An Ecological Survey And Research Of Heavy Metal Contents On Vegetation At Panzhihua Lead/Titanium Mine Area In Sichuan Province

Soil contamination has become the focal point of environmental problems,for hard to extirpate and accumulating year by year.Therefore,phytoremediation-a new green technique was proposed.Hyperaccumulator or tolerant plants was the key to apply the technique to heavy metal contaminated soil,so the author investigated to screening out of such plant species.A survey was conducted on plant vegetation in Pan zhihua Ti-lead mine area,Sichuan Province,respectively in August,2007 and August,2008.By analyzing the soil properties and heavy metal concentrations in both collected plants and soil samples,the major results were revealed as followed:(1)The original subtropical plants were destroyed due to the exploitation of mine, there is no evergreen broad-leaved forest,formed secondary bush and herbaceous land, the coverage of which was about 40%.And it is Vernicia fodii along the road.In plant vegetation,the representative plants were Vernicia fodii for arbor layer; Dodonaea viscose,Lantana camara,Rumex hastatus for brushwood layer; Eriophorum comosum for herbaceous layer.There were 75 kinds of plants which were mostly herbs,belonged to 22 families and 52 genuses.The dominant plant species included Eupatorium adenophorum,Elsholtzia argyi,Eriophorum comosum,Polygonum thunbergii,Deeuxia scabrescens,Rottbellia exaltata,Zinnia elegans,Polygonum multiflorum,Artemisia argyi,Bidens pilosa,Adenostemma lavenia,Crassocephalum crepidioides,Dodonaea viscose,Coriaria sinica,Lantana camara,Vernicia fodii,and Verbena officinalis,Rumex hastatus,Galinsoga parviflora,Conyza Canadensis,Setaria viridis,Indigofera pseudotinctoria in some special places.(2) The mine soil was slightly acali,and the contents of organic matter were quite high in common.Soil there was higly contaminated by Pb,Ti,Cd.The heavy metal concentrations in soils were in an order of:Pb＞Ti＞Zn＞Cr＞Cu＞Cd.(3) The tendency of heavy metal concentrations in plants is:Pb＞Ti＞Zn＞Cr＞Cu＞Cd,which is the same as the concentrations in soil communities.Of these plants, We got 13 kinds of plants which only absorb few Pb and 15 kinds which absorb few Cd,and,we defound these plants be ecosystem revegetation types,such as Eupatorium adenophorum Spreng and Rumex hastatus D.Don etc.(4) The correlation analyses between heavy metal concentrations of soils and plants suggested that there was certain relationship between Cr,Zn concentrations in plant communities and value of CEC,TN,AN,AP,AKin soil,between Pb and TN andAN,Cr and pH,AP,Ti and AP,AK.Additionally,there were certain positive correlations between heavy metal concentrations in plants and associated soils,such as Cu,Cd,Cr.