| With the rapid industrialization and urbanization in the past few decades,China has achieved great economic and social achievements,while environmental problems such as soil and water pollution and ecological destruction have become more prominent.According to the national survey on soil pollution released every year,the soil pollution in some parts of China is quite serious and the soil is polluted by different degrees with national soil total was 16.1%,and the soil pollution of heavy metal pollution is the key of the prevention and cure of soil pollution,soil heavy metal exceeds bid badly,southern and central heavy polluting in enterprises and surrounding soil was 36.3%.Heavy metals such as cadmium,arsenic,chromium and lead are threatening nearly 300 million acres of arable land nationwide.Soil pollution not only affects the soil quality,but also leads to the decline of crop yield,endangers human health,and threatens our arable land and food security.In 2017,with the promulgation of law on the prevention and control of soil pollution,soil pollution,especially the development of mining area of soil heavy metal pollution has become the current state,society,citizens focus on problems,How to scientifically and rationally evaluate the degree of soil contamination and determine the quality grade or category of soil is the key to soil quality evaluation.Domestic and foreign scholars have conducted extensive researches on the causes,mechanisms and laws of soil pollution.According to the causes of soil pollution,the soil pollution in China's mining area is mainly caused by dust diffusion in the mining process and the heavy metal pollution in surrounding areas caused by mine drainage.Excessive use of chemical fertilizers,pesticides,agricultural land membranes and the use of sewage irrigation in agricultural activities are the main causes of cultivated land pollution.Taken together,Soil pollution is a certain period of time,with the process of industrialization and urbanization,people are not reasonable way for farming and production input material and energy in the soil beyond the self-purification ability of soil itself and cause of soil degradation and function degradation and pollution,and a series of process.In this paper,Daye is an investigation and evaluation object.According to the characteristics of the mining production,uniformly collected three section of 624 soil samples,each sample was measured the content of As,Cd,Cr,Cu,Pb zinc element,and selected six of heavy metal elements to build the evaluation index system of daye county soil heavy metal pollution,On the basis of relevant theories,models and predecessors' research.,the soil heavy metal pollution degree and soil quality grade in the study area were evaluated by the comprehensive evaluation method and the comprehensive index method.The results show that:(1)as a traditional mining city.,the heavy metal pollution degree of the soil is serious in Daye,The average content of heavy metals such As As,Cd,Cr,Cu,Pb,Zn in 624 soil samples was 26.61,1.05,69.92,268.51,97.78 and 182.72mg/Kg.The above rates of soil I class standards were 77.39%,422.96%,0%,667.18%,179.39% and 82.72% respectively.The degree of soil heavy metal pollution is: Cu>Cd>Pb>Zn>As>Cr;(2)The evaluation results of fuzzy comprehensive evaluation method and comprehensive index method are slightly different,but the overall evaluation results of the two methods are relatively close.Soil I,II,III,IV and V,based on the fuzzy comprehensive evaluation method,are 56,71,85,212 and 200 respectively.Soil I,II,III,IV and V soil samples based on the comprehensive index method were 50,69,90,230 and 185 respectively.Therefore,fuzzy comprehensive evaluation method and comprehensive index method have their own advantages and disadvantages.and can be applied to soil pollution evaluation.(3)In order to realize the coordinated development of economy,society and environment,the mining development city should establish reasonable environmental capacity and carry out pollution control and monitoring. |
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