Spatial Pattern And Pollution Evaluation Of Heavy Metals In Farmland Soils Of Fuxin City

There is a close correlation between heavy metals and human health. Heavy metals in soil can Hazardous to human health through various channels, such as ingestion,inhalation,absorption through skin lesions et al. Mining activity usually lead serious ecological damage and environmental issues, and it was one of the most important sources of soil heavy metal pollutants. Mining activity and it's related industries Occupy an important position in economy of mining city, meanwhile they has more serious ecological and environmental issues than other citys. Research on soil heavy metal pollution lead by mining activities and it's potential environmental and health risk has been carried on enthusiasticly by scholars at home and abroad.In this study, 180 farmland soil samples were collected in 2650km~2 around the mining intensive region of Fuxin city and the concentrations of As, Cd, Cu, Ni, Pb and Zn were analyzed, then on this basis, applicated spatial analyse and evalution to research the heavy metal pollution. With the aid of geostatistical tools and GIS, a systematic research on As, Cd, Cu, Ni, Pb and Zn was conducted, pollutant sources and polluted ways, the pollution evaluation were discussed to obtain the rational methods of assessing the situation of the soils pollution from heavy metals and the utilization of soils.1. The Box-Cox mean values of Cd, Cu, Ni, Pb and Zn concentrations exceeded the background values, accumulation of heavy metals in soil was universal except for As. None of the soil samples were seriously As, Cu, Ni, Pb and Zn polluted, but soil Cd pollution was more serious than other metals. The concentrations of As, Cu, Ni, Pb and Zn in Vegetable soils were found higher than those in the other land use types, accumulated more seriously in Vegetable soils. The concentrations of six heavy metals showed the similar pattern: urban > suburban, which revealed that the mining activities might be one of the most important source influencing the heavy metal content in these regions. At the same time, the heavy metal contents of the livestock manures were also investigated. The relatively high concentrations of the Cu, Zn and As in the manure implied the possibility to import these pollutants to the farmland soil. Therefore, it should be paid more attention for the farmland and the livestock industry arrangement and production in Fuxin. 2. The spatial structure features of heavy metals were quantitatively described using geostatistical methods. The well-deifined spatial structures of six heavy metals were obtained in this study, their testing variograms completely matched theoretical structure. Semivariogram of Cu, Ni, Pb, Zn could be.fitted well with exponential model. And semivariogram of As, Cd could be fitted well with spherical model. The ranges were from 23.5～126.0km. The obvious nugget effects and moderate spatial dependences suggested that the spatial variabilities of heavy metals might be affected by anthropogenic activities in small-scale. The heavy metals showed obviously directional feature, except Ni was isotropy. Besides the influence from parent soil materials on spatial structures of heavy metal distributions, the minging and the urban citizen activities might contribute primarily.3. Concentration maps of six heavy metals in farmland soils obtained by kriging interpolation. Combined with statistical and geostatistical spatial structure analysis, We found the soil heavy metals has many source, and the spatial distribution affected by various factors. The minging activities was important sources of soil heavy metal pollutants, especially Cd, Cu, Pb, Zn. The accumulation of Cu and Zn in soil was affected by apllication of animal manures and pesticides. As and Ni was mainly from the soil parent material, but the impact of human activities still existed.4. Affected by different migration abilities, the transport distance of various metals present difference in certain extent. Cu, Zn, Cd, Pb have better migration abilities than As, obviously them present a longer transport distance, having a remarkable influence on 4～6km away from mining areas. The heavy metal release from Haizhou strip coal mine have migration trend to farmland soil affect by wind and river, different transfer pattern might result the difference concentration in farmland soil, inducing heavy metal distribution have various directional feature. It indicate that in daily farmland practice Fuxin should pay attention to the pollution risk on the direction of heavy metal transport.5. Heavy metal pollution evalution indicated that the median and Box-Cox mean of single pollution factors of soil Cd, Cu, Ni, Pb and Zn above 1, The Box-Cox mean order of single pollution factors: Cd > Zn > Cu > Ni > Pb > As. From the Nemero pollution factors, the Box-Cox mean was above 1 and below 2, it indicated that the heavy metal pollution level was medium. Starting from environmental and health risk, it should paid more attention to soil Cd pollution. Production and distribution of agriculture should appropriate considered heavy metal pollution risk of mining, especially Haizhou mine.The results of this study provide basic guide for processing the agriculture planning, cure and reclamation abandoned mining land, and also provide base for evaluating environmental pollution risk in farmland soils of Fuxin City.