Chapter 22 Water Pollution 22-1 Types, Effects, & Source of Water Pollution WATER POLLUTION- Any chemical, biological, or physical change in water quality that.
Download ReportTranscript Chapter 22 Water Pollution 22-1 Types, Effects, & Source of Water Pollution WATER POLLUTION- Any chemical, biological, or physical change in water quality that.
Chapter 22 Water Pollution 22-1 Types, Effects, & Source of Water Pollution WATER POLLUTION- Any chemical, biological, or physical change in water quality that has a harmful effect on living organisms or that makes water unsuitable for desired use Approx. 3.4 million people die prematurely each year from waterborne diseases Categories of water pollution Infectious agents Bacteria, viruses, parasites inorganic chemicals Acids, toxic metals organic chemicals Oil, gasoline, cleaning solvents excess heat Sediment • Soil, silt Plant nutrients • Nitrates, manure Water quality Scientists monitor water quality by using bacterial counts, chemical analysis, and indicator organisms. Fecal coliform test Water quality Bacterial source tracking (BST) uses molecular biology techniques to determine subtle differences in strains of E.coli based on their animal host. Biological oxygen demand (BOD)- the amount of dissolved oxygen consumed by aquatic decomposers Monitor populations of indicator species Point vs. nonpoint sources Point sources discharge pollutants at specific locations through drain pipes, ditches, or sewer lines into bodies of surface water. Nonpoint sources are scattered and diffuse and cannot be traced to any single site of discharge. The leading sources of water pollution: agriculture, industries, and mining. About 1.4 billion people in developing countries do not have access to clean drinking water. In a warmer world, too much rain and too little rain can increase water pollution. Pollution Of Freshwater Streams Flowing streams can recover from a moderate level of degradable water pollutants if their flows are not reduced. oxygen sag curve -reduces or eliminates populations of organisms with high oxygen requirements until the stream is cleansed of wastes. Depth and width of curve depend on volume of wastes, flow rate, temperature, pH level Oxygen sag curve Pollution Of Freshwater Streams Most developed countries have sharply reduced point-source pollution, but toxic chemicals and pollution from nonpoint sources are still problems. Stream pollution in most developing countries is serious Cuyahoga River (Cleveland, OH) fire 1959 and 1969 - bottom-up pressure from citizens caused change Case Study: India’s Ganges River Ganges is a holy river More than 1million bathe in river Poor sanitation Waste treatment plants are being build Snapping turtles have been released to feed on bodies Religious beliefs of cremation and throwing ashes into river Many people are poor and cannot burn the bodies, so they are placed in whole and decompose in water Pollution Of Freshwater Lakes Lakes and reservoirs more susceptible to pollution due to lack of flowing water and infrequent mixing of stratified layers, which help dilute pollutants. Contaminants can include runoff of fertilizers, oil, pesticides, toxic substances from mining and industrial waste such as lead, mercury and selenium. Biomagnification (AKA bioaccumulation) can occur as pollutants move through the lake ecosystem (ie. DDT) Cultural Eutrophication Human activities accelerates the input of plant nutrients into a lake. (mostly nitrates and phosphates) Effects include algal blooms, which decrease light penetration needed for photosynthetic organisms. Also, increases decomposing bacteria concentrations which leads to decreases in available oxygen content. Major Sources that leads to Cultural Eutrophication Dealing with Cultural Eutrophication Ways to prevent/ reduce: Ways to clean up lakes: Advance waste treatments systems that remove nitrates and phosphates before discharging water Removal of weeds and excess plant growth Banning/limiting use of phosphates in household cleaners Soil conservation and land control to slow run off Pumping air into lakes and reservoirs to prevent oxygen depletion. Case Study: Lake Washington and Puget Sound- A Success Story?? Sewage going to Lake Washington was diverted to Puget Sound (more flowing of water mixed with Pacific Ocean waters would dilute wastes) Action was taken early to prevent eutrophication of Lake Washington, however, now Puget Sound is seeing eutrophic effects due to rapid rate of sewage discharge from all surrounding cities. Case Study: Great Lakes Pollution Nearly 25 % of Canadian agricultural production and 7 % of American farm production are located in the Great Lakes basin. More than 30M people live in Great lakes basin, which is roughly 10% of US pop and more than 30% of Canadian pop. The daily activities of these people, from the water consumed to the waste returned, directly affect the Great Lakes environments. Major stresses on the lakes include toxic and nutrient pollution, invasive species and habitat degradation. Sources of pollution include the runoff of soils and farm chemicals from agricultural lands, waste from cities, discharges from industrial areas and leachate from disposal sites. The large surface area of the lakes also makes them vulnerable to direct atmospheric pollutants that fall as rain, snow, or dust on the lake surface, or exchange as gases with the lake water. Outflows from the Great Lakes are relatively small (less than 1 percent per year) in comparison with the total volume of water. Pollutants that enter the lakes are retained in the system and become more concentrated with time. 22-4 GROUNDWATER POLLUTION Pollutants in drinking water (which is mostly groundwater) = high risk health problem 1. Pollutant/contaminant can leaks into pores of bedrock surrounding aquifer. (sponge-like) 2. Pollutant slowly flows through aquifer, as a plume of contaminated water, which may reach well used to extract groundwater for drinking and irrigation Groundwater cannot cleanse itself of degradable wastes (nondegradable= permanent) due to slow flow, cold temps, less O2, less bacteria THE EXTENT OF GROUNDWATER POLLUTION 1/3 of US industrial waste ponds have no liners to prevent seepage 76,000+ underground tanks storing gas/fuel/oil are leaking “ Fluoride contamination- crippling backbone and neck damage (China & India ) Nitrate ions (NO3-) cause cancer and “blue baby syndrome” Arsenic- skin, bladder, and lung cancer (mostly in Bangladesh) Clean-up once chemicals reach an aquifer is nearly impossible Erin Brockovich” movie Pacific Gas & Electric had been poisoning the small town of Hinkley’s Water for over 30 years. It was exposed for leaking toxic Chromium 6 into the ground water. This poison affected the health of the population of Hinkley. SOLUTIONS: HOW TO PROTECT GROUNDWATER Preventing groundwater contamination is the most effective and cheapest solution 22-5 OCEAN POLLUTION WE DO NOT KNOW HOW MUCH POLLUTION THE OCEAN CAN TOLERATE The ocean can break down wastes that we put into it so people have taken this fact for granted and added large amounts of waste into the ocean rather than burying them. Scientists say that we do not know how much the ocean can handle, adding wastes would postpone pollution prevention rather than promoting it. EFFECTS OF POLLUTION ON COASTAL AREAS 40% of the world’s population lives on the coast and pollutes the water. Sewage and industrial waste is dumped into the sea without treatment which causes beach pollution and shellfish contamination. Because of the pollution, the coastal waters are full of colonies of viruses Harmful algal blooms (HAB) are formed because of the excess nitrate and phosphate plant nutrients in the water. POLLUTION IN COASTAL AREAS SAVING THE COASTAL WATERS In 1980, the countries surrounding the Baltic Sea signed the Helsinki Convention – the world’s first international agreement to reduce marine pollution To reduce the number and size of oxygen depleted zones, scientists have done some of the following: i. Reduced nitrogen inputs from various sources ii. Restored coastal wetlands iii. Planted forests and grasslands to soak up excess nitrogen and keep it out of waterways CASE STUDY: THE CHESAPEAKE BAY: AN ESTUARY IN TROUBLE The Chesapeake Bay had a large amount of water pollution because of growing population. It received wastes from many point and nonpoint sources. Phosphate and nitrate levels rose which caused algal blooms and oxygen depletion. Populations of oysters, crabs and fish dropped because of pollution overfishing and disease. CASE STUDY: THE CHESAPEAKE BAY (continued) The US implemented The Chesapeake Bay Program where citizens, communities, and the government collectively worked together to reduce pollution into the bay. Between 1985 and 2000, phosphorous levels declined 27% nitrogen levels dropped 16% and grasses came back. Solutions: Can Oysters Help Clean Up the Chesapeake Bay? A way to decrease water pollution in the Chesapeake Bay would be to rebuild the bay’s depleted oyster population with disease-resistant oysters. This is because oysters filter algae and silt from water. Over-harvesting and disease were responsible for the decline in the population. Link: http://www.cbf.org/oysters What is being done to control the dumping of pollutants into the ocean? Although dumping off US coasts has stopped ships still legally dump dredge spoils at 110 sites through the world. Sewage sludge is also being dumped. Since 1992 the US has banned this practice and 50 other countries have agreed to stop dumping. Since the ocean is so vast the agreement is difficult to enforce and is violated all the time. What are the major sources of ocean oil pollution? Human activities on land. Tankers get much of the publicity for oil but over two years twice as much oil is leaked from shore activities than tanker spills. Normal operation of off-shore wells, washing oil tankers and releasing oily water, loading/unloading oil tankers, and leaks from oil pipelines, refineries, and storage tanks are all responsible. Almost half of oil reaching the ocean is from being dumped on the ground, poured down the drain, spilled, or leaked onto land/sewers by cities, industries, and people changing their motor oil. THE EFFECTS OF OIL POLLUTION ON OCEAN ECOSYSTEMS AND COASTAL COMMUNITIES: SERIOUS BUT NOT LONG-LASTING Depend on a number of factors: Types of Oil: Crude Oil- marine life recovers within about 3 yrs. Refined Oil- marine life recovers can take 1015 yrs. Type of Aquatic System Amount Released Distance of Release from Shore Time of Year Weather Conditions Average Water Temperature Ocean Currents Heavy oil components that sink to the ocean floor or wash into estuaries can smother bottomdwelling organisms. (crabs, oysters, mussels, and clams) Water Pollution Solutions: WE CAN'T CLEAN UP OIL SPILLS VERY WELL Mechanical Methods include: floating booms to contain the oil spill or keep it from reaching sensitive areas skimmer boats to vacuum up some of the oil into collection barges absorbent devices such as large mesh pillows filled with feathers or hair to soak up oil on beach on beaches or in waters too shallow for skimmer boats. Chemical Methods include: Coagulating agents to cause floating oil to clump together for easier pickup or to sink to the bottom (less harmful) Dispersing agents to break up oil slicks (damage some organisms) Fire can burn off floating oil (crude oil hard to ignite, and produces air pollution) Biological Methods include: In which “cocktails” of bacteria are sprayed on the oil to break it down into chemicals that the bacteria consume or that disperse harmlessly into the sea. Cheaper and may be more effective than other cleanup methods. Solutions: How Can We Protect Coastal Waters? Think Prevention Solutions Coastal Water Pollution Prevention Cleanup Reduce input of toxic pollutants Improve oil-spill cleanup capabilities Separate sewage and storm lines Ban dumping of wastes and sewage by maritime and cruise ships in coastal waters Sprinkle nanoparticles over an oil or sewage spill to dissolve the oil or sewage without creating harmful byproducts (still under development) Ban ocean dumping of sludge and hazardous dredged material Protect Sensitive areas from development, oil drilling, and oil shipping Require at least secondary treatment of coastal sewage Regulate coastal development Recycle used oil Require double hulls for oil tankers Use wetlands, solar-aquatic, or other methods to treat sewage Reducing Pollution From Nonpoint Sources Most of non point source pollution is caused by the agriculture industry We can prevent pollution by Reducing soil erosion Using less fertilizers Apply pesticides only when needed Control runoff In 2002 EPA required 15,500 of the nation’s largest feed lots/ factory farms to apply for EPA runoff permits by 2006 Annual reports Develop plans to handle manure/wastewater In 2003 Smithfield Foods built a factory to transform waste into bio-diesel fuel Reducing Pollution From Point Sources Clean Water Act (1972 and 1977) Sets standards for allowed levels of certain pollutants Polluters must get permits discussing amount and types of pollutants Water Quality Act Most developing nations do not have regulations and 8090% of waste water goes into watersheds with no treatment Citizens then use this water for drinking, bathing, cooking Reducing Pollution From Point Sources Technological approach Septic Tanks (25% of homes in US) System where sewage from houses can be drained Sewage treatment plant Primary- removes about 60% Secondary- removes aerobic bacteria and 90% of organic waste Advanced/ Tertiary- remove specific pollutants Chlorination Septic Tank Sewage Treatment Plant Animation What to Do With Sewage Sludge Sludge is a mixture of bacterialaden solids and toxic chemicals 36% used to fertilize 55% dumped in landfills or burned Very harmful and causes a lot of health problems due to all of the toxins it contains Improving Sewage Treatment Prevent toxic chemicals from reaching treatment plants so chemicals from the sludge will be eliminated along with discharged water from plants. Convert to waterless, composting toilet systems Composting toilet systems are cheap to install and don’t require intricate and large systems of underground pipes that connect to treatment plants. Treating Sewage through Nature Natural and artificial wetlands and other ecological systems can be used to treat sewage. John Todd developed “living machines” 1. Sewage goes to sedimentation tanks where the solid particles become sludge which is then taken out and made into fertilizer. 2. The liquid is pumped into oxidation ponds where the remaining waste is broken down by bacteria. 3. After about a month, the water is let into the artificial marshes where further filtration and cleansing is done by bacteria and plants. 4. The clean, purified water then flows into the Humboldt Bay. Treating Sewage through Nature (cont’d.) Mark Nelson also developed a wastewater garden system that removes 99.9% of bacteria and more than 80% of nitrates and phosphates from incoming sewage. Small, low tech, inexpensive artificial wetland system for developing nations, hotels, restaurants, and homes. The water flowing out of this system can be used to water lawns or flush toilets to conserve water. 1.7 billion do not have access to proper sanitation, by 2050 it could be up to 3 billion. Reducing Water Pollution Water pollution laws have improved water quality in many areas in the U.S. due to the Clean Water Act of 1972. The number of water systems that met federal health standards increased from 79% to 94%. Also, annual wetlands losses decreased by 80%. Suggestions to strengthen Clean Water Act to increase funding and control of nonpoint source pollution, upgrading computer systems for monitoring, and strengthening programs to prevent/control toxic water pollution. Also, to protect groundwater and surface water from contamination. Many government officials think its too expensive to carry all this out and test for water pollutants. Drinking Water Quality Most drinking water has only disinfection treatments before going out to households In areas where surface water is used for drinking, it goes through a more thorough process of aeration and purification. Do we need to protect water purification systems? The US is upgrading security, but the threat is small The average water reservoir is so big that it is difficult to tamper or poison but because of the large network of purification plants and accessibility, the drinking water is still hard to protect. Growing concerns have produced results in more security measures such as upgrades in security cameras, special chemical indicating technology and emergency response plans. Purifying Drinking Water in Developing Nations Simple ways to purify water: Putting water in a clear plastic bottle and exposing to sunlight Painting one side of the bottle black can improve UV absorption. (but could break down plastic and release harmful chemicals!!!) Using strips of cloth to filter cholera. Using chlorine-disinfectant solution. Simply boiling water or using clear bottles and putting them in the intense sunlight is still the most efficient way to kill bacteria. Most rates of cholera and diarrheal diseases have been reduced by half in India, Kenya, and other tropic nations Water laws US Safe Drinking Water Act of 1974EPA sets standard for contaminants Only public wells/systems are regulated Bottled Water: Solution or Rip-off? Studies and experts show that in the United States bottled water is 240 to 10,000 times more expensive than ordinary tap water!!! Other harmful effects of bottled water include environmental toxic gases and liquids expelled during the manufacturing process. http://www.ppines.com/publics ervices/pdfs/water-report2009.pdf Reducing Water Pollution Most of the worlds developed countries have already enacted laws preventing water pollution. Yet still little has been done to improve conditions in the developing parts of the world. Water Pollution Solutions Reducing poverty Reducing resource waste Reduce nonpoint runoff Reuse treated water Prevent Groundwater contamination Reducing air pollution Bottom-up political pressure