River Sludge In Chengdu Lead Isotopic Composition And Lead Pollution Sources

The author measured the ratios of lead isotopes of the samples that are from main rivers in Chengdu city, NanHe river, FuHe river and ShaHe river. By the principle of Environmental Lead Isotope Tracing, the lead isotope composition of surface layer's sediment of every river and some special samples have been discussed, which helps to, with some factors of environment, trace and find out the distribution rules of the main contributors for lead pollution in riverway sediment and the proportion of contribution.Conclusions have been gained through many serious-minded researches such as collecting materials, sampling, chemic separate and purification, mass spectrum measuring, and data analyzing. The conclusions are as follow:1)The lead isotope composition of two major lead pollution sources ( leaded gasoline and coal) differed considerably from each other, which make it possible to trace the sources of the lead pollution of riverway sullage.2)The lead pollution sources of Chengdu's riverway sullage include geological condition, leaded gasoline , the ash of coal and industrial refuses. The contribution of the coal ash and industial refuses is more in hard-polluted ShaHe river, and the less-polluted rivers, NanHe river and FuHe river, feature with leaded gasoline's lead isotope composition. The lead isotope composition of upriver far from downtown, can be regard as the background of local geological condition.3)The source of diesel oil, which was rarely dealt with before, should be pay more attention to. Two samples (CRD-11 and CRD-15) seems be strongly influenced by this kind of source.4)Lead Isotope Tracing Technology and the lead isotope mixing model, which was used by Richard Bindler to study lake sediment, are introduced to this research and run effectively to tracing lead pollution of sediment of the rivers in Chengdu.5)Lead Isotope Tracing Technology can be used to not only trace the sources of the lead pollution of urban riverway sullage, but also help to offer some important clues for the sources of other elements in sediments.