【作者】 陈三雄；

【导师】 张金池；

【作者基本信息】 南京林业大学 ， 水土保持与荒漠化防汉， 2012， 博士

【摘要】 广东省大宝山矿区存在水土流失剧烈、土壤重金属污染严重、植被和生态恢复困难等生态环境问题。通过实地调查、野外原位小区模拟径流冲刷试验、室内分析及大田试验,对大宝山矿区水土流失特征及植被恢复进行了系统研究。主要研究结果如下：1)以坡长、坡高、侵蚀沟密度为分析指标,经聚类分析、判别分析,构建了矿区土壤侵蚀强度分析模型。经分析,大宝山矿区现有水土流失面积324.48hm2,占矿区总面积的48.8%,土壤侵蚀严重,必须尽快进行整治。2)新弃土、老弃土、自然土的单位面积平均径流量分别为6.52、5.75、0.69L/min,平均含沙量分别为156.79、51.68、23.99g/L,平均产沙率分别为0.99、0.27、0.03kg/min。侵蚀泥沙中,Cd的平均流失率分别为32.55、12.18、0.09mg/(min.rrr),Pb分别为1648.98、432.10、8.07mg/(min.m2),Zn分别为1854.35s460.14s4.92mg/(min.m2),Cu分别为1742.63、429.47、8.69mg/(min.m2),大小顺序均为新弃土>老弃土>自然土。新弃土、老弃土第2min产沙率分别为2.94、1.11kg/min,分别是其平均产沙率的2.96和4.08倍,有明显的“初期冲刷”效应。新弃土、老弃土、自然土侵蚀泥沙中,石砾和砂粒含量之和分别为87.15%、84.45%、32.02%,新弃土、老弃土侵蚀泥沙中的颗粒以石砾和砂粒的含量为主,与自然土明显不同。3)在5°、15°、25°坡度下,侵蚀泥沙中重金属Cd的平均流失率分别为1.64、19.07、32.55mg/(min.nT),Pb为179.23、1788.71、1648.98mg/(min.m2),Zn为178.46、1748.40、1854.35mg/(min.m2),Cu为191.38、1809.89、1742.63mg/(min.m2)。Cd和Zn的平均流失率随坡度增加而增大,而Pb和Cu的平均流失率则表现为15°>25°>5°。4)在径流量为300、500、700L/h的冲刷强度下,单位面积平均径流量分别为4.33、6.52和8.82L/min,平均含沙量分别为151.18、156.79和240.79g/L,平均产沙率分别为0.78、0.99和1.95kg/mino冲刷土壤中,重金属Cd的平均流失率分别为24.08、32.55和48.36mg/(min.m2)，Pb分别为1290.61、1648.98和3169.10mg/(min.m2)，Zn分别为1397.22、1854.35、3437.87mg/(min.m2),Cu分别为1240.47、1742.63、2946.80mg/(min.m2),均表现出随着冲刷流量增加而增大的变化规律。5)在无覆盖和盖度分别为30%、60%、90%的条件下,鱼位面积平均径流量分别为6.52、6.23、5.94和5.80L/min,平均含沙量分别为156.79、43.40、33.17和26.83g/L,平均产沙率分别为0.99、0.25、0.19和0.14kg/min重金属Cd的平均流失率分别为32.55、9.14、8.11和4.03mg/(min.m").Pb分别为1648.98、402.43、294.28和210.64mg/(min.m2),Zn分别为1854.35、382.03、305.02和196.38mg/(min.m2),Cu分别为1742.63、333.24、264.61和191.28mg/(min.m2),呈现出随着覆盖度增加,平均流失率降低。6)对大宝山矿区上壤样品监测表明,Cd和Cu的单因子污染指数均大于1.超标率为100%,Pb、 Zn的超标率为77.8%。土壤样品的综合污染指数变幅在5.74～157.23之间.均高于国家规定的污染指数3.表明矿区上壤已受到严重的重金属污染,且以Cd、Cu的污染最为严重。7)调查的矿区13种优势植物中,铺地黍地上部的Pb含量达到1214.00mg/kg,泡桐叶中Cu含量达到1024.80mg/kg,超过了Pb和Cu超富集植物含量的临界值(1000mg/kg);其运转系数分别为1.77,13.74。可见,铺地黍是Pb的超富集植物,泡桐是Cu的超富集植物。综合植物重金属富集特征和大田试验结果,可以选择泡桐、马尾松、夹竹桃、象草、五节芒、狗牙根作为大宝山矿区植被恢复的先锋物种。更多还原

【Abstract】 The universal environmental problems, such as soil erosion, heavy metal pollution, wick ecological environment and hard to ecological restore, were similar in Dabaoshan Mine, an open-pit mining polymetallic mine in Guangdong Province. Basing on the field investigation, in-situ district simulating runoff scouring experiment, laboratory analysis and outdoor planting experiments, the systematic study was conducted on the soil erosion characteristic and comprehensive measures for the prevention and control of Dabaoshan mine. The main conclusions were drawn as follows:1) Slope length, height and density of erosion gully could be used to represent the characteristics and differences of soil erosion for different slopes of the mining area, and a discriminant model of soil erosion intensity in mining area had been built by cluster analysis and discriminant analysis. After that, the existing soil loss area was324.48hm2in Dabaoshan mining area, accounting for48.8%of the total area. The soil erosion was severe and worthy of great attention.2) The average runoff of new spoil soils, old spoil soils and nature soils were6.52,5.75and0.69L/min respectively, and the average sediment content of each were156.79L.51.68L and23.99L;the sediment yield rate were0.99.0.27and0.03L/min. The average drain rate of soil Cd of new spoil soils, old spoil soil? and nature soils were32.55.12.18and0.09mg/(min·m2) respectively; the average drain rate of soil Pb were1648.98,432.10and8.07mg/(min·m2) respectively; the average drain rate of soil Zn were1854.35,460.14and4.92mg/(min·m2); the average drain rate of soil Cu were1742.63,429.47and8.69mg/(minm2) respectively. The sediment yield rate of new spoil soils and old spoil soils in the second minute were2.94and1.11kg/min. which were2.96and4.08times of its average sediment yield rate, showing the "early-yield-sediment" effect. The sum content of stone particles and sand particles of new spoil soils, old spoil soils and nature soils were87.15%，84.45%and32.02%respectively, significantly different from nature soils3) As the slope gradient were5°,15°and25°. its average runoff were respectively5.06.5.6and6.52L/min; the average sediment content were0.12.0.89and0.99kg/min:the average sediment yield rate were0.120.89and0.99kg/min. With the increase of gradient, the average runoff, sediment content and sediment yield rate increased. As the gradient was5°15°and25°. the average drop-out rate of heavy metals in the eroded sediment was as follows:the average drop-out rate of Cd was64,19.07and32.55mg/(min·m2); the average drop-out rate of Pb was1290.61,1788.71and1648.98mg/(min·m2); the average drop-out rate of Zn was178.46,1748.40and1854.35mg/(min·m2); the average drop-out rate of Cu was191.38,1809.89,1742.63mg/(min·m2).The average drop-out rate of Cd and Zn increased with the increase of slope; The average drop-out rate of Pb and Cu order as follow:15°>25°>5°.4) When the erosion intensity were300,500and700L/h, the average runoff were respectively4.33,6.52and8.82L/min; the sediment content were151.18,156.79and240.79g/L; the sediment yield rate were0.78,0.99and1.95kg/min; the average drain rate of heavy metals were showed as follows: Cd were24.08,32.55and48.36mg/(min·m2); Pb were1290.61,1648.98and3169.10mg/(min·m2); Zn were1397.22,1854.35and3437.87mg/(min·m2), Cu werel240.47,1742.63and2946.80mg/(min·m2) under the erosion strength of300,500and700L/h. All of indexes showed same change law, which increased with the rise of erosion intensity.5) When the coverage condition were0%,30%,60%and90%, the average runoff were respectively6.52,6.23,5.94and5.80n; the average sediment concentration were respectively156.79,43.40,33.17and26.83g/L; the average sediment rate were0.99,0.25,0.19and0.14kg/min; the average drain rate of heavy metals were Cd32.55,9.14,8.11and4.03mg/(min·m2); Pb1648.98.402.43.294.28and210.64mg/(min·m2); Zn1854.35,382.03.305.02and196.38mg/(min·m2); Cu1742.63.333.24.264.61and191.28mg/(min·m2). The average drain rate reduced with the increase of coverage. The single factor indexes of Cd and Cu, within the27soil samples of Dabaoshan mining area, were both more than1, exceeding the standard. The single factor index of21soil samples tested were more than1, and77.8%of all the samples exceeded the standard. The comprehensive pollution index of27soil samples were between5.74and157.23, greater than3, showing that the mining area had been severely polluted by heavy metals, especially Cd and Cu.6)1%limestone and3%manure were used as soil improvement to modify soils samples. and then the germinations ratio of wheat seeds, which were treated with improved soils, was95%and germination index was78%; the average survival (germination rate) and retention rate of experimental plants were94%and88%respectively, while the average height of plants were52.7cm, showing that the soils could meet the growing demands already.7) Between the13kinds of dominant species investigated in the mining area, the Pb content of aerial parts of Panicum repens L. reached1214.00mg/kg: the Cu content of Paulownia fortunei leaves reached1024.80mg/kg. both of which were more than1OOOmg/kg.the threshold of Pb and Cu hyper-accumulation planis: the biological transfer coefficients were1.77and13.74. greater than1.0, which were also satisfied with the standard of hyper-accumulation plants, indicating that Panicum repens L. might be a kind of Pb hyper-accumulation plants, and Paulownia fortunei might be a kind of Cu hyper-accumulation plants of absorbing heavy metals. According to the conclusions of the heavy metal enrichment characteristics of plants and outdoor planting test, Paulownia fortunei, Pinus massoniana, Nerium indicum Mill, Pennisetum purpureum, Miscanthus floridulus and Cynodondactylon(Linn.)Pers. Could be used as pioneer species of Dabaoshan mine vegetation restoration.更多还原