Arsenic

Arsenic

Arsenic properties:

Arsenic is the well know chemical element that listed in periodic table with group 5 periods 4. The symbol know as As and the atomic number is 33 and the atomic mass is 74.92. It is categorized in metalloid which issemi-metal. The standard atomic weight is 74.92160(2) g mol^-1. The electron configuration of As is 4s²3d¹⁰4p³. Arsenic was first documented by Albertus Magnus in year 1250.

Different type of arsenic:

It is a well know poisonous metalloid with much allotropic form show in yellow which is a molecular non-metallic and several black and grey forms are metalloids. The stable form of As is silver-gray which is brittle crystalline solid. It can tarnishes rapidly in air, and at high temperatures of burn it will forming a white cloud of arsenic trioxide.

· Yellow- non-metalloids, with much allotropic arsenic

· Black- metalloids

· Gray- metalloids

· Silver-gray- brittle crystalline solid, forming white cloud arsenic trioxide

Sources:

Arsenic with different forms will have different crystal structure and can found free in nature. So, poison of As is a very common case. We know that about one third of the arsenic in the atmosphere comes from natural sources, such as:

· Volcanoes

· Man-made

Used of arsenic:

Arsenic compounds normally are used in making special types of material such as:

· Glass, as a wood preservative

· Semi-conductor gallium arsenade, which has the ability to convert electric current to laser light.

During the 18th, 19th, and 20th centuries, arsenic compounds have been widely used as medicines. Despite its potential toxicity, arsenic is also an essential element and necessary to our physiology. Only 0.00001% is needed for growth and for a healthy nervous system. If excess 5 mg it will immediate danger our health and may lead to fatal. Our bodies do not readily absorb the element itself, hence pure arsenic is much less dangerous than As (III) compounds such as AsH₃ and As₂O₃ which are absorbed easily and are carcinogenic with high toxicity.

How arsenic bring fatal:

1. Arsenic disrupts ATP production through several mechanisms.

2. At the level of the citric acid cycle, arsenic inhibits lipoic acid which is a cofactor for pyruvate dehydrogenase; and by competing with phosphate it uncouples oxidative phosphorylation, thus inhibiting energy-linked reduction of NAD+, mitochondrial respiration, and ATP synthesis. Hydrogen peroxide production is also increased, which might form reactive oxygen species and oxidative stress.

3. These metabolic interferences lead to death from multi-system organ failure, probably from necrotic cell death, not apoptosis. A post mortem reveals brick red coloured mucosa, owing to severe haemorrhage.

Symptoms of organic and inorganic arsenic:

Organic forms appear to have a lower toxicity than inorganic forms of arsenic. The arsenites (trivalent forms) in drinking water have a higher acute toxicity than arsenates (pentavalent forms). Most reported arsenic poisonings are not caused by elemental arsenic, but by one of arsenics compounds, found in drinking water, arsenic trioxide which is 500 times more toxic than pure arsenic. Symptoms include:

· Changes in respiration

· Tachycardia

· Hypertension

· Light headedness

If chronic and untreated will result in damage to:

· Kidneys

· Heart

· Brain

· Infertility and miscarriages with women

· Skin disturbances

· Declined resistance to infections

· Damage the DNA

Drinking water is needed in our daily life, arsenic exist in our drinking will causes a lot of dieses and even death.

Video:

http://www.youtube.com/watch?v=W3Hvexu5SqM&feature=related

Arsenic is being leading causes of mortality in the whole world. Chronic exposure to inorganic arsenic may also lead to:

· Hypertension

· Involuntary muscular dysfunction (including incontinence)

· Diabetes

· Neuropathy

· Depression

· Obesity

· Heart disease (hypertension related cardiovascular)

· Cancer

· Stroke (cerebrovascular diseases)

· Chronic lower respiratory diseases

· Diabetes

Organic arsenic exposure also can occur by eating food. Organic arsenic is 500 times less harmful than inorganic arsenic. Levels of arsenic in fish and seafood may be high, because fish absorb arsenic from the water they live in. Luckily this is mainly the fairly harmless organic form of arsenic, but fish that contain significant amounts of inorganic arsenic may be a danger to human health.

Step to prevent poison:

If you suspect that you are being exposed to arsenic your diet needs to include lots of sulfur. Sulfur can eliminate some of the arsenic from the body. The foods that contain sulfur are eggs, onions, beans, legumes, and garlic. Sulfur can be bought and taken in tablet form also. The amino acid that provides sulfur is cysteine. Fiber can also help to leech the arsenic from your system by attaching to it and washing it out. Include a lot of fiber in your diet by eating whole grains and cereals, fruits and vegetables.

The arsenic cycle has broadened as a consequence of human interference and due to this, large amounts of arsenic end up in the environment and in living organisms. It cannot be destroyed once it has entered the environment, so that the amounts that we add can spread and cause health effects to humans and animals on many locations on earth.

Effect of arsenic to the environment:

Plants absorb arsenic fairly easily, so that high-ranking concentrations may be present in food. The concentrations of the dangerous inorganic arsenics that are currently present in surface waters enhance the chances of alteration of genetic materials of fish. This is mainly caused by accumulation of arsenic in the bodies of plant-eating freshwater organisms. Birds eat the fish that already contain eminent amounts of arsenic and will die as a result of arsenic poisoning as the fish is decomposed in their bodies.

Water and land-living plants and animals show a wide range of sensitivities to different chemical forms of arsenic. Their sensitivity is modified both by biological factors and by their surrounding physical and chemical environment. In general, inorganic forms of arsenic are more toxic to the environment than organic forms and among inorganic forms, arsenite is more toxic than arsenate. Arsenite is toxic because it binds to particular chemical groups only. Arsenate, on the other hand, affects the key energy producing process that take place in all cells.

Video:

http://www.youtube.com/watch?v=clwHIKIR-aU&feature=related

Arsenic compounds can cause short-term and long-term effects in individual plants and animals and in populations and communities of organisms. The nature of the effects depends on the species and time of exposure. The effects include death, inhibition of growth, photosynthesis and reproduction, and behavioral effects. Environments contaminated with arsenic contain only a few species and fewer numbers within species.

Video:

References:

http://en.wikipedia.org/wiki/Arsenic

http://www.greenfacts.org/en/arsenic/index.htm

http://www.lenntech.com/periodic/elements/as.htm

http://www.chemicool.com/elements/arsenic.html

http://www.essortment.com/all/arsenicpoisonin_rljn.htm

http://emedicine.medscape.com/article/812953-overview

http://www.physics.harvard.edu/~wilson/arsenic/arsenic_project_introduction.html

Video needed to download:

http://www.youtube.com/watch?v=W3Hvexu5SqM&feature=related

http://www.youtube.com/watch?v=hi5DfRy01vE

http://www.youtube.com/watch?v=clwHIKIR-aU&feature=related

Hydrogen Cyanide

Hydrogen Cyanide

Imagine !!! with just a minimal concentration at 3.2g/m³ of hydrogen cyanide , it is more than enough to kill a human in about 1 minute !!! It is no doubt that hydrogen cyanide is one of the potentially deadliest chemical in the world .

Cyanides now no longer keeps any public secrets , it is well know all over the world as a deadly chemical due to some of its bad historical background of related cyanide news . Hydrogen cyanide is once used as a chemical weapon by the Germans during World War II and Iran-Iraq War . It is loaded into tanks or vehicle which transport chemical , so when someone explode the target , cyanide will be released into the open air . Cyanide gasses can able manufactured by mixing certain chemical together .Hydrogen cyanide is commonly listed amongst chemical warfare agent that cause general poisoning and skin blisters .

Chemical and physical properties

Hydrogen cyanide also known as Prussic acid is a colourless , extremely poisonous , and highly volatile liquid that will boils slightly above room temperature at 26^oC . It is a chemical compound with chemical formula HCN .

HCN has a faint , bitter , and burnt almond-like odour that some people are unable to detect due to a genetic traits . It is a linear molecule with a triple bond between carbon and nitrogen .

Molecular formula	Density	Molar mass	Boiling point	Melting point	Appearance	Solubility	Acidity (pKa)	Viscosity
HCN	0.687g/cm3	27.0253 g/mol	25.6oC	-13.4oC	Colourless Gas or pale blue	miscible with water and alcohol	9.21	0.201cP

How it kills ?

Hydrogen cyanide will causes rapid death due to metabolic asphyxiation. The property of highly toxicity of this chemical is caused by the cyanide ion . When a cyanide compounds is dissolved in water , it will releases cyanide ions (CN^-) which will further causes cyanide poisoning . Hydrogen cyanide is one of the cyanide compounds , and it occurs to be one of the deadliest one !

Highly exposure of cyanide for a short moment will harms the brain and heart . This will further causes death or coma . Cyanide ions will stops cellular respiration by inhibiting the enzyme called cytochrome c oxidase. This will results the electron of transport chain to be disrupted , which also means the cell will no longer able to produce ATP for energy due to oxygen are not transported .Cells and tissues that depends on aerobic respiration will be seriously affected .

Symptoms

Inhalation of high concentration of hydrogen cyanide gas will causes a coma with apnea , seizures and cardiac arrest with death following in a matter of minutes . At lower concentration , ones might loses consciousness and affected with general weakness , giddiness , headache , confusion , vertigo or having difficulties in breathing . Ones that are exposed to hydrogen cyanide gasses will felt the following symptoms :

-giddiness

-unconsciousness

-breathing difficulties

-cardiac arrest

-pulmonary edema

-skin colour turns pink (cyanide-haemoglobin complexes)

-low blood pressure

-respiratory failure and lastly death

Sometimes there will have survivors of serious cyanide poisoning , but the survivors might soon develop heart or brain damage .

Exposed to hydrogen cyanide ?

What should we do , if we are so unlucky that we are exposed to hydrogen cyanide? There are few ways to prevent illness after exposed to such deadly chemical .

· firstly , immediately leave the area where the hydrogen cyanide was released and move to a place which have fresh air .

· Remove clothing !!! if possible cut of the clothing instead having it passing through sensitive area such as eyes .Avoid touching any other people's contaminated clothing.

· Wash affected areas !!! after the clothing is removed , wash every single part of your skin which is contacted with the cyanide with a lots of soap and water .If your eyes are burning or vision is blurred , rinse your eyes with plain water for 10 - 15 minutes .

· Discard contaminated items !!! Use a plastic bag to place all the contaminated items into another plastic bag . Avoid touching all the contaminated items with your bare hands. Seal the bag and call the local or health department immediately .

· Visit the nearest hospital , cyanide poisoning is treated with specific antidotes and supportive medical care .

Production and synthesis

Hydrogen can be formed with the combinations of hydrogen , carbon and ammonia. One of the ways of productions of hydrogen cyanide is with the process called Andrussov oxidation which is invented by Leonid Andrussow at IG Farben in which methane and ammonia react in the presence of oxygen at about 1200^oC over a platinum catalyst:

2 CH₄ + 2 NH₃ + 3 O₂ → 2 HCN + 6 H₂O

The energy needed for the reaction is provided by the partial oxidation of methane and ammonia.

References :

http://www.squidoo.com/Ahistoryofcyanide

http://en.wikipedia.org/wiki/Hydrogen_cyanide

http://www.atsdr.cdc.gov/tfacts8.html

http://en.wikipedia.org/wiki/Cyanide_poisoning

http://en.wikipedia.org/wiki/Cyanide

http://www.idph.state.il.us/Bioterrorism/factsheets/cyanide.htm

http://www.answers.com/topic/hydrogen-cyanide