利用土壤Sr-Pb同位素差异性判别山药原产地研究

Application of Sr-Pb Isotopic Difference of Soils in Yam Origin Identification

为研究利用土壤Sr-Pb同位素差异性判别山药原产地的可行性,以山药表面附着土壤为对象,将其划分为5组,采用热电离质谱(TIMS)测定土壤和部分山药的Sr-Pb同位素比率,结合统计分析,进行山药产地判别研究。结果表明,采自于不同地域的I组和II组土壤样品Sr-Pb同位素差异不显著(P>0.05),表明其可能有共同的物质来源。两组样品采样地点均临近黄河,沙化严重,且均具有与黄河沉积物相似的同位素特征,I组、II组土壤样品都可能来源于黄河的沉积,应归为一类。不同产地土壤中Sr-Pb同位素差异显著(P<0.01),其中I组和II组土壤具有低的^(87)Sr/^(86)Sr比值(0.715195~0.715623);III组同时具有高的^(87)Sr/^(86)Sr比值(0.717906~0.718594)和高的^(206)Pb/^(204)Pb(18.643~18.765)、^(207)Pb/^(204)Pb比值(15.649~15.689);IV组同时具有中等的^(87)Sr/^(86)Sr比值(0.716004~0.716747)和中等的^(206)Pb/^(204)Pb(18.642~18.700)、^(207)Pb/^(204)Pb比值(15.634~15.650);V组具有较高的^(87)Sr/^(86)Sr比值(0.716081~0.718581)和最低的^(206)Pb/^(204)Pb(18.504~18.638)、^(207)Pb/^(204)Pb比值(15.572~15.614)。利用该差异可有效判别山药的原产地,产地判别准确率达到94.1%。本研究丰富了农产品原产地溯源判别体系。

The aim of this work was to investigate the feasibility to trace geographical locations yam with the difference of Sr-Pb isotope in soils. The isotope ratios in the soil and partial yam samples were determined with thermal ionization mass spectrometer（ TIMS）. Statistical analysis was employed for geographical origin discrimination. The different soil samples were divided into five groups. The results showed that there was no significant differences between I and II groups of soil samples from different regions（ P 0. 05）. In addition,both groups of soil samples were collected at desertification serious areas close to the Yellow River,indicating the first two groups maybe from the same origin of the Yellow River sediment and should be bracketed together. Significant isotopic differences were found among different groups of soil samples（ P 0. 01） ： groups I and II have the lowest ^（87）Sr/^（86）Sr ratios ranging from 0. 715195 to 0. 715623.Group III had the highest ^（87）Sr/^（86）Sr ratios ranging from 0. 717906 to 0. 718594,the highest^（206）Pb/^（204）Pb ratios ranging from 18. 643 to 18. 765 and the highest ^（207）Pb/^（204）Pb ratios ranging from 15. 649 to 15. 689. Group IV had moderate ratios of ^（87）Sr/^（86）Sr,^（206）Pb/^（204）Pb and^（207）Pb/^（204）Pb with ranges 0. 716004-0. 716747,18. 642-18. 700 and 15. 634-15. 650,respectively. Group V had relatively high ^（87）Sr/^（86）Sr ratios ranging from 0. 716081 to 0. 718581,the lowest ratios of^（206）Pb/^（204）Pb（18. 504-18. 638） and ^（207）Pb/^（204）Pb（ 15. 572-15. 614）. The growing regions of Chinese yam can be effectively distinguished based on the isotopic difference with accuracy up to 94. 1%,This research enriched the geographical origin traceability system of agricultural products.