Uptake from soil and distribution of ⁹⁵Zr in Chinese cabbage

Abstract

In order to quantify the radiation hazard to humans through food, both migration and distribution of ⁹⁵Zr in Chinese cabbage/soil system were examined by using the radioisotope tracer technique. When ⁹⁵Zr was administered with simulated irrigation or simulated rainfall, ⁹⁵Zr was detected in every part of Chinese cabbage, which indicated that ⁹⁵Zr could be translocated to above-ground parts. Although concentrations of ⁹⁵Zr in different parts of Chinese cabbage were different in the two treatments used in the present study, the patterns of ⁹⁵Zr distribution in different parts of the plant were similar. Concentration of ⁹⁵Zr in each part of Chinese cabbage followed the order of root>leaf>lower part of petiole>upper part of petiole>bud in the case of simulated irrigation. Moreover, the ⁹⁵Zr could be accumulated in leaves after being taken up by roots. In the simulated irrigation treatment, ⁹⁵Zr concentrations were 1·7 and 2·9 times higher in the leaf than in the petiole and bud, respectively. In the case of simulated rainfall, a portion of applied ⁹⁵Zr precipitated on the above-ground parts of Chinese cabbage, which led to a higher concentration here than in the case of simulated irrigation. The results of the present study clearly indicate that there is a distinct possibility that foodstuffs produced in the ⁹⁵Zr-contaminated area are radioactively contaminated. More than 90% of total ⁹⁵Zr in soil was retained in the upper layer (0–8 cm), which indicated ⁹⁵Zr could not easily move downwards because of strong adsorption to soil.