Environmental chemistry

Environmental chemistry is the scientific study of the chemical and biochemical phenomena that occur in natural places. It should not be confused with green chemistry, which seeks to reduce potential pollution at its source. It can be defined as the study of the sources, reactions, transport, effects, and fates of chemical species in the air, soil, and water environments; and the effect of human activity on these. Environmental chemistry is an interdisciplinary science that includes atmospheric, aquatic and soil chemistry, as well as heavily relying on analytical chemistry and being related to environmental and other areas of science.

Environmental chemistry involves first understanding how the uncontaminated environment works, which chemicals in what concentrations are present naturally, and with what effects. Without this it would be impossible to accurately study the effects humans have on the environment through the release of chemicals.

Environmental chemists draw on a range of concepts from chemistry and various environmental sciences to assist in their study of what is happening to a chemical species in the environment. Important general concepts from chemistry include understanding chemical reactions and equations, solutions, units, sampling, and analytical techniques Williams, Ian. "Environmental Chemistry, A Modular Approach". Wiley. 2001. ISBN 0-471-48942-5] .

Contamination

A contaminant is a substance present in nature due to human activity, that would not otherwise be there [ [http://www.buzzardsbay.org/glossary.htm Glossary to the Buzzards Bay Watershed Management Plan ] ] [ [http://amsglossary.allenpress.com/glossary/browse?s=c&p=84 AMS Glossary ] ] . The term contaminant is often used interchangeably with "pollutant", which is a substance that has a detrimental impact on the environment it is in [ [http://www.soil.ncsu.edu/publications/BMPs/glossary.html Glossary ] ] [ [http://www.sustainabletable.org/intro/dictionary/ Sustainable Table: Dictionary ] ] . Whilst a contaminant is sometimes defined as a substance present in the environment as a result of human activity, but without harmful effects, it is sometimes the case that toxic or harmful effects from contamination only become apparent at a later date Harrison, R.M (edited by). "Understanding Our Environment, An Introduction to Environmental Chemistry and Pollution, Third Edition". Royal Society of Chemistry. 1999. ISBN 0-85404-584-8] .

The "medium" (e.g. soil) or organism (e.g. fish) affected by the pollutant or contaminant is called a "receptor", whilst a "sink" is a chemical medium or species that retains and interacts with the pollutant.further|Pollution, Pollutant in environmental chestry we have to study about the 1) troposphare 2)hydrosphare 3)biosphare 4)atmosphare

Environmental indicators

Chemical measures of water quality include dissolved oxygen (DO), chemical oxygen demand (COD), biochemical oxygen demand (BOD), total dissolved solids (TDS), and pH.BOD is an organic pollutant which may be defined as the amount of oxygen in milligrams dissolved in water needed to break down the organic matter present in one litre of water for five days at 20 degree Celsius.Pure water contains BOD of 0-3ppm.In case, BOD is 5ppm or little more, this means that water is somewhat contaminated. Thus BOD gives an idea of extent of organic waste present in water.Sometimes, the water in the vicinity of factories is found to have BOD as high as 1000ppm. This means that water is highly contaminated.

Applications

Environmental chemistry is used by the Environment Agency (in England and Wales), the Environmental Protection Agency (in the United States) the Association of Public Analysts, and other environmental agencies and research bodies around the world to detect and identify the nature and source of pollutants. These can include:
*Heavy metal contamination of land by industry. These can then be transported into water flows and be taken up by living organisms.
*Nutrients such as nitrate and phosphate leaching from agricultural land into water courses, which can lead to algal blooms and eutrophication.

Methods

Quantitative chemical analysis is a key part of environmental chemistry, since it provides the data that frame most environmental studies.cite book
last = vanLoon
first = Gary W.
coauthors = Duffy, Stephen J.
title = Environmental Chemistry
publisher = Oxford
year = 2000
location = Oxford
pages = 7
isbn = 0-19-856440-6]

Common analytical techniques used for quantitative determinations in environmental chemistry include classical wet chemistry, such as gravimetric, titrimetric and electrochemical methods. More sophisticated approaches are used in the determination of trace metals and organic compounds. Metals are commonly measured by atomic spectroscopy and mass spectrometry: Atomic Absorption Spectrophotometry (AA) and Inductively Coupled Plasma Atomic Emission (ICP-AES) or Inductively Coupled Plasma Mass Spectrometric (ICP-MS) techniques. Organic compounds are commonly measured also using mass spectrometric methods, such as Gas chromatography-mass spectrometry (GC/MS) and Liquid chromatography-mass spectrometry (LC/MS). Non-MS methods using GCs and LCs having universal or specific detectors are still staples in the arsenal of available analytical tools.

Other parameters often measured in environmental chemistry are radiochemicals. These are pollutants which emit radioactive materials, such as alpha and beta particles, posing danger to human health and the environment. Particle counters and Scintillation counters are most commonly used for these measurements. Bioassays and immunoassays are utilized for toxicity evaluations of chemical effects on various organisms.

ee also

* Green chemistry
* Green Chemistry Journal
* Journal of Environmental Monitoring
* Important publications in Environmental chemistry

References

Further reading

*Stanley E Manahan. "Environmental Chemistry, Fifth edition". 1991.
*Stanley E Manahan. "Environmental Chemistry". CRC Press. 2004. ISBN 1-56670-633-5.
*Julian E Andrews, Peter Brimblecombe, Tim Jickells, Peter Liss, Brian Reid. "An Introduction to Environmental Chemistry". Blackwell Publishing. 2004. ISBN 0-632-05905-2.
*Rene P Schwarzenbach, Philip M Gschwend, Dieter M Imboden. "Environmental Organic Chemistry, Second edition". Wiley-Interscience, Hoboken, New Jersey, 2003. ISBN 0-471-35750-2.

External links

* [http://www.envirofacs.org/links.htm List of links for Environmental Chemistry] - from the American Chemical Society's Division of Environmental Chemistry
* [http://www.liv.ac.uk/chemistry/links/refenviron.html List of links for Environmental Chemistry] - from the WWW Virtual Library
* [http://www.tandf.co.uk/journals/titles/03067319.asp International Journal of Environmental Analytical Chemistry]