Transfer of cadmium and lead from soil to mangoes in an uncontaminated area, Hainan Island, China

Abstract

Exposure to toxic metals from fruits is an important pathway of human exposure to soil pollutants, but few researches on metals accumulation in the soil–fruit system were performed. In this study, we conducted a systemic survey of Cd and Pb accumulations in the soil–mango ( Mangifera indica L.) system from an uncontaminated area, Hainan Island, China. Results indicated that concentrations of Cd and Pb in the soil were controlled by the parent materials, with concentrations ranging from 0.019–0.21 μg g − 1 for Cd and 8–63 μg g − 1 for Pb in total and from 0.003–0.059 μg g − 1 for Cd and 0.8–7.0 μg g − 1 for Pb in labile fractions, respectively. The concentrations of Cd and Pb in the mango fruits showed ranges of 0.3–4.2 and 0.8–209 ng g − 1 (FW), respectively, which varied significantly between cultivars. The transfer factors (TFs) of metals from soil to fruit showed significant differences between cultivars, from 0.01 to 0.025 for Cd and from 0.001 to 0.0019 for Pb. The ANOVA and correlation analyses indicated that the variations of metal in the fruit depended on the difference of cultivars, while the variations of metal concentrations within cultivar were controlled, to some extent, by the soil metal levels. Our finding suggests that the use of the individual cultivar to assess the soil metal bioavailability or metal transfer ability from soil to plant may be more precise than the use of different cultivars. Quantitative chemical analysis was performed using flame or graphite furnace atomic absorption spectroscopy.