Environmental toxicology and health effects associated with dinitrotoluene exposure

Dinitrotoluenes (DNTs) are nitroaromatic compounds appearing as pale yellow crystalline solids at room temperature. Dinitrotoluenes exist as a mixture of 2 to 6 isomers, with 2,4-DNT, and 2,6-DNT being the most significant. About 500 persons are estimated to be potentially exposed yearly to 2,4-DNT and 2,6-DNT during the production of munitions and explosives. The main route of human exposure at ammunition facilities is inhalation, but dermal contact and inadvertent ingestion can also be substantial. In factory workers, exposure to DNTs has been linked to many adverse health effects, including cyanosis, vertigo, headache, metallic taste, dyspnea, weakness and lassitude, loss of appetite, nausea, and vomiting. Other symptoms including pain or parasthesia in extremities, abdominal discomfort, tremors, paralysis, chest pain, and unconsciousness have also been reported. The primary targets of DNT toxicity are the hematopoietic system (pallor, cyanosis, anemia, and leukocytosis), the cardiovascular system (ischemic heart disease), the nervous system (muscular weakness, headache, dizziness, nausea, insomnia, and tingling pains in the extremities) and the reproductive system (reduction of sperm counts, alteration of sperm morphology, and aspermatogenesis). An association between DNT exposure and increased risk of hepatocellular carcinomas and subcutaneous tumors in rats, as well as renal tumors in mice, has been established. Epidemiologic studies of DNT toxicity have been limited to small groups of workers who had been occupationally exposed at various ammunitions production facilities. Clearly defining the health effects of DNTs with a high degree of confidence has therefore been difficult because of the multigenic nature of occupational exposure. In an attempt to update the toxicologic profile of the DNTs, we hereby provide a critical review of the environmental and toxicologic pathology of DNTs, with a special emphasis on their potential implications for public health.