Risk Assessment Of Heavy Metal And The Health Bioassessment Based On Macroinvetebrate Community Structure In Duliujaing River

Duliujiang River,originated from Dushan County in southeastern Guizhou Province,is the upstream of Liujiang River which belongs to Pearl River system.Banpo antimony mine is one of the largest mine in Guizhou Province.The mine waste water contained varieties of heavy metal irons without any treatment is discharged to head stream of Duliujiang River.In order to provide information and scientific basin on protection of water environment and biodiversity,we did the following work.Firstly we set 42 sampling sites from upstream to downstream along the Duliujiang River,where 21 of them are main streams and 21 are branches.Secondly we researched the spatial distribution and potential ecological risk of heavy metal in water and sediments all over the basin.Thirdly we compared the concentration of heavy metals in Protohermes sp..Forthly we have analyzed the relationship between environmental factors and microinvetebrate community structure by CCA and TWINSPAN.Fifthly we evaluated the health condition at Duliujiang River basin by IBI.The main research results are as follows:1.Water heavy metals pollution and health risk assessmentThe result of the concentration of water heavy metals shows that: concentrations of heavy metal in upstream sites of the antimony mine are significantly high than other sites(P<0.05),CK has no significant difference to blank group(P>0.05).We evaluate potential ecological risk of water heavy metals by health risk assessment model.The results show that: five heavy metals(copper,zinc,manganese,chromium,nickel)have no health hazard,lead and antimony with a higher risk in AMD and have the obvious health risk to drinkers.2.Sediment heavy metals pollution and potential ecological risk assessmentThe result of the concentration of sediment heavy metals shows: concentration of antinomy is higher than GB15618-2008 in each sampling sites.Copper,nickel,zinc has a higher trend from upstream to downstream.Copper,nickel,zinc,manganese is significant higher than upstream(p<0.05),antinomy has the opposite trend at following G16.Concentration of metals(copper,manganese)is below in environmental background value in each branch,lead is more than a double than background value in Z13.The potential ecological level are strong under G17 in main streams,only one site(G21)is very strong at the mine area.The result of morphological analysis shows: the main morphological of each metal is residual fraction,manganese is exchangeable from,others from:(copper,cadmium)combined iron-manganese > organic matter-bound > exchangeable from,(zinc,nickel)exchangeable from > organic matter-bound > combined iron-manganese,(chromium,antinomy)organic matter-bound > combined iron-manganese > exchangeable from,lead organic matter-bound > exchangeable from > combined iron-manganese.3.The comparing of heavy metals in Protohermes sp.We found: concentration of the body affected by AMD is significant higher than CK after determining 8 heavy metals in mine sites.Concentration in the Protohermes sp.saved digestive tract is significant higher than it cleaned.So it illustrates that contribution value of concentration of digestive tract cannot be ignored.We can know that Protohermes sp.predates Ephemeoptera,Trichoptera,shake mosquitoes and CROM after anatomising the digestive tract.The enrichment value in saved is significant higher than cleaned,especially copper,manganese,chromium,nickel.So it illustrates Protohermes sp.enrich heavy metals by predicting aquatic insects and CROM.4.Multivariate analysis on macroinvertebrate community structure and environment factorsThe result of CCA shows: vanadium,manganese,cobalt,nickel,copper,zinc and antinomy has highly correlation between each others and is the mainly factor to affecting the community structure,TWINSPAN shows: macrointevebrate can be divided into ten community structure all over the basin,each community structure has their own characteristics and similar habit.So the result is also proved by CCA.5.River ecosystem health assessments using benthic index of biotic integrity22 biological metrics were selected as candidate attributes to assess the biotic integrity,7 of them are used to establish B-IBI assessment criterion after discriminatory power analysis and Pearsons' correlation analysis.38 sampling sites are assessed on evaluation.The result shows: 9 sampling sites are optimal,7 are suboptimal,10 are marginal and 12 are poor,all of the poor sites are impacted by AMD or other reflections deeply,B-IBI index has a high correlated to water quality,habitat score,biotic index and Shannon-Wiener index,so it is useful to assessing the river health status in Duliujiang River.