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General Water Quality Facts
Less than 1% of the earth's total water supply is suitable for drinking. Dirty water kills 5,000 children per day (United Nations, 2006) and 3 million per year globally. 44% of streams, 64% of lakes, and 30% of bays assessed are not clean enough to support uses such as fishing and swimming. (US EPA, 2011) Every day, 2 million tons of sewage and industrial and agricultural waste are discharged into the world’s water. (United Nations, 2003)
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Water Availability Water covers about 72% of the Earth, however only 2.5% of that considered freshwater.
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What is Water Pollution?
Water pollution is… Any chemical, biological, or physical change in water quality that has a harmful effect on living organisms or makes water unsuitable for desired usage.
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Water Pollution & Agriculture
Agriculture is the single largest user of freshwater resources, using a global average of 70% of all surface water supplies. Industrial agriculture is one of the leading causes of water pollution in the United States. Agricultural activity was identified as a source of pollution for 48% of stream or river water and 41% of lake water. (EPA: National Water Quality Inventory, 2000)
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Surface Water Surface water is water collecting on the ground or in a stream, river, lake, wetland, or ocean. Naturally replenished by precipitation, lost through evaporation into the atmosphere, and seeps into groundwater
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Groundwater Groundwater is water located beneath the earth's surface in soil pore spaces and in the fractures of rock formations. Aquifers are defined as water-bearing porous soil or rock strata that yield significant amounts of water to wells.
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Groundwater Solutions
Prevention is easier and less expensive than cleanup.
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Water Pollution Point Source Pollution Nonpoint Source Pollution
comes from a specific source, like a pipe factories, industry, municipal treatment plants can be monitored and controlled by a permit system Nonpoint Source Pollution Nonpoint Source (NPS) Pollution is pollution associated with stormwater or runoff NPS pollution cannot be traced to a direct discharge point such as a wastewater treatment facility
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Point vs. Nonpoint NONPOINT SOURCES Rural homes Cropland Urban streets
Suburban development Wastewater treatment plant Rural homes Cropland Factory Animal feedlot POINT SOURCES
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Nonpoint Water Pollution
Often due to impermeable surfaces Runoff is increased when impervious surfaces are increased Examples include sewage & cleaners from boats household cleaning products litter & garbage oil & grease from cars fertilizers animal waste grass clippings septic systems
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Pollutants Found in Runoff
Sediment Soil particles transported from their source Biochemical Oxygen Demand (BOD) ● Oxygen depleting material Leaves Organic material Debris Litter and illegal dumping Toxics ● Pesticides Herbicides Fungicides Insecticides ● Metals (naturally occurring in soil, automotive emissions/ tires) Lead Zinc Mercury ● Petroleum Hydrocarbons (automotive exhaust and fuel/oil) Nutrients ● Various types of materials that become dissolved and suspended in water (commonly found in fertilizer and plant material): Nitrogen (N) Phosphorus (P) Bacteria/ Pathogens Originating from: ● Pets ● Waterfowl ● Failing septic systems Thermal Stress Heated runoff, removal of streamside vegetation
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5 Types of Water Pollution
Sediment reduces light penetration in stream, clogs gills of fish and aquatic invertebrates. Nutrients act as fertilizer for algae & aquatic plants which can cause low dissolved oxygen levels = eutrophication. At low DO levels, the aquatic life has the potential to be harmed. Trash and Organic Debris Leaves, grass clippings, garbage, and animal waste become part of the runoff entering storm drains. Chemicals can impact life and contaminate drinking water supplies. Bacteria/Pathogens are an indicator of possible viruses present in the system.
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Water Pollution Impacts
fish and wildlife recreational water activities commercial fishing tourism drinking water quality human health harms crops Aquatic diseases and deformities Human health issues Eutrophication
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Sediment When large quantities of soil enter waterways, pollution occurs. In terms of sheer volume, sediment is one of the most devastating pollutants affecting waterways. Sediment pollution reduces streams and reservoirs volume capacity and increases the expense to treat water. Millions of dollars are spent each year to remove excess sediment. Sediment suspended in water destroys fish and wildlife habitat. Sediment from eroding stream banks and land surfaces and agricultural and industrial chemicals carried by that sediment could smother aquatic life, clog fish gills, and off light to underwater plants. Sediment pollution can be just as deadly to aquatic life as chemicals Aquatic diseases and deformities Human health issues Eutrophication
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Nutrients Nutrients are essential to water life, but too much can harm more than help. Phosphorous, nitrogen, and potassium are nutrients that help plants and animals grow. Found in fertilizer, sewage, detergents, and animal wastes Excess nutrients in an already healthy environment can be dangerous. Too many nutrients can cause an overgrowth of vegetation or bloom of algae. Eventually the algae dies and decays. The decaying process depletes oxygen in the water, leaving less for aquatic plants and animals. The balance of life in the stream ecosystem is interrupted and disturbed. An overgrowth of algae also minimizes the amount of light that can reach aquatic plants. An increase in dead organic material from the dying plants exacerbates the problems associated with low oxygen levels. Aquatic diseases and deformities Human health issues Eutrophication
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Eutrophication of Lakes
Eutrophication: nutrient enrichment of lakes mostly from runoff of plant nutrients (nitrates & phosphates) During hot dry weather can lead to algae blooms Decrease of photosynthesis Dying algae then drops DO levels Fish kills, bad odor
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Trash and Organic Debris
Leaves, grass clippings, garbage, and animal waste become part of the runoff entering storm drains and local waterways and clogging the system. Decaying organic matter like leaves contributes to eutrophication. Trash and organic debris is one of the easiest types of NPS pollution to control. Dispose of litter in garbage cans or in recycling bins. Recycle glass, aluminum, plastic, paper, motor oil, and newspapers. Compost yard and garden waste. Pick up pet waste and bag it with regular household trash or flush it in the toilet. And, never intentionally dump anything into a storm drain.
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Chemicals & Heavy Metals
Includes organic chemicals, pesticides, herbicides, formaldehyde, household chemicals, paint, paint cleaners, gasoline, motor oil, battery acid, DDT, PCBs, Medicines, etc. Heavy Metals Mercury Cadmium Lead Copper Arsenic Dichloro-diphenyl-trichloroethane Polychlorinated biphenyls
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Biomagnification of Toxins
Diagram showing biomagnifications of PCBs in an aquatic food chain from the Great Lakes. Increased PCB concentration as toxins move up the food chain.
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Pathogens Most serious water pollutants in terms of human health worldwide are pathogenic organisms. Main source of these pathogens is from untreated or improperly treated human wastes. In developed countries, sewage treatment plants and other pollution-control techniques have reduced or eliminated most of the worst sources of pathogens The situation is quite different in less-developed countries. The United Nations estimates that at least 2.5 billion people in these countries lack adequate sanitation, and that about half these people also lack access to clean drinking water. Aquatic diseases and deformities Human health issues Eutrophication
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Case Study: The Great Lakes
Pollution levels dropped, but long way to go 95% of U.S. freshwater 30% Canadian pop, 14% U.S. 38 million drink 1% flow out St. Lawrence Toxic fish Solution to pollution is dilution nearly 100 percent of all industrial plants use control measures to reduce their toxic discharge, and the number of sewage treatment facilities has doubled.
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Case Study: The Gulf of Mexico
Caused by drainage from the Mississippi River Area varies in size, but can cover up to 6,000-7,000 sq. miles Low oxygen can not support life Devastating to local fisheries The Mississippi River which is the drainage area for 41% of the continental United States, dumps high-nutrient runoff, such as nitrogen and phosphorus, into the Gulf of Mexico. According to a NOAA 2009 fact sheet, "Seventy percent of nutrient loads that cause hypoxia are a result of agricultural runoff of this vast drainage basin"[13] which includes the heart of U.S. agribusiness, the Midwest. The discharge of treated sewage from urban areas (pop. c 12 million in 2009) combined with agricultural runoff deliver c. 1.7 million tons of potassium and nitrogen into the Gulf of Mexico every year.[13] In 2011 it was about 17,521 sq kilometers, which is larger than Connecticut.
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How do you determine if a body of water is healthy or polluted?
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Water Quality Index (WQI)
A WQI provides a single number (like a grade) that expresses overall water quality at a specific location and time based on several water quality parameters. Measures how healthy a body of water is.
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Water Quality Tests Dissolved Oxygen = required to support plants and animals pH = acidic (H+) or basic (OH-) Temperature = too warm or cool is damaging Total Phosphate = essential plant nutrient Nitrates/Ammonia = causes growth, decay, and eutrophication Turbidity = water clarity, light penetration Fecal Coliform = feces, bacteria, pathogens Bioindicators = living organisms that relate to water quality
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Dissolved Oxygen (DO) Amount of gaseous oxygen (O2) dissolved in water
Oxygen gets into water by diffusion from the surrounding air, by aeration, and through photosynthesis DO range from 0-18 mg/L Need 5-6 mg/L to support a diverse population DO < 2 mg/L - Hypoxia
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pH Measures hydrogen ion concentration (H+)
Measured on a logarithmic scale from 0-14 7 is neutral and ideal for many organisms (H2O) High pH up to 14 = alkaline (OH-) Low pH down to 0 = acidic (H+)
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Temperature Thermal pollution
Many power plants use water as a coolant and discharge the water at a higher temperature. Thermal shock can kill aquatic life. Cool water holds more oxygen than warm water. Ice can hold oxygen for a long period of time (ice core samples) Landsat image of Lake Trawsfyndd, Wales illustrating color differentiation of temperature differences induced by power plant thermal pollution. Source: NASA
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Phosphates Phosphates act as a fertilizer for aquatic plants but can create algal blooms when quantities are too high. Sources of phosphorus include human and animal wastes (sewage), industrial wastes, soil erosion, and fertilizers. Phosphate concentrations have been restricted in manufacturing to prevent water quality problems. Phosphate levels higher than 0.03 ppm contribute to increased plant growth. K in laundry detergent
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Nitrates Nitrates (NO3) are formed when bacteria combine the ammonia from animal waste or decay with oxygen. Excess nitrogen causes algal blooms and eutrophication Measured in PPMs
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Turbidity Turbidity = the amount of cloudiness in the water
Caused by suspended matter like silt, sand mud, bacteria, chemical precipitates Can be measured with a Secchi Disk or turbidity tube 5, 50, 500 NTU
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Macroinvertebrates Bioindicators
Animals that have no backbone and are visible without magnification Bioindicators Organisms that provide information about the health of an ecosystem. High quality species = healthy environment Pollution tolerant species: may indicate poor water quality
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So what can we do to protect water? Who regulates water?
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Water Regulations The Clean Water Act (CWA) was enacted in 1948 to ensure all water was kept pollutant free. It was amended in to regulate discharges of pollutants into the U.S. waters and control quality standards for surface waters. The Safe Drinking Water Act (SDWA) was established in 1974 to ensure that all U.S citizens had access to safe drinking water. The U.S. Environmental Protection Agency (EPA) monitors water in the United States.
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Areas of Progress The 1972 Clean Water Act established a National Pollution Discharge Elimination System (NPDES), which requires an easily revoked permit for any industry, municipality or other entity dumping wastes in surface waters. Since the Clean Water Act was passed, much of the effort has been aimed at point sources, especially to build or upgrade thousands of municipal sewage treatment plants. As a result, nearly everyone in urban areas is now served by municipal sewage systems and no major city discharges raw sewage into a river or lake except as overflow during rainstorms.
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Remaining Issues in Water
Nonpoint discharges of pollutants are the greatest impediments to achieving national goals of water quality. About 75% of the water pollution in the United States comes from soil erosion, fallout of air pollutants, and surface runoff from urban areas, farm fields, and feedlots. Nitrates and phosphates in surface water have decreased from point sources but have increased about four-fold since 1972 from nonpoint sources. Fossil fuel combustion has become a major source of nitrates, sulfates, arsenic, cadmium, mercury, and other toxic pollutants.
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Water Pollution Solutions
Establish and enforce laws and regulations Low-impact agricultural practices Improved sewage treatment systems Proper disposal and use of chemicals Use of mitigated wetlands Reduce runoff Buffer strips, bioswales, permeable paving, increase vegetation and decrease slopes Use natural alternatives to chemicals Personal accountability
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