Cadmium arsenide is a chemical compound of cadmium and arsenic. It is a semiconductor and is used in infrared detectors, pressure sensors, magnetoresistors, and photodetectors. Cadmium is a transition metal and chemical element with the symbol Cd and atomic number 48. It is found naturally in the earth's crust, though rarely on it's own. Arsenic is a chemical element that has the symbol As and atomic number 33. It is a poisonous metalloid that has many allotropic forms: yellow (molecular non-metallic) and several black and grey forms (metalloi
belongs to the class of inorganic compounds known as trivalent inorganic arsenic compounds. These are inorganic compounds containing a trivalent arsenic atom.
Cadmium initially binds to metallothionein and is transported to the kidney. Toxic effects are observed once the concentration of cadmium exceeds that of available metallothionein, and it has also been shown that the cadmium-metallothionein complex may be damaging. Accumulation of cadmium in the kidney results in increased excretion of vital low and high weight molecular proteins. Cadmium is a high affinity zinc analog and can interfere in its biological processes. It also binds to and activates the estrogen receptor, likely stimulating the growth of certain types of cancer cells and causing other estrogenic effects, such as reproductive dysfunction. Cadmium causes cell apoptosis by activating mitogen-activated protein kinases. Arsenic and its metabolites disrupt ATP production through several mechanisms. At the level of the citric acid cycle, arsenic inhibits 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. Arsenic's carginogenicity is influenced by the arsenical binding of tubulin, which results in aneuploidy, polyploidy and mitotic arrests. The binding of other arsenic protein targets may also cause altered DNA repair enzyme activity, altered DNA methylation patterns and cell proliferation. (13, 1, 6, 2, 3, 4)
Metabolism
Cadmium and arsenic may be absorbed from oral, inhalation, and dermal routes. Cadmium initially binds to metallothionein and albumin and is transported mainly to the kidney and liver. Toxic effects are observed once the concentration of cadmium exceeds that of available metallothionein, and it has also been shown that the cadmium-metallothionein complex may be damaging. Cadmium is not known to undergo any direct metabolic conversion and is excreted unchanged, mainly in the urine. Arsenic is distributed throughout the body, where it is reduced into arsenite if necessary, then methylated into monomethylarsenic (MMA) and dimethylarsenic acid (DMA) by arsenite methyltransferase. Arsenic and its metabolites are primarily excreted in the urine. Arsenic is known to induce the metal-binding protein metallothionein, which decreases the toxic effects of arsenic and other metals by binding them and making them biologically inactive, as well as acting as an antioxidant. (5, 7)
Chronic exposure to cadmium fumes can cause chemical pneumonitis, pulmonary edema, and lung diseases such as bronchitis and emphysema. Cadmium also accumulates in the kidneys, causing permanent damage. Loss of bone density also occurs. Arsenic poisoning can lead to death from multi-system organ failure, probably from necrotic cell death, not apoptosis. Arsenic is also a known carcinogen, esepcially in skin, liver, bladder and lung cancers. (13, 5, 7)
Symptoms
Acute inhalation of cadmium fumes results in metal fume fever, which is characterized by chills, fever, headache, weakness, dryness of the nose and throat, chest pain, and coughing. Ingestion of cadmium causes vomiting and diarrhea. Exposure to lower levels of arsenic can cause nausea and vomiting, decreased production of red and white blood cells, abnormal heart rhythm, damage to blood vessels, and a sensation of
Treatment
Cadmium poisoning is treated by removal from exposure and supportive care. If ingested, induced vomiting or gastric lavage may be performed. Arsenic poisoning can be treated by chelation therapy, using chelating agents such as dimercaprol, EDTA or DMSA. Charcoal tablets may also be used for less severe cases. In addition, maintaining a diet high in sulfur helps eliminate arsenic from the body. (7, 11)
