1. Review
Water Pollution

2. Major Water Pollutants
Human wastewater: sewage & gray water
Decomposition of organic waste → Huge O2 demand
Excess nutrients (N & P)  eutrophication
Disease-causing organisms (esp. E. Coli & Cholera)
Metals (Pb, Hg, As, Cd)
Acid – rain, deposition, runoff
Synthetic Organics (pharma; pesticides; Military & Industrial compounds)
Oil
Solid Waste (especially plastic!)
Sediment - erosion - turbidity
Thermal & Noise pollution

3. 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

4. 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.
Secondary sewage treatment: a biological process in which aerobic bacteria remove as much as 90% of dissolved and biodegradable, oxygen demanding organic wastes. .
Tertiary Step
Usually not present
Expensive
Added to remove specific pollutant
usually N & P

5. 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 / CO2
Fecal coliform – indicator
Temp
Turbidity
Heavy metal / pH – how linked?
Color / odor
Synthetic Organic Compounds – Pesticides
Gender benders
Pharmaceuticals – antibiotics, hormones
Ammonia
Chlorine
Hardness

6. 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, O2 ↓
Dead zones

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

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

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

10. Clean Water Act
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)

11. 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