2,4-Dinitrotoluene is the most common of the six dinitrotoluene isomers. Dinitrotoluene (DNT) or Dinitro is an explosive with the formula C6H3(CH3)(NO2)2. At room temperature it is a pale yellow to orange crystalline solid. It is a high explosive and one of the precursors for trinitrotoluene (TNT), which is synthesized through three separate nitrations of toluene. The first product is mononitrotoluene, DNT is the second, and TNT is the third and final product. (8)
belongs to the class of organic compounds known as dinitrotoluenes. These are organic aromatic compounds containing a benzene that carries a single methyl group and exactly two nitro groups.
2,4-DNT may cause conversion of oxyhemoglobin to methemoglobin via oxidation of iron(II) to iron(III) by its metabolites. High levels of methemoglobin are removed by catabolism, leading to the development of anemia. Some metabolites of 2,4-DNT are also transported back from the bile to the liver, where the amine group is N-hydroxylated by cytochrome P-450 to form an unstable sulfate conjugate. The sulfate conjugate is degraded into carbonium or nitrenium ions. These ions covalently bind to hepatic macromolecules (DNA, RNA), leading to mutations and subsequently liver tumors. They also bind to DNA of the lung and the intestine. (10, 17, 3, 11)
Metabolism
2,4-Dinitrotoluene can be inhalated as fumes or dust, ingested, or absorbed after contact with the skin. Bioactivation of 2,4-DNT is thought to occur by the following processes: The methyl group is oxidized to an alcohol by a cytochrome P-450 dependent pathway; the benzyl alcohol is conjugated with glucuronic acid and excreted in the bile. Intestinal microflora hydrolyzes the glucuronide and reduces one nitro group, forming an aminonitrobenzyl alcohol which can be readsorbed from the intestine. The amino group is oxidized to an hydroxylamine by hepatic enzymes and conjugated with sulfate, by sulfotransferase. Decomposition of the sulfate ester yields a highly electrophilic nitrenium (or carbonium) ion which can react with DNA and other biological nucleophiles. The major metabolite found in human urine is 2,4-dinitrobenzyl alcohol or its glucuronide conjugate. Other urinary metabolites include 2,4-dinitrobenzoic acid, 4-(N-acetyl)amino-2nitrobenzoic acid, and 2-amino-4-nitrobenzoic acid. The latter two are clearly the product of both oxidative and reductive metabolism. Metabolism is also believed to involve O-acetyltransferase (which transfers the acetyl group of 2,4-DNT) and cytosolic xanthine oxidase (which reduces 2,4-DNT). Small traces of unmetabolized 2,4-DNT can be observed in the urine too. (10, 1, 18, 2, 4, 5)
It is a high explosive and one of the precursors for trinitrotoluene (TNT), which is synthesized through three separate nitrations of toluene. 2,4-Dinitrotoluene can affect the body if it is inhaled, comes in contact with the eyes or skin, is swallowed, or is absorbed through the skin. Even a small amount absorbed from clothes or shoes may cause toxic symptoms. It is assumed that oral ingestion could be a secondary route for occupationally exposed humans. (8, 16)
2,4-Dinitrotoluene poisoning may cause methemoglobinemia, anemia, leukopenia, and liver necrosis. Liver injury may be more common than cyanosis. (19, 10)
Symptoms
Symptoms of 2,4-dinitrotoluene poisoning include blue lips or finger nails, blue skin, vertigo, fatigue, dizziness, weakness, nausea, vomiting, dyspnea, arthralgia, insomnia, tremor, paralysis, unconsciousness, chest pain, shortness of breath, palpitation, anorexia, and loss of weight. (17, 9)
Treatment
Following oral exposure, immediately dilute with 4 to 8 ounces (120 to 240 mL) of water or milk (not to exceed 4 ounces/120 mL in a child). Administer charcoal as a slurry. Gastric lavage and oxygen administration is recommended. Following inhalation exposure, move patient to fresh air. Monitor for respiratory distress. If cough or difficulty breathing develops, evaluate for respiratory tract irritation, bronchitis, or pneumonitis. Administer oxygen and assist ventilation as required. Treat bronchospasm with inhaled beta2 agonist and oral or parenteral corticosteroids. Following eyes exposure, irrigate exposed eyes with copious amounts of room temperature water for at least 15 minutes. Following dermal exposure, remove contaminated clothing and wash exposed area thoroughly with soap and water, and administer a benzodiazepine IV in case of irritation. In all those cases, a physician may need to examine the area if irritation or pain persists. (15)
