APES Chapter 14

Water pollution

The contamination of streams, rivers, lakes, oceans, or groundwater with substances produced through human activities

Wastewater

Water produced by livestock operations and human activities, including human sewage from toilets and gray water from bathing and washing of clothes and dishes

Point source

A distinct location from which pollution is directly produced

Nonpoint source

A diffuse area that produces pollution.

What are the three categories that problems form wastewater fall into

• Oxygen demand

• Nutrient release

• Disease-causing organisms

Oxygen Demand

Biochemical oxygen demand (BOD)

The amount of oxygen a quantity of water uses over a period of time at specific temperatures

Dead zone

In a body of water, an area with extremely low oxygen concentration and very little life.

Nutrient Release

Eutrophication

A phenomenon in which a body of water becomes rich in nutrients

Cultural eutrophication

An increase in fertility in a body of water, the result of anthropogenic inputs of nutrients

Disease-Causing Organisms

Diseases that can be contracted by coming into contact with contaminated water include:

• Cholera

• Typhoid fever

• Stomach flu

• Diarrhea

• Cholera

• Hepatitis

Indicator species

A species that indicates whether or not disease-causing pathogens are likely to be present

Fecal coliform bacteria

A group of generally harmless microorganisms in human intestines that can serve as an indicator species for potentially harmful microorganisms associated with contaminated sewage

Treating wastewater

Two common ways to handle human wastewater:

• Septic systems

• Sewage treatment plants

Septic Systems

Septic system

A relatively small and simple sewage treatment system, made up of a septic tank and a leach field, often used for homes in rural area

Spetic Tank

A large container that receives wastewater from a house as part of a septic system

Sludge

Solid waste material from wastewater

Septage

A layer of fairly clear water found in the middle of a septic tank

Leach Field

A component of a septic system, made up of underground pipes laid out below the surface of the ground.

Sewage Treatment Plants

In developed countries, municipalities use centralized sewage treatment plants that receive wastewater from hundreds or even thousands of households.

In traditional waste treatment plants, there are two phases of treatment: primary and secondary

A sewage treatment plant

In large municipalities, great volumes of wastewater are handled by separating the sludge from the water and then using bacteria to break down both components.

Animal Feed Lots and Manure Lagoons

Manure from concentrated animal feeding operations is a problem because of volume. It can also contain hormones and antibiotics that are given to the animals

Manure lagoon

Human-made pond lined with rubber built to handle large quantities of manure produced by livestock

Heavy Metals and Other Chemicals

Lead

found in pipes and other materials in older construction

Arsenic

occurs naturally and through human activity such as mining and industry

Mercury

occurs naturally and through human activity, primarily burning coal

Arsenic in U.S. well water

The highest concentrations of arsenic are generally found in the upper Midwest and the West

World mercury emissions

Mercury emissions from human activities vary greatly among regions of the world

Acid deposition and acid mine drainage affect terrestrial and aquatic ecosystems

Acid deposition

Acids deposited on Earth as rain and snow or as gases and particles that attach to the surfaces of plants, soil, and water.

Acid deposition occurs when burning coal releases sulfur dioxide and nitrogen dioxide into the air

In the atmosphere, these chemicals are converted to sulfuric acid and nitric acid, which fall back to Earth as acid deposition

Acid deposition reduces the pH of water bodies to levels that are lethal to many organisms

Many coal-burning facilities have installed coal scrubbers to combat this problem

Synthetic organic compounds are human-produced chemicals

Synthetic compounds can enter the water supply from industrial point sources or from nonpoint sources when they are applied over large areas.

These compounds include pesticides, pharmaceuticals, military compounds, and industrial compounds.

Synthetic organic compounds can be toxic, cause genetic defects, and interfere with growth and sexual development.

Contaminants in streams

Streams contain a wide variety of chemicals including pharmaceutical drugs and hormones. These come from a combination of wastewater inputs, agriculture, forestry, and industry

Military Compounds

Perchlorates

A group of harmful chemicals used for rocket fuel. Perchlorates sometimes contaminate the soil in regions of the world where military rockets are manufactured, tested, or dismantled

Industrial Compounds

• Industrial compounds: chemicals used in manufacturing.

• It used to be common for manufacturers in the United States to dump industrial compounds directly into bodies of water

Polychlorinated biphenyls (PCBs)

A group of industrial compounds used to manufacture plastics and insulate electrical transformers, and responsible for many environmental problems.

Oil Pollution

Sources of oil in the ocean

Oil contamination in the ocean, both (a) in North America and (b) worldwide, comes from a variety of sources including natural seeps, extraction of oil from underneath the ocean, transport of oil by tanker or pipeline, and consumption of petroleum-based products.

Ways to remediate oil pollution

Containment: Booms keep the floating oil from spreadig, then boats equipped with giant oil vacuums suck up as much oil as possible

Chemicals: Chemicals break up the oil on the surface, making it disperse before it hits the shoreline

Bacteria: A particular bacterium consumes oil; scientists are currently trying to genetically engineer the bacteria to consume oil even faster

Nonchemical Water Pollution (mod 44)

Solid Waste

Much solid waste is what we call garbage and the sludge produced by sewage treatment plants

Thermal pollution

Non Chemical water pollution that occurs when human activities cause a substantial change in the temperature of water

Thermal shock

A dramatic change in water temperature that can kill organisms

Water Pollution Laws (mod 45)

Clean Water Act

Legislation that supports the “protection and propagation of fish, shellfish, and wildlife and recreation in and on the water” by maintaining and, when necessary, restoring the chemical, physical, and biological properties of surface waters

Safe Drinking Water Act

Legislation that sets the national standards for safe drinking water

The Safe Water Drinking Act establishes maximum contaminant levels (MCL) for 77 different elements or substances in both surface water and groundwater

Maximum contaminant level (MCL)

The standard for safe drinking water established by the EPA under the Safe Drinking Water Act.

Water pollution legislation is becoming more common in the

developing world

Developed countries have addressed the problems of pollution by cleaning up polluted areas and by passing legislation to prevent pollution in the future