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  • Glossary
| Last Updated:21/04/2022



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Acid deposition

               A complex chemical and atmospheric phenomenon that occurs when emissions of sulfur and nitrogen compounds and other substances are transformed by chemical processes in the atmosphere, often far from the original sources, and then deposited on earth in either wet or dry form. The wet forms, popularly called "acid rain," can fall as rain, snow, or fog. The dry forms are acidic gases or particulates. 


Sensitivity to or appreciation of beauty through recognition of its unique and varied components or through its orderly appearance.


An organism, like bacteria, that lives without the presence of oxygen

aerate, aeration

 To supply with air or oxygen; to loosen the soil to add air space to it; to supply running water with additional oxygen, as when a stream runs over falls or rapids or when wind creates waves on a lake.


Non-living factor in an environment; for example, light, water, temperature, or rocks.


Acid deposition
A complex chemical and atmospheric phenomenon that occurs when emissions of sulfur and nitrogen compounds and other substances are transformed by chemical processes in the atmosphere, often far from the original sources, and then deposited on earth in either wet or dry form. The wet forms, popularly called "acid rain," can fall as rain, snow, or fog. The dry forms are acidic gases or particulates.
Acid mine drainage
Drainage of water from areas that have been mined for coal of other mineral ores; the water has low pH, sometimes less than 2.0 (is acid), because of its contact with sulfur-bearing material; acid drainage is harmful because it often kills aquatic organisms.
The condition of water or soil that contains a sufficient amount of acid substances to lower the pH below 7.0 

Adapted, Adaptation

 The process of making adjustments to the environment. For example, plants grow only where soil types, moisture, and sunlight are balanced to the proper degree. Desert plants have adapted so they live under intense sunlight, on poor quality soils, and with a much reduced water supply.


Composite blend of materials made under special conditions. Metal alloys like brass and bronze are well known but there are also many plastic alloys.

Algal bloom

The rapid and excessive growth of algae; generally caused by high nutrient levels combined with other favourable conditions. Blooms can deoxygenate the water leading to the loss of wildlife.

Air pollution

The modification of the natural characteristics of the atmosphere by a chemical, particulate matter, or biological agent.


(Sustainability) An ecologically based farming system, that, through the integration of trees in farms, increases social, environmental and economic benefits to land users.


Planting new forests on lands that have not been recently forested.


Solid or liquid particles suspended within the atmosphere.


Requiring air or oxygen; used in reference to decomposition processes that occur in the presence of oxygen.


One substance taking up another at its surface.

Adaptive radiation

Closely related species that look very different, as a result of having adapted to widely different ecological niches.


A characteristic of an organism that has been favoured by natural selection.

Acid mine drainage

coal mines


The process of an organism adjusting to chronic change in its environment.


substance taking in another, either physically or chemically


on-living chemical and physical factors of the environment


An organism that produces complex organic compounds from simple inorganic molecules using energy from light or inorganic chemical reactions.



General name for the layer of gases around a material body; the Earth's atmosphere consists, from the ground up, of the troposphere (which includes the planetary boundary layer or peplosphere, the lowest layer), stratosphere, mesosphere, ionosphere (or thermosphere), exosphere and magnetosphere.

Arable land

Land that can be used for growing crops.



A bed or layer yielding water for wells and springs etc.; an underground geological formation capable of receiving, storing and transmitting large quantities of water. Aquifer types include: confined (sealed and possibly containing “fossil” water); unconfined (capable of receiving inflow); and Artesian (an aquifer in which the hydraulic pressure will cause the water to rise above the upper confining layer).


The cultivation of aquatic organisms under controlled conditions.


Man-made, not natural.


With abnormally low levels of oxygen.


Not requiring air or oxygen; used in reference to decomposition processes that occur in the absence of oxygen.

Anaerobic digestion

The biological degradation of organic materials in the absence of oxygen to yield methane gas (that may be combusted to produce energy) and stabilized organic residues (that may be used as a soil additive).


Alternative fuels

Fuels like ethanol and compressed natural gas that produce fewer emissions than the traditional fossil fuels.



Adjustment in natural or human systems in response to actual or expected climatic stimuli or their effects, which moderates harm or exploits beneficial opportunities.


Area of Critical Environmental Concern

Alternative energy sources

Energy that does not come from fossil fuels (such as coal, oil, gas), for example wind, flowing water, solar energy and biomass.


See environmental managment system audit. 


Ancillary Material

 Material that is not used directly in the formation of a product or service

Aerobic composting

A controlled process involving microbial decomposition of organic matter in the presence of oxygen


 A description of a surface's reflective properties.

Active solar system

A mechanical system that actively collects, concentrates, and stores solar energy.

Acid Rain

The precipitation of dilute solutions of strong mineral acids, formed by the mixing in the atmosphere of various industrial pollutants -- primarily sulfur dioxide and nitrogen oxides -- with naturally occurring oxygen and water vapor.

Assimilative Capacity

The ability of a natural body of water to receive wastewaters or toxic materials without harmful effects and without damage to aquatic life. 

Acceptable intake

Numbers which describe how toxic a chemical is.   The numbers are derived from animal studies of the relationship between dose and non-cancer effects.  There are two types of acceptable exposure values: one for acute (relatively short-term) and one for chronic (longer-term) exposure.

active transport

 The opposite of passive transport, active transport involves the input of energy (usually in the form of ATP), the building of concentration gradients, and the action of a membrane pump to create high concentrations of molecules.

absolute zero

The theoretical lowest temperature possible at which all molecular motion ceases. Absolute zero, 0 K or -273.15°C, has never been reached. 

Ambient Air Quality Objectives or Standards

Air quality levels for specific pollutants that are determined to be necessary to protect human health and/or the environment. They typically consist of a numeric pollutant concentration, averaging time, and rules or guidance on sampling methodology and how the objectives or standards are to be applied. They may also be referred to as "Ambient Air Quality Criteria" or "Guidelines."  

Ambient Air

Outside air, surrounding air, air occurring at a particular time and place outside of structures.  All living beings are exposed to the ambient air. 

Air Toxics

Air pollutants that are toxic to humans, fish, wildlife and marine animals.  

Air Mass

A large volume of air with with similar temperature and moisture characteristics. Air masses cover many hundreds or thousands of square miles, and slowly change in accordance with the surface below them 

Air Quality Index (AQI)

The Air Quality Index (AQI) reports current air quality based on a specific level of an individual air pollutant. 

Air Quality Health Index (AQHI)

The Air Quality Health Index reports on the current state of the air and identifies the related health risk associated it.  

Air Quality

The state of the air within a specific area. “Air quality” is a neutral term: it can be good or bad (in or between). 

Adaptation (Climate Change)

IPCC Definition "Adjustment in natural or human systems in response to actual or expected climatic stimuli or their effects, which moderate harm or exploits beneficial opportunities." The definition recognizes that humans can adjust to past ("actual") climate change and its impacts, or prepare for projected future ("expected") climate change and its impacts. Adaptation can include changes in behaviour, technology, institutions, policies, and other aspects of human systems.  

Annual Crops

Crops which complete their life cycle from seed to seed within one year.  

Alkaline Soil

Any soil having pH greater than 7 

Alkali Soil

A soil that contains sufficient exchangable sodium to interfere with thegrowth of most of crop plants.  The ESP is generally more than 15 and ECF less than 4 decisiemens per metre.  The soil pH is higher than 8'2 except in systems with chloride and sulphate anions.  


Reducing the degree or intensity of, or eliminating, pollution. 

Anaerobic digestion


a method of composting that does not require oxygen. This composting method produces methane. Also known as anaerobic composting.  

Aerobic composting


a method of com-posting organic wastes using bacteria that need oxygen. This requires that the waste be exposed to air, either via turning or by forcing air through pipes that pass through the material.  




 sharply printed


needle shaped 


Air stripping tower

Air stripping removes volatile organic chemicals (such as solvents) from contaminated water by causing them to evaporate. Polluted water is sprayed downward through a tower filled with packing materials while air is blown upwards through the tower. The contaminants evaporate into the air, leaving significantly-reduced pollutant levels in the water. The air is treated before it is released into the atmosphere. 

Advisory level

The level above which an environmental protection agency suggests it is potentially harmful to be exposed to a contaminant, although no action is mandated. 

Action level

A guideline established by environmental protection agencies to identify the concentration of a substance in a particular medium (water, soil, etc.) that may present a health risk when exceeded. If contaminants are found at concentrations above their action levels, measures must be taken to decrease the contamination. 

Average Lifespan

 The average time the animal lives for


 The bony growth on the head of animals such as deer. Antlers are often much large than horns, branching out as they grow. In most cases, antlers are shed and re-grown every year in connection with the breeding season.


An instrument for measuring wind speed and velocity. 

Ampere, Amps:

The measurement of the flow of an electric current through a conductor. 

Alternating current

 An electric current that reverses directions at regular intervals (typically 60 times per second); abbreviated "AC." This is the current usually found in homes.

Active ingredient

 In any pesticide product, the component that kills, or otherwise controls, target pests. Pesticides are regulated primarily on the basis of active ingredients. 


A suspension of liquid or solid particles in a gas. A suspension of liquid or solid particles in a gas. 

Air mass

 A large volume of air with certain meteorological or polluted characteristics, e,g, a heat inversion or smogginess-while in one location. The characteristics can change as the air mass moves away. 

Airborne particulates

Total suspended particulate matter found in the atmosphere as solid particles or liquid droplets. Chemical composition of particulates varies widely, depending on location and time of year. Airborne particulates include: windblown dust, emissions from industrial processes, smoke from the burning of wood and coal, and motor vehicle or non-road engine exhausts, exhaust of motor vehicles. 

Air emissions

 Gas emitted into the air from industrial and chemical processes, such as ozone, carbon monoxide, nitrogen oxide, nitrogen dioxide, sulfur dioxide and others. 


 A type of hydrocarbon, such as benzene or toluene, added to gasoline in order to increase octane. 


Relating to mud and/or sand deposited by flowing water. Alluvial deposits may occur after a heavy rain storm. 


        The physiological adaptation to climatic variations.


The condition of water or soil that contains a sufficient amount of acid substances to lower the pH below 7.0 

Aqueous Solubility

ability of a solution to be dissolved in water 


 caused by humans rather than nature 


compound for which an analytical laboratory has been requested to analyze a given sample or set of samples 


naturally-occurring group of minerals that are found in the environment as bundles of durable fibers that are fire-, heat-, and chemical-resistant and do not conduct electricity; upon disturbance, fibers become airborne and can become trapped in the lungs upon inhalation 


body of impermeable or distinctly less-permeable material stratigraphically adjacent to one of more aquifers which slows but does not prevent the flow of water to or from an adjacent aquifer


Simple rootless plants that grow in sunlit waters in proportion to the amount of available nutrients. They can affect water quality adversely by lowering the dissolved oxygen in the water. They are food for fish and small aquatic animals. (Source: US EPA)


A corrosive solution with a pH less than 7

Absorption Barrier

 Any of the exchange sites of the body that permit uptake of various substances at different rates (e.g. skin, lung tissue, and gastrointestinal-tract wall)


Absorbed Dose

 In exposure assessment, the amount of a substance that penetrates an exposed organism's absorption barriers (e.g. skin, lung tissue, gastrointestinal tract) through physical or biological processes. The term is synonymous with internal dose.

Abatement Debris

Waste from remediation activities.


Abandoned Well

A well whose use has been permanently discontinued or which is in a state of such disrepair that it cannot be used for its intended purpose.