为了研究乌龙洞国家森林公园内土壤重金属含量的空间分布属性,识别其污染状况,细致的调查势在必行。在武隆东国家森林公园的阴凉和阳坡上选择了900,1000,1069m三个海拔梯度,共收集了300个土壤样本点。土壤样本是分层收集的,和七种土壤重金属元素的含量,Cr,Cd,Hg,Ni,Se,As,还有Pb,被测量。关于国家土壤元素背景值,单因素指数法,内梅罗指数法,采用污染负荷指数对土壤重金属污染进行了全面评估。(1)重金属元素Cr含量,Se,As,乌龙东国家森林公园0-20cm土层中的Pb和Pb均低于国家土壤元素背景值和河南土壤元素背景值;Cd和Hg含量超过国家土壤元素背景值。值与河南土壤元素背景值分别是全国土壤元素背景值的2.2倍和2.92倍,分别是河南土壤元素背景值的2.75倍和9.5倍;Ni含量低于河南土壤元素背景值,但高于全国土壤元素背景值。背景值是其内容的1.03倍。7种重金属元素含量的变异系数均大于50%,其中汞表现出极端的变化,剩下的六个是高度可变的。(2)在同一土层中,阳坡的Cr和As含量低于阴坡,铅的含量,Ni,和汞通常在阳光明媚的斜坡上高于阴凉的斜坡。在阳光明媚的斜坡上,As的内容,Cd,汞随着海拔高度的增加而减少,硒含量随着海拔高度的增加而增加;而在阴凉的斜坡上,Cr的含量,Se,随着海拔高度的增加,Pb和Hg含量随着海拔的增加而增加;重金属元素As的含量随着背坡土层的加深而增加,在阳坡上,汞含量随着土层的加深而降低。其它重金属元素的含量在不同坡向之间没有明显的规律性,海拔和土壤层。(3)单因子指数评价结果表明,在0~20c土层和阳坡上,汞污染严重,Cd中度污染,Ni是轻度污染,和Cr,Se,As,和铅都是无污染的;在阴凉的斜坡上,Cd和Hg中度污染,其他五种重金属元素处于无污染状态。(4)内梅罗指数法评价结果表明,在0~20cm土层中,阳光明媚的斜坡上的土壤比阴凉的斜坡上的土壤受到重金属的污染要严重得多,主要污染物是镍,Cd和Hg。(5)在武隆东国家森林公园0~20cm土层中,三种重金属元素Ni,Cd和Hg已达到污染水平,其中Ni受到轻微污染,Cd和Hg中度以上污染;阳坡土壤轻度污染。重金属污染,阴山斜坡上没有重金属污染。
To scrutinize the spatial distribution attributes of soil heavy metal content and discern its pollution status within the expanse of Wulongdong National Forest Park, a meticulous investigation is imperative. Three altitude gradients of 900, 1000, and 1069 m were selected on the shady and sunny slopes of Wulongdong National Forest Park, and a total of 300 soil sample points were collected. Soil samples were collected in layers, and the contents of seven soil heavy metal elements, Cr, Cd, Hg, Ni, Se, As, and Pb, were measured. With regard to the national soil element background values, the single factor index method, Nemerow index method, and pollution load index were employed to undertake a thorough assessment of soil heavy metal pollution. (1) The contents of heavy metal elements Cr, Se, As, and Pb in the 0-20 cm soil layer of Wulongdong National Forest Park are lower than the national soil element background value and the Henan soil element background value; the Cd and Hg contents exceed the national soil element background value. The value and Henan soil element background value are 2.2 times and 2.92 times the national soil element background value, and 2.75 times and 9.5 times the Henan soil element background value respectively; Ni content is lower than the Henan soil element background value, but higher than the national soil element background value. The background value is 1.03 times its content. The coefficients of variation of the contents of seven heavy metal elements are all greater than 50%, among which Hg shows extreme variation, and the remaining six are highly variable. (2) In the same soil layer, the Cr and As contents are lower on sunny slopes than on shady slopes, and the contents of Pb, Ni, and Hg are generally higher on sunny slopes than on shady slopes. On sunny slopes, the contents of As, Cd, and Hg decrease with increasing altitude, and the Se content increases with increasing altitude; while on shady slopes, the contents of Cr, Se, and As decrease with increasing altitude, and Pb and Hg content increase with the increase of altitude; the content of heavy metal element As increases with the deepening of the soil layer on shady slopes, and the Hg content decreases with the deepening of the soil layer on sunny slopes. The contents of other heavy metal elements have no obvious regularity among different slope directions, altitudes and soil layers. (3) The single factor index evaluation results show that in the 0 ~ 20c soil layer and on the sunny slope, Hg is heavily polluted, Cd is moderately polluted, Ni is lightly polluted, and Cr, Se, As, and Pb are all non-polluted; On the shady slope, Cd and Hg are moderately polluted, and the other five heavy metal elements are in a non-polluting state. (4) The Nemerow index method evaluation results show that in the 0 ~ 20 cm soil layer, the soil on sunny slopes is significantly more polluted by heavy metals than on shady slopes, and the main pollutants are Ni, Cd and Hg. (5) In the 0 ~ 20 cm soil layer of Wulongdong National Forest Park, the three heavy metal elements Ni, Cd and Hg have reached pollution levels, of which Ni is slightly polluted, Cd and Hg are moderately or above polluted; the sunny slope soil is slightly polluted. Heavy metal pollution, no heavy metal pollution on shady slopes.