| The hilly regions in Sichuan province play a important role in supplying food.The impacts of population pressure, fast economy development, industry, and the rural non-point pollution, make the soil of this area polluted and degenerate badly. This paper elect 93 point base on Geostatistics theory at Wutongqiao County of SW Sichuan which was the typical hilly zone, sampled soils and plant at the same time, detected the content of lead, cadmium, copper, zinc, nickel, chrome and arsenic. Applying Geostatistic theory with the help of GIS, to studies the heavy metals spatial variation in the soil and assessed the pollution in soil and plant, while, filter the hyperaccumulator. The main research contents and results are as follows:(1) Concentration of five kinds heavy metals in soils of wutongqiao, including lead, cadmium, copper, zinc, and arsenic, appeared to be lognormal distribution, while that nickel and chromium presented as normal distribution. According to the above conclusion, geometric mean value and standard deviation were adopted representative indexes in calculation of lead, cadmium, copper, zinc, and arsenic concentration in soils, whereas arithmetic mean value and standard deviation were adopted in the other two heavy metals. The distribution range of heavy metal concentration was concluded as following: 33.20±17.21 mg.kg-1 of Pb(cv 47.85%, n=93), 0.80±0.29 mg.kg-1 of Cd(cv33.73%, n=93), 27.9±10.95 mg.kg-1 of Cu(cv37.17%, n=93), 98.73±47.36 mg.kg-1 of Zn(cv43.91%, n=93), 11.50±3.94 mg.kg-1 As(cv32.57%, n=93), 32.63±7.58 mg.kg-1 Ni(cv 23.21 %, n=93), 71.96±19.02 mg.kg-1 Cr(cv32.21%, n=93). Compared to background content of heavy metal, concentration of lead, cadmium, zinc and arsenic was higher than it, and evident accumulation trend already appeared consequently. Whereas no obvious change was detected in the content of copper, nickel and chrome. The increase extent of heavy metal followed the sequence of cadmium>arsenic>zinc>lead>nickel>copper>chrome.(2)The primary pollutant element in soils was lead, cadmium, zinc and arsenic, and the lead, cadmium and zinc show highly correlation, the correlation coefficient were Pb—Zn(0.590), Pb—Cd(0.617) and Zn—Cd(0.708), which indicated the three element had closely source and there was a higher combined pollution between lead, cadmium and zinc; Arsenic has the lowest relativity with other elements, which indicates that it was unique in accumulation. The copper, nickel and chrome in soil were close to the soil background value, and there had a comparatively higher correlation as the coefficient were Ni—Cr(0.455), Ni—Cu(0.594), which indicated the value of three element influence by geochemistry circulation, root in nature mostly.(3) The result of spatial variation analysis of the heavy metals in soil of wutongqiao is as follows: the semi-variance function of lead, zinc and chrome were Exponential model, and the cadmium, copper, nickel and arsenic was Gaussian model; the ratio of nugget value to still value[Co(C+C0)] is zinc>lead>cadmium>chrome>nickel>copper>arsenic. All the ratio were less than 50%, indicated the seven element belong to median correlation in space. Based on semi-variance function fit parameters and Kriging's interpolation theory, applies the Geostatistical Analyst module in the software ArcMap to predict the spatial variability, and protracts the distribution map of the content of seven heavy metals in soil of Wutongqiao, which shows clearly the range of the content of various heavy metal in different region and can be regarded as the fundamental references to pollution monitoring and supervision, and the layout of the secure base of farm products(4) The pollution assessment and spatial variation analysis in soils both show the ranked order of contaminated degree was industrial zone>residential zone>agricultural zone>agricultural-forest zone>forest zone. The content of lead in soil of industrial zone increased 1 times in comparison with the background value and the cadmium increased 9 times, it's more polluted than other zones, indicated that industry was the most source of heavy metal in soil. The heavy metal content in soil were less concentration or not at agricultural zone and forest zone, so the soil environment was secure comparatively.(5) The pollution assessments show that some crops heavy metal content exceeded the national sanitation standard, the exceeded index followed as arsenic(40%), cadmium(32%) and lead(28%). And Sharp difference existed in the assessment results between heavy metal contamination of crops and soil pollution. From the relationship between heavy metal concentration in crops and total content in soil, while the cadmium in soil have a large content, but low bioavailability, there had no obviously contamination in crops; and Brassica pekinensis, Raphanus sativus, Zingiber officinale can evade the poison of cadmium.(6) The investigation of hyperaccumulator discovered Artemisia apiacea, Pinus massonina Lamb and Populus euramevicana CV have the ability to concentrate cadmium. When the content of cadmium in soil closely to 0.8 mg.kg-1, the three plant both emerged the ability of concentration and transformation to cadmium, the concentration coefficient were 2.17, 1.10 and 2.04, though the cadmium proportion in biomass were less than value of traditional hyperaccumulator, but the three plants all grow fast and have big biomass, have comparatively higher absorption capacity coefficient, which show great ability of concentration and transformation to cadmium.
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