1 Water Pollution. 2 Water Pollution. 3 Potable Water. 4 Water Pollution. 5 Sources of Water Pollution. 6 Thermal Pollution. 7 Thermal Pollution

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1 1 Water Pollution 2 Water Pollution Threats to biodiversity from all sources are quickly reaching a critical level. Current extinction rates are 100 to 1000 times higher than prehuman levels. Aquatic environments such as coral reefs and freshwater habitats in lakes, rivers, and wetlands are all at risk of degradation. 3 Potable Water Potable water (water suitable to drink) is a rare commodity in large parts of the world. Access to potable water is limited by: ease of distribution level of water treatment (e.g. sanitation) amount of available water resources (eg rivers) Countries must deal with problems of removing water borne diseases and dissolved toxins. Once treated, distribution and storage of water becomes important. In many countries, distribution of water is difficult and storage of large amounts almost impossible. 4 Water Pollution Water pollution occurs as a result of contamination from sources ranging from urban and industrial to agricultural. Some forms of pollution simply alter the physical state of the water, such as its temperature, ph, or turbidity, but others involve the addition of potentially harmful substances. 5 Sources of Water Pollution Pollutants may enter a waterway via: single or point sources where pollutants have been discharged into the environment through pipes (effluent), sewers, smokestacks or ditches from specific sites. non-point sources where pollutants, such as agrichemicals, smoke from forest fires, transportation vehicles or they can enter water bodies over large areas via groundwater and runoff. 6 Thermal Pollution Thermal pollution of waterways is a common consequence of thermal power generation and water cooled industrial processes. Upstream, water is withdrawn, used for cooling, and then released downstream as a (heated) thermal plume. Restrictions are placed on the percentage of water removed for cooling and the temperature of the release water. However, the increased thermal load reduces oxygen levels and may compromise sensitive species. 7 Thermal Pollution Thermal pollution is the unnatural heating of water which changes the ambient temperature. Heated water is produces during industrial processes, specifically power production, and the released water is cooled in local waterways. In warmer waters the decomposition of waste occurs faster, depleting the water of oxygen; this affects the aquatics organisms ability to metabolize and obtain food. 8 Sediment Pollution 9 Sediment Pollution Acid Rain Acid rain (or more correctly termed acid deposition) can fall to the Earth as rain, snow or sleet, as well as dry, sulfate-containing particles that settle out of the air. It is a world-wide problem because of the widespread use of coal for heating and electricity and the continued use of fossil fuels for transportation. 12 Acidity Tolerance Normal rainfall has a ph between 5.2 and 5.6 where acid rain is more acidic than normal rainfall. Acid rain produces forests with sickly, stunted trees and lakes that are so acid that they cannot support fish. It also releases heavy metals (for example, cadmium and mercury) into the food chain. Changes in species composition of aquatic communities may be used as biological indicators measuring the severity of acid deposition. The graph shows the acidity tolerance of some common aquatic species.

2 13 Ocean Acidity The ocean acts as a CO2 sink, absorbing much of the CO2 produced by the burning of fossil fuels. CO2 reacting with water forms carbonic acid through the chemical reaction: CO2 + H2O H2CO3 An increase in carbonic acid levels is causing the ph of the oceans to fall. This has major implications for marine life. 14 Effect of Ocean Acidification Because the oceans are naturally alkaline, acidification will not produce acid waters. Shells will not dissolve but organisms will find it more difficult to gain the CO3 2- ions needed to make shells. Shell making organisms are able to use CO3 2- but cannot use HCO3 -. Acidification lowers the amount of CO3 2- available. 15 Ocean ph ph is a logarithmic scale, so even a small ph change represents a large change in H +. Thus a ph of 5 is 100x more acidic than a ph of 7. Some areas are affected by ph change more than others. Changes may be due to: higher human activity, e.g. sea traffic in the North Sea natural processes that affect CO2 uptake, e.g. underwater eruptions 16 Chemical Pollutants Organic chemicals are carbon based chemicals like detergents, pesticides, tree and brush debris, and food wastes. Inorganic chemicals are not carbon based, like phosphorous and nitrogen based chemicals and can include acids, salts, and heavy metals. Many inorganic chemicals find their way into both surface water and groundwater from sources such as industries, mines, irrigation runoff, oil drilling and urban runoff from storm sewers. Heavy metals from motor vehicles and acid mine drainage like lead and mercury are poisonous. Mercury exposure to developing fetuses in pregnant women has been linked to a variety of neurological conditions. 17 Organic Pollutants Most organic water pollutants are synthetic, carbon based, chemicals created for human activities. These include pesticides, solvents, industrial chemicals, and plastics. Some organic compounds enter water sources directly or through seepage from landfills, through agrichemical runoff, or by leaching into groundwater. 18 Oil Pollution Oil pollution is particularly acute in harbors and shipping lanes, but more oil is released by normal operation of offshore wells, washing tankers & from pipeline or storage tank leaks. Oil damages aquatic systems because it spreads over water surfaces forming a film. It also coats organisms and is toxic when ingested. 19 Oil Spill Clean-Up Oil spill clean-up and recovery methods include bioremediation (algae and bacteria), controlled burning and dredging. Other oil recovery and clean-up methods include: Skimmer boats that are used to collect and vacuum up some of the oil into storage barges. Many of these boats will use booms as a method of containment. Genetically engineered bacteria can be used as a form of bioremediation to break down or remove oil. Coagulating and dispersing agents cause floating oil to clump together or break apart for easier pickup with absorbent pads 20 Inorganic Pollutants Inorganic chemical pollutants include mercury, lead, road salt, and acid drainage. Most are toxic to aquatic organisms and their presence may make water unsuitable for drinking and other uses. Inorganic chemicals enter water courses from industrial plants, mines, irrigation runoff, oil drilling, and municipal storm drainage. 21 Inorganic Plant Nutrients Fertilizer runoff from agricultural and residential land contributes inorganic plant nutrients, particularly nitrogen and phosphorus, to water bodies. This nutrient enrichment accelerates the natural process of eutrophication, and causes algal blooms and prolific aquatic weed growth. High nitrate levels caused by inorganic fertilizers are also toxic in drinking water, particularly for infants, small children, and pregnant women. 22 Eutrophication Eutrophication is a term describing the enrichment of waters with nutrients especially nitrates and phosphates. It often results in excessive growth of weed and algae. Cultural eutrophication is the acceleration by humans of plant nutrient enrichment.

3 Microorganisms decompose the organic matter in the polluted water and their activity increases the uptake of dissolved oxygen. This reduces the amount of dissolved oxygen available to other aquatic organisms and may subsequently cause their death. 23 BOD Biochemical oxygen demand is a measure of the polluting capacity of effluent where decomposition results in oxygen depletion. Organic matter decays as bacterial activity increases. BOD is measured as the weight (mg) of oxygen used by one liter of sample effluent stored in darkness at 20 o C for five days. Runoff of animal waste can increase nutrient levels and bacterial content in a lake or stream usually this can be measured by the content of fecal coliform bacteria. When the BOD is high and dissolved oxygen becomes depleted, decomposition becomes anaerobic. Anaerobic microorganisms produce compounds with unpleasant odors, leading to a further deterioration in water quality. 24 Biological Oxygen Demand & The Oxygen Sag Curve 25 Sewage Pollution Raw or partially treated sewage is a common water pollutant. Sewage pollution results from the disposal of household and industrial wastes into rivers, lakes, and seas. Most communities apply some treatment to raw sewage prior to discharge from point sources, but even treated sewage can be high in nutrients. Sewage is a source of pathogens (disease-causing agents). During floods, human waste may mix with drinking water and increase the risk of water-borne diseases such as cholera. 26 Pathogens 27 Sewage Treatment Sewage includes all waste water that has been used by a household or industry. It does not include stormwater from road and property runoff, which is usually diverted directly into waterways. In some cities, sewerage and stormwater systems may be partly combined, and sewage may overflow into stormwater during high rainfall. 28 Processing Sewage Sewage usually undergoes several levels of treatment (purification): Pre-treatment removes any large objects, such as tree limbs, leaves, condoms, & tampons, with screens. Primary treatment uses mechanical processes, such as screening and settling, to remove suspended sand and silt. This forms the primary sludge. Secondary treatment uses microorganisms to decompose the suspended organic material in the waste water aeration tank. The bacteria-laden solids settle out as sewage sludge. Disinfection (usually by chlorination but ozone and UV light can also be used) kills any bacteria and other pathogens before the waste water is discharged. Tertiary treatment using biological, chemical, and physical processes is required to remove nitrogen, phosphorus, heavy metals, and synthetic organic compounds. 29 Sewage Treatment Plant Sewage Treatment Plant 33 Sewage Treatment Plant 34 Sewage Treatment Process 35 USA Waterways In the USA, the Clean Water Act (CWA) legislation, administered by the EPA, is used in the protection and management of waterways. The CWA provides for the maintaining and restoring of the physical, chemical and biological integrity of waterways. The Great Lakes Water Quality Agreement between the US and Canada focuses on the water quality of the Great Lakes. 36 USA Waterway Legislation The Clean Water Act (1972) includes the Federal Pollution Control Amendments and the Water Quality Act. The primary goals of the CWA are: Established the creation or expansion of sewage treatment plants. Permit requirements for point source pollution like the required permits for industrial storm water discharges and municipal separate sewer systems. Set up provisions for mitigation or a trade-off program for obtaining permits. Set pollutant levels for individual water bodies, such as rivers, lakes, streams and wetlands Ensures that surface waters are safe for recreation activities such as fishing or swimming. The Safe Drinking Water Act (1974) ensures safe drinking water for the public from above ground to underground water.

4 37 UK Waterways Many rivers and lakes in the UK face the problems that most bodies of water in developed countries face: pollution from agricultural run off (diffuse pollution) pollution from sewage overflow (point pollution) overuse of water for agricultural and municipal use invasion by introduced species In 2008, the government introduced new schemes to improve the quality of water ways by They include: to have 95% of Sites of Special Scientific Interest (SSSIs) in favorable or improving condition by 2010 phase out phosphates in domestic detergent encourage reed bed growth in water ways to absorb sediments and nitrates charge polluters to recover costs of treatment use incentives to encourage farmers to continue improving water quality schemes 38 Bottled Water The U.N. estimates that 5.6 million Americans drink water that does not meet EPA standards. In 2008, U.S. bottled water sales topped 8.6 billion gallons for 28.9% of the U.S. liquid refreshment beverage market, exceeding sales of all other beverages except carbonated soft drinks. Industry pressures to weaken the Safe Drinking Act include Eliminate national tests and public notification of violations Allow rights to pollute if provider cannot afford to comply In 2011, the market is forecast to have a value of $86,421.2 million, an increase of 41.8% since An estimated 50 billion bottles of water are consumed per annum in the US and around 200 billion bottles globally The oil used to produce plastic bottles in the U.S. each year would fuel 100,000 cars 39 Detecting Water Pollution The extent of water pollution can be determined in many ways: The nutrient loading can be assessed by measuring the BOD (the Biochemical (or Biological) Oxygen Demand). Electronic probes and chemical tests can identify the absolute levels of various inorganic pollutants (nitrates, phosphates, and heavy metals). 40 Monitoring Water Quality The quality of water in a stream, river, or lake is defined in terms of its various chemical, physical, and biological characteristics. Some measures of water quality cannot be made in the field; water samples must be transported to a laboratory for analysis. Telemetry stations transmit continuous measurements of the water level to a central control office. 41 Measuring Water Quality The following measurements are routinely made by agencies involved in water quality monitoring: Dissolved oxygen, carbon dioxide, and temperature (in the field) Clarity or turbidity (in the field or the laboratory) Conductivity, ph, color, nutrients (nitrogen and phosphorus), major ions (magnesium, calcium, sodium, potassium, chloride, bicarbonate, and sulfate), organic carbon, and fecal bacteria (coliforms and giardia). 42 Sampling Fish Nets for fish can act as passive traps, or they can be actively pulled through the water to capture organisms in their path. The sampling of fish can determine biodiversity and pollution levels. Common types include: Hoop or fyke nets are constructed of hoops of ever-decreasing size. They act as a passive trap; the fish enter the net and are trapped at its base. Seine nets are pulled through the water and trap fish in the mesh. 43 Radio Tracking Data In a number of Great White sharks were radio tagged in South African waters. The recovered data shows these animals can travel vast distances in relatively short spaces of time. 44 Invertebrates in Water Aquatic invertebrates can be sampled using a variety of methods: Plankton nets provide quantitative samples of zooplankton from ponds and lakes. The volume filtered can be calculated using the length and diameter of the net and the lake depth. Smaller sized meshes will capture smaller species and life stages. Kick sampling is a simple but effective way to provide semi-quantitative samples of invertebrates in streams. 45 Indicator Species The presence (or absence) of indicator species can give a biological indication of the pollution status of the waterway. Different species have different tolerance levels to varying levels of pollution. Clean water communities are typically diverse, dominated by species with high oxygen requirements. Communities in polluted or turbid streams are much less diverse and are dominated by species that are tolerant of low oxygen levels and sluggish water flows.

5 46 Heavy Metals: Mercury & Lead Mercury is released by burning coal and then transported through the air by currents and wind. The mercury can enter water through the water cycle of falling as dry particles. The mercury dumped in Minamata Bay by a factory entered humans through their diet of fish by bioaccumulation. The factory dumping caused mental impairments, birth defects, and death were caused by the chronic effects of exposure to mercury. Lead is introduced through mining and refining processes but is also in batteries. Overexposure to lead can lead to birth defects and neurological effects. 47 The Grand Banks The Grand Banks of Newfoundland consists of a series of underwater plateaux at the edge of the North American continental shelf. The plateaux range from 36 m to 185 m deep. The shape of the deep sea-floor causes nutrient rich water to well up to the surface and the relatively shallow plateaux allow a huge range of fishes to proliferate. The Grand Banks have been fished since the fifteenth century but continual over fishing has devastated many fish stocks. 48 Overfishing 49 Fishing is an ancient human tradition that is now a worldwide resource extraction industry. Several decades of overfishing in all of the world s oceans has pushed commercially important species, e.g. cod, into steep declines from which recovery is unlikely. The maximum sustainable yield (MSY) has been exceeded by too many vessels catching too many fish, especially fish of reproductive age, often using wasteful and destructive methods. The build up of large scale fishing fleets has contributed to widespread overfishing and damage to the marine environment. Bottom trawls and dredges cause large scale physical damage to the sea floor. Sea mounts are particularly vulnerable. Lost fishing gear (particularly drift nets) threatens marine life, including birds and mammals. 50 Sustainable Yields Sustainable yields apply to all harvests that require some organisms to be left after harvesting to replenish the stock. Yields above the sustainable limit will eventually cause the depletion of the stock. Fisheries especially need to use sustainable yields (SY). 51 North Sea Cod Fishery The stock of North Sea cod (Gadus morhua) is one of the world s six large populations of this economically important species. As one of the most intensively monitored and exploited fish stocks in the North Sea, it is considered a highly relevant indicator of how well sustainable fisheries policies are operating. The stock of North Sea cod is presently below safe biological limits and stocks are being depleted in all waters adjacent to the North Sea, where the species is distributed. 52 State of the Cod Fishery The graph shows that recruitment has generally been poor since 1987, and the number of spawning adults has fallen to levels below those required to recruit new individuals into the stock. 53 Cod Recovery Plan ICES (the International Council for the Exploration of the Sea) advised that the spawning stock biomass (an indicator of the number of breeding adults) reached a new historic low in 2001, and that the risk of stock collapse is high. ICES have recommended a recovery plan that will ensure recovery of the spawning stock to a level of more than 150,000 tonnes. Reductions in the TAC alone (it has been set at approximately half that set for the year 2000) are insufficient to stop the declines. 54 The Anchovy Fishery The Peruvian anchovy fishery collapsed in 1972 due to a combination of environmental changes (El Niño) and prolonged overfishing. The industry has never fully recovered. 55 Anchovy Fishery Recovery During the 1990s the anchovy fishery began to recover but was hit by El Niño conditions again in Restriction of the fishery for the following year allowed the rapid recovery of anchovy numbers. A large number of regulations have been placed on the industry. Catches continue to be variable and will probably never fully recover to prefishing levels. 56 North Sea Herring The North Sea herring (Clupea harengus) stocks collapsed during the late 1970s which caused a four year closure of the industry. Stocks

6 decreased again during the 1990s due to a high juvenile catch. A recovery plan was implemented in 1997 with some success. 57 Gemfish Fishery The decline of gemfish (Rexia solandri) in southern Australian waters represents a classic case of fisheries overexploitation. The TAC was set at zero in 1993, but there is still considerable by-catch; the fishery has not recovered and may never do so. The records for the period prior to 1993, when commercial fishing ceased, show a decade of general decline in the gemfish stock. 58 Tragedy of the Commons 59 The Tragedy of the Commons is an essay written in 1968 dealing with the management of a common resource. Because the resource is not owned by any particular person it is in the best interests of the individual to use it as much as possible. In this way their benefit is maximized while the damage is shared by others. The result however, is the eventual destruction of the commons.