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Lecture 4

Earth Science 2WW3 Lecture 4 notes- Pollution & Clean Up.pdf

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Earth Sciences
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Luc Bernier

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Pollution & Clean Up 1) Which BC mining company has recently admitted in Court polluting the Columbia River in Washington State for more than a century? a. Teck Resources Ltd [*] b. Taseko Mines Limited c. Barrick Gold Corporation d. Thompson Creek Metals Part 1 - Water Quality Standards Water Pollution: a global problem  This map illustrates the impact of water pollution on rivers shared by two or more countries  Red = severe impact  The problem of water pollution is distributed worldwide and has grown during the 20th century  This is attributed to population growth, expansion of industry, use of fertilizers and pesticides in agriculture  Water use has increased six fold and there is more waste in the water  This is a concern in 1/5 of the United Nations Environmental program Regions  The major drainage basins Mississippi river, Islands of Caribbean, Indian ocean, and the coral sea Water Pollution and Health Impacts  Water quality standards have been developed to protect human populations from pollution  These standards have been developed with a strict focus on medical issues  They are based on known medical effects  They relate to drinking water for human consumption without considering the environmental context  These standards need to be constantly revised in the face of new knowledge Pollution & Clean Up  Water quality standards have not been developed with the protection of wildlife in mind  The effects of water pollutants on wildlife is more poorly understood  The resistance of one species to a specific pollutant compared to another species varies greatly  The impact of pollutants on behavior need to be taken into account Water Quality Testing  Another problem relies with the monitoring of water quality  It is not practical to test water quality on a continuous basis  Therefore only spot checks tend to be made  Sometimes they are too infrequent to pick up a specific pollution event  Critical peaks of pollution may be missed  Sampling may be arranged to miss critical peaks in pollution on purpose  For example direct release of sewage into the environment stemming from treatment being bypassed in a wastewater treatment facility are predictable  Fecal pollution tends to be highest after rain events  Sampling could be devised to miss these days giving the false impression that the water being released meets environmental standards Part 2 - Agriculture and Water Quality Water Pollution and Agriculture  Agriculture is the greatest source of water pollution in developed countries  Largely because of inadequate legislation  Environmental protection agencies tend to focus on point discharges from industries  For instance a specific pipe discharging a pollutant in a body of water  Pollution from agriculture is harder to pinpoint because it's distributed over a larger area (e.g. multiple fields)  In developing countries water pollution from agriculture has intensifies with the adoption of the practices of green revolution n the 1960's and 1970's  For instance the use of pesticides Nitrates: an increasing threat  Nitrates derived from agricultural fertilizers have been affecting water quality due to a major increase in their use over the last 50 years  They now prohibit the phosphorus in certain countries as the fertilizer of choice for instance England  WHO limit: 45 mg/L  Much above the concentrations depicted on this map that illustrates the flow of nitrates in major bodies of water between 1991-2000  The increased levels in major river systems in the world is problematic and leads to additional environmental consequences downstream for instance eutrophication Pollution & Clean Up Pollution by Nitrates and Health  Well water and  “blue  baby  syndrome”  There are specific health concerns due to the exposure of nitrates that can be found in the drinking water supply  This chart illustrated the increasing levels of nitrate in ground water in various European countries (France, Great Britain, Denmark) since the 1980's  The concentration index has been increasing ever since  Since 1945 there is increasing evidence of a link between blue baby syndrome and well water contaminated by nitrates  The main symptom is blue coloration of the skin  Methaemoglobinemia: o Lack of oxygen in the blood Pollution & Clean Up  Infants suffering from blue baby syndrome are suffering from methaemoglobinemia (lack of oxygen in the blood) Nitrate in the Landscape  Removing nitrates from public water supplies is expensive  It is more efficient to abort their introduction in waters used as a source for the drinking water supply  Up to 50% of organic nitrates are leached out from agricultural fields  For example after a rain event such as in this field in Iowa  Farm field, Iowa  To minimize the potential for drinking water to be contaminated by nitrates we can rely on our understanding of the natural cycle of nitrogen in soils illustrated here  An important component of this process is denitrification (conversion of nitrate to nitrite and then its conversion to nitrogen gas that is released to the atmosphere)  Maintaining the integrity of wetlands may help to achieve this goal Part 3 - Water Quality and Pesticides Herbicides and Pesticides  Herbicides and pesticides are key elements of the green revolution  A revolution in food production that started after WWII  This lead to an increase in the frequency of cropping and the intensification of yields  We try not to rely now on the use of pesticides now that genetically modified crops are resistant to them  We used to believe that they could be filtered by soils however soil erosions brings them back to the rivers and contributed to their pollutions  The map here illustrates the global loads of pesticides in the world  High levels are indicated by red, pink and orange Pollution & Clean Up  High loads of pesticides are seen in the Mississippi river basin, many major river basins of western and eastern Europe and now in China and India Groundwater Pollution and Pesticides  Pollution of groundwater is difficult to monitor and therefore the awareness of the problem is an issue  Because it takes a long time for pollutants to filter down and reach the groundwater  Precipitation and irrigation contribute to the percolation of water which entrains pesticides and eventually they reach the groundwater; the aquifers  Following the groundwater flow it make take a long time before these pollutants can be detected in drinking water wells or also in monitoring wells  Along the way they can be broken down by microbes or biochemical reactions and the by-products can either be safe or toxic Health Impacts of DDT  DDT: dichlorodiphenyltrichloroethane  The fate of DDT in the environment illustrates these issues Pollution & Clean Up  This pesticide has been banned since 1973 in the US and much of the world as a result of Rachel Carson's work "Silent Spring" which documented the impacts on wildlife and the potential human health implications with the use of DDT  DDT persists in the environment many years after its use and it is still widely used in developing countries  The United Nations have a goal or getting rid of DDD by 2020  Very high levels are found in African rivers  It's decay produces DDD which is less toxic that DDT and DDE which is an endocrine disrupter Pesticides And Water Quality  WHO drinking water standards limit for Aldrin: 0.03  μg/L  Pesticides and herbicides are poorly monitored globally for instance only regional monitoring is performed in Europe  Aldrin is a very toxic pesticide  This map illustrates many areas have levels of aldrin that are close to or above this limit (0.03  μg/L)  High levels of aldrin have been documented in Italy, northern France and Belgium but especially in England  WHO drinking water standards limit for Dieldrin: 2  μg/L  Many  areas  have  levels  of  dieldrin  that  are  close  to  or  above  this  limit  (2  μg/L)  High levels have been documented in Italy, northern France and Belgium and again in the United Kingdom Pollution & Clean Up Part 4 - Water Quality and Mercury Minamata & Mercury Poisoning  The significance of mercury as a water pollutant and its associated health impacts emerged in the 1950's following two accidents in Japan including one in the bay of Minamata where discharges of mercury led to the consumption by fish of methyl mercury was eventually consumed by humans  Many of the people who ate the heavily contaminated fish developed Ataxia as a result (a weakening of the muscles and senses)  Infants exposed to high doses of mercury showed signs of developmental problems  Mercury poisoning is often referred to as Minamata Higher & Higher Levels in Wildlife  One important property of mercury is that it tends to bioaccumulate  Many chemicals once released into the environment become more and more concentrated in organisms during their lifetime  From the early stages to later stages in life the contaminated levels in one given organism will increase over time Pollution & Clean Up  Mercury tends to biomagnify as well once introduced in to the environment  It becomes more concentrated up the food chain  We may take DDT as an example of this process  DDT once introduced into the environment can be found at very low concentrations and is absorbed by plankton which will then have a high load in DDT (0.4 ppm)  This plankton is a food source for the level above, he threespine stickleback, and in the process the load in the stickleback increases to 0.26 ppm  The stickleback is a food source for the summer founder so the DDT moves up the food chain and the load increases to 1.28 ppm  The osprey feeds on the flounder and the load in DDT increases to 13.8 ppm  This happens with various pollutants, mercury, DDT, and many other types of endocrine disrupters Bioaccumulation and Mercury  Humans may absorb mercury from various sources in the environment  However, it is more efficiently absorbed in its methylated form (methyl mercury) which is generated in lake sediments by microbes  Eventually this methyl mercury is released to the water column, absorbed by plankton, and then by the biomagnification process moves up the food chain  The fish may be consumed by terrestrial organisms, by birds for instance, which can also be food sources for humans Pollution & Clean Up  Therefore humans may absorb mercury from various sources at the same time; Terrestrial animals, birds, and fish and as a result carry high loads of mercury  Elevated levels of Hg in rivers because of:  Anaerobic decay of forest vegetation  Elevated levels of mercury can be found in Canadian rivers because of the anaerobic decay of vegetation flooded by reservoirs created behind dams  For instance Cree Indians stopped eating fish from the reservoirs of the James Bay hydroelectric reservoirs because of the associated health risks Part 5 - Water & Endocrine Disruptors Water Pollution and Endocrine Disruptors  Hormone release system malfunctions  Human made substances that cause the hormone systems to malfunction  The prevent the systems from responding properly  These are find in many everyday products  Fish has been exposed to endocrine disrupters  This is leading to feminization of males in many environments  Many pesticides are acting as endocrine disrupters (DDT) Pollution & Clean Up  Fish have been impacted from Lake Erie  Bottom figures  Make tested  Arrows indicate female eggs in the male reproductive system of the white perch  Where were these feminized white perch found?  In Cootes Paradise in Hamilton  Female eggs in make reproductive system  In Lake Erie: Caused by PolyChlorinated Biphenyls  Lake Apopka, Florida o The first major instances where the disturbance of endocrine disrupters were seen o Major spill of pesticides in the 1990's o The lake appears to be clean and over the years different patterns of wildlife have emerged o Alligators have been transsexual o Panthers aren't reaching sexual maturity o The eggs of many birds were extremely infertile or thin Governmental Response to Endocrine Disruptors  Bisphenol A  There are also restrictions in children's toys in Europe Drugs in the Water  EPA, 2008: Evidence that 41 million people were exposed to drugs in their drinking water  Multiple studies show that hormones, cancer drugs are found in water  There are multiple sources of these drugs  Houses and the municipal sewage can leak  Male fish exposed to wastewater effluents decreased egg production by 50% (ability to fertilize eggs)  High concentrations of estrogens in water also produce the feminization in fish Pollution & Clean Up Drugs in Canadian Waters  NWRI, 2008: Drugs also found in drinking water  National Water Research Institute (Burlington)  USA: Active pharmaceutical ingredients in 80% of streams 2) Which of the following is a consequence of the trend urbanization, and associated release of drugs
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