Assessment of riveine input soil heavy metal pollution and potential ecological risk
Eight heavy metals were measured and analyzed in the topsoil of 65 riverside fields and 15 sur-rounding river sediments within the study area.Single pollution index,Nemero comprehensive pollution in-dex.Hakanson potential ecological risk index were used to assess the risk of soil heavy metal pollution.The inverse distance weighting(IDW)method was used for interpolation analysis to analyze the spatial dispersion characteristics and causes of soil heavy metal pollution in combination with the microtopogra-phy.The results showed that the content of heavy metals in the sediment from surrounding rivers are sig-nificantly higher than that in the surface soil of the field,and both showed obvious polluted state.Heavy metals in both topsoil of the field and river bottom sediment were at heavy pollution levels,and the river bottom sediment was almost 10 times more polluted than the topsoil of the field.Based on the single-po-tential ecological risks,the average potential ecological risk index of heavy metal Cd in the field is the highest(2 971.67),and it was identified as the most important risk factor.Similarly,Hg(64 097.78)and Cd(13 202.13)are the most important risk factor in the river sedmients.In terms of both pollution level and ecological risk,the condition of river sediments is inferior to that of field soils,and the artificially dug river connects the pollution source to the farmland,and at the same time,the heavy metal elements excee-ding the standard in the river and the field can be traced back to the discharge of the pollutant source,and therefore,the study area can be characterized as a water-input type of pollution,and it can be seen that there is still a need to further regulate the source of irrigation water and control the quality of irrigation water in water-scarce areas for the agricultural production activities.
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