Glossary

Pollution = Undesirable state of the natural environment being contaminated with harmful substances as a consequence of human activities. Pollution can be in the form of chemical substances or energy , such as noise, heat, or light. Pollutants can be naturally occurring substances or energies, but are considered contaminants when in excess of natural levels. Motor vehicles, power stations, oil refineries and ships are considered amongst the worst pollutants. Air pollution leads to respiratory diseases in humans, while water pollution can lead to different types of poisoning and even brain damage (in the case of poisoning with mercury).

Sewage = The waste and wastewater produced by residential and commercial sources and discharged into sewers, which is a frequent source of water pollution in urban areas. A system of sewer pipes (sewers) collects sewage and transports it elsewhere for treatment or disposal. The system of sewers is called sewerage . Sewage treatment is the process of removing the contaminants from sewage to produce liquid and solid ( sludge ) suitable for discharge to the environment or for reuse. It is a form of waste management . A septic tank or other on-site wastewater treatment system such as biofilters can be used to treat sewage close to where it is created. Sewage contains a number of harmful micro-organisms such as bacteria, besides high concentrations of nitrates and phosphates.

Biodiversity = The variety of life in all forms, levels and combinations. The term biodiversity includes genetic diversity, species diversity, and ecosystem diversity. We are currently experiencing a biodiversity crisis, due to the rapid loss of species (refer to extinction) from the Earth as a result of human activities. Species diversity is highest in the tropics (i.e. close to the equator), in places like the Amazon Forest , central Africa and south-east Asia , and is lowest at the North and South poles.

Sustainable = Meeting the needs of the present without compromising the ability of future generations to meet their needs. The concept of sustainability involves using a non-renewable resource responsibly, without any wastage. Most of the societies in the Western world are not sustainable because of the large amounts of raw material they use, such as metal, wood, etc. Some say that the current human population (around 6.2 billion) is also not sustainable and should be controlled.

Ecotourism = A tourism market based on an area's natural resources that attempts to minimize the ecological impact of tourism. Examples of activities encouraged in ecotourism include walking, the observation of wildlife (e.g. birdwatching), cycling, etc. All of these activities minimize pollution and the consumption of resources. Ecotourism also seeks to preserve natural habitats by not promoting large-scale tourism and the building of large resorts and also seeks to employ local indigenous people and to help them preserve their communities. In some countries this type of tourism has developed greatly. Examples include Kenya , Costa Rica and South Africa .

Anti-fouling paints = Paints applied to the underside and sides of vessels to inhibit/prevent the attachment of some marine organisms, such as barnacles. Most of these paints are toxic to a wide variety of marine organisms and are found in highest concentrations close to yacht marinas. For this reason, some anti-fouling paints, such as tributyltin, are now banned from use by many countries.

Ecosystem = An ecosystem is a complete community of living organisms and the nonliving materials of their surroundings. Its components include: plants, animals, and microorganisms ; soil, rocks, and minerals; as well as surrounding water sources and the local atmosphere. The size of ecosystems varies tremendously. An ecosystem could be an entire rain forest, covering a geographical area larger than many nations, or it could be a puddle or a backyard garden.