Distribution Characteristics And Ecological Risk Assessment Of Heavy Metals In The Water Environment Of Taiyangshan Wetland

The concentrations of As,Cd,Hg,Pb,Cr,Cu,Fe,Mn and Zn in water bodies and surface sediments of Taiyangshan wetland were monitored to explore the pollution condityion of heavy metals in the water environment of the Taiyangshan wetland in winter(January),spring(April),summer(July)and autumn(October)of 2019.The level of heavy metal content in the water-sediment system and its temporal and spatial distribution characteristics,ecological risk assessment and early warning,and source analysis have been studied in order to provide a scientific basis for the prevention and control of heavy metal pollution in the Taiyangshan wetland and ecological restoration.The main research results are as follows:(1)The concentration of heavy metals in the water bodies of the Taiyangshan wetland is generally not high,lower than that of most domestic water systems.Only Hg exceeds the surface level III water,but the spatial differences are large.The most severely polluted by heavy metals are East Lake District and West Lake District.In general,As pollution is the most serious in autumn,Hg,Cr,and Mn pollution are the most serious in winter,Cu pollution is the most serious in summer,Fe has no obvious seasonal pollution pattern,and Zn pollution is more serious in summer and autumn.(2)The surface sediments of the Taiyangshan wetland are seriously polluted by heavy metals.The pollution of Hg is the most serious.The contents of Hg and Zn are high in lakes at home and abroad.Only Cr does not exceed the soil background value of Ningxia.The most severely polluted by heavy metals are East Lake District and small South Lake District.As,Cd,Hg,Zn,Cr,and Cu are the most severely polluted in winter,the content of Pb,Fe,and Mn is not obvious seasonally.(3)The water quality index method and Nemerow comprehensive pollution index method show that the pollution level of heavy metals in the waters of the whole water area is relatively low,and the most serious season of heavy metal pollution in the waters of the whole water area and various lake areas is winter,and the factor that contributes the most to the pollution is Hg.The most polluted lake area is the West Lake area.The geo-accumulation index of the annual average value of the heavy metal content of the sediments in the whole water area and each lake area is the largest in Hg,and both have reached the moderate pollution level,and the potential ecological hazard coefficient is the largest in Hg,and both have reached the strong-very strong level of the potential ecological hazard,the comprehensive index has reached the middle level of ecological hazard,the pollution load index method shows no pollution.The geo-accumulation index shows that the most polluted seasons are winters,among which heavy metal pollution in East Lake District is the most serious in winter;the potential ecological hazard coefficient shows that Hg is the most polluted in South Lake District,and Cd is the most polluted in East Lake District;the comprehensive index of potential ecological hazards shows that In general,winter pollution is the most serious,and the main contributing factors to pollution are all Hg;the pollution load index method shows that the winter pollution is the most serious,and the winter pollution in East Lake District is the most serious,which belongs to light pollution.The ecological risk early warning index of the whole water area and the annual average value of a single lake area are all classified as light alarms,and the ecological risk early warning index in winter is the largest,both of which are classified as heavy alarms.(4)The sources of heavy metals in water bodies and sediments mainly include atmospheric dry-wet deposition,Kushui River replenishment,and the weathering of parent rocks and soil leaching from natural sources.The As,Cu,and Zn in the water bodies come from the water supply of the Kushui River,the Hg and Cr come from atmospheric dry and wet deposition,and the Fe and Mn mainly come from the weathering of the parent rock and the leaching of the soil.The As,Pb,Cu,Fe,and Mn in the sediment mainly come from the weathering of the parent rock and the leaching of the soil,and the Cr,Cu,Zn,and Mn come from the Kushui River water replenishment and atmospheric dry and wet deposition.The impact of atmospheric dry and wet deposition,Cd pollution mainly comes from atmospheric deposition and the water supply of the Kushui River.