan Lake. Cu levels did not show a spatial distribution characteristic (p=0.161). Comparing the same fish, crucian carp, carp, yellow-head catfish, culter andParabramis pekinensis from five regions, Cd levels in Xiangjiang River were generally higherthan other regions. The rest heavy metal levels in crucian carp, carp, yellow-head catfishand culter form Three Gorges were relatively higher. Pollution in Dianshan Lake wasat low level, which was associated with surrounding aquatic environment.Comparing different sampling lcations in Xiangjiang River and Three Gorgesreservoir area, Cd and As concentrations in Hengyang and Hg concentrions inZhuzhou were significantly higher than those in other locations from XiangjiangRiver. Heavy metal levels in Daning River and Modao creek from Three Gorgeswere relatively high, which was also effected by surrounding environment.Heavy metal concentrations showed a species distribution characteristic. Hglevels in carnivorous fish from Three Gorges reservoir area were significantlyhighest (p <0.01), followed by omnivorous and herbivorous species. Hgconcentrations from Xiangjiang River showed a similar trend, which may be resulted by biomagnification of Hg. Because of the same reson, the average concentration ofHg in fish from Dianshan Lake was that in selfish. Cd, Cr, As, Zn concentrationswere significantly high in spiral shell, freshwater mussel and corbicula. This can beexplained by that sellfish, a bentonic organism, was close to polluted sediments.Pollution level in fish, exposure value and health risk value was used toexamine whether fish consumption may pose potential health risk to humans. Themaximun over standard rate of heavy metals in fish was15.7%. Cd was relativelyserious, whose over standard rate was9.6%~15.7%. Pb and Hg levels in somesamples were higher than the standards, which were mainly collected fromXiangjiang River and Three Gorges. Cd pollution was serious in Xiangjiang Riverand a slight Hg pollution was in Three Gorges reservoir area and Liaohe River interms of pollution index.Fish, water and rice exposure values of heavy metals and their health risk wereestimated. The weekly intakes through three pathways were from0to385.6μg/week/kg bw, from0.06to31.3μg/week/kg bw, from1.3to840.6μg/week/kg bw,respectively. The mean intakes were all lower than the Provisional Tolerable weeklyIntakes recommended by World Health Organization (WHO). The non-carcinogenicrisks were from0.03to0.07(fish), from0.005to0.3(water), from0.2to1.6(rice),respectively. The health risk of non-carcinogenic effects via fish and waterconsumption can be ignored, but rice consumption may pose a non-carcinogenci riskof Pb and As. Rice consumption was the main exposue pathway of non-carcinogenichealth risk. The carcinogenic risk of As through fish consumption was from0to1.04×10-4, the mean value was1.31×10-5. The risks through water and riceconsumption were5.61×10-5and2.83×10-4, respectively. The carcinogenic riskvalues of As through three pathways were all higher than the guideline value of1×10-6, which may pose a carcinogenic risk. Considered bioaccessibility of heavymetals, the non-carcinogenic risk of Pb was reduced, but the risks of As were stillexist. Synthetic musk compounds, as kinds of emerging organic pollutants, are widelyused in cosmetics, cleaning products, perfume and other personal care products.They enter into the aquatic environment continuously via domestic sewagedischarging.The concentrations and distributions of synthetic musks, includingGalaxolide (HHCB), tonalide (AHTN), musk xylene (MX) and musk ketone (MK)in water, sediments from Taihu Lake were analyzed in this paper.The concentrations of HHCB, AHTN, MX, MK ranged from nd to10.47ng/L,from nd to0.50ng/L, from nd to1.07ng/L, from nd to1.63ng/L in surface water,respectively, and from nd to3.90ng/g dry weight (dw), from nd to0.89ng/g dw,from nd to0.72ng/g dw, from nd to0.89ng/g dw in sediment, respectively. HHCBwere the dominant musk compound in Taihu Lake. Compared with data in othercountries and regions, the average concentrations of musks were at lower level.There were seasonal and spatial variations for synthetic musk concentrations. Themedian in high water period, low water period and normal water period was1.46,0.58,0.59ng/L in water, respectively. This might be attributed to high usefrequencies of personal care products. The seasonal variations of these pollutantswere not obvious for sediment samples. The concentrations of musks showed asimilar spatial distribution in water and sediments. The levels from west Taihu Lakewere apparently higher than those from three other lake areas, and nitro musks werecommon in west Taihu Lake. This may indicate emission source of synthetic musksin this area.The pollution levels, distribution characteristics, health risks through foodconsumption were studied in this paper. The contamination degree of heavy metalsfrom different areas in our country, health risks for people through freshwater fishconsumption can be obtained by this study. This may provide more more evidencefor potential toxicity on environment and organism, as well as more scientificalreferences for healthy diet of human beings. |
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