| Soil is one of the natural resources on which human beings depend.With the increase in human material demand and the development of urbanization,soil heavy metal pollution is an environmental problem that cannot be ignored.County farmland,as an important carrier for agricultural products needed for daily life in the local and surrounding cities,ascertains the distribution characteristics of heavy metal content in the soil,and carries out ecological environment and human health risk assessment of soil heavy metal pollution,can provide a basis for decision-making for future local land use conversion.The research of heavy metal pollution in farmland soil at county level provides a method for reference,which is of great significance for preventing and controlling heavy metal pollution,improving the quality of human life,and promoting the healthy development of society.In this paper,the surface soil of agricultural land in Xianghe County,Langfang City,Hebei Province was used as the research object.Using remote sensing images and land use maps,a1km×1km grid was used to collect 288 samples of surface soil and the heavy metal content data was measured using SPSS.Basic statistical analysis,analysis of the distribution characteristics of the eight heavy metals cadmium,chromium,mercury,nickel,lead,arsenic,copper,and zinc through the interpolation function of Arc GIS,using the single factor index,Nemero pollution index,geoaccumulation index and human body The health risk index comprehensively evaluates the heavy metal pollution of farmland soil in Xianghe County.The main conclusions are as follows:?1?The soil p H value of agricultural land in Xianghe County is 7.25-9.42,which belongs to alkaline soil.The average value of the eight heavy metals is cadmium 0.14mg/kg,chromium55.03 mg/kg,mercury 0.07 mg/kg,nickel 24.52 mg/kg,lead 28.79 mg/kg,arsenic 4.88 mg/kg,copper 24.65 mg/kg,zinc 87.83 mg/kg,all have a skewed distribution.The total range,standard deviation,skewness,and kurtosis of soil zinc are the highest of the eight heavy metals,and the maximum value indicates that the area has a high pollution risk.?2?Using Inverse Distance Weighting?IDW?interpolation method to study the distribution characteristics of heavy metal content in soil,it is found that except for the distribution characteristics of cadmium,which are higher in the northeast,west and south of Xianghe County,and less in other areas,the distribution of the other seven heavy metals is basically higher High and low in the south,with the highest average cadmium content in Anping Town;the highest average chromium,mercury,lead,copper,and zinc content in Antoun Township;and the highest nickel and arsenic content in Qukou Town.Among them,the southern part of Antoun Township is in the region with the highest heavy metal content in the interpolation map of the eight heavy metal content,which requires follow-up analysis and focus.?3?The single factor index and the Nemero comprehensive pollution index are used to evaluate the soil ecological environment.The results show that the average value of the PI of the eight heavy metals is less than 0.7,which is within the safe range,but cadmium and zinc are higher than other heavy metal elements enrichment.Most of the sampling points P are less than 0.7 and are in a non-polluting state.7.2%of the sampling points need to be alert to the risk of pollution;1%of the sampling points have mild pollution;1 sampling point?89?has reached moderate pollution,which is the most polluted serious point.?4?The evaluation of the soil ecological environment using the land accumulation index shows that the minimum value of the accumulation index of the eight heavy metals is less than 0,and the degree of arsenic pollution is the smallest,and the average value of the mercury accumulation index is within the range of 0-1.It belongs to no pollution-light pollution,but from the maximum value,it belongs to moderate pollution-high pollution;the average value of the zinc accumulation index is less than 0,which belongs to no pollution,but the maximum value is in the range of 3-4,which belongs to strong pollution.The average value of the accumulation index of the eight heavy metals is only mercury is greater than 0.It can be considered that Xianghe County has added a new source of mercury pollution in the near future.?5?Human health risk assessment shows that the range of non-carcinogenic health risk index of adults in Xianghe County is 8.77×10-2-1.11×10-1,and the range of children non-carcinogenic health risk index is 5.35×10-1-7.20×10-1.There is no obvious non-carcinogenic health risk;the range of adult carcinogenic health risk index is 4.51×10-6-7.17×10-6,and the range of child carcinogenic health risk index is 4.33×10-5-6.92×10-5There is a certain carcinogenic risk.The main carcinogenic risk factor is arsenic,and soil heavy metal pollution has a higher carcinogenic risk for children.Residents in daily life need to pay attention to whether there are symptoms caused by chronic arsenic poisoning,and stay away from local sources of arsenic pollution. |
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