Water Pollution March 4, 2015 Mr. Alvarez The Basics Water Pollution: Any chemical, biological or physical change in water quality that has a harmful effect on living organisms (including humans!) or makes it unusable for agriculture Point Sources - Discharge pollution from specific locations (single point). EASY TO MONITOR/REGULATE Factories, power plants, oil wells Non-Point Sources - Scattered or diffuse, having no specific location of discharge. HARDER TO CONTROL!! Agricultural fields, feedlots, golf courses 1
15_21.JPG Municipal Runoff 5 Human Wastewater Human Wastewater- Water produced by human activities such as human sewage from toilets and gray water from bathing and washing clothes or dishes. 2
Oxygen-Demanding Waste Oxygen-demanding waste- organic matter that enters a body of water and feeds the growth of microbes that are decomposers Biochemical Oxygen Demand (BOD)- the amount of oxygen a quantity of water uses over a period of time as a specific temperature Natural waters should have BOD of 5-20 mg of oxygen coming from decomposition of leaves, twigs and a few dead organisms (Low BOD is good, less polluted) Domestic Wastewater might have a BOD of 200 mg of Oxygen (High BOD is bad, more polluted with wastewater) Dead Zones- an area with extremely low oxygen concentration and very little life Nutrient Release Eutrophication- A phenomenon in which a body of water becomes rich in nutrients Wastewater is full of Nitrogen and Phosphorus Cultural Eutrophication- An increase in fertility in a body of water, the result of anthropogenic inputs of nutrients Eutrophication Algal Bloom Algal Death Microbes digest algae Increased microbes consume most of oxygen in water Fish Kill Sewage Affects Oxygen Demand 9 3
Disease-Causing Organisms Human wastewater can carry a variety of illnesscausing viruses, bacteria and parasites we can collectively call pathogens These pathogens can cause: Cholera Typhoid Fever Stomach Flu Diarrhea Hepatitis 1.1 Billion people do not have access to suffieceint supplies of safe drinking water 3.1 million annual deaths from diarrheal diseases and malaria could be prevented with safe drinking water, proper sanitation and proper hygiene Fecal Coliform Bacteria Indicator Species- an organism that indicates whether or not disease-causing pathogens are likely to be present Fecal coliform bacteria- a froup of generally harmless microorganisms that live in the intestines of human beings and other animals Most commonly, Escherichia coli (E. coli) Detection indicates human waste has entered the water Does not necessarily mean water is harmful to drink, but does indicate that there is an increased risk of other wastewater pathogens in the water Unsuitable for drinking if any bacteria present Beaches/Pools/Rivers safe for swimming/fishing if under 500-10,000 colonies per 100 ml of water 4
Septic Systems Septic System- a relatively small and simple system with two components: a septic tank and a leach field Septic Tank- large container that receives wastewater from the house (capacity of 1,900-4,700 Liters). Causes three layers to develop: Sludge- Anything heavier than water Septage- fairly clear water layer in the middle Contains large quantities of bacteria and perhaps pathogenic organisms as well as Nitrogen and Phosphorus Scum layer- Anything that will float and rise to top Leach Field- Combination of pipes and lawn where gravity causes septage to go. Septage seeps out of pipes and is absorbed and filtered by the surrounding soil Wastewater Treatment: Septic Tank System 14 Sewage Treatment Plants Primary Treatment- Solid waste settles out of wastewater Solid material dried and classified as sludge, then exposed to bacterial that can digest it. Final form of sludge, removed of water, is placed in landfill, burned or converted into fertilizer pellets Secondary Treatment- Promote aerobic respiration in bacteria to break down 85-90% of organic matter into CO 2 and inorganic Nitrogen and Phosphorus Disinfection and Release- Water sits for several days, particles settle out. Particles are added to sludge from Primary Treatment Remaining water is disinfected using chlorine, ozone or ultraviolet light to kill remaining pathogens Treated water released into a nearby river or lake 5
17 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. 6
Lead Lead- Heavy metal that poses a serious health threat Rarely found in natural sources of drinking water Contaminates water when water passes through pipes f older homes that contained lead-lined pipes, brass fittings containing lead or solder used to fasten pipes Fetuses and infants are most sensitive to lead Exposure can damage the brain, nervous system and kidneys Arsenic Arsenic- A compound that occurs naturally in Earth s crust and can dissolve into groundwater Naturally occurring arsenic in rocks can lead to high concentrations in groundwater and drinking water Human mining breaks up rocks deep underground Industrial uses such as wood preservatives Arsenic can be removed from water via fine membrane filtration, distillation and reverse osmosis Arsenic in drinking water is associated with cancers of the skin, lungs, kidneys and bladder Illness can take 10 years or more after exposure to develop EPA decided under 10 µg/l of Arsenic is safe to drink 7
Mercury Mercury (Inorganic)- a naturally occurring heavy metal found in increased concentrations in water as a result to human activities. Comes from: Burning Coal Incineration of garbage Hazardous waste Medical Supplies Dental supplies Limestone used to make cement released during heating Methylmercury (Organic)- damages central nervous system, particularly in young children and in the developing embryos of pregnant women Bioaccumulation and Biomagnification EPA found that a diet of six pieces of sushi per week would exceed EPA standards for human consumption of Mercury Acid Deposition and Acid Mine Drainage Wet-Acid Deposition- occurs in the form of rain and snow (aka acid precipitation or acid rain) Dry-Acid Deposition- occurs as gases and particles that attach to the surfaces of plants, soil and water Acid Mine Drainage- Abandoned underground mines become flooded with groundwater Combination of water and air allows pyrite to break down and produce iron and hydrogen ions Produces acidic water with a low ph Water finds its way to the surface in the form of springs that feed into streams Low ph also causes solubility of zinc, copper, aluminum and manganese 8
Few species can tolerate ph s below 5 Synthetic Organic Compounds Pesticides- serve an important role in helping to control pest organisms that pose a threat to crop production and human health. Three Concerns: 1. Pesticides do not target a particular species of organism, but generally kill a wide variety of related organisms. Some lethal to unrelated species 2. Specialized pesticides may have unintended consequences, such as DDT. DDT was designed to target nerve transmissions in insects but also moves up food chain and causes thinning shells is Bald Eagles 3. Inert ingredients added to pesticides to make them more effective. Example, inert ingredient in Roundup penetrates tadpole gill cells, cause them to burst and tadpoles suffocate Pharmaceuticals and Hormones Chesapeake Bay: Low concentrations of pharmaceutical drugs that mimic estrogen are connected to male fish growing female eggs in their testes 9
Other Synthetic Compounds Perchlorates- usually found where military rockets are manufactured, tested, or dismantled (Rocket Fuel) Can leach into groundwater and persist for many years Perchlorates can affect the thyroid gland and reduce production of necessary hormones Polychloronated biphenyls (PCBS)- were used in manufacturing plastics and insulating electrical transformers until 1979 Lethal and Carcinogenic (Cancer-causing) Polybrominated diphenyl ethers (PBDE)- Most commonly known as flame retardants (construction materials, furniture, electrical components and clothing) Since 1990 s scientists have been detecting in fish, aquatic birds, and human breast milk Can lead to brain damage, especially in children 10
Biological Magnification Concentrations increase at increasing levels in the food chain PCBs, DDT, etc. Fig. 12 20 Brooks/Cole Publishing Company / ITP Water Resources and Water Pollution by Paul Rich Oil Pollution Effects of Oil Spills Volatile Organics Compounds (VOCs) immediately kill many aquatic organisms (especially plankton and larvae!) Floating oil coats birds and ocean mammals; reduces natural insulation and buoyancy, causing deaths Heavy oil sinks to ocean bottom and washes into estuaries where it contaminates crabs, oysters, mussels, clams, etc. Oil slicks on beaches harm intertidal life and cause economic losses to tourism and fishing industries Brooks/Cole Publishing Company / ITP Water Resources and Water Pollution by Paul Rich 11
Cleaning Up an Oil Spill Oil Cleanup Options Oil Containment- Lay out oil containment booms that consist of plastic barriers floating on the surface of the water and extending down into the water several meters. Suck up oil with giant oil vacuums Dispersants- Apply chemicals that help break up the oil, making it disperse before it hits the shoreline and causes damage to coastal ecosystems (Potentially toxic) Genetically Engineered Bacteria- Naturally occurring bacteria that consume oil are modified to consume even faster High-Pressure Hot Water- Used to clean rocky coastlines after Exxon-Valdez incident. Also removed plants and animals that inhabited the rocks. Also removed fine-grained sediments containing nutrients. Many organisms unable to recolonize the coast 12
March 24, 1989, tanker in Prince William Sound, Alaska, worst oil spill in U.S. waters The most ecologically destructive oil spill in history Coated 1,600 of shoreline, killed wildlife, and caused serious contamination Exxon spent $2.2 billion on direct cleanup + $1 billion fines and damages; another $5 billion being appealed Exxon Valdez Oil Spill Brooks/Cole Publishing Company / ITP Water Resources and Water Pollution by Paul Rich Solid Waste Plastic pollution is a huge problem! 13
Destruction of spawning beds (river/lake bottoms) Adsorption and transport of other pollutants Reduced light penetration, aquatic vegetation Greater nutrients loadings, increased oxygen demand Clogs Fish Gills Thermal & Noise Pollution Thermal pollution is changing water temperature (ex: power plants releasing water from cooling towers) Oxygen levels in water decreases as temperatures increase Noise Pollution disturbs wildlife (ex: boat motors; sonar) 14
Water Laws 1972 Clean Water Act Goal: Restore and maintain the chemical, physical & biological properties of US waters Permits required for point-source discharge Only pertains to surface waters (not groundwater) 1974 Safe Drinking Water Act Establishes Maximum Contaminant Levels (MCLs) for 77 pollutants in both surface & groundwater 15
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