Environmental Science Issues - Essay Example

UNIT 4 – ASSIGNMENT CHAPTER 14 The three major rock types are – igneous, metamorphic and sedimentary. The rock cycle illustrates how rocks are formed, broken down or altered to other rock types due to crystallization, action of heat and pressure, erosion and compaction. Sedimentary rocks due to heat and pressure get converted to metamorphic rocks. These rocks melt to form molten lava which is spewed out during volcanic eruptions as magma. When magma crystallizes it forms igneous rocks. Igneous rocks on weathering or due to erosion and deposition form sediments. These sediments are compacted and cemented to form sedimentary rocks. 2. The earth’s surface is formed of plates constituting both continental and oceanic lithosphere called tectonic plates. These plates are in a constant state of motion, causing tremendous build up of energy. The plates sometimes slip under one another and at other times collide with one another. Collision releases vast amounts of this energy up the rocks causing earthquakes. When tectonic plates diverge or converge, volcanoes are formed. 3. Mining and mineral processing activities generally pollute both surface and ground water of the region, creates noise and dust pollution, alters the land use pattern, wildlife populations and natural vegetation of the region. There is a negative impact on the health of communities living close to mining areas. 4. Governments are certainly not going to stop nuclear power research and nuclear power programmes because we ask the question, “can we dispose off nuclear waste?” Nuclear waste would be generated, so we now have to see how best to dispose off the waste. Yucca Mountains has been selected as the site for a safe repository of nuclear waste based on safety evaluations of the geological, hydrological and geochemical environment including such factors like thickness of overlying rocks and soil, depth of ground water, location of faults, characteristics of rocks that will hold the repository, depth at which the waste would be stored. The material that will be used for packaging the waste and how the waste would be transported to site have all been described in detail. Based on all available information and reports, Yucca seems to be a site suitable for long-term disposal of nuclear waste 5. Earthquakes generally result in large scale loss of life and property. It could trigger landslides, cause tsunamis, damage to dams or large water holding bodies could cause floods, liquefaction could cause buildings and structures to collapse, broken gas lines could cause massive fires. CHAPTER 15: 1. The lower atmosphere consists of the Troposphere, Stratosphere and Mesosphere. The first 12-18km of the air above the earth’s surface constitutes the troposphere. Temperature decreases with raising altitude at the rate of 6.50C for every Km till it reaches the end of the troposphere where the temperature could be -1000C. In the stratosphere one sees an increase in temperature with increasing altitude due to the presence of ozone layer. The outermost layer of the lower atmosphere is the mesosphere. Temperature begins to fall again with increasing height as a result of decreasing air density. The lower atmosphere contains nitrogen, oxygen, argon, neon, helium and krypton gases in a fixed proportion. It also contains carbon dioxide, water vapour, sulphur dioxide, ozone, methane and nitrous oxide in varying proportions. 2. The fraction of incident light that gets reflected is called albedo. The albedo of polar icecaps is high. 3. The day to day variations in temperature, humidity, precipitation of any given location is called weather, whereas the cumulative or average variations of temperature, rainfall and humidity factors of any given area is referred to as climate. Changes in global energy balance, oceanic circulation, changes in atmospheric composition, volcanic eruptions, meteors and comets, greenhouse gas emissions all contribute to climate change. 4. The Kyoto Protocol is a legally binding document signed in 2005 by developed nations stating that they would collectively reduce their greenhouse gas emissions by 5.2% compared to levels of 1990 by 2012. 5. Cycle or walk to work, buy food that is grown locally. CHAPTER 16: 1. Ambient ozone is an air pollutant, a result of combination of various oxides of nitrogen and volatile organic compounds present in the air. The primary sources of these compounds are emissions from industries, vehicular pollution, chemical solvents etc. The ozone found in the stratosphere is naturally occurring and forms a protective covering over the earth protecting it from the harmful UV radiations. Loss of this protective ozone covering could pose serious health for e.g. increased incidence of skin cancer and diseases affecting the immune system and environmental problems like low crop productivity, decreased productivity from oceans due to UV radiation in marine phytoplankton. 2. Unconventional pollutants are those substances produced in less volume than conventional pollutants, but are extremely toxic and hazardous e.g. asbestos, benzene, mercury etc. 3. Lead could affect the neural, reproductive and muscular systems in human beings. It also causes damage to the liver and kidney, brain and in extreme cases also cause death. Major source of lead in the atmosphere is from leaded gasoline used in vehicles, though its use is being actively discouraged. Factories that make or use lead, lead compounds or alloys also release substantial amounts of lead into the atmosphere. Burning of oil, coal, waste also release lead into the atmosphere. 4. LA is a hilly coastal plain surrounded by the Pacific Ocean along its southern and western boundaries and by the San Gabriel mountains in the east. It also has numerous valleys and canyons, thus making it an area of diverse climatic patterns. LA is also one of the busiest business centres in the world. The air quality in the urban areas of LA is poor due to emissions from vehicles, industries and other sources. 5. Pest repellents containing organo-chlorinated pesticides are a major source of indoor pollution. CHAPTER 17: 1. Water evaporates from land and water bodies due to the action of wind and radiant energy from the sun and from vegetation through the process of transpiration. When the air above the earth’s surface gets saturated with water vapour it condenses and comes down as rain, snow etc. Rain water directly enters the system and the cycle continues. 2. The depletion of groundwater in the Ogallala aquifer is a combined result of bad soil and water management and agricultural practices. The depletion of ground water could affect the agriculture productivity of the region and affect the livelihoods of families dependent on agriculture for survival. Appropriate soil and water conservation measures as well as crop management practices could, to a large extent, help increase the water holding capacity and infiltration rate of the soil. 3. The watershed management approach integrates the ecological, cultural, social, political, geological, geographical and economic aspects of a region to provide a comprehensive development plan for the region. 4. Recycle water – use wash water for potted plants, ensure that there are no leaky pipes/faucets, close faucets while brushing, shaving etc., operate dishwashers and washing machines only when they are fully loaded. CHAPTER 18: 1. Some major pollutants of water are effluents discharged from factories, untreated domestic sewage, oil spills, run-off from agricultural fields, discharge of spent water from nuclear installations etc. 2. When excessive nutrients enter a water body, the population levels of photosynthetic algae, planktons and obnoxious plants in the system increase drastically. This is called algal bloom. Algal blooms prevent light from reaching lower regions of the water body thus killing other organisms. A more serious problem occurs when due to death and decay of these algal blooms, oxygen demanding bacteria invade and cause a demand for oxygen within the system resulting in stress and death of other organisms. 3. The Clean Water Act of 1972 was passed to ensure that the physical, chemical and biological integrity of the nations’ water bodies are maintained. To achieve this it set up several modules – water quality standards, anti-degradation policy, water body monitoring and assessment etc. It also reports on the condition of the nation’s waters, total maximum daily loads (TMDLs) etc. and monitors water quality across its borders. Improvement in water quality has been seen since this Act was passed. 4. Oceans are polluted from domestic and industrial waste/garbage, untreated sewage, spent water from nuclear establishments, discharge from factories along the coasts, run off from agriculture lands, oil spills, heavy trawling boats, acid rain etc. Pollution of oceans results in loss of marine biodiversity, reduced productivity, bio- magnification etc. 5. Water quality can be maintained by ensuring that water containing effluents, sewage, spent water etc are treated before disposal, install appropriate systems and practices to prevent run off from agricultural lands, ensure environmental quality. UNIT 5 - ASSIGNMENT CHAPTER 19: 1. Early man depended largely on wind, water, fire and solar energy for his energy requirements. With advances in science and technology, extraction procedures of fossil fuels became sophisticated leading to over-exploitation of this non-renewable resource. Fossil fuels still meet 75% of world’s energy requirement. Experiments with solar wind, wave, nuclear are underway but none of these would be able to meet the current requirements of energy demand completely. 2. Dead decomposed organic matter from plants and animals that lived several billion years ago, deposited in the sea/ocean bed is the main source of fossil fuel. Through the process of sedimentation, the organic matter is entombed in the rocks. An increase in pressure and temperature helped breakdown the organic matter into simple hydrocarbons which remain trapped within the rock. Solar energy is the primary source of energy stored in these substances. 3. Coal, oil and natural gas are all fossil fuels. Coal deposits needs to be mined while oil and natural gas needs to be explored by deep sea drilling. By far, the use of natural gas which is a combination of several gases including methane, ethane, propane, butane, carbon dioxide, nitrogen, oxygen, hydrogen sulphide and rare gases like argon, xenon, helium, neon etc. is cheaper, less polluting and less hazardous to the environment. 4. The United States has the largest reserves of coal followed by Russia and China. The Alberta tar sands, in the Canadian province of Alberta, is the largest reserve of oil. Russia has the largest natural gas reserves in the world. 5. Production of nuclear energy does not have atmospheric discharges and emissions of green house gases. It produces significant amounts of energy in considerably less time. However the major limiting factor is the question of disposal of nuclear waste. CHAPTER 20: 1. Use renewable sources of energy, buy energy saving and energy efficient gadgets, turn off power when not in use, reduce waste, reuse and recycle products as far as possible, use public transport. If everyone takes responsibility, sufficient amount of energy can be saved. The environment we live in would be clean, safe and healthy. 2. Solar energy can be used for a number of applications - lighting, heating, construction, agriculture, processing heat, cooking, vehicles, generate electricity. 3. Major renewable energy sources are – solar, wind, hydro, wave and biomass. CHAPTER 21: 1. A sanitary landfill is an area where waste is stored till it is physically, chemically and biologically safe. This area needs to have leachate security, it should have a formal waste disposal and restoration plan, trained staff for operation and maintenance, planned waste emplacement and covering procedure. A secure landfill is a place where hazardous wastes are isolated and stored so that it does not contaminate the overall environment. It is a closed system. A garbage disposal area for the locality is called a dump. Garbage may or may not be segregated. 2. Recycling and reusing waste saves energy, money, reduces pollution, reduces the pressure on natural resources. If contaminated waste is recycled it could persist in the environment and cause several downstream negative effects. 3. Hazardous wastes must be stored only in secure landfills or designated areas and all instructions regarding procedures for disposal must be stringently followed. Any deviation or accident must be reported immediately to the authorities concerned. CHAPTER 22: 1. The demand for space and resources in urban areas are playing a limiting role in the urbanization process. The city therefore spreads into the suburbs and adjoining rural areas. The consequences of this can be felt and seen at various levels – land use pattern shifts from agriculture to commercial interests, localised over crowding, increase in traffic, decrease in air, water and land quality, increased cost of living, reduced social capital, law and order problems increase. 2. Smart growth is a development plan for urban areas that would sustain livelihoods, make the area more liveable and safe, energy efficient, provide services at affordable costs and ensure overall sustainability. 3. Cities can become sustainable if they reduce their greenhouse gas emissions, waste and pollutants, recycle and reuse resources, use renewable sources of energy, exert minimum pressure on natural resources. CHAPTER 23: 1. When supply meets demand the price of commodities are stable and affordable, however if the supply falls short of demand, there is an increase in price and when supply exceeds demand there is a general decline in prices. 2. There are several components in any ecosystem that are constantly interacting with one another to establish a state of equilibrium. Unlimited growth of one component is always at the expense of one or several other components leading to instability. When ecosystems become unstable limiting factors come into play to re-establish equilibrium. 3. Businesses can support sustainability by ensuring that the services they provide promote sustainable practices and products. If local businesses are able to provide such services the consumer would respond positively. Some ways that businesses could help: stock food products that are organic and locally grown, reuse packaging material etc. CHAPTER 24: 1. A bill is presented by a member of the Senate. This is referred to a committee which considers the bill. The committee reports to the senate, it is read, amended, read again and then debated. At the end of the debate it is voted. If it is passed it is sent to the other chamber where the same process is repeated. If passed, the bill becomes a law, otherwise it is vetoed by the Governor. The legislature may vote and override the veto, in which case the bill is passed as a law without the approval of the Governor. 2. The Environmental Protection Agency is the apex scientific body in the US committed to protection of human health and the environment through research, education and assessment. Legislation for environmental protection has played a crucial role in solving environmental problems. For e.g. the Clean Air Act that came into effect from January 01, 1996 ensured that use of leaded petrol was completely stopped for use in on-road vehicles. CHAPTER 25: 1. Awareness generation is the first step to action. People need to be well informed before they can make an informed choice; ordinary citizens can play a crucial role in creating awareness on environmental issues. Decisions concerning communities must be made based on actual ground situations and must consider the interests of all the stake holders. 2. Various topics have been presented in the course – population ecology, environmental protection, geological cycles, energy concerns, ecosystem development, evolution etc. To a beginner these may seem as unrelated topics, but as one goes through the course the inter-connectedness and links that each of these topics have to, and with one another becomes clear. It helps one understand the basic principle of ecology – “All is one and inter-related”. 3. The environment has been used and in several cases abused for short-term economic benefits of a select few. This must change, we must understand that we are only custodians of this earth. The following two statements of Mahatma Gandhi sums up my philosophy with regard to the environment. “The earth, the air, the land and the water are not an inheritance from our fore fathers but on loan from our children. So we have to handover to them at least as it was handed over to us.” "The earth provides enough to satisfy every mans needs, but not every mans greed" 4. Human beings or for that matter any living thing cannot survive without food. The current mainstream system of agriculture production is very chemical and resource intensive. It exerts severe pressure on the available natural resources and the environment. I would support any initiative towards a more sustainable method of food production for e.g. organic agriculture. REFERENCES: http://www.epa.gov/ow/ Read More