3. Impact of acid deposition 

There are many reasons why we consider acid deposition as one of the most serious environmental problems facing developed as well as developing countries today. How does acid deposition affect our ecosystem? In Europe and North America, the environmental effects are already well documented whereas in our region, there is a need for more studies focusing on the tropical ecosystem. Let us look at some of the impacts. 

Impacts on Human Health 

In extreme cases, high levels of acid in the air cause skin problems and eye irritations. Chemical reactions occur between acids and alkaline substances in the atmosphere to form compounds which, when inhaled, can affect human health. One of these compounds is ammonium sulphate, which is produced in large quantities during large-scale biomass burning events. When inhaled at high concentrations, these compounds are found to aggravate respiratory related problems in sensitive groups. The highly hygroscopic nature of ammonium sulphate allows it to absorb moisture under humid conditions resulting in a reduction of visibility or hazy conditions.   

The biggest problem associated with acidic water is that it dissolves metals from both soil and water pipes. In Sweden, wells impacted by acidified groundwater contain more corrosive water with elevated levels of potentially harmful metals, particularly copper and aluminium. The effect from drinking the such acidified water is still a subject of debate among experts, but there is no doubt that consuming high levels of copper, iron, zinc an cadmium from pipes can be harmful to our health.

Impacts on Aquatic Life 

Acidification affects the ecosystem balance in lakes and rivers. Most species of aquatic animals, insects, plants and micro-organisms cannot tolerate large changes in acidity and their population are reduced when acidity increases. Eventually the species may be wiped out in very acidified waters. Aquatic insects, animals and plant plankton are amongst the most sensitive and they experience large decline in numbers in acid waters. Frogs and toads suffer reproduction disorders. On the other hand, mosses and some species of algae are known to thrive in acid waters.  

Some sensitive fish species are unable to tolerate slight increases of acidity while others are killed due to aluminium poisoning, a consequence of acidification. In the Scandinavian countries several fish species including Atlantic salmon and brown trout, disappeared after rivers and lakes become acidic. Snow with acidic substances deposited during the very cold winters common in Scandinavian and North American countries rapidly melt in spring. Salmon spawn in autumn and their fry normally remain in the rivers where they are born for about half a year until spring. Many salmon fry do not survive the acid surge associated with the snow-melting season.

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