Tuesday, 30 July 2013

Calcium carbide update

1.      The fast ripening of fruits means that they may contain various harmful properties. A commonly used agent in the ripening process is calcium carbide, a material most commonly used for welding purposes. Calcium carbide treatment of food is extremely hazardous because it contains traces of arsenic and phosphorous. Once dissolved in water, the carbide produces acetylene gas. Acetylene gas may affect the neurological system by inducing prolonged hypoxia. The findings are headache, dizziness, mood disturbances, sleepiness, mental confusion, memory loss, cerebral edema and seizures. 

A previously healthy 5 year-old girl with no chronic disease history came to ER with an 8-h history of coma and delirium. A careful history from her father revealed that the patient had eaten unripe dates treated with calcium carbide. (Per H, Kurtoğlu S, Yağmur F, et al. Calcium carbide poisoning via food in childhood. J Emerg Med 2007 Feb;32(2):179-80).

2.      Bharani A, Walia R, Ramteke G, et al. Electrocardiographic abnormalities mimicking acute myocardial infarction in calcium carbide poisoning. Indian Heart J 2006 May-Jun;58(3):288.

3.      Bello F, Seeger A, Bruna CG, et al. Acute arsenic poisoning as contamination of commercial calcium carbide. Rev Med Chil 1987 Apr; 115(4):357-8.

4.      Acetylene is a commonly found industrial agent that, when mixed with oxygen, is used for welding. A case of a 40-year-old male who died of acetylene gas poisoning has been reported. (Williams NR, Whittington RM. Death due to inhalation of industrial acetylene. J Toxicol Clin Toxicol 2001;39(1):69-71).

5.      The primary target organs for arsenic toxicity are the gastrointestinal tract, heart, skin, bone marrow, kidneys, and peripheral nervous system. 

6.      Acute toxicity typically starts in the gastrointestinal system and includes nausea, vomiting, abdominal pain, and diarrhea. These symptoms are soon followed by dehydration, hypotension and QTc prolongation. In severe cases, patients may experience cardiac arrhythmias, shock, acute respiratory distress syndrome, and sometimes death.

7.      In chronic poisoning, the peripheral neurologic complaints and skin manifestations are usually more prominent than the gastrointestinal symptoms. Chronic arsenic exposure is associated with increased all-cause mortality.

8.      Arsenic is rapidly cleared from the blood, so measurement of urinary arsenic either in a 24-hour urine collection or spot urine (along with a creatinine to correct for the concentration of the spot urine) is generally preferable. A concentration greater than or equal to 50 mcg/L or 100 mcg of arsenic per gram creatinine in the absence of recent fish, seaweed or shellfish intake strongly suggests arsenic poisoning. For more accurate assessment, both total and inorganic arsenic species should be measured in the urine. 

9.      To reduce the risk of cancer and other chronic effects, the US Environmental Protection Agency (EPA) lowered the arsenic standard for drinking water from 50 parts per billion (ppb) to 10 ppb, and the US Food and Drug Administration (FDA) has set 10 ppb for bottled water.

In the US, drinking water generally contains an average of 2 mcg/L of arsenic, although 12 percent of water supplies from surface water sources in the North Central region of the country and 12 percent of supplies from ground water sources in the Western region have levels exceeding 20 mcg/L 

10.  People also eat small amounts of inorganic arsenic in their diet. US dietary intake of inorganic arsenic has been estimated to range from 1 to 20 mcg/day. There have also been concerns about elevated arsenic levels detected in some samples of apple and grape juice. Toddler milk formulas containing organic brown rice syrup as a sweetener also have been blamed to be high in arsenic.

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