Indicators of Waterbody Pollution

1. Physical
   1. Turbidity: Suspended solids can make water cloudy, indicating erosion or runoff.
   2. Colour: may indicate algal bloom, discharge, or chemicals.
   3. Odour: can signal organic waste, discharge, chemicals or anaerobic conditions.
   4. Foam: may be benign, or the result of chemicals, sewage or other discharges.
   5. High Temperature: may be caused by cooling water discharge.
   6. Debris: trash, foam, or oil slicks suggests littering, sewage, or industrial discharges.
2. Chemical
   1. pH: Extreme values can indicate acid mine drainage, industrial waste, or agricultural runoff.
   2. Dissolved Oxygen (DO): Low DO levels suggest organic pollution (e.g., sewage or agricultural runoff) or excessive algal growth.
   3. Nutrients: Nitrates and phosphates from fertilizers, sewage, or runoff can lead to eutrophication and algal blooms.
   4. Heavy Metals: Lead, mercury, cadmium, or arsenic can indicate industrial or mining pollution.
   5. Pesticides: Presence of these chemicals suggests agricultural runoff.
   6. Organic Compounds: Hydrocarbons, PCBs, and other synthetic chemicals point to industrial or urban pollution.
   7. Chlorine and Ammonia: may indicate sewage or wastewater treatment discharges.

### 3. **Biological Indicators**
  - **Algal Blooms**: Excessive growth of algae (e.g., green or blue-green algae) indicates nutrient pollution and can deplete oxygen levels.
  - **Fish Kills**: Sudden death of fish or other aquatic life suggests severe pollution, such as chemical spills or low oxygen levels.
  - **Macroinvertebrate Populations**: A decline in sensitive species (e.g., mayflies, caddisflies) and an increase in pollution-tolerant species (e.g., sludge worms) indicate poor water quality.
  - **Bacterial Counts**: High levels of coliform bacteria (e.g., E. coli) suggest fecal contamination from sewage or animal waste.
  - **Plant Health**: Dead or dying aquatic vegetation may indicate chemical pollution or oxygen depletion.

### 4. **Ecological Indicators**
  - **Loss of Biodiversity**: A reduction in the variety of species in the watercourse can indicate chronic pollution.
  - **Habitat Degradation**: Destruction of aquatic habitats (e.g., siltation, loss of vegetation) often results from pollution or altered land use.

### 5. **Human Health Indicators**
  - **Waterborne Diseases**: Outbreaks of illnesses like cholera or giardiasis suggest contamination by pathogens.
  - **Taste and Odor in Drinking Water**: Unusual taste or odor in water sourced from the watercourse may indicate pollution.