宝鸡市植被叶子重金属分布规律及生态风险评价

以宝鸡市滨河路植被叶子为研究对象,对不同种类以及不同高度的植被叶子重金属含量和污染程度进行分析.结果表明,植物叶子中重金属含量随着植被高度呈递减的变化趋势;其中Cr、Mn和Pb含量在植被叶子中富集最多,Cr、Cu、Ni和Mn含量的最高值均出现在金叶女贞的植被叶子中; Pb富集最多的是大叶女贞,Cd富集最多的是塔松,As富集最多的是红叶李;运用单因子污染指数法和内梅罗综合指数法对植被叶子的污染程度进行评价,Hakanson潜在生态风险评价法评估了滨河路不同类型植被叶子中Cr、Cu、Ni、Mn、Pb、Cd和As等7种重金属的潜在生态危害,滨河路7种植被叶子综合污染指数属重度污染,具有极强的综合危害性; 7种重金属的平均潜在生态风险程度大小顺序为:Cd Ni Cr As Pb Cu Mn,RI值变化范围为19. 04～4 020. 29.

Analysis of Heavy Metal Pollution and Ecological Risk Assessment on Vegetation Leaves in Baoji City

Using seven types of vegetation and seven heavy metals (Cr, Cu, Ni, Mn, Pb, Cd, and As), the present study explored the ability of accumulation and degree of contamination in the leaves of vegetation in Binhe Road. The results demonstrated a negative trend between vegetation height and heavy metal content of vegetation leaves, i.e., as plant height increased, heavy metal contamination decreased. Leaves varied in the accumulation of heavy metals depending on the heavy metal and vegetation type. Cr, Mn, and Pb content were the most abundant in vegetation leaves. The highest values for Cr, Cu, Ni, and Mn were observed in the vegetative leaves of Hybrida vicary privet and were 217.33, 58.61, 36.79, 1676.14 mg·kg^-1, respectively. The highest Pb content was 1295.64 mg·kg^-1 in Ligustrun lucidum, the highest Cd content was 110.19 mg·kg^-1 in Cedrus deodara, and the highest As content was 139.42 mg·kg^-1in Prunus cerasifera. The degree of pollution in vegetation leaves was evaluated using the comprehensive index method Single-factor pollution index method and the Nemero Composite Index Method. The Single-factor pollution index of vegetation leaves with Prunus cerasifera, Platanus acerifolia, Cercis chinensis were between 0.02-1.23, and the Nemero Composite Index values were 1.01, 0.82, 0.4, respectively, with light pollution. The Single-factor pollution index of vegetation leaves by Cedrus deodara, Platycladus orientalis, Hybrida vicary privet and Ligustrun lucidum were much higher than 1, and the Nemero Composite Index was 16.53, 140.64, 98.80, and 37.52, respectively, with high levels of pollution. The potential ecological risk of heavy metals in vegetation leaves was determined using the Hakanson potential ecological risk assessment method. The order of the average potential ecological risk degree of the seven examined heavy metals was as follows:Cd > Ni > Cr > As > Pb > Cu > Mn, and the RI value range was 19.04-4020.29, with high levels of pollution.