Think-Pair-Share. How does EPA set MCL Standards? Water Quality Standards & Factors. Waterborne Pathogens. Discuss with another student:

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1 Think-Pair-Share Discuss with another student: What water contamination issues do you think about most often? What are the relative merits of bottled vs. tap water? 1 2 Water Quality Standards & Factors 3 major types of contamination Pathogens Organic Natural, mostly inorganic Different standards for different situations Stream water quality Drinking water quality How are standards set? How do we determine if something is hazardous? How does EPA set MCL Standards? 1. The contaminant causes adverse health effects Requires assessment of toxicity Animal vs. Human studies Single vs. Complex mixtures Acute vs. Chronic effects 2. Risk assessment and cost-benefit considerations 3. It is known to occur in drinking water Primary vs. Secondary standards The smaller the MCL, the greater the risk. 3 4 Waterborne Pathogens Pathogens disease causing microbes Bacteria E. coli; fecal coliforms Protozoa Cryptosporidium, p Giardia lamblia Viruses - hepatitis A, rotaviruses, and Norwalk Waterborne pathogens are disease-causing bacteria, viruses, and protozoans that are transmitted to people when they consume untreated or inadequately treated water. Two protozoans in the news today are Giardia and Cryptosporidium. Their consumption can lead to severe problems of the digestive system, which can be life-threatening to the very young, very old, or those with damaged immune systems. ga.water.usgs.gov/edu/urbanpath.htm Headlines: Brain-Eating Amoeba Kills Arizona Boy [ARIZONA] Fourteen-year-old Aaron Evans of Lake Havasu City in Mohave County, Arizona became the year's sixth victim of an organism that attacks the body through the nasal cavity, quickly eating its way to the brain. Naegleria fowleri, an organism that infected Evans while swimming in Lake Havasu, is always fatal but mercifully rare. Cases have also been reported in Texas and Florida. According to Michael Beach, a specialist in waterborne illnesses at the Centers for Disease Control in Atlanta, Georgia, the amoeba typically lives in the sediment on lakebeds and feeds on algae. People become infected when they wade through shallow water and stir up the sediment; if water shoots up the nose (while diving, for example), Naegleria can travel to the brain. The easiest ways to prevent infection are to avoid areas of warm, standing water with visible algae and to plug one's nose when swimming or diving. - summary by Louise Shaler 5 6 1

2 Headlines: Cryptosporidium outbreak hits the West Outbreaks of diarrhea, abdominal cramps, and nausea caused by the waterborne parasite cryptosporidium have afflicted 229 residents of Boise and Meridian in Idaho and over 1600 residents in parts of Utah this summer, reported the two states' Departments of Health and Welfare. Officials believe that "splash parks" where children play in spouts of continually recycled water are spreading the parasite. Cryptosporidium can survive for up to a year because its hard outer shell resists chlorine, the normal purification treatment at public swimming facilities, said the Centers for Disease Control and Prevention in Atlanta, Georgia. The best way to eradicate it is to add ultraviolet light to the purification process. - summary by Louise Shaler Is all pollution anthropogenic? Class suggestions for natural pollution sources: Natural decay of organic matter Volcanic emissions (e.g. sulfur compounds) Radon gas produced through decay of natural Uranium and Thorium in geologic units. Natural methane production 7 8 Temperature High Temperature can be detrimental to aquatic life High Temperature reduces the dissolved oxygen concentration in water Species respond to rapid temperature fluctuations Dissolved Oxygen Animals need oxygen to survive. Many aquatic animals such as fish and dragonfly larvae breath oxygen dissolved in the water. Groundwater is naturally lower in dissolved oxygen (DO) than surface water; therefore, spring water may have low DO levels. Too much organic matter in a water body will decrease the DO when it decomposes ph ph refers to the concentration of hydrogen ions. Fish species each have a narrow range of ph preference. World Health Organization drinking water standards: ph = 6.5 to 8.5. Alkalinity Alkalinity is related to the total carbonate concentration The higher the alkalinity, the less susceptible the water is to acidification

3 Turbidity Most of the water used is from groundwater Turbidity is the relative measure of clarity. It is the result of suspended matter in water that reduces the transmission of light. Toxic chemicals can attach to suspended particles Tucson Water Quality Drinking water standards Regularly reported factors: Temperature Acidity (ph) Mineral content (TDS) Hardness (Alkalinity) Additives (Cl, F) Bacteria Annual Water Quality Reports Tucson 2004 ( link Where does my water come from? Were any contaminants detected in my drinking water? Why are there contaminants in my drinking water? Where there any monitoring failures or violations? More information about CAP and TARP. Hardness Hardness is the amount of dissolved calcium and magnesium present in water. Hard water often creates a buildup of scale on hot water heaters, showers, and pipes. It is more difficult to create soap suds in Hard water. Hardness rating Concentration of Calcium Carbonate (mg/l) Concentration of Calcium Carbonate (grains/us gallon) Soft 0 to <75 0 to <5.2 Medium hard 75 to < to <10.5 Hard 150 to < to <21 Very hard 300 and greater 21 and greater

4 Inorganic Contaminants Disinfection by-products Trihalomethanes (THM), HaloAcetic Acids (HAA5), Bromate, Chlorite Radioactive Elements Radon Toxic Metals lead (Pb), mercury (Hg), arsenic (As) Insulation Asbestos Organic Contaminants Pesticides DDT, Petrochemical Oil, gas, MTBE Pharmaceuticals & Hormones Steroids, antibiotics, drugs Electrical Dioxin, PCB Fertilizers Lead to Hypoxia National Geographic, Water special issue, 3/ Point Source Pollution Examples Factories Wastewater Treatment Plants Landfills Abandoned Mines Underground and Above-Ground Tanks Can you think of others? Point source pollution Contamination discharged from a discrete, identifiable location

5 Nonpoint Source Pollution Examples Agricultural Practices Construction Activities Lawns, Gardens, and Golf Courses Street Refuse Dredging Activities Can you think of others? Nonpoint source pollution Contamination discharged from broad, diffuse sources that can be difficult to identify and quantify. Precipitation falling on soil will dissolve pesticides and fertilizers, which then runoff and lead to stream degradation Environmental History Other Sources of Information Rivers & Harbors Act 1948 Fed. Water Pollution Control Act 1965 Water Quality Act 1969 Nat. Environmental Policy Act (NEPA) -> EIS 1970 Clean Air Act 1972 Clean Water Act 1973 Endangered Species Act Safe drinking Water Act Resource Conservation and Recovery Act (RCRA) Cradle to Grave control of active hazardous waste streams & stores Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA; Superfund) Historical and inactive sites EPA Envirofacts Integrated Risk Info. Sys - Agency for Toxic Substances and Disease Registary (ATSDR; CDC) - ToxFAQ s - USGS - Health & Treatment