Total and bioavailable metals in two contrasting mining regions (Sudbury in Canada and Lubumbashi in DR-Congo): relation to genetic variation in plant populations

摘要

Knowledge of total and bioavailable metal contents in soil is important for regional risk assessment and management. The main objective of the present study was to analyse the concentrations of metals in soils in two contrasting mining regions (Sudbury in Canada and Lubumbashi in DR-Congo). Genetic variation of plant populations was investigated to assess the potential impact of metal contamination on forest sustainability. The levels of copper, cobalt, zinc, arsenic, and lead were significantly higher (up to 200-fold) in mining sites in the Lubumbashi compared to the most highly contaminated Sudbury sites. The nickel content in soil samples from Lubumbashi was much lower compared to Sudbury region samples. Only 3.5% and 4 % of total copper and nickel, respectively, were phytoavailable, with values of 6%, 5.7%, 3.6%, and 5.4% for cobalt, magnesium, manganese, and zinc, respectively. There were significant positive correlations between total metal and phytoavailable metal concentrations for copper (r = 0.99), nickel (r = 0.86), cobalt (r = 0.72), strontium (r = 0.71), and zinc (r = 0.66). Although genetic variation was high in Picea glauca populations from the Sudbury region, no association was found between metal contamination levels and genetic variation within and among the P. glauca populations.