Assessment of Acid Rain on Leaching of Elements from Delaware Soils Into Groundwater

摘要

The effects of acid rain on the kinetics of elemental release from three major Delaware soil types were investigated. All three soils contained low clay and organic matter contents which would indicate rather low buffering capacities. The kinetics of elemental release were evaluated by leaching the soils with simulated acid rain at pH levels of 2.5, 3.4, 4.8, and 5.6. Leachates were collected until an apparent equilibrium in elemental release was obtained. In all soils and at all acid rain pH levels, quantities of basic elemental release were in the order Ca K Mg Na. The amount of heavy metals and Si release were very low. As the pH of the acid rain decreased, the total quatity of each released element increased. In all cases, a rapid initial release of each element was followed by slower release rates. The kinetics of A1 release were characterized by a similar time trend.