[ltr]
Pollution is the release of
environmental contaminants. The major forms of pollution include:[/ltr]
- [ltr]Air pollution, the release of chemicals and particulates into the atmosphere. Common examples include carbon monoxide, sulfur dioxide, chlorofluorocarbons (CFCs), and nitrogen oxides produced by industry and motor vehicles. Ozone and smog are created as nitrogen oxides and hydrocarbons react to sunlight.[/ltr]
- [ltr]Water pollution via surface runoff and leaching to groundwater.[/ltr]
- [ltr]Soil contamination occurs when chemicals are released by spill or underground storage tank leakage. Among the most significant soil contaminants are hydrocarbons, heavy metals, MTBE, herbicides, pesticides and chlorinated hydrocarbons.[/ltr]
- [ltr]Radioactive contamination, added in the wake of 20th-century discoveries in atomic physics. (See alpha emitters and actinides in the environment.)[/ltr]
- [ltr]Noise pollution, which encompasses roadway noise, aircraft noise, industrial noise as well as high-intensity sonar.[/ltr]
- [ltr]Light pollution, includes light trespass, over-illumination and astronomical interference.[/ltr]
- [ltr]Visual pollution, which can refer to the presence of overhead power lines, motorway billboards, scarred landforms (as from strip mining), open storage of trash or municipal solid waste.[/ltr]
- [ltr]Thermal Pollution, is a temperature change in natural water bodies caused by hum[/ltr]
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Sources and causes[/ltr]
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[/ltr]
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[/ltr]
[ltr]Air pollution[/ltr]
[ltr]Motor vehicle emissions are likely the leading cause of air pollution.
China,
United States,
Russia,
Mexico, and
Japan are the world leaders in air pollution emissions; however,
Canada is the number two country, ranked per capita. Principal stationary pollution sources include chemical plants, coal-fired
power plants,
oil refineries,
[1] petrochemical plants,
nuclear waste disposal activity, incinerators, large animal farms,
PVC factories, metals production factories, plastics factories, and other heavy industry.[/ltr]
[ltr]Some of the more common
soil contaminants are
chlorinated hydrocarbons (CFH),
heavy metals (such as
chromium,
cadmium--found in rechargeable
batteries, and
lead--found in lead
paint,
aviation fuel and still in some countries,
gasoline),
MTBE,
zinc,
arsenic and
benzene. Ordinary municipal
landfills are the source of many chemical substances entering the soil environment (and often groundwater), emanating from the wide variety of refuse accepted, especially substances illegally discarded there, or from pre-1970 landfills that may have been subject to little control in the U.S. or EU.[/ltr]
[ltr]Pollution can also be the consequence of a natural disaster. For example
hurricanes often involve water contamination from sewage, and
petrochemical spills from ruptured
boats or
automobiles. Larger scale and environmental damage is not uncommon when coastal
oil rigs or
refineries are involved. Some sources of pollution, such as
nuclear power plants or
oil tankers, can produce widespread and potentially hazardous releases when accidents occur.[/ltr]
[ltr]In the case of
noise pollution the dominant source class is the
motor vehicle, producing about ninety percent of all unwanted noise worldwi[/ltr]
Effects on human health
Pollution Prevention and Control is a regime for controlling pollution from certain industrial activities. The regime introduces the concept of Best Available Techniques ("BAT") to environmental regulations. Operators must use the BAT to control pollution from their industrial activities. The aim of the Best Available Techniques is to prevent, and where that is not practicable, to reduce to acceptable levels, pollution to air, land and water from industrial activities. The Best Available Techniques also aim to balance the cost to the operator against benefits to the environment. The system of Pollution Prevention and Control is replacing that of Integrated Pollution Control (which was established by the Environmental Protection Act 1990) and is taking effect between 2000 and 2007. The Pollution Prevention and Control regime implements the European Directive (EC/96/61) on integrated pollution prevention and control.Pollution sucks.
[ltr]Pollution of controlled waters[/ltr]
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[/ltr]
[ltr]Water pollution[/ltr]
The second part of the statutory definition of contaminated land covers where polluting material is entering or likely to enter controlled waters. The statutory guidance provides that the likelihood of the entry of the contaminant is to be assessed on the balance of probabilities. The definition of contaminated land within Part IIA (in relation to pollution of controlled waters), in that the contamination will need to be deemed to be significant.
There is currently no guidance available on what may, or may not, be significant pollution of controlled waters except that one that is based upon risk is considered to be appropriate. This approach has already been taking place throughout the industry and widely accepted by the regulators as a means of assessing the significance of groundwater contamination. As such pollutant linkages with respect to ground and surface water targets/receptors are considered in a similar manner to that for significant harm.
[ltr]Soil contamination[/ltr]
Two sources of published generic guidance are currently commonly used in the UK:
- [ltr]The Contaminated Land Exposure Assessment (CLEA) Guidelines[/ltr]
- [ltr]The Dutch Standards.[/ltr]
Guidance by the Inter Departmental Committee for the Redevelopment of Contaminated Land (ICRCL) has been formally withdrawn by the Department for Environment, Food and Rural Affairs (DEFRA), for use as a prescriptive document to determine the potential need for remediation or further assessment. Therefore, no further reference is made to these former guideline values.
Other generic guidance that may be referred to (to put the concentration of a particular contaminant in context), include the United States EPA Region 9 Preliminary Remediation Goals (US PRGs), the US EPA Region 3 Risk Based Concentrations (US EPA RBCs) and National Environment Protection Council of Australia Guideline on Investigation Levels in Soil and Groundwater.
The CLEA model published by DEFRA and the Environment Agency (EA) in March 2002 sets a framework for the appropriate assessment of risks to human health from contaminated land, as required by Part IIA of the Environmental Protection Act 1990. As part of this framework, generic Soil Guideline Values (SGVs) have currently been derived for ten contaminants to be used as “intervention values”. These values should not be considered as remedial targets but values above which further detailed assessment should be considered.
Three sets of CLEA SGVs have been produced for three different land uses, namely:
- [ltr]residential (with and without plant uptake)[/ltr]
- [ltr]allotments[/ltr]
- [ltr]commercial/industrial[/ltr]
It is intended that the SGVs replace the former ICRCL values. It should be noted that the CLEA SGVs relate to assessing chronic (long term) risks to human health and do not apply to the protection of ground workers during construction, or other potential receptors such as groundwater, buildings, plants or other ecosystems. The CLEA SGVs are not directly applicable to a site completely covered in hardstanding, as there is no direct exposure route to contaminated soils.
To date, the first ten of fifty-five contaminant SGVs have been published, for the following: arsenic, cadmium, chromium, lead, inorganic mercury, nickel, selenium ethyl benzene, phenol and toluene. Draft SGVs for benzene, naphthalene and xylene have been produced but their publication is on hold. Toxicological data (Tox) has been published for each of these contaminants as well as for benzo[a]pyrene, benzene, dioxins, furans and dioxin-like PCBs, naphthalene, vinyl chloride, 1,1,2,2 tetrachloroethane and 1,1,1,2 tetrachloroethane, 1,1,1 trichloroethane, tetrachloroethene, carbon tetrachloride, 1,2-dichloroethane, trichloroethene and xylene. The SGVs for ethyl benzene, phenol and toluene are dependent on the soil organic matter (SOM) content (which can be calculated from the total organic carbon (TOC) content). As an initial screen the SGVs for 1% SOM are considered to be appropriate.
Perspectives
The earliest precursor of pollution generated by life forms would have been a natural function of their existence. The attendant consequences on viability and population levels fell within the sphere of
natural selection. These would have included the demise of a population locally or ultimately, species extinction. Processes that were untenable would have resulted in a new balance brought about by changes and adaptations. At the extremes, for any form of life, consideration of pollution is superseded by that of survival.
For mankind, the factor of technology is a distinguishing and critical consideration, both as an enabler and an additional source of byproducts. Short of survival, human concerns include the range from quality of life to health hazards. Since science holds experimental demonstration to be definitive, modern treatment of toxicity or environmental harm involves defining a level at which an effect is observable. Common examples of fields where practical measurement is crucial include
automobile emissions control, industrial exposure (eg
OSHA PELs),
toxicology (eg
LD50), and
medicine (eg
medication and
radiation doses).
"The solution to pollution is dilution", is a dictum which summarizes a traditional approach to pollution management whereby sufficiently diluted pollution is not harmful.
[10][11] It is well-suited to some other modern, locally-scoped applications such as laboratory safety procedure and
hazardous material release emergency management. But it assumes that the dilutant is in virtually unlimited supply for the application or that resulting dilutions are acceptable in all cases.
Such simple treatment for environmental pollution on a wider scale might have had greater merit in earlier centuries when physical survival was often the highest imperative, human population and densities were lower, technologies were simpler and their byproducts more benign. But these are often no longer the case. Furthermore, advances have enabled measurement of concentrations not possible before. The use of statistical methods in evaluating outcomes has given currency to the principle of probable harm in cases where assessment is warranted but resorting to deterministic models is impractical or unfeasible. In addition, consideration of the environment beyond direct impact on human beings has gained prominence.
Yet in the absence of a superseding principle, this older approach predominates practices throughout the world. It is the basis by which to gauge concentrations of effluent for legal release, exceeding which penalties are assessed or restrictions applied. The regressive cases are those where a controlled level of release is too high or, if enforceable, is neglected.
[12] Migration from pollution dilution to elimination in many cases is confronted by challenging economical and technological barriers.
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