w h a t e v e r c h e m i s t r y ! !: 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 AsH₃and 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: