Enviromental
pollution
Sources and causes
Air pollution produced by ships may alter
clouds, affecting global temperatures.
Air pollution comes from both natural and human-made
(anthropogenic) sources. However, globally human-made pollutants from
combustion, construction, mining, agriculture and warfare are increasingly
significant in the air pollution equation.[11]
Motor vehicle emissions are one of the leading causes of air
pollution.[12][13][14] China, United States, Russia, India[15] Mexico, and Japan are the world leaders in air pollution emissions. Principal
stationary pollution sources include chemical plants, coal-fired power plants, oil refineries,[16] petrochemical plants, nuclear waste disposal activity, incinerators, large livestock
farms (dairy cows, pigs, poultry, etc.), PVC factories, metals
production factories, plastics factories, and other heavy industry. Agricultural air pollution comes from
contemporary practices which include clear felling and burning of natural
vegetation as well as spraying of pesticides and herbicides[17]
About 400 million metric tons of hazardous wastes are generated each year.[18] The United States alone produces about 250 million metric tons.[19] Americans constitute less than 5% of the world's population, but produce roughly 25% of the world’s CO2,[20] and generate approximately 30% of world’s waste.[21][22] In 2007, China has overtaken the United
States as the world's biggest producer of CO2,[23] while still far behind based on per capita
pollution - ranked 78th among the world's nations.[24]
In February 2007, a report by the Intergovernmental Panel on
Climate Change (IPCC), representing the work of 2,500 scientists, economists,
and policymakers from more than 120 countries, said that humans have been the
primary cause of global warming since 1950. Humans have ways to cut greenhouse
gas emissions and avoid the consequences of global warming, a major climate
report concluded. But to change the climate, the transition from fossil fuels
like coal and oil needs to occur within decades, according to the final report
this year from the UN's Intergovernmental Panel on Climate Change (IPCC).[25]
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 leadpaint, aviation fuel and still in some countries, gasoline), MTBE, zinc, arsenic and benzene. In 2001 a series of press reports culminating
in a book called Fateful Harvest unveiled a widespread practice of recycling industrial byproducts
into fertilizer, resulting in the contamination of the soil with various
metals. 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. There have also been some unusual releases ofpolychlorinated dibenzodioxins, commonly called dioxins for simplicity, such as TCDD.[26]
Pollution can also be the consequence of a natural disaster. For
example, hurricanes often involve water
contamination from sewage, andpetrochemical spills from ruptured boats or automobiles.
Larger scale and environmental damage is not uncommon when coastal oil rigsor 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.
In the case of noise pollution the dominant source class is the motor vehicle, producing about ninety percent of all unwanted
noise worldwide.
Effects
Human health
Adverse air quality can kill many organisms
including humans. Ozone pollution can cause respiratory disease, cardiovascular disease, throatinflammation, chest
pain, and congestion. Water pollution causes approximately 14,000
deaths per day, mostly due to contamination ofdrinking water by untreated sewage in developing countries. An estimated 500 million Indians have no access to a proper toilet,[30][31]and 580 Indians die of water-related pollution
every day.[32] Nearly 500 million Chinese lack access to safe
drinking water.[33] A 2010 analysis estimated that 1.2 million
people died prematurely in a year in Chinabecause of air
pollution.[34] In 2007 it was estimated that in India, air pollution is believed to cause 527,700 fatalities.[35] Studies have estimated that the number of people
killed annually in the US could be over 50,000.[36]
Oil spills can cause skin irritations and rashes. Noise pollution induceshearing loss, high blood pressure, stress, and sleep disturbance.Mercury has been linked to developmental deficits in children andneurologic symptoms. Older people are majorly exposed to
diseases induced by air pollution. Those with heart or lung disorders are at
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.
Environment
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.
·
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.
Environmental health information
The Toxicology and Environmental Health Information Program
(TEHIP)[37] 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)[38] 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.
