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This project arose from news in the media about the damage that acid rain can do to the environment.
As well as acidifying waterways, killing trees and plants and eroding buildings, acid rain leaches heavy metals from soil and rocks and reacts with metals used in buildings. When the metal ions get into waterways and into potable water and move up the food chain, they can cause health problems in humans such as kidney damage. Acidification also affects the human nervous system (implicated in Parkinson’s disease), respiratory system and digestive system.
Acid rain is mainly a mixture of sulfuric and nitric acids depending upon the relative quantities of oxides of sulfur and nitrogen emissions. Due to the interaction of these acids with other constituents of the atmosphere, hydrogen ions are released causing an increase in the soil acidity.
This project investigates firstly, the effect of simulated acid rain on heavy metals that are used structurally and secondly, the effect of acid rain on leaching metal ions from soil.
There were 2 parts to the project, (i) metals were exposed to simulated acid rain for ten minutes and (ii) simulated acid rain (SAR) was pumped through columns of artificially contaminated soil.
We found that the SAR affected all the metals tested and that it leached ions from the soil. These results have serious implications for construction and the addition of nutrients to the soil (fertilisers).
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