Ch 20 Water pollution

Point-Source Pollution

Direct, identifiable sources of pollution such as factories, sewage treatment plants, power plants, or oil wells.

Nonpoint-Source Pollution

Scattered, diffuse pollution sources such as agricultural runoff, stormwater runoff, lawns, or atmospheric deposition.

Pathogens

Disease-causing organisms like bacteria, viruses, and parasites found in human or animal waste.

Chemical Pollutants

Toxic inorganic or organic substances such as heavy metals, acids, solvents, petroleum, pesticides, and detergents.

Nutrients

Inorganic materials essential for plant growth, especially nitrogen and phosphorus, which become pollutants when they cause algae overgrowth.

Sediment

Soil particles entering water from erosion, construction, farming, or runoff, clouding water and disrupting habitats.

Inorganic Chemicals

Non-carbon-based pollutants such as lead, mercury, arsenic, acids, and road salts.

Organic Chemicals

Carbon-based pollutants like petroleum, pesticides, industrial solvents, detergents, and PCBs.

Biomagnification

Process where toxins increase in concentration as they move up the food chain from prey to predators.

Eutrophication

Excess nutrient enrichment that leads to algal blooms, oxygen depletion, and aquatic ecosystem collapse.

Eutrophic

Water rich in nutrients with high algae growth and low oxygen levels.

Oligotrophic

Water low in nutrients, clear, and high in dissolved oxygen; less susceptible to eutrophication.

Suspended Load

Particles carried within the water column that remain floating.

Bed Load

Particles pushed or rolled along the bottom of a river or stream.

Storm Drains

Systems that collect precipitation runoff from streets and parking lots, sending it directly to waterways.

Sanitary Sewers

Systems that collect and treat household wastewater from sinks, toilets, and drains.

Debris & Grit

Solid materials in wastewater such as sand, gravel, rags, and plastics removed during primary treatment.

Primary Treatment

The first stage of wastewater treatment that removes debris and grit and allows solids to settle as sludge.

Secondary Treatment

Treatment where microorganisms break down dissolved and colloidal organic matter; followed by disinfection.

Septic Systems

On-site wastewater systems where solids settle in a tank and liquid effluent percolates into soil for treatment.

Composting Toilets

Toilets that break down human waste using aerobic decomposition, producing compost instead of sewage.

Cuyahoga River Fire (1969)

A river in Ohio caught fire due to heavy oil and chemical pollution, leading to public outrage and the Clean Water Act.

Clean Water Act of 1972

Federal law requiring protection of the chemical, physical, and biological integrity of U.S. waters; created strong pollution regulations.

Point vs. Nonpoint Sources

Point sources are identifiable (factories, sewage plants); nonpoint sources are diffuse (farms, streets, runoff).

Examples of Point Sources

Factories, sewage treatment plants, power plants.

Examples of Nonpoint Sources

Agricultural runoff, stormwater runoff, atmospheric deposition.

Pathogen Problems

Pathogens cause diseases like cholera, dysentery, and hepatitis from contaminated water.

Organic Waste Problems

High biological oxygen demand leading to oxygen depletion as microbes decompose organic material.

Chemical Pollutant Problems

Can be toxic at low levels, causing poisoning, birth defects, or ecosystem damage.

Nutrient Problems

Excess nitrogen and phosphorus cause algal blooms and dead zones.

Sediment Problems

Sediments block sunlight, reduce photosynthesis, and smother aquatic habitats.

Biomagnification Process

Toxins accumulate in organisms and increase at higher trophic levels (e.g., mercury in fish).

Major Fertilizer Nutrients

Nitrogen and phosphorus; enter water from sewage outfalls (point source) or fertilizer runoff (nonpoint).

Process of Eutrophication

Nutrient enrichment → algal bloom → decomposition → oxygen depletion → fish kills and habitat loss.

Fighting Eutrophication

Methods include herbicides, aeration, harvesting algae, reducing fertilizer use.

Sediment Transport Methods

Suspended load floats; bed load rolls or slides along bottom; both contribute to sediment pollution.

Great Pacific Garbage Patch

A massive accumulation of floating plastic debris in the Pacific Ocean driven by ocean currents.

Required Water System Installations

Storm drains and sanitary sewers to manage runoff and wastewater separately.

Water Treatment Overview

Primary removes solids; secondary uses microbes to break down organic matter; final step disinfects water.

Septic System Process

Solids settle in tank; bacteria break down waste; liquid effluent filters into soil for natural treatment.

Composting Toilet Process

Waste is decomposed aerobically into safe, soil-like compost.

Constructed Wetlands

Artificial marshes that use soil, plants, and microbes to naturally treat wastewater.