科研之友
微信
新浪微博
Facebook
分享链接
摘要
Three index including single factor pollution index, Nemero index and potential ecological risk index were used to evaluate the effects of flooding on the heavy metal pollution and the soil quality of the flooded area and the non-flooded agricultural areas, which are along the downstream of a river nearby a non-ferrous metal mine in the southwest of China. The results showed that the main pollutants in the investigated area were Cd, Sb, Pb, As and Zn. The average concentrations of six heavy metals in the flooded area were 36.66, 63.48, 82.54, 128.21, 0.61 and 39.46 mg?kg-1 for As, Cr, Pb, Zn, Cd and Sb, respectively, while the average values in non-flooded area were 7.38 (As), 71.44 (Cr), 13.27(Pb), 35.27(Zn), 0.16(Cd) and 5.62 (Sb) mg?kg-1, respectively. The significant differences were observed between the heavy metals except Cr in the flooded and non-flooded areas (p<0.05). The over-proof ratios of the heavy metals in the flooded area were 52.23%, 44.54%, 48.14%, 72.03% and 88.25% for As, Pb, Zn, Cd, and Sb, respectively, while the relative ratios in the non-floode area were only 4.12%, 3.23%, 2.16%, 15.03%, and 22.00%. The soil-quality class of the non-flooded area belonged to the safely utilizable land, and its comprehensive potential ecological risk was strong (RI=600.3). As for the non-flooded area, it was classified to the high-priority land, and its its comprehensive potential ecological risk was slight (RI=69.1). Long-term flooding caused the aggravation of the pollution of As, Pb, Zn, Cd and Sb in the investigated area., which was attributed to the special geological background. In the soil of the studied area, there is much iron-manganese oxide film which has a strong adsorption to heavy metals. When a lot of heavy metals is transferred by the river flood, the iron-manganese oxide film in the flooded soil traps a part of these metals into the middle and lower layers of the soil, and then results to a heavier pollution of heavy metals. ? 2019, Science Press. All right reserved.
- 单位
