Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of chemical substances or energy, such as noise, heat or light. Pollutants, the components of pollution, can be either foreign substances/energies or naturally occurring contaminants. Pollution is often classed as point source or nonpoint source pollution.
Air pollution has always accompanied civilizations. Pollution started from the prehistoric times when man created the first fires. According to a 1983 article in the journal Science, “soot found on ceilings of prehistoric caves provides ample evidence of the high levels of pollution that was associated with inadequate ventilation of open fires.” The forging of metals appears to be a key turning point in the creation of significant air pollution levels outside the home. Core samples of glaciers in Greenland indicate increases in pollution associated with Greek, Roman and Chinese metal production, but at that time the pollution was comparatively less and could be handled by nature.
London also recorded one of the earlier extreme cases of water quality problems with the Great Stink on the Thames of 1858, which led to construction of the London sewerage system soon afterward. It was the industrial revolution that gave birth to environmental pollution as we know it today. The emergence of great factories and consumption of immense quantities of coal and other fossil fuels gave rise to unprecedented air pollution and the large volume of industrial chemical discharges added to the growing load of untreated human waste.
Forms of pollution
* Air pollution:- the release of chemicals and particulates into the atmosphere. Common gaseous pollutants include carbon monoxide, sulfur dioxide, chlorofluorocarbons (CFCs) andnitrogen oxides produced by industry and motor vehicles. Photochemical ozone and smogare created as nitrogen oxides and hydrocarbons react to sunlight. Particulate matter, or fine dust is characterized by their micrometre size PM10 to PM2.5. * Light pollution:- includes light trespass, over-illumination and astronomical interference. * Littering:- the criminal throwing of inappropriate man-made objects, unremoved, onto public and private properties. * Noise pollution:- which encompasses roadway noise, aircraft noise, industrial noise as well as high-intensity sonar. * Soil contamination occurs when chemicals are released by spill or underground leakage. Among the most significant soil contaminants are hydrocarbons, heavy metals, MTBE,herbicides, pesticides and chlorinated hydrocarbons.
* Radioactive contamination, resulting from 20th century activities in atomic physics, such as nuclear power generation and nuclear weapons research, manufacture and deployment. (Seealpha emitters and actinides in the environment.) * Thermal pollution, is a temperature change in natural water bodies caused by human influence, such as use of water as coolant in a power plant. * Visual pollution, which can refer to the presence of overhead power lines, motorway billboards, scarred landforms (as from strip mining), open storage of trash, municipal solid waste or space debris.
* Water pollution, by the discharge of wastewater from commercial and industrial waste (intentionally or through spills) into surface waters; discharges of untreated domestic sewage, and chemical contaminants, such as chlorine, from treated sewage; release of waste and contaminants into surface runoff flowing to surface waters (including urban runoff and agricultural runoff, which may contain chemical fertilizers and pesticides); waste disposal and leaching into groundwater; eutrophication and littering.
Overview of main health effects on humans from some common types of pollution. Adverse air quality can kill many organisms including humans. Ozone pollution can cause respiratory disease, cardiovascular disease,throat inflammation, chest pain, and congestion. Water pollution causes approximately 14,000 deaths per day, mostly due to contamination of drinking water by untreated sewage in developing countries. An estimated 700 million Indians have no access to a proper toilet, and 1,000 Indian children die of diarrhea every day.Nearly 500 million Chinese lack access to safe drinking water.656,000 people die prematurely each year in China because of air pollution.
In India, air pollution is believed to cause 527,700 fatalities a year. Studies have estimated that the number of people killed annually in the US could be over 50,000. Oil spills can cause skin irritations and rashes. Noise pollution induces hearing loss, high blood pressure, stress, and sleep disturbance. Mercury has been linked to developmental deficits in children and neurologic symptoms. Older people are majorly exposed to diseases induced by air pollution. Those with heart or lung disorders are under additional risk. Children and infants are also at serious risk. Lead and other heavy metals have been shown to cause neurological problems. Chemical and radioactive substances can cause cancer and as well as birth defects.
Pollution has been found to be present widely in the environment. There are a number of effects of this: * Biomagnification describes situations where toxins (such as heavy metals) may pass through trophic levels, becoming exponentially more concentrated in the process. * Carbon dioxide emissions cause ocean acidification, the ongoing decrease in the pH of the Earth’s oceans as CO2 becomes dissolved. * The emission of greenhouse gases leads to global warming which affects ecosystems in many ways. * Invasive species can out compete native species and reduce biodiversity.
Invasive plants can contribute debris and biomolecules (allelopathy) that can alter soil and chemical compositions of an environment, often reducing native species competitiveness. * Nitrogen oxides are removed from the air by rain and fertilise land which can change the species composition of ecosystems. * Smog and haze can reduce the amount of sunlight received by plants to carry out photosynthesis and leads to the production oftropospheric ozone which damages plants. * Soil can become infertile and unsuitable for plants. This will affect other organisms in the food web. * Sulfur dioxide and nitrogen oxides can cause acid rain which lowers the pH value of soil.
Environmental health information
The Toxicology and Environmental Health Information Program (TEHIP) at the United States National Library of Medicine (NLM) maintains a comprehensive toxicology and environmental health web site that includes access to resources produced by TEHIP and by other government agencies and organizations. This web site includes links to databases, bibliographies, tutorials, and other scientific and consumer-oriented resources. TEHIP also is responsible for the Toxicology Data Network (TOXNET) an integrated system of toxicology and environmental health databases that are available free of charge on the web. TOXMAP is a Geographic Information System (GIS) that is part of TOXNET. TOXMAP uses maps of the United States to help users visually explore data from the United States Environmental Protection Agency’s (EPA) Toxics Release Inventory and Superfund Basic Research Programs.
Regulation and monitoring
To protect the environment from the adverse effects of pollution, many nations worldwide have enacted legislation to regulate various types of pollution as well as to mitigate the adverse effects of pollution. Pollution control is a term used in environmental management. It means the control ofemissions and effluents into air, water or soil. Without pollution control, the waste products from consumption, heating, agriculture, mining, manufacturing, transportation and other human activities, whether they accumulate or disperse, will degrade theenvironment. In the hierarchy of controls, pollution prevention and waste minimization are more desirable than pollution control. In the field of land development, low impact development is a similar technique for the prevention of urban runoff.
Pollution control devices
* Dust collection systems Sedimentation (Primary treatment) * Baghouses Sewage treatment * Cyclones Activated sludge biotreaters * Electrostatic precipitators Aerated lagoons * Scrubbers Constructed wetlands * Baffle spray scrubber Industrial waste treatment * Cyclonic spray scrubber API oil-water separators * Ejector venturi scrubber Biofilters * Mechanically aided scrubber Dissolved activated carbon treatment * Spray tower Ultrafilteratiion * Wet scrubber Vapor recovery system * Sedimentation (Primary treatment)
Air pollution * Air dispersion modeling * Arden Pope * Atmospheric Chemistry Observational Databases – links to freely available data. * Climate change * Emission standard * Light Pollution * Greenhouse gas| Soil contamination * Environmental soil science * List of solid waste treatment technologies * List of waste management companies * List of waste management topics| Water pollution * Cruise ship pollution * Marine debris * Marine pollution * Ship pollution * Stormwater * Wastewater * Wastewater quality indicators| Other * Contamination control * Earth Day * Externality * Genetic pollution * Global warming * Heat pollution * List of environmental issues * Noise health effects * Space debris|