Acid RainINTRODUCTION: Acid rain is a great problem inour world. It causes fish andplants to die in our waters. As well it causes harm to our own race as well,because we eat these fish, drink this water and eat these plants.
It is aproblem that we must all face together and try to get rid of. However acid rainon it’s own is not the biggest problem. It cause many other problems such asaluminum poisoning. Acid Rain is deadly. WHAT IS ACID RAIN? Acid rain is all the rain, snow, mist etc that falls from the sky onto ourplanet that contains an unnatural acidic.
It is not to be confused withuncontaminated rain that falls, for that rain is naturally slightly acidic. Itis caused by today’s industry. When products are manufactured many chemicals areused to create it. However because of the difficulty and cost of properlydisposing of these products they are often emitted into the atmosphere withlittle 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 be causinggreat ecological damage to the planet. The problem was that by the time that thescientist found the problem it was already very large. Detecting an acid lake isoften quite difficult. A lake does not become acid over night. It happens over aperiod of many years, some times decades.
The changes are usually to gradual forthem 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 local inspectors werenoticing that many of the lakes were beginning to show signs of death. Fish werefound dead along the banks of many rivers. As the winters ice began to melt offmore and more hundreds upon hundreds more dead fish (trout in particular) werebeing found. It was at this time that scientist began to search for the reason.
As the scientists continued to work they found many piles of dead fish, up to5000 in one pile, further up the river. Divers were sent in to examine thebottom of the rivers. What they found were many more dead fish. Many live anddead specimens were taken back to labs across Norway.
When the live specimenswere examined they were found to have very little sodium in their blood. This istypical a typical symptom of acid poisoning. The acid had entered the gills ofthe fish and poisoned them so that they were unable to extract salt from thewater to maintain their bodies sodium levels. Many scientist said that this acid poising was due to the fact that it wasjust after the winter and that all the snow and ice was running down into thestreams and lakes. They believed that the snow had been exposed to many naturalphenomena that gave the snow it’s high acid content.
Other scientists were notsure that this theory was correct because at the time that the snow was added tothe lakes and streams the Ph levels would change from around 5. 2 to 4. 6. Theybelieved that such a high jump could not be attributed to natural causes. Theybelieved that it was due to air pollution.
They were right. Since the beginningof the Industrial 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 the southernparts of Europe. Because of the constant onslaught of acid rain lakes and riversbegan to lose their ability to counter act their affects.
Much of the alkalineelements; such as calcium and limestone; in the soil had been washed away. It isthese lakes that we must be worried about for they will soon become extinct. A fact that may please fishermen is that in lakes/rivers they tend to catcholder and larger fish. This may please them in the short run however they willsoon have to change lakes for the fish supply will die quickly in these lakes. The problem is that acid causes difficulties the fish’s reproductive system.
Often fish born in acid lakes do not survive for they are born with birthdefects such as twisted and deformed spinal columns. This is a sign that theyare unable to extract enough calcium from the water to fully develop their bone. These young soon die. With no competition the older,stronger can grow easily. However there food is contaminated as well by the acid in the water.
Soon theyhave not enough food for themselves and turn to cannibalism. With only an olderpopulation left there is no one left to regenerate themselves. Soon the lakedies. By the late 1970s many Norwegian scientists began to suspect that it wasnot only the acid in the water that was causing the deaths. They had proved thatmost fish could survive in a stream that had up to a 1 unit difference in PH.
After many experiments and research they found that their missing link wasaluminum. 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 it cannotdissolve into the water and harm the fish and plants. However the acid from acidrain can easily dissolve the bond between these elements.
The Aluminum is thendissolved into a more soluble state by the acid. Other metals such as Copper(Cu), iron (Fe) etc can cause such effects upon the fish as well however it isthe aluminum that is the. . .
. . most common. For example: CuO + H2SO4———->CuSO4 + H2OIn this form it is easily absorbed into the water. When it comes in contactwith fish it causes irritation to the gills. In response the fish creates a filmof mucus in the gills to stop this irritation until the irritant is gone.
However the aluminum does not go always and the fish continues to build up moreand more mucus to counteract it. Eventually there is so much mucus that it clogsthe gills. When this happens the fish can no longer breath. It dies and thensinks to the bottom of the lake.
Scientists now see acid, aluminum and shortagesof calcium as the three determining factors in the extinction of fish. As well there is the problem of chlorine. In many parts of the world it iscommonly found in the soil. If it enters the fish’s environment it can be deadly. It affects many of the fish’s organisms and causes it to die.
As well itinterferes in the photosynthesis process in plants. NaOH + HCl —-> NaCl + H2OThe carbon in the water can become very dangerous for fish and plants in thewater if the following reaction happens: CaCO3 + 2HCl —> CaCl2 + H2CO3 then H2CO3 —> H2O + CO2The salt created by this reaction can kill. It interferes directly with thefish’s nervous system. Acid lakes are deceivingly beautiful. The are crystal clear and have aluscious carpet of green algae on the bottom. The reason that these lakes are soclear is because many of the decomposers are dead.
They cannot break down thatmaterial such as leaves and dead animals. These materials eventually sink to thebottom instead of going through the natural process of decomposition. In acidlakes decomposition is very slow. “The whole metabolism of the lake is sloweddown. ” During this same period of time the Canadian department of fisheries spenteight years dumping sulfuric acid (H2SO4) into an Ontario lake to see theeffects of the decrease in the PH over a number of years.
At the PH of 5. 9 thefirst organisms began to disappear. They were shrimps. They started out at apopulation of about seven million, but at the pH of 5.
9 they were totally wipedout. Within a year the minnow died because it could no longer reproduce it’sself. 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 wiped outearlier. With not enough food the older fish did not have the energy toreproduce.
Upon reaching the pH of 5. 1 it was noted that the trout becamecannibals. It is believed this is due to the fact that the minnow was nearlyextinct. At a pH of 5. 6 the external skeletons of crayfish softened and they weresoon infected with parasites, and there eggs were destroyed by fungi.
When thepH went down to 5. 1 they were almost gone. By the end of the experiment none ofthe major species had survived the trials of the acid. The next experimentconducted by the scientists was to try and bring the lake back to life.
They cutin half the amount of acid that they dumped to simulate a large scale cleanup. Soon again the cuckers and minnows began to reproduce again. The lake eventuallydid come back; to a certain extent; back to life. THE NEW THEORY: A scientist in Norway had a problem believing that it was the acid rain onit’s own that was affecting the lakes in such a deadly way. This scientist wasDr Rosenqvist.
“Why is it that during heavy rain, the swollen rivers can be up to fifteentimes more acid than the rain? It cannot be the rain alone that is doing it, canit?” Many scientist shunned him for this however they could not come up with abetter answer. Soon the scientists were forced to accept this theory. Sulfuric acid is composed of two parts, know as ions. The hydrogen ion iswhat make a substance acid. The other ion is sulphate. When there are morehydrogen ions then a substance is acid.
It is this sulphate ion that we areinterested in. When the rain causes rivers to overboard onto the banks the riverwater passes through the soil. Since the industrial revolution in britain therehas been an increasing amount of sulphur in the soil. In the river there is notenough sulphur for the acid to react in great quantities. However in the soilthere is a great collection of sulphur to aid the reaction.
When it joins thewater the pH becomes much lower. This is the most deadly effect of acid rain onour water!!! The water itself does not contain enough sulphur to kill off it’spopulation of 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, our rivers, ourwild life and most importantly us.
As well it causes other problems that arevery serious as well such as the release of aluminium and lead into our watersupplies. We are suffering because of it. In Scotland there are many birthdefects being attributed to it. We must cut down the releases of chemicals thatcause it. But it will take time, even if we were to stop today we would have theproblem for years to come because of the build up in the soil.
Let’s hope we cando something. BIBLIOGRAPHYPenguin Publishing House, 1987 , Pearce Fred Acid Rain. What is it andwhat is it doing to us?