Saturday, November 5, 2011


All hell was let loose with the recent news that there is an expected shower of acid rain across the geographical region of Nigeria. The mass media, both electronic and print, the internet, as well as mouth to mouth information have all been awash by stories of a looming bout of acid rain.

In the wake of an SMS which was sent out to a large number of people, informing them of an oncoming acid rain which was misconstrued to cause cancer and death. The full text of the message reads thus:

Be careful from the 20th to 28th of this month, there is possibility of an ACID RAIN. The dark circle appeared around the moon on 17th of last month & this is an indication of Acid Rain. Apparently this happens once in 750yrs. It rains normally but It may cause skin cancer if you expose yourself to it. So ALERT your dear ones. This information is from NASA in the USA. DO NOT neglect. Please forward this to your friends. Better to be cautious than sorry.

Granted, bad news is expected to spread with more voracity and intensity, this explains how and why the current wave of stories about the acid rain has circulated across Nigeria. But some reasonable questions to be asked are: what is an acid rain, and is it a new occurrence? What are the effects of acid rain? How come it is just beginning to take preeminence in the minds of people?

First, let us understand the phenomenon described as acid rain and shed more light on the principles that govern its formation, activation and eventual release.

What is an acid rain?
Acid rain is rain or any other form of precipitation that is unusually acidic, i.e. elevated levels of hydrogen ions (low pH). It can have harmful effects on plants, aquatic animals, and infrastructure through the process of wet deposition. Acid rain is caused by emissions of compounds of ammonium, carbon, nitrogen, and sulfur which react with the water molecules in the atmosphere to produce acids.

What is the history of acid rain?
Since the Industrial Revolution, emissions of sulfur dioxide and nitrogen oxides to the atmosphere have increased. In 1852, Robert Angus Smith was the first to show the relationship between acid rain and atmospheric pollution in Manchester, England. Though acidic rain was discovered in 1852, it was not until the late 1960s that scientists began widely observing and studying the phenomenon. The term "acid rain" was generated in 1972. Canadian Harold Harvey was among the first to research a "dead" lake. Public awareness of acid rain in the U.S increased in the 1970s after the New York Times promulgated reports from the Hubbard Brook Experimental Forest in New Hampshire of the myriad deleterious environmental effects demonstrated to result from it.

What are the effects of acid rain?
Surface waters and aquaticv animals
Both the lower pH and higher aluminium concentrations in surface water that occur as a result of acid rain can cause damage to fish and other aquatic animals. At pHs lower than 5 most fish eggs will not hatch and lower pHs can kill adult fish. As lakes and rivers become more acidic biodiversity is reduced. Acid rain has eliminated insect life and some fish species, including the brook trout in some lakes, streams, and creeks in geographically sensitive areas, such as the Adirondack Mountains of the United States.

Soil biology and chemistry can be seriously damaged by acid rain. Some microbes are unable to tolerate changes to low pHs and are killed. The enzymes of these microbes are denatured (changed in shape so they no longer function) by the acid. The hydronium ions of acid rain also mobilize toxins such as aluminium, and leach away essential nutrients and minerals such as magnesium.

Forests and other vegetation
Adverse effects may be indirectly related to acid rain, like the acid's effects on soil (see above) or high concentration of gaseous precursors to acid rain. High altitude forests are especially vulnerable as they are often surrounded by clouds and fog which are more acidic than rain.

Other plants can also be damaged by acid rain, but the effect on food crops is minimized by the application of lime and fertilizers to replace lost nutrients. In cultivated areas, limestone may also be added to increase the ability of the soil to keep the pH stable, but this tactic is largely unusable in the case of wilderness lands. When calcium is leached from the needles of red spruce, these trees become less cold tolerant and exhibit winter injury and even death.

Human health
Scientists have suggested direct links to human health. Fine particles, a large fraction of which are formed from the same gases as acid rain (sulfur dioxide and nitrogen dioxide), have been shown to cause illness and preature deaths such as cancer and other diseases.

Other adverse effects
Acid rain can also damage buildings and historic monuments, especially those made of rocks such as limestone and marble containing large amounts of calcium carbonate. Acids in the rain react with the calcium compounds in the stones to create gypsum, which then flakes off.

Clearly, it is obvious that the case of the recent alarm oozes out of the thoughts of some mischievous individuals or groups who decided to cash in on the wide gap of illiteracy in the country. Contrary to the contents of the SMS's that have been sent out, “Scientists have suggested direct links to human health.” and cancer have not been directly linked to acid rain.

The simple truth is that as long as we (humans) continue to embarrass mother nature and pollute her with our knack for comfort, we would in turn, be embarrassed by mother nature. Acid rain has been around for a very long time, it is as old as the very first time that we have released ammonium, carbon, nitrogen, and sulfur into the atmosphere.

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