Water Pollution

Types and Effects of Water Pollution

1. Inorganic Chemicals- Heavy Metals: Mercury, Lead, Cadmium, Arsenic and Aluminum, Nutrients, Pesticides, Wastes.

2. Agricultural Waste and Human Sewage

* A. Cultural Eutrophication- nitrates and phosphates from human or animal sources cause rapid algal growth on water surface. Deeper aquatic plants die (no light), BOD (Biochemcial Oxygen Demand) rises as aerobic decomposers break down plants, Dissolved Oxygen decreases and fish suffocate. Water becomes lifeless.
* B. Red Tide- dense algal blooms containing neurotoxins accumulate in marine food chain and decimate marine life.
* C. Pathogenic Organisms and Human Health- coliform bacteria test: E. coli bacteria is indication of human waste in drinking water.

3. Oil Spills- leaking oil tankers and dumping oil down storm drains

4. Thermal- from industrial and ower plants. Dissolved Oxygen decreases, organisms die from high temperatures and low oxygen

Monitoring Water Quality: Point vs non point sources:

*Point, from specific location such as pipe

*Non-point, from over an area such as runoff

1. Chemical Tests- BOD: biological oxygen demand, amount of dissolved oxygen needed by aerobic decomposers to break down organic materials, Dissolved Oxygen: measure the amount of oxygen in water, pH, Nitrates, Phosphates.

2. Aquatic Species Monitoring

* A. Pollution intolerant (highly sensitive to pollution): Stonefly nymph, mayfly nymph, water penny and caddisfly larva
* B. Somewhat pollution tolerant (mildly polluted water okay): beetle larvae, cranefly larvae, clams, crayfish, dragonfly nymph, damselfly nymph, black fly larvae
* C. Pollution tolerant (tolerates highly polluted waters): midge larva, snails, leech, aquatic worms

Water Pollution Control

1. Sewage Treatment 95% of sewage in undeveloped countries goes directly into water bodies.

2. Water Remediation Adsorption & absorption, aeration, constructed wetlands, deep well injection, precipitation & coagulation & flocculation, UV oxidation

3. Water Legislation Clean Water Act of 1972- sets as national goal to make all surface water fishable and swimmable. Funded municipal sewage treatment plants.