Impacts of cyanobacterial growth and decline on environmental behaviour of heavy metals in sediments of Chaohu Lake
In order to explore the impacts of cyanobacterial growth and decline on the environmental behaviour of heavy metals in surface sediments of Chaohu Lake,the content level,spatial and chemical form variation of Cr,Co,Ni,Cu,Zn,As,Cd,Pb and Hg in the sediments during the dormancy and bloom periods of cya-nobacteria were analyzed.The pollution status and potential ecological risk of heavy metals in sediments were assessed by the geoaccumulation index method and the potential ecological risk index method.The results showed that the average contents of Cd and Cr per kilogram sediment increased by 0.70 and 0.35 times,re-spectively,while that of other elements decreased due to cyanobacteria outbreak.There was a shift towards a more even spatial distribution pattern for almost all studied elements during the bloom period.The elements were primarily present in residual form with the ratios of 58％-97％during the dormancy and bloom periods,except for Cd and Hg.During the bloom period,ratios of each bioavailable form of the elements changed in varying degrees,while total ratios of bioavailable forms and ratios of residual form barely changed,except for Cd,which showed the highest migration and mobility.Cd and Hg had higher environmental risks in two peri-ods.The comprehensive potential ecological risks increased,while the individual element showed more bal-anced spatial distribution during the bloom period.
cyanobacterial growth and declineChaohu Lakesedimentsheavy metalsenvironmental behaviour
万方数据
维普
