بحث عن التلوث بالانجليزي
Pollution is the introduction of contaminants into an environment that causes instability, disorder, harm or
discomfort to the physical systems or living organisms they are in.[1] Pollution can take the
form of chemical substances, or energy, such as noise, heat, or light energy. Pollutants, the
elements of pollution, can be foreign substances or energies, or naturally occurring; when naturally occurring,
they are considered contaminants when they exceed natural levels. Pollution is often classed as point
source or nonpoint source pollution.
Prehistory
But gradually increasing populations and the proliferation of basic industrial processes saw the emergence of
a civilization that began to have a much greater collective impact on its surroundings. It
was to be expected that the beginnings of environmental awareness would occur in the more
developed cultures, particularly in the densest urban centers. The first medium warranting official policy measures
in the emerging western world would be the most basic: the air we breathe.
The earliest known writings concerned with pollution were Arabic medical treatises written between the 9th
and 13th centuries, by physicians such as al-Kindi (Alkindus), Qusta ibn Luqa (Costa ben Luca),
Muhammad ibn Zakarīya Rāzi (Rhazes), Ibn Al-Jazzar, al-Tamimi, al-Masihi, Ibn Sina (Avicenna), Ali ibn Ridwan,
Ibn Jumay, Isaac Israeli ben Solomon, Abd-el-latif, Ibn al-Quff, and Ibn al-Nafis. Their works covered
a number of subjects related to pollution such as air contamination, water contamination, soil contamination,
solid waste mishandling, and environmental assessments of certain localities.[3]
King Edward I of England banned the burning of sea-coal by proclamation in London in
1272, after its smoke had become a problem.[4][5] But the fuel was so common in
England that this earliest of names for it was acquired because it could be carted
away from some shores by the wheelbarrow. Air pollution would continue to be a problem
there, especially later during the industrial revolution, and extending into the recent past with the
Great Smog of 1952. This same city 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. Chicago and Cincinnati were the
first two American cities to enact laws ensuring cleaner air in 1881. Other cities followed
around the country until early in the 20th century, when the short lived Office of
Air Pollution was created under the Department of the Interior. Extreme smog events were experienced
by the cities of Los Angeles and Donora, Pennsylvania in the late 1940s, serving as
another public reminder.[6]
Modern awareness
Early Soviet poster, before the modern awareness: “The smoke of chimneys is the breath of
Soviet Russia”
Pollution became a popular issue after WW2, when the aftermath of atomic warfare and testing
made evident the perils of radioactive fallout. Then a conventional catastrophic event The Great Smog
of 1952 in London killed at least 8000 people. This massive event prompted some of
the first major modern environmental legislation, The Clean Air Act of 1956.
Pollution began to draw major public attention in the United States between the mid-1950s and
early 1970s, when Congress passed the Noise Control Act, the Clean Air Act, the Clean
Water Act and the National Environmental Policy Act.
Bad bouts of local pollution helped increase consciousness. PCB dumping in the Hudson River resulted
in a ban by the EPA on consumption of its fish in 1974. Long-term dioxin
contamination at Love Canal starting in 1947 became a national news story in 1978 and
led to the Superfund legislation of 1980. Legal proceedings in the 1990s helped bring to
light Chromium-6 releases in California–the champions of whose victims became famous. The pollution of industrial
land gave rise to the name brownfield, a term now common in city planning. DDT
was banned in most of the developed world after the publication of Rachel Carson’s Silent
Spring.
The development of nuclear science introduced radioactive contamination, which can remain lethally radioactive for hundreds
of thousands of years. Lake Karachay, named by the Worldwatch Institute as the “most polluted
spot” on earth, served as a disposal site for the Soviet Union thoroughout the 1950s
and 1960s. Second place may go to the to the area of Chelyabinsk U.S.S.R. (see
reference below) as the “Most polluted place on the planet”.
Nuclear weapons continued to be tested in the Cold War, sometimes near inhabited areas, especially
in the earlier s***es of their development. The toll on the worst-affected populations and the
growth since then in understanding about the critical threat to human health posed by radioactivity
has also been a prohibitive complication associated with nuclear power. Though extreme care is practiced
in that industry, the potential for disaster suggested by incidents such as those at Three
Mile Island and Chernobyl pose a lingering specter of public mistrust. One legacy of nuclear
testing before most forms were banned has been significantly raised levels of background radiation.
International catastrophes such as the wreck of the Amoco Cadiz oil tanker off the coast
of Brittany in 1978 and the Bhopal disaster in 1984 have demonstrated the universality of
such events and the scale on which efforts to address them needed to engage. The
borderless nature of atmosphere and oceans inevitably resulted in the implication of pollution on a
planetary level with the issue of global warming. Most recently the term persistent organic pollutant
(POP) has come to describe a group of chemicals such as PBDEs and PFCs among
others. Though their effects remain somewhat less well understood owing to a lack of experimental
data, they have been detected in various ecological habitats far removed from industrial activity such
as the Arctic, demonstrating diffusion and bioaccumulation after only a relatively brief period of widespread
use.
Growing evidence of local and global pollution and an increasingly informed public over time have
given rise to environmentalism and the environmental movement, which generally seek to limit human impact
on the environment.
