Effects of sulfur dioxide pollution on the translocation and accumulation of heavy metals in soybean grain

Background: Open-top chambers were used to study the impact of simultaneous exposure to atmospheric SO2 pollution and heavy metal contamination in soils on the metal contents and productivity of soybean plant. Methods: Plants were exposed at ambient levels as control SO2 (1.2 ppb), low SO2 (97 ppb), and high SO2 (490 ppb) over the whole growing season while simultaneously being exposed to either Cd (0.5 mg kg-1), Pb (250 mg kg-1), Cu (100 mg kg-1), or Zn (150 mg kg-1) in soil. Results: This experimental study covering the whole growth season has shown that SO2 has a synergistic effect in enhancing the heavy metal contents in aboveground tissues of soybean plant, and the effects of high SO2 treatment were found to be highly significant, showing increases of 42% and 29% for Cu and Cd content of grain, respectively. Conclusion: The research findings are of practical significance in the environmental control for the combined pollution of air and soil to ensure the quality of agricultural products and therefore benefits for human health