Water Pollution: Contaminants in Drinking Water and Their Health Effects, Slides of Water and Wastewater Engineering

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Useful resources Supplemental reading on Stellar web site for course 1.85 CDC fact sheets: Pronunciation guide: Images: Chemical contaminants in drinking water Organic chemicals Disinfection byproducts Inorganic chemicals Radionuclides Physical and aesthetic characteristics “Emerging pollutants” Organic chemicals See: Chemical classes: Pesticides and herbicides Organic solvents Fuel components Polynuclear aromatic hydrocarbons Organic chemical Health effect of organic chemicals: Carcinogenicity – cause or suspected to cause cancer Teratogenicity (terra-tau-genicity) – cause birth defects Nervous system impairment Liver and other organ impairment Reproductive impairment Docsity.com Disinfection byproducts Disinfection with chlorine causes reaction byproducts with organic matter in water Main classes of chemicals: TTHMs – Total trihalomethanes HAA5 – Five haloacetic acids All are suspected human carcinogens Trihalomethanes Chloroform Bromodichloromethane Cl Cl Cl C Cl Br C Cl H H Chlorodibromomethane Bromoform Br Cl Br C Br Br C Br H H Five haloacetic acids Monochloroacetic acid H Cl C COOH H Dichloroacetic acid Trichloroacetic acid Cl Cl H C COOH Cl C COOH Cl Cl Bromoacetic acid H Br C COOH H Dibromoacetic acid Br H C COOH Br Inorganic chemicals Chemical Adverse effect Antimony Blood disorders Arsenic Skin damage, cancer Barium Increased blood pressure Beryllium Intestinal lesions Cadmium Kidney damage Chromium Dermatitis Copper Gastrointestinal, liver or kidney damage Docsity.com 40 U.S. Safe Drinking Water Act Primary Drinking Water Standards: legally enforceable standards apply to public water systems protect public health by limiting the levels of contaminants in drinking water Secondary Drinking Water Standards: non-enforceable guidelines regulate contaminants that may cause cosmetic effects or aesthetic effects recommended to water systems but compliance not required by EPA 41 Maximum Contaminant Levels (MCLs) http://www.epa.gov/safewater/mcl.html 42 Maximum Contaminant Levels (MCLs) Docsity.com Northern sewage works Southern sewage works Wastewater effects on receiving water City of London WWTPs Docsity.com 1953 100 75 25 50 0 Extent of anaerobic zone in 1952 to November. Miles above/below London Bridge D is so lv ed o xy g en ( p er ce n t sa tu ra ti o n ) River is completely anaerobic (DO = 0) from River Mile 8 to River Mile 26. The graph is a bit tricky to read. The horizontal axis is time and shows the duration of anaerobic conditions. Uninterrupted anaerobic conditions extend from mid-May The vertical axis is distance in river miles and shows the length of the river experiencing anaerobic conditions. Only about ten miles are anaerobic in May but over 20 miles in September. Docsity.com Emerging pollutants Triclosan Caffeine Estrogen Fate and transport Timeline of major environmental legislation 1970 Clean Air Act 1972 Federal Water Pollution Control Act 1974 Safe Drinking Water Act 1976 RCRA 1976 TSCA (Toxic Substances Control Act) 1977 Clean Water Act 1980 Superfund 1986 EPCRA (Emergency Planning and Community Right-To-Know Act) Safe Drinking Water Act 1974 – Safe Drinking Water Act Required establishment of primary drinking water standards for public water supplies 1977 – DW Standards become effective Establish turbidity as health-based standard 1986 – SDWA Amendments Establishes current system of MCLs and MCLGs Added standards for radionuclides and disinfection by-products Docsity.com Safe Drinking Water Act 1989 – Surface water treatment rule Aimed at reducing Giardia and other pathogens Sets filtration as technology standard 1993 – Milwaukee water supply contamination Cryptosporidium contamination causes 400,000 illnesses and more than 50 deaths 1996 – SDWA Amendments Increased source water protection Safe Drinking Water Act 1998 – Enhanced surface water treatment rule Lowers turbidity standard Requires 99-percent removal of Cryptosporidium 1998 – D/DBP Rule Lowered standards for THMs, added HAA5 2001 – Revised standard for arsenic Clean Water Act Pre-1972 – Limited controls Limited refuse in navigable waters Provided some funding for wastewater treatment 1965 – Water Quality Act Requires states to establish stream standards Wastewater controls required as needed to protect stream water quality Clean Water Act 1972 – Federal Water Pollution Control Act Amendments Established National Pollutant Discharge Elimination System Emphasized technology-based discharge limits (new control paradigm) Dramatically increased funded for treatment Docsity.com Comparison of standards Clean Water Act 1977 – Clean Water Act Included controls on toxic pollutants 1987 – Water Quality Act Added permit requirements for stormwater Water-quality constituent Units U.S. EPA European Union World Health Organization E. coli number/100 ml Detected in <5% of samples 0 0 Arsenic µg/l 10 10 10 Copper mg/l 1.3 2 2 Lead µg/l 15 10 10 Nitrate mg/l as N 10.0 11.3 11.3 TTHM µg/l 100 100 200/100/100/60a Chloride mg/l 250 250 250 Iron µg/l 300 200 No guideline Benzene µg/l 5 1 10 Carbon tetrachloride µg/l 5 4 4 Tetrachloroethylene µg/l 5 10b 40 Trichloroethylene µg/l 5 70 a Chloroform/bromoform/dibromodichloromethane/bromodichlorodimethane b Sum of trichloroethylene and tetrachloroethylene Docsity.com