Water Pollution

Chapter 22Lara, Nanor, Natalie, Sosi, Greg

Water Pollution is any physical or chemical change in water that negatively affects the health of humans and other organisms.

There are different causes of it, such as coal, oil, and coal ash

Tennessee Valley Authority coal power plant.

8 types of water pollution Sewage Disease-causing agents Sediment pollution Inorganic plant and algal nutrients Organic compounds Inorganic chemicals Radioactive substances Thermal pollution

Sewage Includes disease-causing agents and

plant and algal nutrients such as nitrogen and phosphorus.

Causes environmental problems of enrichment and oxygen demand.

Sewage and other organic waste are measured in terms of their BOD (Biochemical Oxygen Demand), expressed in mg dissolved O2/L of water for a certain temperature & time period.

Disease-Causing Agents

Infected organisms that cause diseases; come from the wastes of infected individuals.

E. Coli is used to measure the amount of sewage & the presence of disease causing agents in the water. A fecal coliform test is used.

Sediment Pollution Soil particles settle at

the bottom of a body of water.

Comes from things such as erosion of agricultural lands, construction, and overgrazed rangelands.

Inorganic plant and algal nutrients

Chemicals such as nitrogen and phosphorus that stimulate the growth of plants and algae. Could be healthy, but becomes harmful when there’s a lot of it.

Comes from human and animal wastes & fertilizer runoff.

Low levels of oxygen in the water, creates bad odors.

Dead Zone

Section of ocean/sea where the oxygen has been depleted to the point where most animals and bacteria cannot survive. Caused by runoff of chemical fertilizers or plant/animal wastes.

Organic Compounds

Chemicals that contain carbon atoms. Synthetic ones include pesticides, industrial chemicals, and plastics. They seep from landfills and through the soil to groundwater.

They are suspected endocrine disruptors that cause hormonal effects to many aquatic organisms.

Inorganic Chemicals

Contaminants that contain elements other than carbon. Ex: acids, salts

Don’t easily break down, and remain there for a long time.

Appear in water due to irrigation runoff, oil drilling, mines, etc.

Two main inorganic chemicals are lead and mercury.

Radioactive Substances

Contain atoms of unstable isotopes that spontaneously emit radiation.

Many industries use radioactive substances; mostly nuclear power plants and nuclear weapons industries, but also medical and scientific research facilities.

Thermal Pollution

Increases the temperature of a lake, stream or river and can cause several chemical, physical, and biological effects.

Chemical reactions will take place faster, which will deplete the oxygen in the water.

Point Source pollution is water pollution

that can be traced to a specific origin. Nonpoint Source pollution are

pollutants that enter bodies of water over large areas rather than being concentrated at a single point of entry.

According to the World Health Organization, 1.4 billion people lack acces to safe drinking water.

Worldwide, at least 250 million cases of water-related illnesses occur each year.

Purifying Water Most municipal water supplies are treated

before being used so that the water is safe to drink. Water is usually treated with aluminum sulfate to cause suspended particles to clump and settle out.

Chlorine is causing health hazards, so other methods are being used to purify water such as UV radiation and ozonation.

Municipal Sewage Treatment

Primary Treatment Secondary Treatment Tertiary Treatment

Water Pollution Acts Safe Drinking Water Act sets uniform

federal standards for drinking water to guarantee safe public water supplies throughout the U.S.

Clean Water Act eliminates the discharge of pollutants into U.S. waterways and attains water quality levels that make these waterways safe to fish and swim in.