Heavy Metal Pollution Status And Health Risk Assessment In Shenwo Reservoir

Liaoning Province is a province with a severe water shortage in China.As an important nature reserve in Liaoyang City,Shenwo Reservoir,its water pollution and water ecological safety have become important environmental and social problems in the region.Based on the continuous improvement of water quality and water environment in Shenwo Reservoir,systematically carrying out the heavy metal pollution status and health risk assessment of fish in Shenwo Reservoir can provide the reference for improving its water environment function,developing fishery aquaculture,maintaining the healthy development of water bodies and achieving sustainable use of water resources,which also provide the reference for the scientific decision-making of relevant departments.On account of the research trends and hotspots of Shenwo Reservoir at domestic and abroad through bibliometrics,selecting three sampling points in Shenwo Reservoir and trawling fish from banks by boat,in order to analyze the composition of the catches in the Shenwo Reservoir,the characteristics of heavy metal content in the catches,the level of fish pollution and the health risk of fish resources.The results show:（1）The fish samples collected in the Shenwo Reservoir in this survey consisted of 2phylums,2 classes,4 orders,6 families,10 genera,and 10 species in which Cyprinidae is the most common,followed by Perciformes in fish class.The fish samples collected in this survey in the Shenwo Reservoir are small in length and weight.In general,the fish species have good plumpness and normal growth and development.In terms of the dominant fish species,four dominant species,namely,the Phoxinus lagowskii,the Pseudorasbora parva,the Gobiide,and the Carassius auratus Linnaeus,were dominant in the community.（2）The content of heavy metals in the water of Shenwo Reservoir is lower than the Class I Environmental quality standard of surface water,and the heavy metal pollution at each site was at the pollution-free level.In terms of health risks,the health risks of heavy metals in the water of Shenwo Reservoir are at a safe level.The overall trend of heavy metals in the sediments of Shenwo Reservoir showed the trend of Zn>Cu>Pb>Cd>As>Hg.Cd,Zn,Cu,Hg,Pb exceeding the standard rate is high.The overall trend of sediment heavy metal geoaccumulation index is:Cd>Zn>Cu>Pb>Hg>As.The pollution levels of Cd and Zn are higher,and the others are lower.The potential ecological risk coefficient of a single heavy metal in the sediments of Shenwo Reservoir is in descending order: Cd>Hg>Cu>Pb>As>Zn.The ecological risk levels of Cd and Hg are higher,and the rest are lower.The potential ecological risk level at each point is high,and Cd is the main risk element.（3）Regarding the content of heavy metals in the catches,the detection rate of Cd,Cu,Zn,and As in the six heavy metals was 100%,and the detection rate of Pb and Hg was 0.In terms of excess rate,As has the highest excess rate,reaching 100%,followed by Zn and Cd,which are 87.5% and 50%,respectively,and Cu has 0.In terms of heavy metal content,the order of heavy metal content shows the trend of Zn>As>Cu>Cd.Judging from the enrichment of heavy metals in different organs,viscera>muscle>gill is a general rule.Judging from the enrichment of heavy metals in different organs,viscera>muscle>gill is a general rule.In terms of the distribution of habitat water layer,it showed the characteristics of bottom layer > middle and lower layer > middle and upper layer,and in terms of food distribution,it showed the characteristics of omnivorous > carnivorous > herbivorous.（4）In terms of the pollution index,all kinds of fish are relatively polluted,and most of the fish are at a heavy pollution level.Through the correlation analysis of heavy metal sources,Cu and Zn have similar enrichment reasons.Through the method of target hazard quotient（THQ）to assess the health risk of heavy metals in the catches in the Shenwo Reservoir,the result shows that the catches in the Shenwo Reservoir have a relatively high risk of exposure to heavy metals.The THQ of As is greater than 1 in all kinds of fish,and the THQ of Cd,Cu,and Zn are all less than 1 except the Freshwatershrimps whose THQ of Zn is greater than 1.For the contribution rate of THQ,the contribution rate of As is as high as 90%,which is the main source of health risks.