Lexikon

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anthracene
anti-inflammatory

anti-infalammatory drugs reduce swelling, fever, and pain, the signs of inflammation. Anti-inflammatory drugs include Aspirin, Motrin, Advil, and Tylenol.

Anti-inflammatory drugs belong to different chemical groups, such as steroid and non-steroid anti-inflammatory drugs, combined ones and antirheumatic agents.

The groups of drugs according to the WHO ATC (Anatomical Therapeutic Chemical Classification) system, are the following:

1 Anti-inflammatory and antirheumatic products, non-steroids

1.1 Butylpyrazolidines

1.2 Acetic acid derivatives and related substances

1.3 Oxicams

1.4 Propionic acid derivatives

1.5 Fenamates

1.6 Coxibs

1.7 Other anti-inflammatory and antirheumatic agents, non-steroids

2 Anti-inflammatory/antirheumatic agents in combination

2.1 Anti-inflammatory/antirheumatic agents in combination with corticosteroids

2.2 Other anti-inflammatory/antirheumatic agents in combination with other drugs

3 Specific antirheumatic agents

3.1 Quinolines

3.2 Gold preparations

3.3 Penicillamine and similar agents

3.4 Other specific antirheumatic agents

antiandrogen

antoandrogen is a substance that blocks the action of androgens, the hormones responsible for male characteristics. Used to treat prostate cancers that require male hormones for growth.

Many of the natural and man-made environmental contaminants have antiandrogenic effect, phtalates are one example for that.

Environmental compounds affecting the endocrine system, are called are antagonistic to any biochemical molecule of the hormon system. Antiandrogenic chemical substances antagonistically affect androgen receptors and androgen production can negatively affect individuals that come in contact with the compounds. As antoandrogens affect male sex-hormone system, thay are considered as reprotoxic chemical substances, impacting future generations too.

Certain pesticides and insecticides as well as in industrial chemicals contain antiandrogenic chemicals. Natural compounds, such as biologically active phytochemicals may also have antiandrogenic effects. Exposure to these environmental antiandrogens has resulted in adverse effects on animals and from animal testresults and biomonitoring data we can predict the human health riskss of these chemical compound.

Exposure to pesticides and insecticides with antiandrogenic properties has been found to negatively affect humans and laboratory animals. Androgens are important in fetal development as well as in pubertal development. Exposure during critical periods of development can cause reproductive malformations in males while exposure after birth and before puberty can delay pubertal development (Wikipedia).

Animal studies with vinclozolin, procymidone, linuron, and the DDT metabolite dichlorodiphenyldichloroethylene (p.p’-DDE) show irregular reproductive development due to their function as androgen receptor antagonists that inhibit androgen-activated gene expression. Even with low doses of antiandrogenic pesticides, developmental effects such as reduced anogenital distance and induction of areolas were seen in male rats (Gray et al. 2001).

Animal studies show that deformities result in offspring exposed to antiandrogens. Male mice can display malformations that resemble the reproductive organs of females as in the case of exposure to vinclozolin or proymidone. Exposure to vinclozolin or procymidone in utero feminized male offspring, as seen in abnormalities of anogenital distance, small or absent sex accessory glands, hypospadias, undescended testes, retained nipples, cleft phallus, and presence of a vaginal pouch. Male mice exposed before puberty to vinclozolin experienced delayed pubertal development visualized by delayed onset of androgen-dependent preputial separation (Grey et al. 2001).

Ketoconazole's imidazole derivative is used as a broad-spectrum antifungal agent effective against a variety of fungal infections. Although ketoconazole is a relatively weak antiandrogen, side-effects seen as a result of exposure include serious liver damage and reduced levels of androgens from both the testicles and adrenal glands (Grey et al. 2001)

Many organophostphate insecticides behave as androgen receptor antagonists.

Industrial chemicals with antiandrogenic effects are ubiquitous in the environment. Consumer products such as toys and cosmetics may contain phthalates. Phthalates are mainly found in plastics. Fetuses that are exposed to a mixture of pthalates in utero may show signs of disrupted reproductive development. When Di-n-butyl phthalate (DBP), diisobutyl phthalate (DiBP), benzyl butyl phthalate (BBP), Bis(2-ethylhexyl) phthalate (DEHP) and di-n-pentyl phthalate (DPP) were combined, reductions in both testosterone synthesis and gene expression of steroidogenic pathway proteins were seen. The result in male rats was undescended testes and abnormal development of reproductive tissues ( Rieder et al. 2010)

Parabens are commonly found in cosmetics and pharmaceuticals. Paraben esters have been found to mimic androgen antagonist activity. Antiandrogenic endocrine disruption has been shown in aquatic species but the mechanism is unknown.

Natural antiandrogenic chemicals of plant origin are mentioned here (Wikipedia):

3,3'-Diindolylmethane (DIM) is definitely antiandrogen, deriving from the digestion of indole-3-carbinol, found in cruciferous vegetables such as broccoli, Brussels sprouts, cabbage and kale. Spearmint tea has antiandrogenic properties in females with hirsutism (excessive hairiness on women). The plant Scutellaria baicalensis (North American skullcap) may also have antiandrogenic properties. The compound N-butylbenzene-sulfonamide (NBBS) isolated from Pygeum africanum (an evergreen tree from Sub-Saharan Africa) is a specific androgen antagonist. Glycyrrhiza glabra (liquorice, a plant to extract sweetener from) has shown antiandrogenic activity in male rats. A herbal formula (termed KMKKT) containing Korean Angelica gigas (a perennial plant grown in China and Korea) Nakai (AGN) root and nine other oriental herbs has shown in vitro anti-androgen activity.

Sources:

Gray LE, Ostby J, Furr J, Wolf CJ, Lambright C, Parks L, Veeramachaneni DN, Wilson V, Price M, Hotchkiss A, Orlando E, Guillette L. (2001). "Effects of environmental antiandrogens on reproductive development in experimental animals". Human Reproduction Update 2: 248–64, http://www.ncbi.nlm.nih.gov/pubmed/11392371

Rider CV, Furr JR, Wilson VS, Gray LE Jr. (Apr 2010). "Cumulative effects of in utero administration of mixtures of reproductive toxicants that disrupt common targe tissues via diverse mechanisms of toxicity". International Journal of Andrology 33: 443–62, http://www.ncbi.nlm.nih.gov/pubmed/2048704

Wikipedia: http://en.wikipedia.org/wiki/Antiandrogen

antibiotic resistance

antibiotic resistance is the ability of a microorganism to withstand the effects of antibiotics. Antibiotic resistance evolves via natural selection acting upon random mutation, but it can also be engineered by applying an evolutionary stress on a population. Once such a gene is generated, bacteria can then transfer the genetic information in a horizontal fashion (between individuals) by plasmid exchange.

If a bacterium carries several resistance genes, it is called multiresistant.

Antibiotic resistance can also be introduced artificially into a microorganism through transformation protocols. This can aid in implanting artificial genes into the microorganism. If the resistance gene is linked with the gene to be implanted, the antibiotic can be used to kill off organisms that lack the new gene.

antibiotics

an antibiotic (from the Ancient Greek: anti = "against", and bios = "life") is a substance or compound that kills or inhibits the growth of bacteria or other microorganisms. It is based on a natural phenomenon, antibiosis, which means antagonistic association between an organism and the metabolic substances produced by another. Formerly only the microbes-made substances were called "antibiotics", but today all man-made, synthetic or semisynthetic compounds are called "antibiotic", which are prodused and used for the inhibition or killing microbes. We distinguish between antibacterial, antifungal, antiprozoal etc. Antibiotics, depending on the target of the antibiotic agent. Antibiotics belong to the broader group of antimicrobial compounds, used to treat infections in humans and animals caused by microorganisms, to treat food or fodder to prevent fauling and infections through nutrition, etc.

microorganisms easily get resistant to antibiotics, due to a special mechanism, where the gene responsible for the antibiotic resistence moves from one organism to the other in form of mobile genetic elements, causing rapid transformation of a sensitive bacterial populations (e.g. in human body) into a resistent one.

See also antibiotic resistance

antibodies
antibody

an antobody is a special fighter protein synthetized by the immune cells of the immune system. They help protect the organism from disease. The immune system prepares a special protein for each kind of "intruder" that enters the body from the outside. These "intruders" are called antigens, which may be an isolated molecule (a protein or a glycoprotein, etc.) or a part of a living cell (e.g. the building blocks of the bacterial cell wall). The fighter proteins link up with the antigens like pieces of a puzzle. Once they're linked, the antigen is inactivated or killed.

antigen

antigen binds to a specific antibody, the product of the immune-system. The interaction is similar to a „lock and key”.

antineoplastic agents

chemotherapy is the treatment of cancer with an antineoplastic drug or with a combination of such drugs into a standardized treatment regimen.

The most common chemotherapy agents act by killing cells that divide rapidly, one of the main properties of most cancer cells. This means that chemotherapy also harms cells that divide rapidly under normal circumstances: cells in the bone marrow, digestive tract, and hair follicles. This results in the most common side-effects of chemotherapy: myelosuppression (decreased production of blood cells, hence also immunosuppression), mucositis (inflammation of the lining of the digestive tract), and alopecia (hair loss).

Newer anticancer drugs act directly against abnormal proteins in cancer cells; this is termed targeted therapy and, in the technical sense, is not chemotherapy.

The types of antineoplastic agents are the following:

1 Alkylating agents

1.1 Nitrogen mustard analogues

1.2 Alkyl sulfonates

1.3 Ethylene imines

1.4 Nitrosoureas

1.5 Epoxides

1.6 Other alkylating agents

2 Antimetabolites

2.1 Folic acid analogues

2.2 Purine analogues

2.3 Pyrimidine analogues

3 Plant alkaloids and other natural products

3.1 Vinca alkaloids and analogues

3.2 Podophyllotoxin derivatives

3.3 Colchicine derivatives

3.4 Taxanes

3.5 Other plant alkaloids and natural products

4 Cytotoxic antibiotics and related substances

4.1 Actinomycines

4.2 Anthracyclines and related substances

4.3 Other cytotoxic antibiotics

5 Other antineoplastic agents

5.1 Platinum compounds

5.2 Methylhydrazines

5.3 Monoclonal antibodies

5.4 Sensitizers used in photodynamic/radiation therapy

5.5 Protein kinase inhibitors

5.6 Other antineoplastic agents

5.7 L01XY Combinations of antineoplastic agents

Source: http://en.wikipedia.org/wiki/ATC_code_L01

antioxidants

antioxidant is a substance capable of slowing or preventing theoxidation of other molecules. Oxidation reactions can produce free radicals, which start radical chain reactions that damage cells and organs. Antioxidants terminate these chain reactions by removing free radical intermediates, and inhibit other oxidation reactions by being oxidized themselves. Tehrefore antioxidants are often reducing agents, such as ascorbic acid or polyphenols.

Low levels of antioxidants, or inhibition of the antioxidant enzymes, cause oxidative stress and may damage or kill cells. This kind of oxidative stress might be an important part of many human diseases.

Antioxidants are widely used as ingredients in dietary supplements with the aim of maintaining health and preventing diseases such as cancer and coronary heart disease. In addition antioxidant compounds have many industrial uses, such as preservatives in food and cosmetics and preventing the degradation of rubber and gasoline.

antropogenic
AOS
AOS (Adsorbable Organic Sulfur compounds) includes only partly overlapping portions of the total concentration of dissolved organic sulfur compounds (DOS) in water. It is a group parameter used, for example, for waste water monitoring or for investigation of water quality changes along flowpaths. Lignine sulfonates and fulvic and humic acids containing sulfur, aromatic sulfonic acids and detergents are typical organic sulfur compounds in surface waters. The method for determining adsorbable organic sulfur compounds (AOS) in water/wastewater is similar to the standard method for determining AOX (DIN 38 409 - H 14). The method is based on the adsorption of sulfur-containing organic compounds on activated carbon, incineration of the loaded carbon and detection of the sulfur dioxide formed. Nowadays there are instruments to carry out the determination automatically. (Source: Schullerer, S. and Frimell, F.H. (1993) Characterization of organic sulphur compounds in surface water by ion-pair adsorption under different conditions. Analytica Chimica Acta 283, 251-257)
AOX
AOX stands for “Adsorbable Organically bound halogens" expressed as chloride, and determined according to the relevant European Standard method. AOXs are substances that are adsorbed from water onto activated carbon. They may be volatile substances like trichloromethane (chloroform), chlorophenols and chlorobenzenes or complex organic molecules like dioxins and furans. Most AOXs are chlorine-containing molecules, but bromo- and iodo-AOXs may also occur. These compounds are of industrial origin, persistent, well accumulating, and mostly carcinogenic. They can be formed during industrial processes, and also at chlorination of drinking water. Certain organohalogen compounds are discharged directly into bodies of water or waste water, e.g. pesticide residues from agriculture or components of commercial or household cleaning agents. In waste water, especially in industrial waste water AOX concentrations >1 mg/l are common. The effluents of hospitals may also contain high AOX concentrations because of the x-ray contrast materials with iodine-compounds. The acceptable limit of AOX in drinking water is 50 microgramms/l.

Principle of the European Standard method (ISO 9652:2004):

  1. Addition of activated carbon to the water sample. After the adsorption of water soluble organic compounds on the activated carbon, an elution step is applied to remove the inorganic chloride ions from the carbon by shaking with acidified nitrate solution.

  2. Combustion of the loaded carbon in oxygen stream.

  3. Absorption of the hydrogen halides produced followed by the determination of the halide ions by an argentometric titration, such as microcoulometry. Expression of the result as the mass concentration of chloride.

The detailed description of the method can be found at the following URL address: http://www.ecn.nl/docs/society/horizontal/STD310_AOX.pdf

Recently some biotests have been developed for determination of AOX.

APFO and PFOA

APFO = ammoniumpentadecafluorootanoate EC Number: 223-320-4; CAS number: 3825-26-1

PFOA is used as a group name for PFOA and its salts, and PFOA is mainly produced and used as its ammonium salt, ammonium pentadecafluorootanoate (APFO). However, the perfluorooctanoate anion is the molecule of primary interest. APFO and PFOA are sometimes used interchangeably as both PFO-anion and PFOA (neutral species) exist in solution.

Ammonium perfluorooctanoate (APFO, PFOA or C8) is a surfactant associated with the production of Teflon®, and is also present in products such as fire-fighting foams and may be formed from the microbial degradation of grease-resistant coatings applied to items such as pizza boxes and other food packages. APFO is hardly hydrolyzed, photolyzed or biodegraded under environmental conditions

It is recommended to be classified based on GHS as toxic, irritant, reprotoxic, toxic for specific target organs.

  • Carc. 2, H351
  • Repr. 1B, H360D
  • STOT RE 1, H372
  • STOT RE 2, H373
  • Acute Tox. 4, H332
  • Acute Tox. 4, H302
  • Eye Irrit. 2, H319
  • Toxic; irritant

R phrases: 40-61-48/23-48/22-20/22-36

S phrases: 53-45

Sources:

http://echa.europa.eu/doc/consultations/cl/clh_axrep_afpo.pdf

http://echa.europa.eu/doc/consultations/cl/clh_axrep_pfoa.pdf

apoptosis

apoptosis is the process of programmed cell death that may occur in multicellular organisms. Programmed cell death involves a series of biochemical events leading to a characteristic cell morphology, such as blebbing, changes to the cell membrane, cell shrinkage, nuclear fragmentation, chromatin condensation, and chromosomal DNA fragmentation and finally death. Processes of disposal of cellular debris whose results do not damage the organism differentiate apoptosis from necrosis.

In contrast to necrosis, which is a form of traumatic cell death that results from acute cellular injury. Apoptosis, in general, confers advantages during an organism's life cycle. For example, the differentiation of fingers and toes in a developing human embryo occurs because cells between the fingers apoptose; the result is that the digits are separate. Between 50 and 70 billion cells die each day due to apoptosis in the average human adult. For an average child between the ages of 8 and 14, approximately 20 billion to 30 billion cells die a day. In a year, this amounts to the proliferation and subsequent destruction of a mass of cells equal to an individual's body weight.

Research in and around apoptosis has increased substantially since the early 1990s. In addition to its importance as a biological phenomenon, defective apoptotic processes have been implicated in an extensive variety of diseases. Excessive apoptosis causes hypotrophy, such as in ischemic damage, whereas an insufficient amount results in uncontrolled cell proliferation, such as cancer.

Source: Wikipedia

applet, IT
application of microbial inoculant for soil remediation
application of microbial inoculatnts
applied research and development
approved dosimetric service

approved dosimetric service: a body responsible for the calibration, reading or interpretation of individual monitoring devices, or for the measurement of radioactivity in the human body or in biological samples, or for assessment of doses, whose capacity to act in this respect is recognized by the competent authorities.

Source: Council Directive 96/29 EURATOM, http://ec.europa.eu/energy/nuclear/radioprotection/doc/legislation/9629_en.pdf

approximation

approximation is a mathematical quantity that estimates a desired quantity.

aquatic toxicology

aquatic toxicology is based on the response of aquatic ecosystem, both marine and freshwater. Aquatic ecosystem may investigate the whole ecosyste, the diversity of species in a certain ecosystem and compares it to the healthy state of the same ecosystem. According to an other concept toxicology applies toxicity tests on some selected memberes of the aquatic ecosystem and from these results extrapolates on the total ecosystem. The burden of failures is very high in both cases.

aqueous solubility
aquifer

a subsurface layer or layers of rock or other geological strata of sufficient porosity and permeability to allow either a significant flow of groundwater or the abstraction of significant quantities of groundwater.

aquifer, WFD definition

aquifer is a subsurface layer or layers of rock or other geological strata of sufficient porosity and permeability to allow either a significant flow of groundwater or the abstraction of significant quantities of groundwater

Sources of the definition: Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for Community action in the field of water, http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2000:327:0001:0072:EN:PDF

arable land

agricultural land that is cultivated by ploughing, usually to 20 or 30 cm depth. More than 30 cm represents deep ploughing.

Archaea
are

basic unit of area in the metric system, equal to 100 square metres and the equivalent of 0.0247 acre. Its multiple, the hectare (equal to 100 ares), is the principal unit of land measurement for most of the world.

aressquare meters100
aressquare yards119.599
area

the measure, in square units, of the inside of a plane figure. The area must be a measure of a closed region or figure.

area of water protection
area source
ARfD
Acute Reference Dose, is the maximum acceptable oral or dermal dose of a toxic substance for humans due to short term exposure. The Acute Reference Dose is an estimate of a chemical substance, expressed on a bodyweight basis, to which a human population (including sensitive subgroups) can be exposed over a short period of time (24 hours or less), without an appreciable risk of deleterious effects during a lifetime.
The US EPA defines a "lifelong" oral reference dose too, (abbreviated RfD) as: "an estimate, with uncertainty spanning perhaps an order of magnitude of a daily oral exposure to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime.
argument

the communication, in verbal or written form, of the reasoning process that leads to a valid conclusion; a valid argument is the result of the conjecture/reasoning process.

arithmetic

the simplest part of mathematics. Arithmetic means addition, subtraction, multiplication, and division (called operations). They are the foundation for all higher mathematics.

aromatics
compounds containing one or more benzene rings that also may contain sulfur, nitrogen and/or oxygen. Typical contaminants of soil and ground water generally originated from mineral oil. The monoaromatics such as benzene, toluene, xylene and ethyl benzene (BTEX) contain one benzene ring in a molecule. There are more aromatic rings in the molecular stucture of polyaromatic or polycyclic aromatic compounds (PAH).
array

qan arrangement of objects or numbers, usually in rows and/or columns.

Arsenic As

elemental arsenic occurs in two solid modifications: yellow, and grey or metallic, with specific gravities of 1.97, and 5.73, respectively. The element is a steel grey, very brittle, crystalline, semimetallic metalloid solid. It tarnishes in air, and when heated rapidly oxidises to arsenous oxide which has a garlic odour.

Arsenic does not often form in its elemental state and is far more common in sulfides and sulfosalts such as arsenopyrite, orpiment, realgar, lollingite and tennantite. Due to the abundance of these arsenic bearing ores and the rarity of native arsenic, it is not an important ore of itself. Native arsenic is found in silver ore veins and is processed along with the silver ore and is therefore is a minor source of arsenic.

Native arsenic is usually found to have a trigonal symmetry but a very rare orthorhombic arsenic is known from Saxony, Germany and is named arsenolamprite. The two minerals are called polymorphs many shapes because they have the same chemistry, As, but different structures.

Arsenic toxicity occurs when a person is exposed to arsenic. Arsenic is a naturally occurring element in the earth crust.

There are two primary forms of arsenic:

  • Inorganic arsenic—arsenic combined with oxygen, chlorine, or sulfur; found in the environment
  • Organic arsenic—arsenic combined with carbon and hydrogen; found in animals and plants.

Inorganic arsenic is usually more harmful than organic arsenic.

Arsenic occurs naturally in soil and minerals, and may enter the air, water, and soil.

In Hungary there are areas where background concentration of Arsenic is rather high 10 mg/kg in soil and 10 μg/lit in water and as consequence poses risk on human health.

Arsenic toxicity may occur when a person is exposed to toxic amounts of arsenic due to

  • Breathing air containing arsenic
  • Eating food contaminated with arsenic
  • Drinking water contaminated with arsenic
  • Living in areas with high natural levels of arsenic
  • Working in a job that involves arsenic
article, REACH
article means an object which during production is given a specific shape, surface or design which determines its function to a greater degree than does its chemical composition. REACH Article 3 (3).
artificial water body

a body of surface water created by human activity.

ASCII, IT

American Standard Code for Information Interchange

ash content
asphaltene
constituents of petroleum products with a high molecular mass (3 000-10 000) not dissolving in pentene, but dissolving in carbon disulfide. Chemically they are PAHs linked by aliphatic chains or rings and functional groups.
aspiration

the entry of secretions or foreign material − including gaseous chemical substances, vapours of liquids or particles of solids − into the trachea and lungs. One of the exposure routes of hazardous chemicals, causing chemical pneumonia, which is an unusual type of lung irritation. Pneumonia usually is caused by a bacteria or virus. In chemical pneumonia, inflammation of lung tissue is from poisons or toxins. Only a small percentage of pneumonias are caused by chemicals.

Many substances can cause chemical pneumonia, including liquids, gases, and small particles, such as dust or fumes, also called particulate matter. Some chemicals only harm the lungs; however, some toxic materials affect other organs in addition to the lungs and can result in serious organ damage or death.

    aspiration, inhaling foreign body

    inhaling fluid or a foreign body into the bronchi and lungs, often after vomiting.

    See also: aspiration

    ATC code

    ATC code is the Anatomical Therapeutic Chemical Classification System, a system of alphanumeric codes developed by the WHO for the classification of drugs and other medical products.

    atmosphere

    atmosphere of Earth is a layer of gases surrounding the planet Earth that is retained by Earth's gravity. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention (greenhouse effect), and reducing temperature extremes between day and night. Dry air contains roughly (by volume) 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.039% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor, on average around 1%.

    The atmosphere has a mass of about 5 × 1018 kg, three quarters of which is within about 11 km (6.8 mi; 36,000 ft) of the surface. The atmosphere becomes thinner and thinner with increasing altitude, with no definite boundary between the atmosphere and outer space. An altitude of 120 km (75 mi) is where atmospheric effects become noticeable during atmospheric reentry of spacecraft. The Kármán line, at 100 km (62 mi), also is often regarded as the boundary between atmosphere and outer space.

    Source: Wikipedia

    atmosphere of the Earth

    atmosphere of Earth is a layer of gases surrounding the planet Earth that is retained by Earth's gravity. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention (greenhouse effect), and reducing temperature extremes between day and night. Dry air contains roughly (by volume) 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.039% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor, on average around 1%.

    The atmosphere has a mass of about 5 × 1018 kg, three quarters of which is within about 11 km (6.8 mi; 36,000 ft) of the surface. The atmosphere becomes thinner and thinner with increasing altitude, with no definite boundary between the atmosphere and outer space. An altitude of 120 km (75 mi) is where atmospheric effects become noticeable during atmospheric reentry of spacecraft. The Kármán line, at 100 km (62 mi), also is often regarded as the boundary between atmosphere and outer space.

    Source: Wikipedia

    atomic absorption spectrometry
    abbreviated as AAS, the most common technique for detecting elements. It is a high through-put method: it takes not more than 5-6 min to measure the concentration of an element. Atoms of the element of interest in the sample are reduced to free, unexcited ground state atoms, which absorb light at characteristic wavelengths. The decrease in the light intensity is in direct connection with the concentration of the atoms absorbing the light at the given wavelength. Atomization can be induced by flame (flame atomic absorption spectroscopy) or with graphite furnace (graphite furnace atomic absorption spectroscopy). The method is widely applied for determination of elements in environmental samples (soil, ground water, sludge, sediment) and in wastes. Atomic absorption spectrometry is a fairly universal analytical method for determination of metallic elements when present in both trace and major concentrations. The EPA employs this technique for determining the metal concentration (dissolved, suspended and total) in samples from a variety of matrices. About 70 elements can be measured except B, C, N, O, S, halogens, noble gases and transuranic elements with short life time. A disadvantage of the AAS technique is the non linearity of the calibration curves when absorbance becomes higher than 0.5 to 1. Detection limits (LOD) for flame AAS vary enormously: from 1 - 5 ppb (e.g. Ca, Cd, Cr, Cu) to more than 1000 ppb (e.g. P).
    atomic absorption spectroscopy being founded analysis