| Cadmium and Lead in dustfall is harmful to environment and human health. Study on environmental chemical behaviour of Cadmium and Lead in dustfall is helpful to precaute and eliminate the harmness.In this paper, enviromental chemical behaviour of Cadmium and Lead in dustfall in economical region of Chengdu has been studied, including the investigation of pollution state of Cadmium and Lead in dustfall in economical region of Chengdu, the chemical speciation of Cadmium and Lead in dustfall, the correlationship between dustfall character and chemical speciation of Cadmium and Lead , and eluviating experiment on dustfall.The reasearch show that the concentration of Cadmium and Lead in the dustfall was 1.647.80 μg.g-1 The dustfall was slightly polluted by Cadmium and Lead, whose synthesis pollution index is 1.72 and 1.84.The speciation of Cd and Lead in dustfall samples from Chengdu economic region was studied by Tessier extraction method. Results indicated that the main speciation of Cd and Pb residual form. The distribution sequerce of speciation for Cd and Lead in dustfall is residual > carbonates-bound > exchangeable > Fe-Mn oxides-bound > organic-bound. The bioactivity of exchangeable Cd and carbonates-bound Cd are much higher than that of the other three speciation. The percentage of exchangeable Cd and carbonates-bound Cd is 6.42 % and 8.92 %, respectively. The percentage of Fe-Mn oxides-bound Cd, organic -bound Cd and residual Cd is 3.42 %, 2.37 % and 78.91 % respectively. The percentage of exchangeable Pb and carbonates-bound Pb is 8.88 % and 9.15 %, respectively. The percentage of Fe-Mn oxides-bound Pb, organic -bound Pb and residual Pb is 7.05 % 2.00 % and 74.14 % respectively.The factor of Cd and Pb speciation in dustfall may be affected by the hunmus ,pH values and the concention of Fe and Mn. The result indicated that humus has certain correlation with Fe-Mn oxide-bound Cd and Pb, organic-bound... |
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