Acid RainannonINTRODUCTION: Acid rain is a great problem in our world. It causes fishand plants to die in our waters. As well it causes harm to our own race aswell, because we eat these fish, drink this water and eat these plants. Itis a problem that we must all face together and try to get rid of.
Howeveracid rain on it’s own is not the biggest problem. It cause many otherproblems such as aluminum poisoning. Acid Rain is deadly. WHAT IS ACID RAIN?Acid rain is all the rain, snow, mist etc that falls from the skyonto our planet that contains an unnatural acidic. It is not to beconfused with uncontaminated rain that falls, for that rain is naturallyslightly acidic.
It is caused by today’s industry. When products aremanufactured many chemicals are used to create it. However because of thedifficulty and cost of properly disposing of these products they are oftenemitted into the atmosphere with little or no treatment. The term was first considered to be important about 20 years ago whenscientists in Sweden and Norway first believed that acidic rain may becausing great ecological damage to the planet. The problem was that by thetime that the scientist found the problem it was already very large. Detecting an acid lake is often quite difficult.
A lake does not becomeacid over night. It happens over a period of many years, some timesdecades. The changes are usually to gradual for them to be noticed early. At the beginning of the 20th century most rivers/lakes like the riverTovdal in Norway had not yet begun to die. However by 1926 localinspectors were noticing that many of the lakes were beginning to showsigns of death.
Fish were found dead along the banks of many rivers. Asthe winters ice began to melt off more and more hundreds upon hundredsmore dead fish (trout in particular) were being found. It was at this timethat scientist began to search for the reason. As the scientists continuedto work they found many piles of dead fish, up to 5000 in one pile,further up the river.
Divers were sent in to examine the bottom of therivers. What they found were many more dead fish. Many live and deadspecimens were taken back to labs across Norway. When the live specimenswere examined they were found to have very little sodium in their blood. This is typical a typical symptom of acid poisoning. The acid had enteredthe gills of the fish and poisoned them so that they were unable toextract salt from the water to maintain their bodies sodium levels.
Many scientist said that this acid poising was due to the fact thatit was just after the winter and that all the snow and ice was runningdown into the streams and lakes. They believed that the snow had beenexposed to many natural phenomena that gave the snow it’s high acidcontent. Other scientists were not sure that this theory was correctbecause at the time that the snow was added to the lakes and streams thePh levels would change from around 5. 2 to 4. 6.
They believed that such ahigh jump could not be attributed to natural causes. They believed that itwas due to air pollution. They were right. Since the beginning of theIndustrial revolution in England pollution had been affecting all thetrees,soil and rivers in Europe and North America. However until recently the loses of fish was contained to thesouthern parts of Europe. Because of the constant onslaught of acid rainlakes and rivers began to lose their ability to counter act their affects.
Much of the alkaline elements; such as calcium and limestone; in the soilhad been washed away. It is these lakes that we must be worried about forthey will soon become extinct. A fact that may please fishermen is that in lakes/rivers they tend tocatch older and larger fish. This may please them in the short run howeverthey will soon have to change lakes for the fish supply will die quicklyin these lakes. The problem is that acid causes difficulties the fish’sreproductive system.
Often fish born in acid lakes do not survive for theyare born with birth defects such as twisted and deformed spinal columns. This is a sign that they are unable to extract enough calcium from thewater to fully develop their bone. These young soon die. With nocompetition the older,stronger can grow easily. However there food iscontaminated as well by the acid in the water. Soon they have not enoughfood for themselves and turn to cannibalism.
With only an older populationleft there is no one left to regenerate themselves. Soon the lake dies. By the late 1970s many Norwegian scientists began to suspect that itwas not only the acid in the water that was causing the deaths. They hadproved that most fish could survive in a stream that had up to a 1 unitdifference in PH. After many experiments and research they found thattheir missing link was aluminum.
Aluminum is one of the most common metals on earth. It is stored in acombined form with other elements in the earth. When it is combined itcannot dissolve into the water and harm the fish and plants. However theacid from acid rain can easily dissolve the bond between these elements.
The Aluminum is then dissolved into a more soluble state by the acid. Other metals such as Copper (Cu), iron (Fe) etc can cause such effectsupon the fish as well however it is the aluminum that is the most common. For example: CuO + H2SO4 ———-> CuSO4 + H2OIn this form it is easily absorbed into the water. When it comes incontact with fish it causes irritation to the gills.
In response the fishcreates a film of mucus in the gills to stop this irritation until theirritant is gone. However the aluminum does not go always and the fishcontinues to build up more and more mucus to counteract it. Eventuallythere is so much mucus that it clogs the gills. When this happens the fishcan no longer breath.
It dies and then sinks to the bottom of the lake. Scientists now see acid, aluminum and shortages of calcium as the threedetermining factors in the extinction of fish. As well there is the problem of chlorine. In many parts of the worldit is commonly found in the soil. If it enters the fish’s environment itcan be deadly.
It affects many of the fish’s organisms and causes it todie. As well it interferes in the photosynthesis process in plants. NaOH + HCl —-> NaCl + H2OThe carbon in the water can become very dangerous for fish and plantsin the water if the following reaction happens:CaCO3 + 2HCl —> CaCl2 + H2CO3 thenH2CO3 —> H2O + CO2The salt created by this reaction can kill. It interferes directlywith the fish’s nervous system. Acid lakes are deceivingly beautiful. The are crystal clear and havea luscious carpet of green algae on the bottom.
The reason that theselakes are so clear is because many of the decomposers are dead. Theycannot break down that material such as leaves and dead animals. Thesematerials eventually sink to the bottom instead of going through thenatural process of decomposition. In acid lakes decomposition is veryslow. “The whole metabolism of the lake is slowed down. “During this same period of time the Canadian department of fisheriesspent eight years dumping sulfuric acid (H2SO4) into an Ontario lake tosee the effects of the decrease in the PH over a number of years.
At thePH of 5. 9 the first organisms began to disappear. They were shrimps. Theystarted out at a population of about seven million, but at the pH of 5. 9they were totally wiped out.
Within a year the minnow died because itcould no longer reproduce it’s self. At this time the pH was of 5. 8. New trout were failing to be producedbecause many smaller organisms that served as food to it had been wipedout earlier.
With not enough food the older fish did not have the energyto reproduce. Upon reaching the pH of 5. 1 it was noted that the troutbecame cannibals. It is believed this is due to the fact that the minnowwas nearly extinct.
At a pH of 5. 6 the external skeletons of crayfish softened and theywere soon infected with parasites, and there eggs were destroyed by fungi. When the pH went down to 5. 1 they were almost gone.
By the end of theexperiment none of the major species had survived the trials of the acid. The next experiment conducted by the scientists was to try and bring thelake back to life. They cut in half the amount of acid that they dumped tosimulate a large scale cleanup. Soon again the cuckers and minnows beganto reproduce again. The lake eventually did come back; to a certainextent; back to life.
THE NEW THEORY:A scientist in Norway had a problem believing that it was the acidrain on it’s own that was affecting the lakes in such a deadly way. Thisscientist was Dr Rosenqvist. “Why is it that during heavy rain, the swollen rivers can be up tofifteen times more acid than the rain? It cannot be the rain alone that isdoing it, can it?” Many scientist shunned him for this however they couldnot come up with a better answer. Soon the scientists were forced toaccept this theory. Sulfuric acid is composed of two parts, know as ions. The hydrogenion is what make a substance acid.
The other ion is sulphate. When thereare more hydrogen ions then a substance is acid. It is this sulphate ionthat we are interested in. When the rain causes rivers to overboard ontothe banks the river water passes through the soil. Since the industrialrevolution in britain there has been an increasing amount of sulphur inthe soil.
In the river there is not enough sulphur for the acid to reactin great quantities. However in the soil there is a great collection ofsulphur to aid the reaction. When it joins the water the pH becomes muchlower. This is the most deadly effect of acid rain on our water!!! Thewater itself does not contain enough sulphur to kill off it’s populationof fish and plants.
But with the sulphur in the soil it does. CONCLUSION:Acid rain is a big problem. It causes the death of our lakes, ourrivers, our wild life and most importantly us. As well it causes otherproblems that are very serious as well such as the release of aluminiumand lead into our water supplies.
We are suffering because of it. InScotland there are many birth defects being attributed to it. We must cutdown the releases of chemicals that cause it. But it will take time, evenif we were to stop today we would have the problem for years to comebecause of the build up in the soil. Let’s hope we can do something. BIBLIOGRAPHYPenguin Publishing House, 1987 , Pearce Fred Acid Rain.
What is it andwhat is it doing to us?New York Publishers, 1989, William Stone Acid Rain. Fiend or Foe?Lucent books, Inc. 1990, Steward Gail Acid Rain.
