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Keeping Our Water Clean Protecting Our Streams and Our Groundwater. CPES 5.1 and 4.12. Topics. Toxic chemicals in the water (5.1) Groundwater and groundwater pollution (5.1 and class model) Drinking Water (5.5) Treating Wastewater – sewage treatment and septic systems (4.12)
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Keeping Our Water CleanProtecting Our Streams and Our Groundwater CPES 5.1 and 4.12
Topics • Toxic chemicals in the water (5.1) • Groundwater and groundwater pollution (5.1 and class model) • Drinking Water (5.5) • Treating Wastewater – sewage treatment and septic systems (4.12) • Mapping a Watershed (class activity) • Watersheds in PA (class activity/worksheet)
Toxic Wastes • Over 70,000 used in and to make products • During manufacturing – wastes produced • EPA • Over 650 toxic chemicals reported • Over 2 billion pounds created – much released into environment • Where do these toxics come from? • Currently created wastes • Legacy of past: • waste dumps • injection wells • Underground tanks
Toxic Chemicals – Effects on People • Irritants-corrosives; acids,metal fumes, chlorine, formaldehyde • Asphyxiates-prevent or interfere with oxygen uptake; carbon monoxide and hydrogen cyanides • Allergens-formaldehyde; • Neurotoxins-lead & mercury; chlorinated hydrocarbons (DDT, Aldrin) organophosphates (malathion) • Mutagens-damage DNA; cancer;inheritance • Teratogens-PCBs • Carcinogens – cancer causing - PCBs
Lead • Example of inorganic “heavy” metal • Damages nervous system and can cause anemia, kidney disease, cancer • Source: • Atmosphere (previous, from leaded gasoline) • Plumbing – lead pipes
Toxics in the Environment • Bioaccumulation-selective absorption and storage in selective tissues • Result: increased concentration above environmental exposure • Biomagnification- • Increasing concentration as move up food chain - chlorinated hydrocarbons such as DDT • Not Biodegradable – persistent in environment • may offer advantage in using • CFCs, plastics, DDT and other chlorinated hydrocarbons
How Do Toxics Get Into Us? • Air – toxic “precipitation” • Mercury – major source burning coal for electricity • Water- • Groundwater – • Underground tanks • Dumping chemicals onto surface - • Fertilizers, etc • deep-well injection – of industrial wastes (pg. 386) • Greatest concern in PA - old landfills (pg 387) • Dumping into waterways – • Industrial (point sources) – now permitted • from “your” homes through sewage plants, septic systems • Food – biomagnification, especially fish
How “Poison” is a PoisonAssessing Toxicity • “The dose makes the poison” • Concentration • How does chemical enter organism? • What is LD50 • Different organisms react differently • Different individuals react differently • Is a mouse a human? • Health affects vs. ecological affects
A Story: Love Canal • Near Niagara Falls, NY • ’47 to ’52 – Hooker Chemical Corp. and others – dumped toxic chemicals into abandoned cnal • Covered canal given to school district – elementary school built on site • Local residents exhibit cancer cluster – higher than expected cancers, birth defects, other health problems • Became Superfund site – over $140 million • Many years litigation – homes, school finally relocated
Another Story – Woburn, Mass. • Basis for movie A Civil Action • Disease (leukemia) “cluster”: 12 cases vs. expected 5.3 (note: study of disease incidence is epidemiology) • Residents claimed: organic chemicals used in paper processing dumped, then entered public wells – • Courts agreed • Now EPA Superfund Site – money now used to clean wells • Many individuals received compensation from W.R. Grace and Co.
Atmospheric Deposition • Polluted precipitation • Metals and acids as air pollutants, end up in water • Numerous fish advisories – greatest in many lakes • In PA – mercury from coal burning – major water contaminate • Maps of PA
Fish (378) • Lakes – now key source of toxics, including PCBs, is atmospheric deposition • Over 2000 advisories nationwide • Fish can be used as bioindicators - the “canaries in the coalmine” (biomonitoring) – page 377 • Combined effects of many different chemicals • Synergism – multiplied effect of being exposed to many different chemicals, such as carcinogens
Hudson River and GE PCB Contamination • Northern part of Hudson at Hudson Falls, New Your • 200 mile stretch Hudson River a Superfund site • Controversy – Should the sediments containing PCBs be dredged, or just left alone? • Example of differing viewpoints • Videos in class showing differing viewpoints
Groundwater – YOU drink it • Groundwater model and reading worksheet – in class activities
Where is Pennsylvania’s Ground Water? Everywhere ! • Below Water Table • Filling pore space • Filling fractures
5 Years Recharge Area Recharge Area Discharge Area
>50% Homes >50% GW Where is Ground-Water Most Important?
Aquifers by Rock Type Sandstone & Shale Carbonate Crystalline Unconsolidated Sand & Gravel
Carbonate Rock Aquifers Sandstone & Shale Carbonate Carbonate Crystalline Unconsolidated Sand & Gravel
Crystalline-Rock Aquifers Sandstone & Shale Carbonate Crystalline Crystalline Unconsolidated Sand & Gravel
Characteristics of Carbonate Rocks Precipitation • Large Openings • High Yields • Vulnerable • High Recharge
Wellhead Protection Area contributing Recharge to well Supply Well
What’s in Underground Storage Tanks (380 and discussion of model) • Organics – many carcinogens • Petroleum products, including gasoline • Other stored chemicals • Why is cleaning up groundwater much more difficult than dealing with most surface water problems? • If necessary, how can groundwater be cleaned? (380)
Chemical Pollutants from Farms(380) • Nitrates, phosphates, pesticides • Pesticides can be organic or inorganic • Nitrates and “blue baby syndrome” • Oxygen carrying of hemoglobin messed up! • So, what are some solutions to prevent these problems?
Waste Disposal – Septic Systems
Factors Related to Bacteria in Well Water • Lack of sanitary seal • Lack of grout
Protecting Groundwater (386) • Build “secure” Landfills (389) • biggest problem is leachate • Solution - secure landfills Expensive • NIMBY • Remove leaking tanks • Protect recharge areas
Treatment of Wastes • Biological - bacteria will break down some wastes • These are called biodegradable • Physical methods – job of environmental engineers • Example: remove by air stripping - Emmaus • Chemical treatments - neutralize, render much less harmful – • Job of chemical and environmental engineers • Problem is cost – how much should be removed • Industries regulated by DEP and EPA • Incineration in high temperature incinerators – • Problem - expensive and some small amounts into air
Sewage - Why A Problem4.12 • Sure, it stinks :-( • Diseases • Cholera, dysentery – Number one cause of death in children in developing countries • Decreases DO • Sewage has high BOD • Increases turbidity – solid materials in sewage - undissolved • Adds nitrates and some phosphates • Causes eutrophication, result is low DO
Clean Water Act of 1972 • Focused on point sources of pollution • Goal: all rivers and lakes in U.S. cleaned to point of fishable and swimmable • Much better than pre-1970, but about 45% of lakes and rivers not yet meet goal • See chart page 365
Detecting Fecal Matter in a Water BodyFecal Coliform Not pathogenic Indicator of fecal pollution
Factors Related to Bacteria in Well Water • Lack of sanitary seal • Lack of grout
Sewage Disposal • Natural processes - natures way • When does it stop working? • Outhouses • Septic Systems • Sewage Treatment • Wetlands
Septic system: Tank and Drainage field Soil acts as filter; bacteria in tank and soil break down sewage
Sewage Treatment (365-366) • Primary • Secondary • Tertiary
Primary Preliminary • Metal Grating - large solids • Grit Tank • Sedimentation Tank • Undissolved solids settle • About 30% efficient
Secondary • Biological degradation of dissolved organic matter • Trickling Filter or aeration tank • Removes about 95% of BOD • Disposal of sludge (anaerobic digestion) • Biosolids – as fertilizer • Ends with chlorinating – WHY? • Most communities use this
Summary of Sewage Treatment • What enters - mostly water • Bacteria and viruses • Undissolved solids – high BOD • Dissolved waste materials – High BOD • Some organic and inorganic chemicals • Garbage, stones, pebbles and stones
What leaves? • Water clean enough to swim in!! • Treated Sludge – solids that came out of plant • Used on farms - biosolids • If can’t find farms, then to landfill