Water Pollution

Types of Pollutants

Microorganisms• Cryptosporidium• Giardia• Fecal coliform bacteria

Types of Pollutants

Disinfectants• Chlorine• Bromate• Chlorite Inorganic chemicals• Arsenic, cadmium, lead mercury

Types of Pollutants

Organic chemicals• Benzene• Dioxin• Vinyl chloride Radionuclides • Uranium and radium

Sources of Pollutants

Human and animal waste (microorganisms)Naturally occurring in geologic deposits (As, U)Human activities– industry, mining, agriculture

deliver many inorganic and most organic pollution

Sediments from erosion and activities such as excavation & construction

Pollution Interaction with Water

Dissolved chemicals can be toxic or carcinogenic

Non-aqueous phased liquids (NAPLs) form a separate phase that does not mix with water

• Include gasoline, chlorinated hydrocarbons• Difficult to remove, slowly dissolve

Pollutant Interaction with Water

Soluble pollutants enter ground water , flow as plumes

• Concentrations fall as plumes spread, large area affected

• Some contaminants bind to soil (sorption)• Sorption may prevent migration of

contaminants; contaminants stick around even if contaminated plume is pumped out

Water Pollution Control

Easier to control if it comes from a point source

Approaches include:• Improving stormwater mgt systems• Regulating land use• Limiting broad app of pesticides, herbicides,

fertilizer• Restoring wetlands

Water Pollution Control

Coastal areas and estuaries are impacted by pollution and sedimentation

• Ocean pollution kills fish, wildlife• Damages ecosystems• Human illness• Economic damage

Water Pollution Control

2000 National Research Council cited nutrient pollution as one of the most important ocean pollution problems

• Stimulates plankton to increase photosynthesis (blooms)

• When excess plankton die and sink, O2 is used up

• Leads to hypoxic (dead) zones

Gulf of Mexico Dead Zone

Treatments for Human and Animal Wastewater

Septic systems- a large container that receives wastewater from the house.

Treatments for Human and Animal Wastewater

Sewage Treatment Plants- centralized plants in areas with large populations that receive wastewater via a network of underground pipes.

WATER-RELATED DISEASE

Some Statistics

More than 2 million people die each year (cholera, typhoid, dysentery)

1993 – cryptosporidium in Milwaukee killed 110, sickened 400,000

After the outbreak, federal regulators increased testing requirements for turbidity

Waterborne Diseases

• Includes cholera, typhoid, dysentery• Drinking water contains viruses/bacteria• Often from human or animal waste

Water-washed Diseases

• Includes skin and eye infections• Lack of clean water for washing

Water-based Diseases

• Such as schistosomiasis• Spread by organisms that develop in water

that become human parasites• Spread by water and insufficiently cooked

food

Water-related Insect Vectors

• Mosquitoes are the main meanies!• Diseases include dengue fever and malaria• Not directly related to water supply or

quality

Water-Related Diseases

• 1 billion people lack safe drinking water• The spectrum of disease is altering and the

incidence of many water-related microbial diseases is increasing

• Urbanization & dam construction can spread water related disease

• Global climate change is also a factor

MAJOR LAWS AND TREATIES

Clean Water Act of 1972

• Focuses on point sources• Sources obtain permits for discharges into

navigable waters• Federal aid to sewage treatment• Protection for wetlands has been an issue

(developers)

Safe Drinking Water Act

• Regulates contaminants in public water supplies

• Sets mandatory limits on 90 contaminants• Recommends voluntary standards for other

substances that alter water quality

United Nations Convention on the Law of the Sea (1982)

• Creates a comprehensive framework for nations’ use of oceans

• Outlines rights and responsibilities• Including pollution control, research

resource management