Review Water Pollution Major Water Pollutants 1 Human

Review Water Pollution

Major Water Pollutants 1. Human wastewater: sewage & gray water • Decomposition of organic waste → Huge O 2 demand • Excess nutrients (N & P) eutrophication • Disease-causing organisms (esp. E. Coli & Cholera) 2. Metals (Pb, Hg, As, Cd) 3. Acid – rain, deposition, runoff 4. Synthetic Organics (pharma; pesticides; Military & Industrial compounds) 5. Oil 6. Solid Waste (especially plastic!) 7. Sediment - erosion - turbidity 8. Thermal & Noise pollution

• Water Pollution: • Point Sources - Discharge pollution from specific locations (single point). EASY TO MONITOR/REGULATE • Effluent • 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

Disinfect: Chlorine Ozone U. V. light Primary sewage treatment: a physical process that uses screens and a grit tank to remove large floating objects and allows settling. Tertiary Step Usually not present Expensive Added to remove specific pollutant usually N & P Secondary sewage treatment: a biological process in which aerobic bacteria remove as much as 90% of dissolved and biodegradable, oxygen demanding organic wastes. • .

Water Quality Indicators • Know your list – be able to give examples / sources / causes / effects • N&P • Biodiversity: macroinvertebrates, fish, plants, amphibians, algae, bacteria • DO / BOD / CO 2 • Fecal coliform – indicator • Temp • Turbidity • Heavy metal / p. H – how linked? • Color / odor • Synthetic Organic Compounds – Pesticides • Gender benders • • Pharmaceuticals – antibiotics, hormones Ammonia Chlorine Hardness

Eutrophication • Natural vs. Cultural • Oligotrophic: nutrient-poor water • Eutrophic: nutrient-rich water • Sources - agricultural runoff (fertilizer, feedlots), detergents (P only), disturbed soil, products of decomposition (so any organic matter) • Indicators • Elevated N and P levels • Decreased DO levels, increased BOD levels • Cloudy water: from algae and cyanobacteria • Effects – Eutrophication nutrients ↑, algae grows, blocks sunlight, dies and decomposes, O 2 ↓ • Dead zones

Gulf of Mexico Dead Zone Worst in summer Affects fish & shrimp harvests

Milk Lab Be able to describe in detail what happened & why Farm or animal feedlot Be able to describe impact of runoff

Oxygen Sag Curve A. Clean Zone • DO high • BOD low demand B. Pollution enters stream C. Decomposition Zone • DECOMPOSITION increases to break down pollution • OXYGEN decreases as it is used up by decomposers D. Septic zone – DEAD ZONE - Hypoxic • dissolved oxygen levels are very low and very few species can survive E. Recovery Zone • Waste concentrations decrease • DO � , BOD � F. Clean Zone • DO is high, BOD is low and normal biodiversity levels are present.

Clean Water Act - 1977 • EPA to set water quality standards for industry and for all contaminants in surface waters • regulates discharges of pollutants in the US - point sources • Requires a permit to discharge any pollutant into a navigable waterway. • Goal: Make lakes & streams fishable & swimmable • sets daily limits for total pollutant discharges • Total Maximum Daily Load (TMDL)

Safe Drinking Water Act - 1974 • established to protect the quality of drinking water in the U. S • All waters designed for drinking use - above ground or underground sources • EPA sets Maximum Contaminant Levels (MCLs) for drinking water • Standards for dozens of contaminants