- Slides: 67
Chapter 14 Water Pollution
Water Pollution © Water pollution- the contamination of streams, rivers, lakes, oceans, or groundwater with substances produced through human activities and that negatively affect organisms. © Point sources- distinct locations that pump waste into a waterway. These are easily identified © Nonpoint sources- diffuse areas such as an entire farming region that pollutes a waterway. These are more expensive and difficult to clean up.
Can you identify which of these is point source Pollution?
Categories of Water Pollution • • • Sewage disease-causing agents sediment pollution inorganic plant and algal nutrients organic compounds inorganic chemicals radioactive substances thermal pollution Noise pollution
Water Pollution is a Problem Worldwide Half of the world’s major rivers are seriously depleted and polluted They poison surrounding ecosystems Threaten the health and livelihood of people The invisible pollution of groundwater has been called a “covert crisis”
Water Pollution Over two-thirds of U. S. estuaries and bays are severely degraded because of nitrogen and phosphorous pollution Every year almost 25% of U. S. beaches are closed at least once because of water pollution Over 73 different kinds of pesticides have been found in the groundwater that we eventually use to drink 1. 2 trillion gallons of sewage, storm water and industrial waste are discharged into U. S. waters every year A large number of U. S. rivers are too polluted for aquatic life to survive Americans use over 2. 2 billion pounds of pesticides every year, which eventually washes into our rivers and lakes
Leading causes of water pollution 1. Agriculture activities • Sediment eroded from the lands • Fertilizers and pesticides-almost all waters are polluted with pesticides • Bacteria from livestock and food processing wastes 2. Industrial facilities- heavy metals, corrosive materials organic and non-organic chemicals 3. Mining- acid drainage pollutes water by leeching out heavy metals
Agriculture major source of water pollution § Agriculture is leading source of water pollution in US § Animal wastes and plants residues have high BOD § Chemical pesticides can leach into groundwater § Almost all streams and rivers are polluted with agricultural pesticides
Agricultural Runoff is the main cause of the Dead Zone in the Gulf of Mexico; The U. N. documented 250 dead zones worldwide in 2005
Sediment runoff from farmland is the highest Pollution from agriculture by weight.
Eutrophication © Eutrophication is an abundance of fertility to a body of water. © Eutrophication is caused by an increase in nutrients, such as fertilizers. © Eutrophication cause a rapid growth of algae which eventually dies, causing the microbes to increase the BOD and oxygen levels to fall eventually may cause a die-off of all organisms.
Solutions to Reduce Eutrophication • Phosphate-free detergents • Planting vegetation to increase nutrient uptake • Treat wastewater • Reduce fertilizer application
Different industries add different pollutants § Food processing plants- high BOD § Paper mills- High BOD and toxic compounds § Textile industry-the World Bank estimates that 17 -20 percent of industrial pollution comes from textile industry with 72 toxic chemicals being added to water
According to Greenpeace, the discharge from these factories includes heavy metals and “hazardous and persistent chemicals with hormone-disrupting properties” were found being discharged from China’ s factories
Heavy Metals and Other Substances that can threaten human Health and the Environment © Lead © Arsenic © Mercury © Acids © Synthetic compounds (pesticides, pharmaceuticals, and hormones)
More on heavy metals §Lead §Found in old paint, industrial pollutants, leaded gasoline §Mercury bioaccumulates in the muscles of top predators of the open ocean
Arsenic found naturally in rocks and water • When arsenic is found in water, it may be from natural causes • Highest levels of arsenic in U. S. found in upper Midwest and West • Individual wells dug in Southeast Asiamany are contaminated by arsenic causing arsenic posioning
World Mercury Production from Human Activities
Pharmaceuticals and Hormones Found in Water
Industrial Compounds • Chemicals used in manufacturing • Local examples include PCBs in Hudson River from General Electric Co. and cadmium from foundry in Cold Spring • PCBs cause brain damage, are lethal and carcinogenic
Marine pollution threatens resources • • Even into the mid-20 th century, coastal U. S. cities dumped trash and untreated sewage along their shores Oil, plastic, chemicals, excess nutrients make their way from land into oceans Raw sewage and trash from cruise ships Abandoned fishing gear from fishing boats In 2006, 359, 000 Ocean Conservancy volunteers from 66 nations picked up 3. 2 million kg (7 million lbs. ) of trash
Ways to Remediate Oil Pollution © Containment using booms to keep the floating oil from spreading. © Chemicals that help break up the oil, making it disperse before it hits the shoreline. © Bacteria that are genetically engineered to consume oil
Water Pollution from Mining • Acid Mine Drainage-low p. H of water causes iron to precipitate from pyrite and cause a rusty red color • Heavy metal contamination and leeching • Mine waste and tailings • Processing chemicals pollution • Sedimentation of waters and erosion
Mining often pollutes waters
Other Water Pollutants © Solid waste pollution (garbage) © Sediment pollution (sand, silt and clay) © Thermal pollution © Radioactive pollution © Noise pollution
Solid Waste Pollution • • Much solid waste is garbage North Pacific Gyre-Great Pacific Garbage Patch Plastic waste is dangerous to marine animals and humans Found in the stomachs of dead baby sea birds as parent birds think the small pieces of plastic is phytoplankton.
Plastic rubbish deposits
Plastic Pollution of Water • Plastics can release harmful chemicals into the water • Plastic is a synthesized organic compound (carbon-hydrogen bonds) that does not decompose • Plastic breaks up into extremely tiny pieces that is mistaken for food by many organisms.
Sediment Pollution §Excessive amounts of suspended soil particles §Originates from erosion of agricultural lands, forest soils exposed by logging, degraded stream banks, overgrazed rangelands, strip mines, and construction §Problems §Limits light penetration §Covers aquatic animals and plants §Brings insoluble toxins into waterways
Land disturbance results in poor water quality Clear-cutting, mining, poor cultivation practices Dramatically changes aquatic habitats, and fish may not survive Solutions: better management of farms and forests; avoid large-scale disturbance of vegetation
Radioactive Substances § Contain atoms of unstable isotopes that spontaneously emit radiation § Sources § Mining § Processing radioactive materials § Nuclear power plants § Natural sources
Thermal Pollution Occurs when heated water produced during industrial processes is released into waterways Temperature affects digestive rates, heart rates, and respiration rates Warmer water holds less dissolved oxygen Removing streamside cover also raises water temperature
Noise Pollution • Sounds from ships and submarines • Sonar equipment could negatively affect whales, causing them to be beached • U. S. Military exempt from environmental laws related to sonar use
Organic Compounds found in Polluted Water
Human Wastewater © Water produced by human activities such as human sewage from toilets and gray water from bathing and washing clothes or dishes.
Why human and animal waste water needs to be treated Pathogens and toxins enter water supply via inadequately treated human waste and animal waste via feedlots Causes more human health problems than any other type of water pollution
Three reasons scientists are concerned about human wastewater: © Oxygen-demanding wastes like bacteria that put a large demand for oxygen in the water © Nutrients that are released from wastewater decomposition can make the water more fertile causing eutrophication © Wastewater can carry a wide variety of disease-causing organisms.
Biochemical Oxygen Demand (BOD) © BOD- the amount of oxygen a quantity of water uses over a period of time at a specific temperature. © As BOD increases Dissolved Oxygen (DO) decreases © Lower BOD values indicate the water is less polluted and higher BOD values indicate it is more polluted by wastewater.
Sewage and pollutants in drinking water Currently, 1. 1 billion people are without safe drinking water 2. 4 billion have no sewer or sanitary facilities Mostly rural Asians and Africans An estimated 1. 6 to 5 million people die per year from unsafe drinking water
Common Diseases from Human Wastewater
Major Water Pollutants and Their Sources Table 20 -1, p. 532
Solutions • Treat sewage • Disinfect drinking water • Public education to encourage personal hygiene • Government enforcement of regulations
Treatments for Human and Animal Wastewater © Septic systems- a large container that receives wastewater from the house.
Treatments for Human and Animal Wastewater © Sewage Treatment Plants- centralized plants in areas with large populations that receive wastewater via a network of underground pipes. © Test for human and animal waste using fecal coliform bacteria test
Levels of Treatment and Success Primary treatment: Some pathogenic bacteria and some solids removed Secondary treatment: some viruses, more waste solids, more pathogenic bacteria, and some dissolved organics removed, BOD lowered Tertiary treatment: Phosphorous and nitrogen levels lowered, dissolved organics and pathogenic bacteria lowered, waste solids completely removed Chlorination treatment: Pathogenic bacteria completely removed, nitrogen amounts lowered further, viruses lowered further
Tertiary treatment of waste water often includes Chlorine treatment §Chlorine Dilemma §Chlorine byproducts are linked to numerous cancers, miscarriages and birth defects §Peru stopped using chlorine § 1991: huge cholera epidemic that infected 300, 000 people §Fluoridation §Prevents tooth decay §Linked to cancer, kidney disease
Treatments for Human and Animal Wastewater © Manure lagoons- large, human-made ponds line with rubber to prevent the manure from leaking into the groundwater. After the manure is broken down by bacteria, it is spread onto fields as fertilizers.
Problems with Manure Lagoons Containment of lagoons may burst if containment walls break. During high precipitation events lagoons may overflow bringing pathogenic bacteria to water supply
We have better methods- We can improve traditional sewage treatment Use of natural wetlands Remove toxic wastes before sewage enters treatment plants Use composting toilets Reduce use of toxic materials
Using Nature to Purify our waste water and sewage water • Natural water purification system • • • Sewage flows into anaerobic digester Cleaner water then passes through artificial marsh to remove some nutrients water flows into a passive greenhouse Solar energy and natural processes remove and recycle nutrients Diversity of organisms used
Use of a Living Machine to purify waste water Omega Center in Rhinebeck NY
Water Laws © Clean Water Act- (1972) supports the “protection and propagation of fish, shellfish, and wildlife and recreation in and on the water”. © Issued water quality standards that defined acceptable limits of various pollutants in U. S. waterways. © Effectively improved water quality from point sources
Water Laws © Safe Drinking Water Act- (1974, 1986, 1996) sets the national standards for safe drinking water. © It is responsible for establishing maximum contaminant levels (MCL) for 77 different elements or substances in both surface water and groundwater.
Indicators of water quality • Scientists measure properties of water to characterize its quality • • • Biological indicators: presence of fecal coliform bacteria and other disease-causing organisms Chemical indicators: p. H, nutrient concentration, taste, odor, hardness, dissolved oxygen Physical indicators: turbidity, color, temperature
Streams Can Cleanse Themselves If We Do Not Overload Them • Dilution of pollutants does help • Biodegrading of wastes by bacteria (takes time) Some substances are not biodegradable • Higher human population stresses natural system of cleansing • Prevention is less costly and more effective and cleanup
Dilution and Decay of Degradable, Oxygen-Demanding Wastes in a Stream Fig. 20 -7, p. 534
Solutions: Methods for Preventing and Reducing Water Pollution
What Can You Do? Reducing Water Pollution