Arsenic Compounds and Their Uses

Arsenic Compounds

• Arsenious oxide (arsenic trioxide) is the most toxic form of arsenic, with no taste or smell, and is sparingly soluble in water.
• It is used in fruit sprays, sheep-dips, weed-killers, insecticides, rat poisons, flypapers, calico-printing, wallpapers, and as a mordant in dyeing.

Copper Arsenite and Copper Acetoarsenite

• Copper arsenite (Scheele's green) and copper acetoarsenite (Paris green or emerald green) are used as coloring agents in substances, including confectionary.

Arsenic Sulphide and Arsine

• Arsenic sulphide is used as a depilatory, coloring pigment, and in flypaper.
• Arsine is a colorless gas with a garlic-like odor.

Natural Sources of Arsenic

• Arsenic can be found naturally in soil, water, and some sea fish (mussels, prawns).
• High arsenic content in soil and subsoil water can cause endemic toxicity.

Action of Arsenic

• Arsenic interferes with cellular respiration by uncoupling mitochondrial oxidative phosphorylation.
• It combines with sulfhydryl groups of mitochondrial enzymes, inhibiting cellular glucose uptake, gluconeogenesis, fatty acid oxidation, and acetyl CoA production.
• Locally, arsenic causes irritation of mucous membranes, and remotely, depression of the nervous system.

Carcinogenic Effects of Arsenic

• Arsenic is a carcinogenic substance linked to lung, skin, and bladder carcinoma in populations with multiple exposures.

Absorption and Excretion of Arsenic

• Arsenic is absorbed orally through the GIT, skin, and lungs, and can also be absorbed parenterally.
• It is present in almost all tissues, with the highest concentration found in the liver, kidneys, and spleen.
• Arsenic is excreted mainly by the kidneys, but also through feces, bile, sweat, milk, nails, and hair.

Signs and Symptoms of Acute Poisoning

• Symptoms usually appear within 1 hour of ingestion, but may be delayed if arsenic is taken with food.
• GIT symptoms include sweet metallic taste, nausea, persistent vomiting, burning in the mouth and throat, difficulty in swallowing, and garlic odor in breath.
• Other symptoms include intense thirst, pain in the esophagus and abdomen, purging accompanied by tenesmus, and pain and irritation around the anus.
• Renal symptoms include oliguria, uremia, albuminuria, red cells, and casts, as well as pain during micturition.
• CVS symptoms include hypotension, circulatory collapse, ventricular tachycardia, and fibrillation.
• Hepatic symptom includes fatty infiltration.
• MS symptoms include pain in limbs and weakness.
• CNS symptoms include headache, vertigo, and hyperthermia.