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Effects Of Thermal Pollution On Aquatic Species

Paper Type: Free Essay Subject: Environmental Sciences
Wordcount: 4082 words Published: 28th Apr 2017

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The pollution is the biological, chemical or physical alteration of the water, land, or air that is harmful to living organisms, ocean waters and surface waters. The surface waters, such as lakes, rivers, streams, and underground aquifers can get affected in different way. They can get polluted in common way including human and animal wastes, pathogenic microorganisms, pesticides, and sediment. The water pollution can happen in industrial nations by wasting toxic metals, organic chemicals, pharmaceuticals, and acids. The human activities that can contribute to pollution are constructions, drilling, dam construction, salting of roads and driveways to melt the ice, waste disposal and agriculture. Sometimes even hot water can consider as a pollutant. The effects of water pollution follow the path of the waters as they trickle through soil, filter through rock beds, and flow down streams and river system, and into oceans. The excess amount of inorganic nutrients such as nitrates and phosphates or raw sewage pollutes lakes or ponds, algae and aquatic plants overgrow. As of the aquatic plants die, they fall in the bottom of the water and the bacteria and other microorganisms decompose the remaining of them and that uses up all the dissolved oxygen in the water and suffocating the other aquatic life in the lake or pond.

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Thermal pollution is the degradation of water quality by any process that changes ambient water temperature, which is associated with increase in water temperature in streams, lakes or the ocean due to the discharge of heated water from industrial processes. How does the water quality change? It changes when water is used in industrial and power plants as a coolant. Whenever it is used and returned to the natural environment, the temperature changes, because warmer water effluent creates a reduced oxygen supply in the environment and therefore it affects aquatic ecosystems. Whenever the power plants are opened or shut off for repair, the fish and other aquatic species, cannot adapt to sudden changes in temperature and they are killed by thermal shock. In addition to harming aquatic life that cannot tolerate the warmer water, the warmer temperatures lower the amount of dissolved oxygen. The elevated temperature decreases the dissolved oxygen in water and this harms aquatic animals by increasing the metabolic rate of aquatic animal due to increased enzyme activity, which results in increase in food consumption within organism shorter period of time. Sometimes this results in disruptions of the food chain and decrease in biodiversity. The higher water temperature can also result in increases in aquatic plant growth rates, shorter lifespan and over population of the species. Algae blooms also reduce oxygen levels. The higher temperature denatures the life supporting enzymes by breaking disulphide and hydrogen bond in enzyme’s structure, which results in the inability to break down lipids which leads to malnutrition. The heated water has multiple effects on the nearby ecosystem. The warmer temperatures increase the ability of plants to photosynthesize, which may spur an algal bloom. It also increases the stress on plants and animals in the water. The temperature changing harms the fish and other aquatic organisms in many ways. The fish and invertebrates are ectotherms; where they are cold blooded animals, which are slow moving, slow growing and adapted to specific water temperature. This warmer temperature speeds up their metabolism, which harms their ability to survive and reproduce. The native fish like trout may lose their ground while nonnative take place instead of them. All these power plants have different types of cooling systems, which is easiest and cheapest cooling method, where cool water is withdrawn from a nearby water body and hot water is returned to the same water body. Soon as the system is by far the most environmentally destructive, the closed cycle cooling reuses the cooling water so that the waste heat does not leave the plant, but still excess heat is released into the atmosphere from the plant towers.

The nuclear energy is the No 1 source of the free electricity which provides 20% of the United States’ electricity. There are 437 nuclear power plants are in operation and 55 are under construction worldwide. Those 437 plants have a net capacity of about 371 GW and the 55 will have capacity of 51 GW to generate the energy. The 20% of the electricity is provided by 104 reactors in whole United State, where 35 of the reactors are boiling water reactors and 69 of them are pressurized water reactors. In the boiling water reactors, 14 of them are one reactor; 9 of them are two reactors and 1 has three reactors. For the pressurized water reactors, 15 of them are one reactor, 24 of them are two reactors and 2 of them have three reactors. There are 32 companies which are licensed to operate the nuclear reactors in United States. As of the 2009 records, 8 of the states have 31 reactors and those states generate largest percentage of the electricity. The Vermont state has generated largest percentage of the electricity in 2009, which was 72%, then 2nd largest comes to New Jersey 55.1%, following Connecticut 53.4%, South Caroline 52.0%, Illinois 48.7%, New Hamphshire 44.1%, Virginia 39.6% and at last in 8 state Pennsylvania with 35.1%. The United State’s largest nuclear plant is located at Palo Verde in Arizona. That plant has 3 reactors which generates 1,311 MW, 1,314 MW, and 1,317 MW for a total of 3,942 megawatts. On the other side United’s smallest nuclear power plant is at the Ft. Calhoun in Nebraska with 1 reactor and capacity of the 482 MW of generation electricity. In the time line the newest nuclear power plant that was built was in June 1996, in Tennessee. This plant is called Watts Bar 1, which is located in the spring city, and the capacity for generation if 1,123 MW. From 1990s to 2000s there have been 4 other plants have been built, which are in August 1993, the Comanche Peak 2 with capacity of 1,158 MW and in 1990, the Comanche Peak 1, with capacity of 1,209 MW. The other 2 were in August 1990, the Seabrook 1 in New Hampshire with 1,244 MW capacity and in January 1990, Limerick 2 in Pennsylvania with 1,134 MW by Exelon Corporation. The oldest operating nuclear plant is Oyster Creek in New Jersey, operating license since April 1969.

The nuclear reactor is a device to initiate, control and sustain a nuclear chain reaction. The most common use of it is in generation of electrical power and to transport the power. The nuclear reactor is usually involves heat from the reactor chamber to power steam turbines. These reactors are made by 4 major manufacturers. The reactor manufacturers are GE Hitachi Nuclear Energy, Westinghouse, AREVA NP and Asea Brown Boveri/Combustion Engineering (ABB-CE), where ABB-CE is the worldwide nuclear business company. As of the generation capacity by all the nuclear power plants in United Nations 20.2% or 798.7 billion kilowatt-hours (bkWh) of the total U.S. electricity and 14% or 2,560 billion kilowatt-hours of the world’s electricity in 2009. In comparison to other sources, 1,000 MWe reactors has 90% of amount of electricity has generated in 1 year. The generated electricity is 7.9 billion KWh, which is good for 740,000 households. To generate that much amount of energy by other fuel sources, it would require 13.7 million barrels of the oil or 3.4 million tons of coal or 65.8 billion cubic feet of the natural gas. As of the plant performance the South Texas Project 2 in Texas has generated of 11.8 billion KWh in 2007 with most electricity generation record and the longest operating period between refueling goes to LaSalle 1 from Illinois in February 2006 for 739 days.

Oyster Creek, Hope Creek, Salem Nuclear Power Plant

Figure : Oyster Creek Nuclear Generating Station.The Oyster Creek Nuclear Generation Station (OCNGS) is oldest operating nuclear power plant in United States, which is located in Forked River in the Lacey Township, in New Jersey. This plant is spread out in 700 acres of the land and build by Burns & Roe, Inc. and owned by the Exelon Corporation. It is one of the four nuclear power plant unit in New Jersey. The other 2 units are at the Salem Nuclear Power Plant, and the Hope Creek Nuclear Generating Station. The OCNGS plant was built in 1965 and started power generating in December, 1969 with a license to work for 40 years, but in 2009 the license was extended for another 20 years by The Nuclear Regulatory Commission. The plant draws its cooling water from Barnegat Bay, and dumps the water into the Atlantic Ocean through Barnegat Inlet. “The Nuclear Regulatory Commission (NRC) issued the license for first 40 years on the basis of the economic and antitrust considerations, but not technical limitations” (Peter N. Tabbot M.P.H. and Mark G. Robson, M.P.H. – September 2006). The OCNGS has a capacity of producing 619 MWe, the total power generated in 2007 was 5077 GW-h and from last 5 year average generation capacity is 5042 GW-h by using a boiling water reactor (BWR). This power plant has generated 4.9 million MWh with capacity factor of 91% and served 600,000 homes as of 2009 record. “Each day the OCNGS uses 1.3 billion gallons of Barnegat Bay Water for its antiquated cooling system, which is 2.2% of the total volume of the bay per day and over 790% of the bay per year” (CITATION). When the plant automatically shuts downs for safety reasons, fish gets killed due to lack of warm water that input into the bay. In 2002, 5,876 fish were killed, and plant was fined $1 million, where as in 2006, only 80 fish died; 2007 another 5,304 were killed, and the plant was fined $67,859 and in 2008, 38 fish died in following a shutdown. These cooling towers should prevent these fish kills that is causing by higher temperature and somehow reduce the higher temperatures near the plant’s current discharge area back to normal. This plant has approximately 700 employees, which their payroll is around $53 million in 2003 and $63 million in 2009 also where the property tax for 2009 was $2.4 million. This plant has increased output associated with 1034 jobs in New Jersey and 915 jobs in Ocean County. This plant has sponsorship the united way of Ocean County by contributing more than $277,000 in 2009 and counted as largest employee run campaign in Ocean County. The plant intakes and discharges 1.4 billion gallons of the water on daily basis, and it taken in at a speed of 1-2,000 cubic feet per second, which is the force of medium sized river. The giant sucking action brings the assortment of the smaller aquatic life that flows through the grate and gets killed in the process of the cooling the reactor, which is called as entrainment. Where the larger aquatic life such as striped bass, white perch and endangered sea turtles, gets pinned on the grate and often die, or seriously gets injured by the rush of oncoming water, which is impingement. This plant has developed a record of killing sea turtles in last ten years from 1992 to 2000, 17 sea turtles and 6 sea turtle mortalities. In September 2002, the plant has largest fish kill since 1985, they has over half a million fish dead, due to plant operators fault. They had failed to turn off the dilution pumps during emergency shut-downs and allowing millions of gallons of the hot water to enter the creek and bay. The modern pollution controls require them to install a closed cycle cooling system, which draws water into the plant for cooling, re-circulates and expels the heat through cooling towers. This system reduces the water intake and discharge by 95%, saving 13 million fish and shellfish and a loss of tens of millions additional larvae annually. It also eliminates the fish kills caused by thermal shock from the discharge, stop the dumping over 365 tons of toxic ware into the bay annually. The NJ DEP’s current draft permit for oyster creek does not require the plant to install a closed cycle cooling system. But they have gotten 3500 acres of wetlands for restoration for fall back option as the alternative way.

Figure : Salem Nuclear Power Plant.

Figure : Hope Creek Nuclear Generating Station. The other three nuclear power stations are located in Lower Alloways Creek Township, New Jersey in United States. Those all three plants owned by PSEG Nuclear LLC and Exelon Generation LLC. Two of the power stations are called Salem Nuclear Power Plants, which are pressurized water reactor nuclear power station and the other one is called a Hope Creek Nuclear Generating Station, which is a thermal nuclear power plant. These three plants share an artificial island in the Delaware Bay. “As of the 2004 record, the plants have paid $1.23 million in property taxed to Lower Alloways Creek, accounting for 55% of the township’s $2.25 million property tax. The plants have expenditures in the four counties surrounding the plants totaled more than $170 million in 2004. The labor has represented $145.5 million, the goods and services represented as $24.7 million. These spending within region represents, around 27% of the plants total spending of $617.8 million and 66% of the $256.3 million spent in New Jersey and Delaware” (Nuclear Energy Institute – September 2006). The Salem Nuclear Power Plant has two units, which were started in 1977 and 1981 and those two plants have a combined capacity of 2275 MWe. The unit 1 is licensed to operate until August, 2016 and unit 2 is licensed to operate until April, 2020. The PSEG have applied for a 20 year extension of license for both of these units. The technical problem made the Salem Reactors to shut down for two years in 1990s. They had found several difficulties, including leaky a generators, and unreliable controls on the reactor. In 2004, the Nuclear Regulatory Commission revised the oversight of this plant and ordered authorities to increase the monitoring overnight. Those plant uses more than 3 billion gallons of the Delaware Bay’s water every single day for cooling, replacing the closed cooling system. The Hope Creek Nuclear Generating Station which is thermal nuclear power plant was established in 1986, and it has license to operate the plant until April, 2026. It also has applied for a 20 years extension for license renewal. This plant has producing capacity of 1059 MWe, and in 2007 it has produced 8104 GW-h, where it has average of 7528 GW-h in last 5 years of energy production. This is the plant has the cooling towers, which is designed to remove the heat by pumping water up into the tower and allowing it to fall down inside the tower. Soon as the heat passes the water, it exchanges the some of the heat and evaporates some of the water. The evaporated flows out the top of the tower and form of a fine cloud like mist, where the cooled water is collected at the bottom of the tower and pumped back into the plant for reuse. This kinds of cooling towers are used where the land and water is expensive and where the state of federal regulations make alternatives impractical. The New Jersey has been ranked 10th in nuclear capacity and 9th place in nuclear generation in 2008.

Effects of the Nuclear Power Plants

The discarded radioactive materials from nuclear submarines and military waste have been a major source of radioactivity in the oceans. Those discarding materials have caused fatal harm to marine life, and it has also entered the food chain as some organisms like shell fish concentrate radioactivity in their bodies which are later consumed by humans. The pesticides like DDT and PCBS can enter the oceans through city waste water and industrial discharges from farms and forests. The Thermal pollution is when high or low temperature water is discharged from an industrial source. The difference in temperatures can kill corals and other sensitive marine organisms that are not developed to handle the different temperatures. The Thermal discharges of unused heat from fossil fuel or from fission in the nuclear fuel constitute another kind of environmental impact. Thermal effects in biota include problems with reproduction, growth, survival of larval forms, juveniles and adults. Regulatory agencies establish water temperature standards to govern heated discharges from the power plants to prevent catastrophic kills to occur, or thermally induced demise of aquatic populations. Fish, plankton and benthos are all affected at various degrees by thermal discharges from power plants. Other environmental impact common to all nuclear power plants are the highly visible transmission lines associated with the generation and distribution of electricity. Underground cables are not yet an economically feasible solution for most cases of transmission of electricity. Radioactive effluents released from nuclear power plants are, however, the main object of monitoring and control to minimize exposure of the public to ionizing radiation.

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Another effect of the nuclear power plant would be acid rain. The acid rain is the slightly acidic, with the pH of 5.6 of lower, which is due to small amount of carbon dioxide in water droplets to form mild carbonic acid. The other steps which lead to acid rain is the sulfur dioxide and nitrogen oxides released into the atmosphere primarily by nuclear power plants and metal ore refineries. All these oxide gases then react with water vapor to produce sulfuric acid, nitric and nitrous acid, which dissolve in the water droplets, and then combine with normal droplets and form into raindrops, in this case count as acid raindrops. In the Northeastern United States, have very low buffering capacity, therefore if the rainfall is acidic the most rocks and soils have increased their acid levels by 5 to 10 fold in the past few decades. The acidic soil lover the pH of the streams those flow over them, and the Environmental Protection Agency has reported in 2000, that approximately 580 of the streams in the Mid-Atlantic coastal plain were found to be acidic including 90% of the streams in the Pine Barrens of New Jersey and that was highest percentage in the nation. This combined acidity has lowered the pH of some lakes around 5.0 and even Little Echo Pond in Franklin, New York got lowered until pH of 4.2 in the Northeastern United States.

Effect on the Ocean mammals

Figure : The Green Turtle.The Green sea turtle is the larger sea turtle with binomial name Chelonia mydas from Cheloniidae family with only species in the genus Chelonia. It is the endangered species listed by IUCN and CITES. It is with low, broadly oval carapace and small head with one pair of pre frontal scales that are unique to them. Their shell length ranges from 36-43 inches and weights average between 200-300 pounds. They evolved more than 150 million years ago, and they spend entire lives in the sea, even more then come to the surface to breathe, and remain underwater for several hours for resting. They inhabit warm, tropical and subtropical waters, they migrate northward as temperature increase in the late spring, and stays there until late fall. Their nesting occurs in warm temperate and subtropical regions on open sandy beaches above high tide mark in front of well developed sand dunes. As of the Harold Haines and William Kleese, the scientist from the Miami, Florida, proved that the role of water temperature in the induction and maintenance of a dermal herpes virus infection (gray-patch disease) of young, green sea turtles, which influence of other recognized stress factors were negligible. In their research the animals that were subjected to a gradual increase in water temperature from 25 to 30’C and a subsequent decrease to 25’C, where they were maintained, had a period before onset of clinical signs and severity closer to that of control animals. In their findings they indicated that both the induction of clinical gray-patch disease and the severity of the lesions are affected by water temperature and suggest that one possible means of control of this herpes virus infection under intensive aquaculture conditions might be water temperature manipulation. The endangered Kemps Ridley, Atlantic Green and Loggerhead turtles are killed each year as they are attracted to the warm water and then sucked toward death on the fooling system intake.

The manatees, the large, fully aquatics, and mostly herbivorous marine mammals, which sometimes known as sea cows. They eat over 60 different plant species such as mangrove leaves, turtle grass, and types of algae, using their divided upper lip. The adult manatee eats around 10% of their body weight per day and especially small amounts of fish from nets. They have very few natural predators, like sharks, crocodiles and alligators over time to time. The main causes of their death for sea cows are human related issues, human objects, habitat destruction and natural causes such as disease and temperatures. Another main natural event and unpreventable cause for the manatee’s death would be red tide which is proliferation of tiny marine organisms knows as dinoflagellates.

Figure : phytoplankton.The phytoplankton is the autotrophic component of the plankton community. They are too small to see it with naked eye, but if they are in higher numbers, than it can appear as green discoloration of the water due to presence of chlorophyll in their cells. The Phytoplankton obtains energy from the process of photosynthesis, also it accounts for half of all photosynthetic activity on Earth. The effects of the elevated water temperatures and residual chlorine at a coastal nuclear power plant on the biomass and productivity or periphyton and phytoplankton, but not productivity was significantly lower in the outlet region than in the intake region. The phytoplankton is the key food item in both aquaculture and mariculture, where both utilize phytoplankton for the feeding of the animals being farmed. In mariculture, the phytoplankton is naturally occurring and is introduced into enclosures with the normal circulation of seawater, where in aquaculture; the phytoplankton must be obtained and introduced directly. The phytoplankton is used as a food stock for the production for rotifers, which are in turn used to feed other organisms, and also used to feed aquaculture molluscs. The species made of only one or few cells, the phytoplankton is the responsible for 50% of the primary productivity on the earth.

Waste Product of the Nuclear Power Plant

Figure : Decay in radioactivity of HLW.The waste product of the nuclear power plant is the radioactive waste. The radioactive wastes are very small relative to the waste produced by the fossil fuels and other sources. This waste product is containing radioactive material, which is the product of the nuclear fission, which comes from not directly connected to the nuclear power industry. The waste that has been produce diminishes over time, so in principle to that that material needs to be isolated for long time to no longer pose a hazard. The waste can be generally classified either low level or high level. The low level radioactive waste considers as highly radioactive part of nuclear reactors and waste from medical procedures, which comparatively easy to dispose and relatively small half life. The high level radioactive waste is material from the core of the nuclear reactor or from nuclear weapon. Most of the high level waste emit large amounts of radiation and have really long half lives. The radiation coming of the radioactive waste exposes the human and that can cause about 1% of all cancers, which increase cancer risk by 0.002% of reducing the life expectancy. Each year the nuclear power plants produces the 200,000 m3 of low level waste and about 10,000 m3 of the high level waste products including fuel as waste. 1000 MWe of the light water reactor generates about 200-350 m3 low level waste per year, it also discharges about 20 m3 of used fuel, which corresponds to 75 m3 disposal volume. Where the used fuel is reprocessed only 3 m3 of glass is produced, which is similar to 28 m3 of disposal canister. All this compares with an average of 400,000 tons of ash produced from coal, plant and other power sources of the same power capacity.


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