Study On Soil Nutrients And Heavy Metal Pollution Of Coal Waste Pile In Different Reclamation Years

Coal gangue is the emissions from coal mining and coal washing process waste,the most will be stacked to form coal gangue hill in the mining area.And around the coal gangue hill will produce a series of environmental pollution problems in the storage process,such as the destruction of vegetation,atmospheric pollution,water,soil,therefore,for reclamation of coal gangue hill to improve the ecological environment of mining area,the implementation of the premise and the core of ecological reconstruction in coal mining area.The push soil after reclamation is the main measures to control the coal gangue,heavy metals contained in coal gangue reclamation process but will push into the migration and transformation of soil formed after the reconstruction of the soil,soil pollution caused by reconstruction,become the Gangue Mountain Vegetation heavy reclamation To limit factors.Therefore,to carry out Coal Gangue Mountain reclamation work situation and find out the nutrient content of gangue reclaimed soils,pollution degree and risk status of heavy metals,for guiding the mining pollution of farmland according to local conditions,reasonable has important significance for agricultural production.This paper takes Shanxi city of Huozhou province Cao cun coal gangue coal mine reclamation farmland reclamation(R-3a),reclamation(R-5a)and reclamation 7a in farmland reclamation of farmland farmland(R-7a)as the research object,using the method of data collection,field sampling and indoor test analysis,the average of the 3reclaimed soil reconstruction 1m the soil nutrient content,soil nutrient profile and0-40 cm of heavy metals has been studied and analyzed,and the pollution status of the ecological risk assessment.The main results are as follows:(1)from the average 1m of reconstructed soil nutrient content in the soil with the reclamation(reclamation 3a farmland,farmland reclamation 5a and farmland reclamation 7a)increased,soil organic matter,total N,total P,total K and available N,available P,available K also showed an increasing trend with normal agricultural;field control compared to CK,although the reclaimed soil nutrient increased,but soil organic matter,total nutrients and available nutrients(except available K)is still lower than the ordinary farmland.(2)From the profile reconstruction of soil 1m soil organic matter and total nutrients: in 0-40 cm,with the increase of reclamation time,organic matter,soil reclamation of total N,total P and total K content increased gradually,but in40-100 cm,soil organic matter,the performance of the entire N and total K content increase gradually decreased with age,while the contents of total P was gradually increased trend with age.Compared with CK,0-40 cm,3 years of reclamation,reclamation area,soil organic matter,total N and total P were less than CK(all except K),and in the reclamation area of soil organic 40-100 cm Quality,full N,full P and full K four nutrients showed different degrees of higher than CK.(3)From the profile reconstruction of soil 1m and soil available nutrients:in 0-40 cm,with the increase of reclamation time,soil available N,available P and K(except 20-40cm)content showed the trend of rising volatility,while in 40-100 cm,the content of available N with the reclamation time does not change,the content of available P and K appears to be a downward trend.Compared with CK,3 years of reclamation,available N in the content of 0-20 cm increased gradually with age higher than CK,the content of 20-100 cm in most less than CK,available P and K in0-100 cm The content increased with the increase of age was lower than CK.(4)From the reclamation reconstruction of soil heavy metal content(0-40cm)situation: in 0-40 cm,with the increase of reclamation time,5 kinds of elements Pb,Hg,Cd,As and Ni content was increased,and the deep 20-40 cm heavy metal content is higher than that of surface 0-20 cm.compared with CK,with the increase of reclamation time,20-40 cm soil Pb,Hg,Cd,As and Ni of the 5 elements all exceeded CK,but only Hg and Cd content in 0-20 cm soil exceeded CK.(5)The results of environmental evaluation: single factor evaluation,comprehensive evaluation of Nemero and the potential ecological risk assessment of the 3 evaluation results show that with the increase of reclamation time,5 kinds of heavy metals in soil reclamation Pb,Hg,Cd,As and Ni pollution levels are increased.With the national soil standard class two on the basis of single factor evaluation and comprehensive evaluation of Nemero,said the study area belongs to the soil pollution,clean level;soil environmental background value in Shanxi on the basis of single factor evaluation,said Hg in the severe accumulation of Cd in moderate Pb,As and Ni accumulation in mild accumulation.Nemero comprehensive evaluation The comprehensive pollution degree price the 3 plots are in the reclamation of severe accumulation level,serious soil pollution.According to the evaluation of potential ecological risk index showed that Hg belongs to extremely strong ecological harm;Cd belongs to the strong ecological risk;Pb,As and Ni belong to slight ecological harm.The total potential ecological risk level as follows: R-7a>R-5a>R-3a,3 reclamation plots belong to the ecological harm is very strong.