四川省南部县土壤地球化学元素分布特征研究

A study on distribution of elements of soil in Nanbu County,Sichuan Province

基于成渝地区土地质量地球化学调查资料,研究四川南部县土壤中54种元素的地球化学特征。结果表明,与全国土壤相比,研究区重金属元素As、Cu、Hg、Pb、Zn基准值较低,Cd、Cr较高,Ni相当;多数重金属元素和植物营养元素背景值低于全国A层土壤背景值,仅CaO、Cd、MgO、Cr、F等的背景值高于全国土壤水平。多数元素(指标)背景值与基准值相当,说明表生作用和人为活动对表层土壤影响较小;而C、CaO、Cd、Org.C、I、MgO、N、P、S、Se等10种元素(指标)在表层土壤富集,表明这些元素受自身地球化学行为和人为活动输入影响。第四系和侏罗系遂宁组地层表层土壤元素分布差异较大,富集或贫化特征明显。就pH值而言,Cd、F、Cl、Mn、N、P、K;O、S、CaO、C、Org.C均在碱性环境含量较高,As、Cr、Cu、Ni、Pb、Zn、Co、B、Mo、Ge、TFe_(2)O_(3)、SiO_(2)在酸性环境含量高,多数元素在中性环境中趋于稳定。

Basing on geochemical survey data of land quality in Chengdu-Chongqing area, this paper discusses distributions and geochemical backgrounds of 54 elements of soil in Nanbu County, Sichuan Province.Compared with elements backgrounds of soil in China, the contents of heavy metal elements of As、Cu、Hg、Pb、Zn are lower, while Cd, Cr are higher and Ni is equivalent. Compared with the layer A soil in China, the backgrounds of most heavy metal elements and plant nutrient elements are lower, while 10 elements such as CaO, Cd, MgO, Cr, F are with a higher background. Except heavy metal elements, element backgrounds of soil of most other elements in Nanbu County are equal to those in China, indicating that the effect of epigenetic and human activity on the surface soil is slight.The elements of C, CaO, Cd, Organic C, I, MgO, N, P, S, Se are concentrated in the surface soil, suggesting that these elements are concentrated by their geochemical behaviors and human activity inputs. The element distributions in surface soil of the Quaternary and the Jurassic Suining Formation are quite different, and the concentration or dilution characteristics are obvious.As far as the pH value ranges are concerned, with regard to the range of Ph values, contentsof Cd, F, Cl, Mn, N, P, K;O, S, CaO, C, organic C are higher in alkaline environment, while contents of As, Cr, Cu, Ni, Pb, Zn, Co, B, Mo, Ge, TFe_(2)O_(3)and SiO_(2)are higher in acidic environment, and most elements tend to be stable in neutral environment.