Distribution Characteristics Of Heavy Metals As And Cd And Their Relationship With Organic Carbon From Soil In Huainan,China

In this paper,109 samples(99 samples from Huainan city and 10 samples from Xinzhuangzi reclamation area)from the surface soil and Xinzhuangzi reclamation area were collected in Huainan City(excluding Shouxian,Maoji Experimental Area and part of Xiejiaji Area)to understand the impact of mining activities on the pollution of heavy metals As and Cd,and the relationship between heavy metals and organic carbon in this area.Through the initial investigation,sampling and testing,the content characteristics,spatial distribution and Source resolution were analyzed.And the accumulation index and potential ecological risk index were used to evaluate the accumulation degree of heavy metals and the degree of ecological damage.The results showed that:(1)The maximum and minimum content of As in Xinzhuangzi reclamation area was 16mg/kg,10.4mg/kg,with an average value of 13.26mg/kg,which exceeded the Huainan city soil background value(10.05mg/kg).The maximum and minimum value of heavy metal Cd in the soil was 0.48mg/kg,0.01mg/kg,with an average value of0.16mg/kg,which exceeded the Huainan city soil background value(0.06mg/kg).The results of the land accumulation index method and the potential ecological index method were consistent,which indicated that the heavy metal of As in the Xinzhuangzi reclamation area was little pollution.However,the pollution of Cd was complex,relatively.The pollution degree of Cd in the corn field was strong polluted,while the pollution degree in the soybean field was moderate polluted.There was a positive correlation between As,Cd and SOC.(2)The maximum value of soil heavy metal As content in the study area of Huainan was 39.50mg/kg,the minimum value was 3.20mg/kg,and the average value was 9.53mg/kg,which was not exceed the Huainan city soil background value(10.05mg/kg).The maximum value of soil heavy metal Cd content was 0.48mg/kg,the minimum value was 0.00mg/kg,and the average value was 0.066mg/kg,which slightly exceeded the Huainan soil background value(0.06mg/kg).The proportion of As samples exceeding the background value of heavy metals in Huainan soil was:non-mining farmland(5%)< forest land(10%),urban soil(10%)< mining farmland(30%)< Xinzhuangzi reclamation area(45%);The proportion of Cd samplesexceeding the standard is Woodland(5%)< non-mining farmland(10.00%)< mining farmland(25%),urban(25%)< Xinzhuangzi reclamation area(35%);Urban heavy metal As,Cd,woodland Cd and soil SOC were positively correlated.There was a negative correlation between As and Cd in farmland in coal mine area,As in farmland in non-mining area,Cd,As in forestland and SOC in soil.In addition,the correlations of heavy metals As,Cd and SOC in soil of the other three different land use modes are similar,that is,with positive correlation or with negative correlation.(3)the polluted areas of As and Cd were farmland in mining areas(coal gangue stacking sites),Badongshan forest area and Shangyao forest area in Fengtai county;Most of the data of heavy metal accumulation index were less than 0,which is pollution-free.The maximum value of Eir of As < 40 was a minor pollution.In addition,the Eir maximum value of Cd in the badong mountain area,> 80,belongs to strong.Other than pollution,other parts were mild to moderate pollution;The arithmetical mean values of As potential ecological hazard indexes in urban,non-mining farmland,forest land and mining farmland soil were 8.45,7.53,6.97 and9.81,respectively.The arithmetic mean values of Cd potential ecological hazard indexes of urban,non-mining farmland,forest land and mining farmland soil were18.08,18.50,19.47 and 22.81,respectively.The average value of the potential ecological harm index of heavy metals As and Cd is less than 40,which was pollution-free.(4)According to the PMF model,the contribution rate of heavy metals from natural sources in Huainan city was the highest(30.60%),followed by industrial activities(25.50%),atmospheric subsidence(22.40%)and agricultural activities(21.45%).In general,the soil heavy metal enrichment areas in Huainan region are few,and there was no significant impact on the soil environment due to industrial activities.Figure 24 table 13 reference 84...