| Lead isotope for environmental pollution tracing has been intensively applied mainly based on the geochemical characteristics. Also, the geochemical action of Pb was not controlled by temperature, pressure, pH and Eh values, even the biological effect. And Pb isotope fractionation could not happen. In order to investigate the feasibility of isotope technique in trace back the sources and the way of lead pollution of agricultural products in high exposure area, and the contribution rate of various lead pollution sources. We made some explorative research on the lead isotope ratios of Xihu Longjing Tea, soil, atmospheric dust, ore and industrial firing coal in Zhejiang province by MS detection(MAT-261); and the contents of Pb, Cd, Cr, Fe, Mn in tea and soil samples by ICP-MS and ICP-AES detection. Analyze of Influencing Factors on lead content of tea leaf. Investigate the relationship of the tea, soil, industrial firing coal, ores, with lead isotope ratios. And build a contribution rate model of lead pollution source to lead contamination in tea, using the chemical mass balance theory as reference.The results showed that lead isotope ratios of pollution sources were differences and had their respective characteristic. While the ratios of 206Pb/207Pb and 208Pb/207Pb of tea was insignificant in different producing area. Processing had little effect on it. The closer to the downtown, the higher content of Lead presented in tea leaf. The lead content of tea did not correlate significantly with that of soil. And growing leaf were higher than tender leaf. The lead isotope ratios of Xihu LongjingTea located in a overlay area consisting of atmospheric dust, automobile exhaust and industrial coal. Especially the ratios of atmospheric dust were quite the same. It showed that the most important source of tea lead pollution were vehicle tail gas and coal-fired emissions. The pollution way of tea was atmospheric dust not soil. At last we draw the conclusion by the practical study: the method based on lead isotope ratio to trace back the lead pollution in this paper was feasible. The application of chemical mass balance model method for pollution source identification and apportionment in tea was acceptable.Besides, the study on determination of the geographical origin of tea based on FT-IR spectroscopy analysis and pattern recognition Technique aimed to investigate the feasibility of tracing the geographical origin of tea with FT-IR spectroscopy. 28 dried Longjing tea samples from main tea-producing areas of Zhejiang province in China were crushed and sieved.Based on NIR spectroscopy of the pre-processing tea, samples were subjected to principal component analysis (PCA), cluster analysis (CA) ,discriminate analysis (DA). The results showed that obvious spectral differences could be observed of Longjing tea. The difference of Longjing tea from different geographical origins was relatively unconspicuous,whereas recognizable. The near-infrared reflectance spectra of tea are studied by the principal component analysis after mathematical treatment. It was indicated by the results that principle component score of Longjing tea is positive . The analysis on principal component of two different space distribution types expressed the characteristics of the tea samples. However, via a principle component analysis (PCA) disposal of Longjing tea, The characteristics can be defined as the particular features which distinguish Xihu Longjing tea from Zhejiang Longjing tea. And coefficient of variation of characteristic parameters was analyzed to determine dispersion in spatial distribution of Xihu Longjing tea was larger than that of the other cities and counties in Zhejiang province.According to the Euclidean distance of NIR spectroscopy, geographical origin can be identified by cluster analysis. So applying FT-NIR fingerprint spectroscopy to trace geographical origin of tea is accurate, rapid and low cost.
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