Distribution Characteristics And Sources Of Heavy Metals In Soil Of An Ecological Park In Huainan

Coal is one of the important energies in our country. However, due to the irrational exploitation of coal resources, large area of land subsided and coal gangue piled up in mining area. It led to poor soil fertility and serious heavy metal pollution. Pollutants could be lurking in soil for a long time, then transferred to crops through enrichment, finally entered the human and animal body by the food chain, which posed a threat to health. An ecological park in Huainan was chosen as the study area. By determined the contents of Cu, Zn, Cd, Pb, As, Cr in soil under different land-use patterns to describe the distribution characteristics of heavy metal. The contents of heavy metal in pig manure, soils and crops of Chizhou and Bozhou, Lixin were also determined to compare and verify the sources of heavy metal in soil of the ecological park. The main conclusions of this study were as follows:(1) The soil bulk density was decreased, the total soil porosity and non-capillary porosity were improved of each land-use patterns of the ecological park. The reclaimed soil trended undisturbed soil gradually, water permeability and air permeability of soil were enhanced, soil function was promoted. The rank of humus content, humification degree and stability was vegetable field> corn-wheat field> woodland.> bare land. The composition of soil humin (HM) were various under different land use patterns, the content sequence was HMr>HMi>HMc in humin composition. The content of HM fractions was significantly increased with application of organic fertilizer.(2) All the contents of heavy metal in soil were not exceed the national secondary standard. The contents of Cu, Cd and Cr were higher than the soil background values of Huainan. The contents of Zn, Pb and Cd in cabbage were exceed 3,11 and 2 times than the limit standard of vegetables. Large quantities of heavy metals were accumulated by crops easily, especially Cd and Zn. The moisture content, total porosity and non-capillary porosity had a synergistic effect with Cu, Zn and Cd, while pH and unit weight had an antagonism with them in soil. Cu, Zn and Cd were significantly positively correlated with soil organic carbon and humus components. It showed that the increase of the contents of organic carbon and humus components, so did the contents of heavy metal.(3) Compared with fresh pig manure, Cu, Zn and Cd in fermented pig manure were exceed 2 times. The contents of Cu and Zn in piglet feed were exceed 46 and 29 times than feed hygiene standards. Both Cu and Zn in fresh and fermented pig manure were higher than the standard of rotten compost in Germany in Chizhou and Lixin. The contents of Cu were exceed 76,56,10 and 22 times than feed standard in the adult pigs and piglets of Chizhou and Lixin. Zn were exceed 5,7,2 and 3 times. By the principal component analysis, the soil heavy metals sources were organic fertilizer applied and gangue filled of the ecological park. The results, obtained through the nemerow index method, showed the contents of heavy metals under each land-use patterns were in light pollution level.