Lec-14

Arsenic as a Toxic element

Arsenic Poisoning Arsenic poisoning was first detected in Bangladesh in 1993 by the Department of Public Health Engineering (DPHE). But the fact remained behind the screen till 1996. According to the latest surveys conducted at Government levels, at least 53 out of the total 64 districts of Bangladesh are affected with Arsenic pollution.

HISTORICAL 

Arsenic is known as 'Senko Bish' among the Bengali-speaking people. This term is also used in the books in Bengali on medical science.   The use of arsenic as a deadly poison has been known since long years back. After winning the War of Waterloo, the British force reportedly used arsenic to kill French Emperor Nepoleon  Bonapart  who was in exile at St. Helena island.

HISTORICAL 

After his death on May 5, 1821, it was announced that Nepoleon died of stomach cancer. But many people thought that the Englishmen applied slow poisoning to kill Napoleon. The British people denied the allegation. But after many years, the hair of the French Emperor, reserved at a museum, was tested and it was proved that he was killed by poison, and the name of poison is arsenic. Arsenic was found in Nepoleon's hair 13 times more than the normal level. 

Arsenic: 

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Arsenic is a highly toxic, naturally occurring grayish-white element used as a poison in pesticides and herbicides. Arsenic is also found as an ingredient in pigments and wood preservatives, Arsenic contained in womanized lumber will not release toxic compounds unless burned.

Sources of Arsenic 

Mining and processing: Arsenic is a constituent of may alloys, including those of copper, lead , zinc, silver and germanium. It is alloyed with lead in making, for example, lead shot, leadbased bearing metals and battery grids. Arsenic is often removed as an impurity during the smelting of copper, led and zinc.

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Wood preservation: Wood fibers are impregnated under pressure with copper chrome arsenate.

• USES OF ARSENIC: Arsenic compounds are mainly used in agriculture, forestry, and industrial processes. Arsenic tri-oxide is used in manufacturing of agricultural chemicals (pesticides), glass and glassware, industrial chemicals, copper and lead alloys and pharmaceuticals. In agriculture , arsenic compounds such as lead arsenate, copperacetoarsenite, sodium arsenite, calcium arsenate and organic arsenic compounds are used as pesticides. Substantial amount of methyl arsonic acid and dimethyl arsinic acid are used as selective herbicides. Chromated copper arsenite, sodium arsenate and zinc arsenate are used as wood preservatives.

• Some phenylarsenic compounds such as asranilic acid are used as feed additives for poultry and swine. Small amount of arsenic continue to be used as drugs in some countries. As medicine arsenic is used since the 5th century BC when Hippocrates recommended the use of an arsenic sulfide for the treatment of abscess. • Arsenic preparations were used for the treatment of skin disorder, tuberculosis, leukemia, asthma, leprosy, syphilis, amoebic dysentery etc.. • Homeopaths are also using arsenic as drug. Besides, arsenic is used in the preparation of dyes, poisonous gas, transistor, as a component of semiconductor, as a preservative in tanning and in the industry of textile, paper etc..

Sources of Arsenic 

Herbicide: Monosodium methyl arsenate, disodium methyl arsenate and sodium arsenate are used extensively in agriculture.

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Pesticide: Lead arsenate is used to some extent in horticulture. Arsenic trioxide is used in termite control. Laboratory procedures: Arsenic trichloide is used in organo-arsenic chemistry and in chemical analysis procedures

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Sources of Arsenic Glass making: Arsenic trioxide and pentroxide are used to produce clear glass, free from the green stain of iron impurity Hide preservation: Arsenic trioxide and sodium arsenite are used as hide preservatives. Food additive: Derivatives of phenyl arsenic acid are added to fowl and pig feed.

Arsenic poisoning recognition The Arsenic poisoning has mainly been detected through  Testing samples of tube-well water  Human tissues-hair,  Nail,  Skin and urine.

Arsenic poisoning recognition Regular intake of Arsenic at higher level (more then the recommended value at 0.01 milligram Arsenic for per liter of water by WHO.) through food and drinking water causes various diseases, especially skin diseases. Arsenic causes both physical and intellectual damage to the human

Disease caused by arsenic poisoning

Disease caused by arsenic

Disease caused by arsenic poisoning

Arsenic can be harmful through Inhalation  Absorption through skin and mucous membrane,  Skin contact, and ingestion. 

Accidental poisoning can occur through 

breathing fumes,

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licking paintbrushes to a point when using pigments containing arsenic,

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from wearing inadequate clothing when applying arsenic-based products.

Effects of mild poisoning from inhalation include: Loss of appetite,  Nausea, and  Diarrhea, 

Effects of more severe chronic or acute exposure include     

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skin rash and lesions, chronic headaches, apathy, garlic odor on breath, a metallic taster in the mouth, a bronzing pigment of the skin resembling “raindrops on a dusty road’ and possible damage to the liver. Arsenic and arsenic compounds are known cancer causing agents and have been implicated in lung and skin cancer and associated with birth defects.

Skin lesions typical of arsenic poisoning

Symptom of Arsenic toxicity Symptomatology of arsenical toxicity may develop insidiously after 6 months to 2 years or more, depending on the amount of water intake and the arsenic concentration in the water sample.

Symptom of Arsenic toxicity 

Darkening of skin (diffuse melanosis) in the whole body or on the palm of the hand is the earliest symptom. People suffering from arsenic toxicity do not necessarily show symptoms of diffuse melanosis

Symptom of Arsenic toxicity 

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Spotted pigmentation is an early symptom that is common and is usually seen on the chest, back or limbs. Leucomelanosis (white and black spots side by side) is also seen on many patients. Leucomelanosis is common in persons who have stopped drinking arseniccontaminated water but who

Symptom of Arsenic toxicity 

Buccal mucus membrane melanosis (diffuse, patchy melanosis) on the tongue, gums, lips etc. may also be manifestartions of arsenic toxicity.

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Keratosis is a late feature of arsenical dermatosis.

Symptom of Arsenic toxicity 

Other symptoms of arsenic toxicity that are sometimes found are conjunctival congestion and nonpitting swelling of the feet. Complications such as liver enlargement, spleen enlargement, and fluid in the abdomen are seen in sever cases.

Symptom of Arsenic toxicity 

Squamous cell carcinoma, basal cell carcinoma, Bowen disease and carcinoma affecting the lung, uterus, bladder, genitourinary tract of other sites are often seen in patients with advanced cases that have suffered for many years.

Homeopathy-a cure for arsenic poisoning  Researchers from University of Kalyani, West Bengal, have discovered that a homeopathic remedy, effectively cured mice afflicted by arsenic poisoning. They suggest that “Arsenicum Album” could reduce the liver damage caused by arsenic poisoning in humans. It was also inexpensive, easy to administer, effective in low doses as well as non-toxic. It not only has the ability to help remove arsenic from the body, but these drugs in micro doses appear to have the ability to detoxify the ill effects produced by arsenic in mice, (May 30, 2004