Heavy Metal Concentrations Of Soils And Dominant Plants At Some Mine Tailings Area Of Nandan

At present, heavy metal pollution is more and more serious. Phytoremediation mayoffer a new solution of this problem. Finding out a series of ideal hyperaccumulators isthe main groundwork of phytoremediation. The soils and dominant plants wereinvestigated at some mine tailing area of Nandan County in Guangxi Province. Theheavy metal concentrations of dominant species and associated soils were analyzed. Andthen Ageratum conyzoides, Buddleja lindleyana and Boehmeria frutescensvar viridulawere identified by soil pot experiment. The major results were summarized as follows:(1) The soils were investigated at some mine tailing area of Nandan County inGuangxi Province, the results showed that acid soil dominated mine tailing area. Andthe soils mainly belong to combined pollution, especially Cd—Zn—Pb combinedpollution. Concretely, 1st,4th and 9th sample point is Cd pollution; 3rd sample point isCd—Zn combined pollution; 2nd,7th,8th and 13th sample point is Cd—Zn—Pbcombined pollution; 5th,10th and 11th sample point is Cd—Zn—Pb—Ni combinedpollution; 12th sample point is Cu—Cd—Zn—Pb combined pollution. The 5th samplepoint pollution by Cd, Zn and Ni was the most serious.(2) There were 33 species of dominant plants belonging to 21 families wereinvestigated. Among them, Compositae was the family with most species, its 6; andSolanaceae had 3; Urticaceae, Polygonaceae, Fabaceae, Cramineae and Ericaceaef had 2 respectively and the others had only 1. The investigation showed that the plantof the highest Zn and Pb in shoots is Boehemeria nivea(2974.25mg/kg,583.85mg/kg), theplant of the highest concentration of Ni in shoots was Polygonum multiflorm(157.93mg/kg), the plant of the highest concentration of Cd in shoots was Ageratumconyzoides(131.50mg/kg), the plant of the highest concentration of Cu is Phytolaccaacinosa (61.24mg/kg)。And also showed that Ageratum conyzoides, Phytolacca acinosa,Chenopodium ambrosioides, and Buddleja lindleyana Fort, could be useful inphytoremediation.(3) Ageratum conyzoides had strong accumulation capability of Cd. The fieldinvestigation showed that the concentration of Cd in leaf of Ageratum conyzoides was131.50mg/kg. Soil pot experiment showed that Ageratum conyzoides' shoot had highconcentration Cd (83.82mg/kg) growing in the soil 2.(4) Buddleja lindleyana Fort had strong accumulation capability of Pb, especiallygrow in the soil 2. The result agreed with the investigating conclusion.(5) Boehmeria frutescensvar viridula had strong accumulation capability of Pb andZn when growing in the soil 2.