1. Major Water Pollutants

2. Leading Causes of Water Pollution
Most water pollution comes from:
Agriculture
Fertilizers, pesticides, bacteria, food wastes
Industrial Facilities
Sewage Treatment
Inorganic and organic chemicals
Mining
Sediment erosion, toxic chemical runoff/leaching

3. Agriculture Nutrient Runoff Chemical Pollution Infectious Diseases
Fertilizers & Manure
Pesticides
Infectious Diseases
Sedimentation
Overgrazing

4. Industrial Organic & Inorganic Compounds Heavy Metals
Thermal Pollution

5. World Wide
Disposing sewage
Drinking
Same Water Source
Bathing
Washing

6. Wastewater
Two main systems:
Septic Systems
Sewage Treatment Plants

7. Septic Systems Septic Tank Leach Field
Large container holding wastewater from a household
Two parts:
Sludge – bottom layer of solids
Septage – middle liquid layer
More bacteria and nutrients
Leach Field
Septage distributed into
soil

8. Sewage Treatment Plants
Urban areas
Sewage plants are used in urban areas bc there is not sufficient land for leach fields
Primary – Screen & settling tank for large solid waste (Sludge is taken to landfill or burned)
Secondary – bacteria to break down organic waste
Tertiary – treatment with chemicals (chlorine, ozone) and/or UV light
Last is released into streams

9. Testing for Water Pollutants
Temperature
Dissolved Oxygen
BOD pH
Nitrates
Phosphates
Turbidity
Indicator species
Coliform bacteria (E. coli)

10. Temperature Range of Tolerance
Inverse relationship with Dissolved Oxygen (DO)

11. Dissolved Oxygen Amount of oxygen available Range 5 ppm and up
Things affecting DO:
Water movement  higher DO
Decomposition  lower DO
Temperature  Inverse
relationship

12. Biochemical Oxygen Demand (BOD)
Amount of oxygen a water system uses over a period of time at a specific temperature
Low BOD = Low Pollution
High BOD = High Pollution
High microbial activity leads to high BOD

14. pH Determines solubility of nutrients Affects organism physiology
Species dependent
Water that has more free hydrogen ions is acidic, whereas water that has more free hydroxyl ions is basic.
. For example, in addition to affecting how much and what form of phosphorus is most abundant in the water, pH also determines whether aquatic life can use it. In the case of heavy metals, the degree to which they are soluble determines their toxicity. Metals tend to be more toxic at lower pH because they are more soluble. 

15. Nitrate & Phosphate Limiting nutrients in aquatic ecosystems
Can result in extreme algal growth
Algal blooms
Red tide

16. Turbidity
A measure of the degree to which the water loses its transparency due to the presence of suspended particulates.
Affects sunlight penetration
Affects predator/prey interactions
Affects gill function