| Poyang Lake’s Migratory Birds Reserve includes nine lakes and their grasslandsuch as Bang Lake, Sha Lake, Dahuchi Lake and so on. It’s an important base toresearch and protect birds, which is the largest wintering area for white crane Grusleucogeranus and Swan Goose Anser cygnoides.And more than95%white crane and258species of birds in the word choose to spend winter here. In addition, fishery isrelatively developed in this area. It’s a perfect spawning place for fishes. Vegetation isrich in the reserve. Graziery developed well for the large area of grassland in dry season.To insight into the interrelation between protection zone and human activity, it isnecessary to assess the water quality and ecological risk.The study includes three parts: water quality assessment, heavy metal riskassessment and biological toxicity research. The sampling sites mainly focus on BangLake, some months Sha Lake and Dahuchi Lake included due to restrictions oftransportation and natural conditions.Single factor evaluation results showed that each month Bang lake’s water qualitylevel fluctuated between Ⅳ to Ⅴ except May. The concentration of mostphysicochemical indexes such as COD, TP, ammonia nitrogen, nitrate nitrogen andChl-a changed seasonally, wet season was lowest and dry season was highest. Slightdifferences existed among three lakes. In wet season Bang Lake’s water quality wasworse than that of the other two lakes, but an opposite result showed in the normalseason. The differences between the result of fuzzy comprehensive analysis and singlefactor evaluation were that the water quality level in May changed from Ⅲ to Ⅱ.TNwas the main factor to reflect the water quality.Five kinds of sediment heavy metals were detected in Poyang Lake’s MigratoryBirds Reserve. The concentrations of Zn, Pb and Cd were between that of the estuary ofGan River and Xiu River. The concentrations of Cu and Cr were significant higher thanthose of the two rivers’ estuary. The concentrations of all the elements except Cr werelower than that of Poyang Lake. Each heavy metal had different enrichment degree.RSP of Zn and Cd was far less than1, it can be explained that this water area hadn’tbeen contaminated by these two kinds of heavy metal. RSP of Cu, Pb, Cr of a fewsampling sites’ was big than one, but some of them closed to one. Therefore thepotential hazards could not be ignored. Because of the high RSP in each cross section of depth, the contamination of Pb was serious in Bang Lake’s estuary. Geo-accumulationindex and potential ecological risk index were used to evaluate the heavy metalpollution and the result was exactly the same. Enrichment degree wasCu>Zn>Pb>Cr>Cd. Sequence of contamination degree was Sha Lake＞Bang Lake＞Dahuchi Lake and the degree of contamination in this area was mild.Activity of MT in liver is significant negative correlation with sublethalconcentration of Pb2+in water body. It’s a perfect biomarker to evaluate heavy metalcontaminate. The result of biomarker research on carp in Bang Lake showed thatoxidative stress and lipid peroxidation in carp bodies were low as same as the degree ofoxidative damage. Affected by low heavy metal concentration, synthesis of MT slightlyinhibited. Overall, aquatic organisms in Poyang Lake migratory birds reserve affectedlittle toxic effect from exogenous pollutants. The ecotope was so well for aquaticorganisms to growth and reproduction. |
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