Glossary

Aquifer
A porous, water-saturated layer of sediment and bedrock.

Biomagnification
Microscopic living organisms which can aid in pollution control by consuming or breaking down organic matter in sewage or by similarly acting on oil spills or other water pollutants.

Bacteria
A process by which chemical substances are ingested and retained by organisms, either from the environment directly or through consumption of food containing the chemicals.

Bioaccumulation
A cumulative increase in the concentration of a persistent substance in successively higher levels of the food chain.

Carbon dioxide
A colourless, odourless, non-poisonous gas, which results from fossil fuel combustion and is normally a part of the air.

Chlorofluorocarbons (CFCs)
A family of inert, non-toxic, and easily liquified chemicals used in refrigeration, air conditioning, packaging, insulation, or as solvents. Gaseous CFCs can deplete the ozone layer when they slowly rise into the stratosphere and their chlorine atoms react with ozone molecules.

Composting
The natural biological decomposition of organic material in the presence of air to form a rich, dark soil conditioner.

Contaminant
Any physical, chemical, biological, or radiological substance or matter that has an adverse effect on air, water, or soil.

DDT
An organochloride used as an insecticide. It has been banned since 1969 in North America since it is a possible cause of cancer, but it is still widely used in developing countries.

Decomposition
The breakdown of matter by bacteria and fungi. It changes the chemical make-up and physical appearance of materials.

DNA
Deoxyribonucleic acid. Large molecules that carry genetic information in living organisms.

Endangered species
A species threatened with imminent extinction or extirpation throughout all or a significant portion of its range.

Environment
Everything that surrounds an organism or organisms, including both natural and human-built elements.

Erosion
The wearing away of land surface by agents such as wind, water, glaciers, chemicals, and exposure to the atmosphere. Erosion occurs naturally but can be intensified by land-clearing practices related to farming, residential or industrial development, road building, or timber cutting.

Extinct species
A species that no longer survives anywhere in the world.

Extirpated species
A species that no longer survives in a particular country or region.

Food chain
A specific nutrient and energy pathway in ecosystems, proceeding from producing organisms to consuming organisms.

Fossil fuels
Coal, oil, and other hydrocarbons that developed out of biotic materials in a previous geological age.

Habitat
The geographical location(s) and the associated set(s) of environmental conditions that are necessary for the flourishing of a particular species.

Hazardous waste
Refuse that could present dangers through the contamination and pollution of the environment.

Herbivore
An animal that feeds on plants.

Heritage
The set of all things, places, and ideas inherited from the past which are of special significance to the collective life of a community, including both natural and human-built elements.

Incineration
The burning of certain types of solid, liquid, or gaseous materials.

Inorganic compounds
All compounds, except carbon compounds containing hydrogen.

Leachate
Water that is contaminated as it trickles through waste, agricultural pesticides, or fertilizers.

Nitrogen fixation
A process by which certain kinds of organisms (mainly a type of bacteria called cyanobacteria) transform nitrogen gas into water-soluble compounds that can be taken up by the roots of plants.

Organic compounds
Compounds composed of carbon and hydrogen. Organic compounds form the basic building blocks of living tissue.

PCBs
Polychlorinated biphenyls. PCBs are organic compounds that are stable and have good insulating properties, including fire resistance. They have been used in electrical transformers, electrical capacitors, and in the making of carbonless copy papers. Banned in North America since 1977, they may contribute to wildlife deformities, chloracne (a painful skin condition), liver damage, and cancer.

Photosynthesis
The process by which solar energy is used by plants to turn carbon dioxide and water into sugar and other carbohydrates, releasing oxygen in the process.

Respiration
The process whereby a living organism or cell takes in oxygen and food and converts these to water and carbon dioxide, producing usable energy.

Sewage
Waste discharged in liquid form from households and industries.

Threatened species
A species likely to become endangered if the factors affecting its vulnerability do not become reversed.

Vermicomposting
A type of indoor composting that uses a special kind of worm to break down organic materials, producing a rich, sweet-smelling compost.

Vulnerable species
A species at risk because of low or declining numbers.

Wetlands
An area regularly saturated by surface or ground water and characterized by a prevalence of vegetation that is adapted for life in saturated soil conditions.