The spatial distribution pattern of heavy metals and risk assessment of moso bamboo forest soil around lead–zinc mine in Southeastern China

Abstract

Southeast China serves as a vast habitat of moso bamboo situated adjacent to the mining area. Heavy metal contamination of the soils poses a great threat to bamboo plantations in the region. The present study aimed at determination of the heavy metals concentration in mined soils and bamboo shoot, the spatial distribution pattern of heavy metals in soils and the spatial correlations between heavy metal pollution in soils and bamboo shoots, and risk assessment of metals in soil. The soil samples (97) were collected from the study area to assess the status of metal pollution in soils adjacent to bamboo plantations around the mining area of southeast China. The median soil Cd, Cr, Cu, Mn, Pb and Zn concentrations were 0.50mgkg−1, 58.31mgkg−1, 27.89mgkg−1, 405.89mgkg−1, 286.32mgkg−1, 209.53mgkg−1, respectively. Correlation analysis suggested that soil metal species except Cr mostly exceeded the threshold values and accumulated as a result of mining activities. In addition, the mean heavy metals concentrations in moso bamboo rhizome were very low from the study area; the metals could be based on their prevalence as: Zn>Mn>Cu>Pb>Cr>Cd. The spatial statistics and autocorrelation analysis showed that most of the soil heavy metals represented a geographically increasing concentric trend (from the surrounding area to mining center). A low correlation existed between metals concentrations of soil and bamboo shoots. Pb concentrations in bamboo shoots exceeded the standard limits and supposed to have spatial correlation with its concentration in soil. The metal distributions in soil were held responsible for their bioaccumulation in edible portions of vegetables. The risk assessment confirmed that about 60.82% of the study area suffered from metal contamination. The pollution evaluation map provides a reference for the food security and the classification management of bamboo forest.