Acid rain is perhaps the most well-known and recognizable form of pollution that is affecting the world today. Acidity is measured using a pH scale with 7 being neutral. So anything below 7 is considered to be acidic. but as far as acid rain goes. the baseline for identifying acid rain is generally below the pH level of 5.6. But there have been many debates over this value and many scientists believe that it should be closer to a pH of 7. So any precipitation that has a pH value of less than 5.6 is considered to be acid precipitation. Readings of pH 2.4 as acidic as vinegar were recorded during storms in New England and during one particular acid rain storm the paint was actually stripped of a car and left it ruined. One of the main causes of acid rain is sulfur dioxide there are natural sources that emit sulfur dioxide like volcanoes sea spray rotting vegetation. and plankton.
But the burning of fossil fuels. such as oil and coal. are blamed for approximately half of the emissions oi this gas in the world. When sulfur dioxide reaches the atmosphere. it oxidizes to form a sulfate ion and it then becomes sulfuric acid as it joins With hydrogen atoms in the air as it falls back down to earth. The oxidation occurs the most in clouds and especially in heavily polluted air where other compounds such as ammonia and ozone to catalyze the reaction. converting more sulfuric dioxide to sulfuric acid. The equations below are the stoichiometric equation for the formation of sulfuric acid. The charts below indicate the pH levels of wet deposition over time at the proVinces in Canada. Accompanied with it are charts of emissions over time in Canada compared with the United States. One of the most serious impacts of acid rain is on forests and soils, Great damage is done when sulfuric acid falls onto the earth as rain.
It washes away all the nutrients in the soil and aluminum that is present in the soil is freed and this toxic element can be absorbed by the roots of trees and thus be deprived of vital nutrients and die. But not all sulfur dioxide is converted to sulfuric acid on the way back down to earth. In fact. a substantial amount can float into the atmosphere. move over to another area and return to the soil unconverted. As the gas returns to the land. it clogs up the stomata of leaves, and thus stopping photosynthesis. It is also thought that severe frosts may further aggravate the acid rain problem. With sulfur dioxide. ammonia. and ozone present in the air. the ability for trees to deal With frost is reduced dramatically. Ammonia oxidizes With sulfur dioxide to form ammonium sulfate and this product forms on the surface of trees. When the ammonium sulfate reaches the soils. it reacts to form both sulfuric and nitric acid.
These conditions Will stimulate the growth of fungi and pests like the ambrosia beetle that will kill the tree and effect the forests. The effects of acid rain on the trees and soil of the earth are profound and have to be stopped to save the forests. Perhaps the most damaging effect of acid rain is its direct effect on lakes and aquatic ecosystems. There are several ways through which acidic chemicals can enter the lake. Some chemical substances exist ol dry particles in the air while others enter the lakes as wet particles such as rain. sleet. snow. hail, dew or fog. Another harmful way in which acids can enter a lake is called spring acid shockt When snow melts during the spring thaw. it releases its chemicals and acids into the son and then the melted snow runs off to streams and rivers and gradually makes its way to the lakes.
This sudden drastic change in the pH levels of the water gives the aquatic ecosystem no time to adjust and thus causes great damage. The aquatic Wildlife is especially vulnerable because it is when most are laying eggs. causing death and deformities in the young. The fish in lakes can be affected by sulfuric acid in two ways: directly and indirectly. Sulfuric acid directly interferes with the fish 5 ability to take in oxygen. salt and nutrients needed to live. Acid molecules in the water cause a mucus to build up in the fishes gills and thus hampering their oxygen intake. A low pH level Will also throw off the balance of salts and minerals In the fishes tissue. Salt levels of some fish can not be maintained due to the pH level. This results in poor reproduction by effecting the strength of the eggs they lay Decreased Ca+2 levels also result in weak spines and deformities.
That is a few ways that acid rain can directly affect the lakes and aquatic Wildlife. Sulfuric acid can affect lakes and aquatic ecosystems in indirect ways. It releases heavy metals present in soils to be dissociated and released, For example Al+2 is harmless as part of a compound. but because acid rain causes AI+2 to be released into the soils and gradually into the lakes and becoming lethal to the health of fish. So some fish can survive in water that has a pH level of below 5, but it all depends on the levels of other harmful substances like Al+2 and mercury in the water. In 1976, scientists did a study on a lake called lake 223. They monitored the pH levels of the water and noted that as the pH level went up over the years, a number of species of crustaceans died out. At a pH of 5,6‘ algae growth almost ceased and a great number of it all died out. Finally in 1983 the pH level went down to 5 and all that was left in the lake were thin, deformed adult fish that no longer had the capability of reproducing. This study shows how much damage acid rain does Below is a chart that shows the effects that certain pH levels have on a lake and its wildlife.
Believe it or not, acid rain has a big effect on the way humans live their lives. The main serious side effect that acid rain has on humans is respiratory problems. The 502 and N02 emissions give rise to respiratory problems such as asthma, dry coughs, headaches and eye irritation. An indirect effect of acid rain on humans is that the toxic metals dissolved in the water are absorbed in fruits. vegetables and tissues of animals. Aluminum and mercury found in the tissues of animals such as fish can be extremely harmful to humans and can cause serious health problems. There really isn t a solution that will stop acid rain dead in it 5 tracks, but there are several things we can do to slow it s harmful effects down. The slowrng down of burning fossil fuels would be a good start. We need to find some alternative ways to get energy, so we won t have to use so much fossil fuels and thus slow down the release of 502 into the air.
We also have to find ways to reduce the emissions that car exhausts release into the air because that is a major source for 502. There really isn t any direct solution to stopping acid rain, so for now we have to concentrate on reducing our 302 emissions into the air. In conclusion, it is obvious that we need to do something to try and stop or slow the effects of acid rain on the earth. The lakes trees and soils are all being damaged by acid rain and it is starting to affect humans and the earth in major ways. We have to wake up and try find a solution to the acid rain dilemma because we have to save the earth. The earth is in dire trouble and by stopping or slowing acid rain, we can take a large step towards preserving our home.
