Variation of strontium stable isotope ratios and origins of strontium in Japanese vegetables and comparison with Chinese vegetables

To evaluate the utility of ⁸⁷Sr/⁸⁶Sr ratio for determining the geographical provenance of vegetables, we compared ⁸⁷Sr/⁸⁶Sr ratios and Sr concentrations in five vegetable species grown in Japan and China, and we also examined the relationships between ⁸⁷Sr/⁸⁶Sr ratios in vegetables, the soil-exchangeable pool, irrigation water, and fertilizer from 20 Japanese agricultural areas. The vegetable ⁸⁷Sr/⁸⁶Sr ratios in Japan were similar for all species within a given agricultural area, but tended to be low in northeast Japan and high in southwest Japan. The median ⁸⁷Sr/⁸⁶Sr ratio in Japanese vegetables was similar to that in fertilizer, suggesting that in addition to rock-derived Sr, vegetables contain Sr derived from fertilizers. In most cases, the ⁸⁷Sr/⁸⁶Sr ratios for the Japanese and Chinese vegetables differed by approximately 0.710. Linear discriminant analysis using both ⁸⁷Sr/⁸⁶Sr and the Sr concentration allowed more accurate discrimination between vegetables from the two countries.