Effects of Soil Erosion of Accumulative Soil on the Migration of Heavy Metals in Dabaoshan Mining Area, Guangdong Province

The characteristics of soil and water loss and migration of heavy metals in accumulative soils with different ages in the Dabaoshan mining area of Guangdong were studied using in situ runoff experiments. The results show that:(1) The runoff of new spoil, old spoil, and natural soil all increased with time. The average runoff at 20 min was 6.52, 5.75 and 0.69 L·min^-1, respectively. For the same time period, the average runoff of the new spoil and old spoil soils were much higher than those of natural soils; (2) The sediment concentration and rate of sediment yield of the new spoil and old spoils were higher than natural soils. The average sediment concentrations of new spoil soil and old spoil soil were 156.79 and 51.68 g·L^-1, respectively, and the average rates of sediment yield were 0.99 and 0.27 kg·min^-1, respectively. (3) The average contents of Cd in new spoil and old spoil soil erosion sediments were 11.43 and 11.20 times of that in natural soils, respectively, and the average loss rates were 361.67 and 135.33 times of that in natural soils, respectively; The average content and loss rate of heavy metals in the erosion soil of new spoil and old spoil were much higher than those in natural soil, and there was obvious "initial flushing" effect; The migration patterns of Pb, Zn, and Cu were similar to Cd; (4) There was a significant positive correlation between Cd, Pb, Zn and Cu content in runoff sediments and runoff. The loss rate of heavy metals was significantly positively correlated with runoff sediment content and sediment production rate. Runoff and sediment loss have a significant impact on the migration of heavy metals.