The Health Condition And Risk Assessment Of Rural Soil In A County-Level City Along The Coastal

Research purposes:With the development of science and technology,the acceleration of the modernization process,the excessive exploitation and utilization of human natural resources,industrial "three wastes" and arbitrary discharge of domestic sewage,overuse of pesticides fertilizer,resulted in a large number of toxic and hazardous substances into the living environment and a serious threat to the human body health,Environmental pollution has become an increasingly significant global problem.As one of the material basis of Human survival and development,soil's environ nous substances can harm the public health through biological enrichment and food chain amplification.It is of great significance to understand the environmental quality of rural soils.So that we can speed up the construction of the production environment of high-quality agricultural products,and ensure the agricultural products meet the hygienic standards and reduce the health risk of the population.Through the dynamic monitoring of lead,cadmium,chromium content and trends in a coastal county-level city rural in recent years,assess objectively health status,potential ecological risks and population health risks.Ultimately we can provide the basic data to administrative agencies and relevant government departments that develop policies and take appropriate measures.Method:According to the national rural environmental health monitoring project and soil monitoring technical requirements,detect the ascaris eggs and lead,cadmium,chromium of soil,combining with the local situation.The study area was divided into the area near the mine(that the distance from the mine was less than 10 kilometers)and the area far away from the mine(that the distance from the mine is more than 10 kilometers)according to the distance from the mining area.In 2011-2016 years,each year randomly selected 20 administrative villages,detecting a soil in every village,altogether 120.We have determined lead,cadmium and chromium of soils,according to the GB/T17141-1997 "soil quality determination of lead and cadmium-graphite furnace spectrophotometry" and HJ491-2009 "the determination of total chromium in soil by flame atomic absorption spectrophotometry".At the same time,we determined ascaris eggs in soil by using saturated sodium nitrate solution floating method according to "fecal harmless hygienic requirements"(GB7959-2012).Set up the Excel database and analyzed the results by spss20.0.Based on the "soil environmental quality standard"(GB 15618-1995)and the rural soil element background value of prefecture-level city,to evaluate the status of rural soil quality in the study area by using the single factor pollution index,comprehensive pollution index and Hakanson potential ecological risk index method.At the same time,evaluate the health risk that was caused by the way of skin exposure and feeding soil heavy metal.Result:(1)The detection rate of lumbricoides was about 15%in the study area in 2011-2016.(2)The average of pH was 6.53,and the pH of 43.27%was less than 6.5 and 4.81%more than 7.5.(3)The content range of lead,cadmium and chromium in soil were separately12.60?81.60 mg/kg,0.05?1.09 mg/kg,40.60?147.00 mg/kg.There was a certain correlation between lead and cadmium in the whole study area soils(r=0.374,P<0.01),and chromium levels were increasing year by year during monitoring(F=5.72,P<0.01).(4)There was a certain correlation between lead and cadmium in the soil that far from the mine area(r=0.396,P<0.01),but the lead,cadmium,chromium three elements had no correlation in soil near the mine area(P>0.05).The results showed that the lead content near the mine was higher than that far from mine area(P<0.01).(5)The single factor pollution index method showed that lead,cadmium belonged to the mild pollution levels(index was 1.27 and 1.30 respectively),chromium in the alert limit state(index=0.85)near the mine,and cadmium belonged to the mild pollution levels(index=1.25),lead and chromium in the alert limit state(index was 0.89 and 0.83 respectively)far from the mine.The nemero comprehensive pollution index showed that the area near the mine area and the area far from the area were mildly polluted(the comprehensive pollution index was 1.10 and 1.06 respectively).(6)According to the potential ecological.risk index,the pollution degree of lead and chromium were risk free range(index<40).The ecological risk index of cadmiun was medium risk range(index=82.44)in 2013,and in other years were light pollution levels(40<index<80).The ecological risk index of lead near the mine was higher than far from the mine(8.17 and 5.71 respectively).The order of three elements' contribution to the soil ecological risk was cadmixum>lead>chromium.(7)The total carcinogenic risk of adults and children were greater than 1.0×10-4,which was recommended as the highest acceptance level by international agencies(adults was 1.23×10-4,children was 1.36×10-4).The non-carcinogenic risk of children by feeding was 8.13 times as large as adults,and the carcinogenic risk was 2.71 times.Conclusion:(1)The soil in the study area was contaminated with ascetic eggs,but the pollution changed little over the years.(2)The soil in the study area was contaminated with lead,cadmium and chromium differently,and the potential ecological harm of cadmium was highest.The pH of soil was partial acid,that could increase the dissolution of heavy metals in soil.(3)The lead and cadmium of entire area soil may come from the same source.(4)The carcinogenic risk was higher than the acceptable highest level that was recommended by international agencies.The health risk value of children was higher than adults by feeding.