Transcript Chapter 14
Chapter 14 Water Pollution Water Facts Every 20 seconds, a child dies from a water-related illness in the world More than 3 times as many people lack access to clean water than live in the United States More people have cell phones worldwide than have access to a toilet Half of the hospital beds in the world are occupied by patients suffering from diseases associated with lack of access to safe drinking water, inadequate sanitation, and poor hygiene Diarrhea is the second leading cause of death among children under five in the world. It kills more children than malaria, AIDS, and measles combined Of the 60 million people added to the world's towns and cities every year, most move to informal settlements (i.e. slums) with no sanitation facilities An American taking a five-minute shower uses more water than the average person in a developing country slum uses for an entire day 1.1 billion people still practice open defecation In 3 days, the amount of untreated fecal matter in the world would fill up the Superdome Courtesy of water.org 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 Nonpoint sources - diffuse areas, such as an entire farming region, that pollutes a waterway Point source Nonpoint source Point Source vs. Nonpoint Source It is easier to control pollution that comes from a distinct source than pollution that does not come from a distinct source Point sources discharge pollutants at specific locations through pipes, ditches, or sewers (ex: factories, sewage treatment plants, mines, oil wells, oil tankers) Nonpoint sources cannot be traced to a single site of discharge (ex: acid deposition, runoff, seepage into groundwater) Nonpoint source water pollution from agriculture is the largest source of water pollution in the U.S. (64% of pollutants entering streams and 57% of pollutants entering lakes) Human Wastewater Water produced by human activities such as sewage from toilets and gray water from bathing and washing clothes/dishes Warm-Up 1. What is the difference between point source and nonpoint source pollution? 2. Name 2 examples of each. Human Wastewater Oxygen-demanding waste – organic matter that enters a body of water and feeds microscopic decomposers that use oxygen Nutrients that are released from wastewater 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 Lower BOD values indicate the water is less polluted Higher BOD values indicate the water is more polluted Biochemical Oxygen Demand (BOD) BOD: the amount of dissolved oxygen needed by aerobic decomposers to break down organic materials in a certain volume over a 5–day incubation period at 20° C It is measured as a rate (mg O2 per liter per 5 days) Biochemical Oxygen Demand (BOD) Dissolved oxygen (DO) is an indicator of water quality and measured in ppm DO supplies oxygen to fish, amphibians, and zooplankton in water It is the basis of aquatic food chains Eutrophication Eutrophication - an abundance of fertility in a body of water Caused by an increase in nutrients, such as fertilizers Eutrophication can cause a rapid growth of algae, which eventually dies and causes the microbes to increase the BOD Courtesy of www.lakescientist.com Oxygen Sag Curve Flowing water (including rivers and streams) can recover rapidly from oxygen-demanding wastes by dilution and bacterial decay “Dead Zone” “Dead Zone” Pollution of Lakes Natural nutrient enrichment of lakes is called eutrophication Cultural eutrophication human activities accelerate the input of nutrients to a body of water Courtesy of www.lakescientist.com Common Diseases from Human Wastewater Cholera Typhoid fever Stomach Diarrhea Hepatitis flu Fecal Coliform Bacteria coliform bacteria – group of bacteria found in the intestines and feces of vertebrate animals Fecal Escherichia coli (E. coli) is usually the bacteria tested for – its presence indicates a risk of other wastewater pathogens Warm-Up DO BOD Wastewater Treatment Septic systems - a large container that receives wastewater from a house Primarily used in rural and suburban areas Traps large solids in the tank and discharges the liquid over the leach field Wastewater Treatment Sewage Treatment Plants - centralized plants in areas with large populations that receive wastewater via a network of underground pipes Primary sewage treatment involves screens and settling tanks to remove solids from sewage Secondary sewage treatment uses biological processes to break down biodegradable, oxygen-demanding wastes Sludge to Fuel http://www.waste-enterprisers.com/our-businesses/ Treatments for Animal Wastewater Manure lagoons - large, human-made ponds lined 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 fertilizer Heavy Metals and Other Substances that can threaten human Health and the Environment Lead Enters Can water through lead pipes cause behavioral problems, learning disabilities, and kidney problems Arsenic Enters water through natural deposits, coal mining/burning, and pesticide use Can cause cancer, nervous system problems, birth defects Mercury Enters Can water through natural deposits, coal burning, and mining damage nervous and immune systems, and embryos Acids Synthetic organic compounds (SOC) World Mercury Production Acid Damage 1908 1969 Acid Deposition – lower pH due to air pollution (CO2, SOx, NOx) produces lower than normal pH in rain and snow Acid Mine Drainage – pyrite breaks down in groundwater, creating low pH water Acid Deposition Acid Deposition Acid Mine Drainage Synthetic Organic Compounds (SOC) Pesticides & inert ingredients – DDT, atrazine Hormones & pharmaceuticals – estrogen, caffeine, antibiotics Military compounds – perchlorates Industrial compounds – PCBs, PBDEs Synthetic Organic Compounds (SOC) Bioaccumulation – increase in tissue concentrations of a material above normal environmental levels Biomagnification increase in concentration of materials in organisms from eating the tissues of other organisms (concentration increases up the food chain) Contaminants Found in U.S. Streams Groundwater Pollution Groundwater pollution is a greater threat to humans than surface water pollution Groundwater is typically recharged slowly, so pollution lingers for long periods of time Up to 25% of usable groundwater in the U.S. is estimated to be contaminated It is extremely difficult and expensive to clean-up contaminated groundwater; prevention is more effective Groundwater Pollution Prevention Reduce sources of water pollution that feed into the aquifer Monitor aquifers near landfills and underground storage tanks Require leak detection systems and liability insurance for existing and new underground tanks that store hazardous liquids Ban or more strictly regulate disposal of hazardous wastes in deep injection wells and landfills Store hazardous liquids aboveground with more safeguards Oil Pollution Oil is accidentally and deliberately released into the environment from various sources Most anthropogenic oil leaks are released in normal operation of offshore wells, pipelines, and storage tanks Accidents can release large amounts of oil in a short period of time Oil Pollution Oil Pollution Some aquatic organisms (esp. plankton and larvae) are killed immediately Oil coats birds and marine mammals, destroying natural insulation and buoyancy Heavy oil sinks to ocean bottom and washes into estuaries, contaminating crabs, oysters, mussels, etc. Oil slicks on beaches harms intertidal life and causes economic losses to tourism and fishing industries Case Study: Exxon Valdez Oil Spill On March 24, 1989, the Exxon Valdez tanker went off course, hit submerged rocks in Prince William Sound, Alaska, & created the worst oil spill in U.S. waters (at the time) Coated 1,600 miles of shoreline, killed wildlife, & caused serious contamination Exxon spent $2.2 billion on direct cleanup + $1 billion fines & damages; another $5 billion damages being appealed Case Study: BP Oil Spill On April 20, 2010 the BP offshore drilling platform Deepwater Horizon exploded in the Gulf of Mexico 11 workers were killed in the explosion Almost 5 million barrels of oil were spilled into the water during the 87 day leak BP has committed to pay up to $30 billion in clean-up costs and compensation http://www.ifitweremyhome.com/dis asters/bp Courtesy of USA Today Ways to Remediate Oil Pollution Containment using booms to keep the floating oil from spreading Chemicals (dispersants) that help break up the oil, making it disperse before it hits the shoreline Bacteria that are genetically engineered to consume oil Other Water Pollutants Solid waste pollution (garbage) Sediment pollution (sand, silt and clay) Thermal Noise pollution pollution Solid Waste Pollution Pacific Trash Vortex Courtesy of good.net.nz Solid Waste Pollution Coastal areas have enormous inputs of waste into oceans Half of the world’s population lives within 60 miles of the ocean About 35% of municipal sewage ends up virtually untreated in U.S. ocean water Many countries still dump large quantities of toxic substances into the ocean Sediment Pollution Human activities increase the amount of sediment entering waterways Construction and plowing agricultural fields are leading causes of increased sediment levels Sediment reduces infiltration of sunlight and clogs gills of aquatic species Thermal Pollution Two effects: Temperature affects dissolved oxygen (DO) “Thermal Shock” Noise Pollution 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 Clean Water Act Restores and maintains the chemical, physical, and biological integrity of the nation’s waters Sharply reduces direct pollutant discharges into waterways Finances municipal wastewater treatment facilities Manages polluted runoff Clean Water Act Programs 1. Water quality standards (WQS) 2. Policies against water degradation 3. Waterbody monitoring and assessment 4. Reports on condition of the nation’s waters 5. Define total maximum daily loads (TMDL) of pollutants 6. National Pollutant Discharge Elimination (NPDES) system permit programs for point sources 7. Program for nonpoint sources 8. Program regulating filling of wetlands and other waters Water Laws Water Quality Act (1965) – states directed to develop water quality standards establishing water quality goals for interstate waters By early 1970s, every state has adopted such water quality standards States have revised their standards to reflect new scientific information, the impact on water quality of economic development, and the results of water quality controls 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 Dealing with Water Pollution Agriculture is the primary nonpoint source of water pollution Reducing nonpoint water pollution requires changing farming practices to reduce runoff from fertilizer, pesticides, and livestock, as well as reduce soil erosion Non-farm use (golf courses, lawns, etc.) of fertilizers and pesticides are another major nonpoint source of pollution