discuss varuous sources of pollution
Answers
Answer:
There are four main types of air pollution sources: mobile sources – such as cars, buses, planes, trucks, and trains. stationary sources – such as power plants, oil refineries, industrial facilities, and factories. area sources – such as agricultural areas, cities, and wood burning fireplaces.
Answer:
varuous sources of pollution are
Explanation:
SOURCES OF POLLUTION - OVERVIEW
What is pollution?
Pollution is the harm that results because of the presence of a substance or substances where they would not normally be found or because they are present in larger than normal quantities. Polluting substances may occur as a solid, liquid or gas.
The consequences of pollution may be direct, through the toxic effect of a substance. For example, an accidental spill of a pesticide entering a river may well have an immediate effect and be very harmful to the aquatic life. Or the consequences of pollution may be indirect. Nitrogen and phosphorus are essential for plant growth, but excessive plant growth can be harmful to water. For example, enhanced phosphorus levels in surface waters (that contain adequate nitrogen) can stimulate excessive algal growth. In time, the process of algal decay reduces the oxygen available in the water, harming fish and other aquatic life.
Our use of water can cause pollution, not only because of substances we put into water either deliberately or accidentally, but also by abstracting water from rivers and lakes we reduce the ability of water bodies to tolerate the presence of potentially-polluting substances. Where the volume of receiving water is low, the relative concentration of a polluting substance entering the water will be higher and consequently its impact will be greater. Hence, the reduction of water pollution relies not only on preventing potentially-polluting substances entering water bodies, but also on reducing the amount of water we use.
Some useful definitions
Pollutant – contaminant present in the environment or which might enter the environment which, due to its properties or amount or concentration, causes harm.
Contaminant – substance, material or agent that is unwanted in the environment.
Harm – physical injury or damage to the health of people or damage to property or the environment.
Hazard – potential source of harm.
Risk – combination of the probability of occurrence of harm and the severity of that harm.
Perceived risk – sum of calculated risk and outrage (a strong expression of concern).
Pathway – the means by which harm is transmitted from the source to the receptor
Dose – the amount received by the receptor: this is an essential consideration – as Paracelsus said 500 years ago ‘the dose makes the poison’.
Nature of pollution sources
Pollution is often described as point source or diffuse (or non-point) pollution.
Point source pollution enters a water body at a specific site and is generally readily identified. Potential point sources of pollution include effluent discharges from sewage treatment works and industrial sites, power stations, landfill sites, fish farms, and oil spillage via a pipeline from industrial sites.
Point source pollution is generally readily prevented since it is possible to identify where it is coming from and, having done so, those responsible for causing the pollution can take preventative measures through immediate remedial action or longer-term investment in treatment and control facilities.
Diffuse pollution arises where substances are widely used and dispersed over an area as a result of land-use activities such as urban development, amenity, farming and forestry. These activities may be recent or have been carried out in the past. It is often difficult to identify specific sources of such pollution and therefore take immediate action to prevent it, since prevention often requires major changes to land use and management practices.
Examples of diffuse pollution include the leaching to surface water and groundwater of contaminants from roads, manures, nutrients and pesticides used in agriculture and forestry, and atmospheric deposition of contaminants arising from industry. A special case arises where, for example, a power station may emit sulphur dioxide and nitrous oxide to the air. Although this is a point source, the deposition (fallout) and hence, impact, will be over a wide area as diffuse pollution.
Substances that may cause pollution
Some of the major substances that may cause pollution are:
Nutrients
The main potentially-polluting nutrients in relation to water are nitrogen, ammonia (a gas containing nitrogen and hydrogen), phosphorus and sulphur. They arise from the natural breakdown of crop residues and soil organic matter, rainfall, fertilisers, urine and manure, silage, landfill sites, wastewater and industrial effluents, power generation and other fuel-burning activities. For example, nutrients are the principal cause of eutrophication which is the enrichment of lakes, rivers and the marine environment leading to increased plant growth and the occurrence of algae.