1. Water Pollution

2. Introduction – Detecting Water Pollution
Chemical analysis
Indicator species
Computer modeling
Point sources
Non point sources

3. Types of Water Pollution
Indicator of Surface Water Pollutants:
Suspended Sediment
Fecal coliform
Total phosphorus
Nitrate
Dissolved solids
Dissolved Oxygen

4. Sediment Pollution Particles suspended – settle on bottom
reduced light penetration – lowered photosynthesis of aquatic vegetation
cover aquatic organisms
bring in toxins
fill water ways

5. Sewage Disease causing organisms enrichment – high N and P
BOD - biological oxygen demand
E. coli – indication of sewage

6. Disease-Causing Agents
bacteria, viruses, parasitic worms
typhoid, cholera, bacterial dysentery, polio, infectious hepetitus

7. Inorganic Plant and Algal Nutrients
Runoff – increase N and P  algal growth  off-balance of producers and consumers  high BOD  hypoxia  anoxia

8. Organic Compounds
Most synthetic pesticides – pesticides, solvents, industrial chemicals, plastics
Groundwater seeping from landfills or leach through soil
Runoff to surface water or groundwater

9. Inorganic compounds Sources –
Industries
Mines
Irrigation runoff
Oil drilling
Urban runoff
Lead – human activities- leaded gas – atmosphere
Middle-aged men  hypertension
Pregnant women  miscarriages
Children  mental and physical impairment

10. More inorganic compounds
Mercury
Industrial processes
Batteries, paints,
Plastics burned in incinerators
Settles out in aquatic systems
Methyl mercury – tuna, swordfish, shark
Human health impacts – mental retardation and kidney failure

11. Radioactive substances
Mining and processing of radioactive minerals
uranium
thorium
radon  groundwater

12. Thermal pollution Electric power plants
various effects on the organisms
increase productivity
increase BOD

13. Genetic pollution Introduced species zebra mussel
aquatic vegetation – water chestnut, purple loosestrife
introduced fish – sea lamprey

14. Eutrophication An enrichment problem Oligotrophic – low in nutrients
Eutrophic – high in nutrients
Can be natural or artificial (anthropogenic)
P and N most limiting nutrients in aquatic systems

15. Sources of Pollution

16. General sources Point source pollution Pipe Sewers Factories
Non-point source pollution
Large areas rather than specific point
Soil erosion
Agricultural runoff
Urban runoff

17. Water pollution from agriculture
Leading source of surface water pollution in the US
Chemical pesticides
Fertilizer runoff
High BOD
Animal wastes
plant residues
Soil erosion – sediment pollution

18. Municipal waste Sewage – developed countries
Untreated sewage in undeveloped countries – goes into surface water
Non-point – urban runoff
Salt
Garbage
Traffic emissions
Other contaminants

19. Industrial waste Food processing – organic wastes – high BOD
Pulp and paper – toxic compounds and sludge
electronics – heavy metals and PCBs

20. Groundwater pollution
50% population of US uses groundwater as source of drinking water
contamination by fertilizers, pesticides, organic compounds
Source of contamination: land fills, leaking underground storage tanks (LUST), agriculture
Soil Pollution
salts, petroleum, heavy metals, organic chemicals
expensive and difficult cleanup
gets into groundwater

21. Improving water quality
Purification of Drinking Water
Most municipal water treated
turbidity – treated with aluminum sulfate- suspended particles settle out
organic compounds removed through active charcoal filtration
final step – chlorine, ozone, ultraviolet radiation

22. Chlorination and Fluoridation
20th Century
Chlorine eliminated: typhoid, cholera, dysentery
Concerns of cancer with use of chlorine
Peru 1991 stopped chlorination of drinking water
Outbreak of cholera
300,000 cases, 3,500 people died
Fluoridation started in mid 1940s for cavity reduction

23. Treating Waste Water
Septic tanks
Sewage treatment plant

24. Sewage Treatment Primary treatment
Removal of suspended and floating particles
Mechanical process
No organic compounds removed

25. Secondary treatment Uses microorganisms to decompose organic material
Aerated for aerobic bacteria
Sewage sludge settles out
Bacteria and solids
Free of organic wastes
Still has: dissolved minerals, heavy metals, viruses and organic compounds

26. Tertiary treatment Biological, chemical or physical processes
Remove N and P

27. Sludge disposal Anaerobic digestion Application to soil as fertilizer
Incineration
Ocean dumping
Sanitary landfill