Species and leaching characteristics of soil heavy metals in Gaoxinsha reservoir and its impact on water quality safety
In order to evaluate the risk of heavy metals in Gaoxinsha reservoir for the water quality safety,the distribution characteristics and potential ecological risk of heavy metal were studied by the determination of heavy metal,the geo-accumulation index and ecological risk index.The leaching characteristics of heavy metals and their effects on water quality were also investigated by the leaching solutions.These results indicated that the contents of Cu,Zn,Cd,Pb,Ni,Cr,Hgand As ranged from 11-42.5,70.75-119.5,0.01-0.16,24.5-100,20.25-35,89-177,0.05-0.17,10.15-22.1 mg·kg-1,in which these heavy metals generally had not exceeded the standard(GB15618-2018),only the concentration of As slightly exceeded the standard.Heavy metals were mainly in the residue state,whose proportion of Zn,Ni,Cr,Hg and As were more than 70％,these suggested that their potential ecological risks were generally at slight level.In the leaching experiments(pH=6.34,5.6 and 3.6),the concentration of most heavy metals had not exceeded the limit of drinking water(GB 5749-2022),while at the extreme pH of 1.0,Cu,Zn,Cd,Pb,Ni and As exceeded the standard at different degrees.In the case of actual water,the damage of the geomembrane generally had no significant adverse effect on the water quality,but only one soil sample that the Ni slightly exceeded the standard.Based on the above results,the risks of heavy metal pollution in the reservoir soil were at a relatively safe level,and the environmental risk was very limited,while the management of heavy metals in water,especially Pb and Ni,should be strengthened in the actual operation of the reservoir.
heavy metalsreservoir soilrisk assessmentleaching riskwater safety
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