1. A PRESENTATION ON ACID RAIN AND AQUATIC ORGANISMS BY UWAMOSE OSAIGBOKAN MARTINS CHIEF LIBRARIAN DEPARTMENT OF ANIMAL AND ENVIRONMENTAL BIOLOGY, DELTA STATE UNIVERSITY, ABRAKA. MARCH, 2014 1

2. INTRODUCTION Acid rain was first reported in Manchester, England, which was an important city during the Industrial Revolution. The term acid rain was first used by Robert Angus Smith in 1872. Acid rain is a phenomenon that results from industrial activities where sulfuric and nitric acids are produced by the release of sulfuric oxides (SOx) and nitrogen oxides (NOx) into the atmosphere. This induces the acidification of inland waters which results in damage to aquatic ecosystems, including fish. Acid rain flows into streams, lakes, and marshes after falling on forests, fields, buildings, and roads. It also falls directly on aquatic habitats. According to the US energy information administration, CO2 emissions from Nigerian gas flaring was about 42.71 million metric tonnes in 1980 but reduced to 34.38 million metric tonnes in 2002. 2 3. Fig. 1. CO2 Emissions from Nigerian Gas Flaring, 1980-2002 Source: US Energy Information Adminisrtation 3 4. CAUSES Acid rain occurs when sulphur dioxide and nitrogen oxides are emitted into the atmosphere, which then undergo chemical transformations and are absorbed by water droplets in clouds. The droplets then fall to earth as rain, or snow. This can increase the acidity of the soil, and affect the chemical balance of lakes and streams. This sulphur and nitrogen compounds which are the principal cause of acid rain arise from human sources such as electricity generation, burning of any fuel that contains sulfur and nitrogen compounds, including public utilities, industrial broilers, motor vehicles, and chemical plants. These gases can be carried hundreds of miles in the atmosphere before they are converted to acids and deposited (Satake et al., 1995). 4 5. Fig. 2. Emissions of sulphur dioxide and nitrogen oxides 5 6. Fig. 3. View of Agip gas flares at Ebocha, Rivers State, Nigeria. Source: Google images 6 7. MEASUREMENT OF ACID RAIN Acid rain is measured using a scale called "pH." The term "pH" was originally derived from the French term "pouvoir hydrogne," which means "hydrogen power" in English. the pH scales ranges from 1-14. The lower a substance's pH, the more acidic it is. Normal rain is slightly acidic because carbon dioxide dissolves into it, so it has a pH of about 5.5. Very high (greater than 9.5) or very low (less than 4.5) pH values are unsuitable for most aquatic organisms. Young fish and immature stages of aquatic insects are extremely sensitive to pH levels below 5 and may die at these low pH values. High pH levels (9-14) can harm fish by denaturing cellular membranes (Leivested and Muniz 1976). 7 8. Fig. 4. A scientist testing pH levels of water. 8 9. EFFECTS Acid rain causes acidification of lakes and streams and contributes to damage of trees at high elevations and many sensitive forest soils. In addition, acid rain accelerates the decay of building materials and paints, including irreplaceable buildings, statues, and sculptures that are part of our nation's cultural heritage. Acid deposition penetrates deeply into the fabric of an ecosystem, changing the chemistry of the soil as well as the chemistry of the streams and narrowing sometimes to nothing, the space where certain plants and animals can survive. Because there are so many changes, it takes many years for ecosystems to recover from acid deposition, even after emissions are reduced and the rain becomes normal again. 9 10. 10 Fig. 5. Acid rain effect on statues Source: Google images 11. How it Affect Aquatic Organisms Acid rain causes a cascade of effects that harm or kill aquatic organisms, reduce population numbers, completely eliminate organisms species from a water body, and decrease biodiversity. Not all aquatic organisms can tolerate the same amount of acid in water, for example, frogs can tolerate water that is more acidic (i.e., has a lower pH) than trout. Others, however, are acid-sensitive and will be lost as the pH declines. Generally, the young of most species are more sensitive to environmental conditions than adults. At pH 5, most fish eggs cannot hatch while at lower pH levels, some adult fish die. Lakes that have are very acidic and have no aquatic organisms are called dead lakes. 11 12. 12 Fig. 6. Fish killed by acid rain Source: Google images 13. 13 Fig. 7. Summary of the effects of water acidification on physiology and behaviour of fish. Source: Ikuta et al. 1997 14. How Does Acid Rain Affect Ecosystems The plants and animals living within an ecosystem are highly interdependent. For example, frogs may tolerate relatively high levels of acidity, but if they eat insects like the mayfly, they may be affected because part of their food supply may disappear. Because of the connections between the many fish, plants, and other organisms living in an aquatic ecosystem, changes in pH or aluminum levels affect biodiversity as well. Thus, as lakes and streams become more acidic, the numbers and types of fish and other aquatic plants and animals that live in these waters decrease. And because there are so many changes, it takes many years for ecosystems to recover from acid deposition, even after emissions are reduced and the rain becomes normal again (Ikuta et al., 1999) 14 15. 15 Fig. 8. Chart showing the different levels of pH toleration of aquatic organisms Source: Google images 16. REDUCING THE HARMFUL EFFECTS Awareness is being generated among the masses worldwide about acid rain and its harmful effects. The following are a few steps that could be taken in this regard to reduce, or even eliminate, the acid deposition problem. Use of alternative energy sources The use of other sources of electricity besides fossil fuels such as nuclear power, hydropower, wind energy, geothermal energy, and solar energy can help to reduce the emissions of sulphur dioxide and nitrogen oxides. Also the use of alternative energies available to power automobiles, including natural gas powered vehicles, battery- powered cars, fuel cells, and combinations of alternative and gasoline powered vehicles. 16 17. REDUCING THE HARMFUL EFFECTS (cont.) Clean up smokestacks and exhaust pipes Another option for reducing SO2 emissions, involves using coal containing less sulfur, washing the coal, and using devices called scrubbers to chemically remove the SO2 from the gases leaving the smokestack. Power plants can also switch fuels using technologies that don't burn fossil fuels; for example burning natural gas creates much less SO2 than burning coal. Liming Limestone or lime (a naturally-occurring basic compound) can be added to acidic lakes to "cancel out" the acidity. It tends to be expensive and is considered a short-term remedy because it has to be done repeatedly to keep the water from returning to its acidic condition. Other options is the actions taken by individuals; since energy production causes the largest portion of the acid deposition problem, individuals are advised to conserve energy. 17 18. Prevention of Acid rain is very important for the future of our environment. Since acid rain is caused mainly by the emission of sulphur dioxide from coal-fired power plants. There are a number of preventions, including: switching fuel sources to natural gas, oil, or renewable energy sources; switching to low-sulphur coal; removing the sulphur from the coal before burning; using fluidised-bed combustion processes to burn the coal; and removing the sulphur from the smoke stack after combustion through the installation of pollution control equipment. Other prevention methods are catalytic converters, road traffic restrictions, and equalising acidity in affected water systems by using powdered limestone and reduction in the sulphur content of fuels. Things you could do in the community to prevent are protest against the use of coal fire in industry, walking more and driving less, buy fuel efficient cars or alternative fuel powered vehicles and head community campaigns promoting awareness of the issue. 18 PREVENTION 19. CONCLUSION Acid rain, which is a broad term used to describe several ways in which acids fall out of the atmosphere is an environmental problem that affects not only aquatic organisms but also humans and the ecosystem in general. However like many other environmental problems, acid deposition is caused by the cumulative actions of millions of individual people. Therefore, each individual can also reduce their contribution to the problem and become part of the solution. Individuals can reduce the problem directly by conserving energy, since energy production causes the largest portion of the acid deposition problem. 19 20. THANK YOU FOR YOUR TIME 20