Impact of simulated acid rain on trace metals and aluminum leaching in latosol from Guangdong Province, China
Acid rain is one of the most serious ecological and environmental problems worldwide. This study investigated the impacts of simulated acid rain (SAR) upon leaching of trace metals and aluminum (Al) from a soil. Soil pot leaching experiments were performed to investigate the impacts of SAR at five different pH levels (or treatments) over a 34-day period upon the release of trace metals (i.e., Cu, Ni, Pb, Zn, and Fe) and Al from the Latosol (acidic red soil). The concentrations of trace metals in the effluent increased as the SAR pH level decreased, and were highest at the SAR pH = 2.0. In general, the concentrations of Cu, Pb, Fe, and Al in the effluent increased with leaching time at the SAR pH = 2.0, whereas the concentrations of Zn, Fe, and Al in the effluent decreased with leaching time at the SAR pH¡Ý4.0. The increase in electrical conductivity (EC) with leaching time at five different SAR pH levels was primarily due to the concentrations of Al and Fe in the effluent. There were good linear correlations between the effluent Al concentrations and the effluent pH at the SAR pH = 2.0 (R2 = 0.87) and pH = 3.0 (R2 = 0.83). More soil trace metals and Al were activated and released into the soil solution as the SAR pH level decreased.