洛川苹果林地重金属分布特征和污染评价

Distribution features and environmental risk assessment of heavy metals in apple tree plantations in Luochuan tableland

通过取样调查和试验分析,选用As、Cr、Cu、Ni、Pb、Zn、Mn、Co、V等9种重金属元素研究了洛川苹果林地典型剖面(LC剖面)的重金属分布特征,并利用地累积指数法、重金属富集指数法、重金属潜在生态危害指数法,对洛川苹果林地重金属的污染状况和金属元素富集规律进行了初步研究。结果表明:As、Cr、Ni、Mn、V含量变化走势基本相同,总体上由表层向下波动递增,Cu、Pb、Zn、Co4元素含量垂向变化特征基本相似,由表层向下总体呈先减少后增多趋势;除Pb和Zn外,As、Cr、Cu、Ni、Mn、Co和V均有一定程度的富集。As的生态危害指数(Eri)较高,在9种重金属元素中最大,潜在生态危害指数(RI)为39.9,但小于轻微生态危害的阈值150,表明该区苹果林地重金属尚未构成污染危害。

Based on systematic sampling and experimental analysis, the distribution features and environmental risk assessment of heavy metals in a typical profile, LC profile, of apple tree plantation in Luochuan tableland were investigated. The heavy metals investigated in the study included As, Cr, Cu, Ni, Pb, Zn, Mn, Co and V. Geoaccumulation index, element accumulation index and potential ecological risk index were used in the assessment. Based on the assessment, As, Cr, Ni, Mn and V have similar vertical distribution trends, generally increasing from top to bottom. However, Cu, Pb, Zn and Co almost exhibits the same distribution trend in the soil profile, generally initially decreasing and then increasing from top to bottom. There is some degree of As, Cr, Cu, Ni, Mn, Co and V accumulation, the phenomenon not observed for Pb and Zn. Ecological risk index for As is the highest among the 9 heavy metals investigated. As has potential ecological risk index of 39.9, though far less than slight ecological risk threshold.