By Henrylito D. Tacio
A day after an 8.9-magnitude earthquake and tsunami struck Japan, the Fukushima power station exploded. Warnings of radioactive clouds and acid rains were circulated through text messages.
Government officials immediately stamped down the public’s fears. The Philippine Atmospheric Geophysical and Astronomical Services Administration (PAGASA) said there was no basis for such claims.
“The winds from Japan are moving away from us. It’s not true that these winds contain acid rain,” PAGASA forecaster Aldczar Aurelio said in an interview on dzBB radio
A bulletin, which was released after a second explosion at the Fukushima plant, gave this assurance: “Based on (our) monitoring, there has been no increase in the levels of radioactivity since the time of the Fukushima event.”
Acidic rain was discovered in 1853 but it was not until the late 1960s that scientists started widely observing and studying the phenomenon. In 1872, the term “acid rain” was coined by Robert Angus Smith.
Acid rain was first reported in the Scandinavian countries, then in the northeastern United States and southeastern Canada, and finally in northern Europe. In subsequent years, it became apparent in Japan, Taiwan, and China and in some parts of Southeast Asia.
Public awareness of acid rain in the United States increased in the 1970s after The New York Times published reports from the Hubbard Brook Experimental Forest in New Hampshire of the myriad deleterious environmental effects shown to result from it.
Asia is not spared from it. A report released by the Washington, D.C.-based World Resources Institute (WRI) in 2001, pointed out: “The dimensions of the acid rain problem are growing rapidly in Asia, with sulfur dioxide emissions expected to as much as triple from 1990 levels by 2010 if current trends continue.”
Acid rains refers to all types of precipitation — rain, snow, sleet, hail, fog — that is acidic in nature. Acidic means that these forms of water have a pH lower than the average 5.6 average in rainwater.
Science tells us that the acid in acid rain comes from two kinds of air pollutants — sulphur dioxide and nitrogen oxides. These are emitted primarily from utility and smelter “smoke stacks” and automobile, truck and bus exhausts, but they also come from burning wood. When these pollutants reach the atmosphere, they undergo chemical reactions.
“The sulphur dioxide is oxidized to sulphur trioxide, which then dissolves in water droplets to form sulfuric acid,” explain Penelope ReVelle and Charles ReVelle, authors of The Environment: Issues and Choices for Society. “Nitric oxide is oxidized to nitrogen dioxide, which dissolves in water droplets to form nitric acid.”
These two acids — sulfuric acid and nitric acid — as well as salts of these acids are responsible for acid rain. The more of these acids that are present in the atmosphere, the more acidic the rainwater becomes.
Wikipedia says the principal cause of acid rain is sulfur and nitrogen compounds coming from human sources. These include electricity generation, factories, and motor vehicles. “Electrical power complexes utilizing coal are among the greatest contributors to gaseous pollutions that are responsible for acidic rain,” it says. “The gases can be carried hundreds of kilometers in the atmosphere before they are converted to acids and deposited.”
Acid rain affects lakes, streams, rivers, bays, ponds and other bodies of water by increasing their acidity until fish and other aquatic creatures can no longer liver. In Sweden, Norway, and eastern North America, commercial and sport fishing have suffered as fish populations have declined or disappeared.
According to a handbook for journalists, Reporting on the Environment, aquatic plants grow best between pH 7.0 and 9.2. As acidity increases, submerged aquatic plants decrease, depriving waterfowl of their basic food sources. At pH 6.0, freshwater shrimp cannot survive. At pH 5.5, bottom-dwelling bacterial decomposers begin to die and leave undecomposed leaf-litter and other organic debris to collect on the bottom.
“This deprives plankton — tiny creatures that form the base of the aquatic food chain — of food, so that they too disappear. Below a pH of about 4.5, all fish die,” the handbook points out.
Acid rain harms more than aquatic life. It also harms vegetation. The great forests of Germany and elsewhere in Western Europe, for instance, are believed to be dying because of acid rain. Scientists believe that acid rain damages the protective waxy coating of leaves and allows acids to diffuse into them, which interrupts the evaporation of water and gas exchange so that the plant no longer can breathe.
“This stops the plant’s conversion of nutrients and water into a form useful for plant growth and affects crop yields,” the handbook says.
Perhaps the most important effects of acid rain on forests may result from nutrient leaching, accumulation of toxic metals and the release of toxic aluminum. Nutrient leaching occurs when acid rain adds hydrogen ions to the soil, which interact chemically with existing minerals. This displaces calcium, magnesium and potassium from soil particles and deprives trees of nutrition.
Toxic metals such as lead, zinc, copper, chromium, and aluminum are deposited in the forest from the atmosphere. The acid rain releases these metals and they stunt the growth of trees and other plants and also that of mosses, algae, nitrogen-fixing bacteria and fungi needed for forest growth.
Directly, acid rain does not affect human health. The acid in the rainwater is too dilute to have direct adverse effects. “However, the particulates responsible for acid rain (sulfur dioxide and nitrogen oxides) do have an adverse effect. Increased amounts of fine particulate matter in the air do contribute to heart and lung problems including asthma and bronchitis,” notes the US Environmental Protection Agency.
Unknowingly, acid rain can damage buildings, historic monuments, and statues, especially those made of rocks, such as limestone and marble, that contain large amounts of calcium carbonate. Acids in the rain react with the calcium compounds in the stones to create gypsum, which then flakes off.
Acid rain has no respect for boundaries of states or nations. Great Britain and northern Europe export acid rain to Sweden and Norway. Emissions in the United States contribute to acid rain in Canada, and Canada donates emissions that produce acid rain in the United States.
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