Health effects of 2,4,6-trinitrotoluene
Contents
Introduction
2,4,6-Trinitrotoluene is a yellow, odorless, solid manufactured compound that does not occur naturally in the environment. It is made by combining toluene with a mixture of nitric acid and sulfuric acid. 2,4,6-Trinitrotoluene is also known by other names such as sym-trinitrotoluene, TNT, and 1-methyl-2,4,6-trinitrobenzene. 2,4,6-Trinitrotoluene is produced in the United States only at military arsenals. It is not produced commercially. 2,4,6-Trinitrotoluene is an explosive used in military shells, bombs, and grenades, in industrial uses, and in underwater blasting. When a chemical is released from a large area, such as an industrial plant, or from a container, such as a drum or bottle, it enters the environment as a chemical emission. This emission, which is also called a release, does not always lead to exposure. You can be exposed to a chemical only when you come into contact with the chemical. You may be exposed to it in the environment by breathing, eating, or drinking substances containing the chemical or from skin contact with it. If you are exposed to a hazardous chemical such as 2,4,6-trinitrotoluene, several factors will determine whether harmful health effects will occur and what the type and severity of those health effects will be. These factors include the dose (how much), the duration (how long), the route or pathway by which you are exposed (breathing, eating, drinking, or skin contact), the other chemicals to which you are exposed, and your individual characteristics such as age, sex, nutritional status, family traits, life-style, and state of health. (Health effects of 2,4,6-trinitrotoluene)
Pathways for 2,4,6-Trinitrotoluene in the environment
2,4,6-Trinitrotoluene enters the environment in waste waters and solid wastes resulting from the manufacture of the compound, the processing and destruction of bombs and grenades, and the recycling of explosives. The compound moves in surface water (Hydrologic cycle) and through soils to groundwater. In surface water, 2,4,6-trinitrotoluene is rapidly broken down into other chemical compounds by sunlight. Microorganisms in water and sediment break down the compound more slowly. Small amounts of 2,4,6-trinitrotoluene can accumulate in fish and plants.
Exposure to 2,4,6-Trinitrotoluene
You may be exposed to 2,4,6-trinitrotoluene as a result of its movement from chemical waste disposal sites to drinking water. Children may also be exposed through eating contaminated soil. Most exposure would result from drinking contaminated water, breathing contaminated air, or eating contaminated foods such as fruits and vegetables. 2,4,6-Trinitrotoluene has been measured at waste disposal sites in groundwater at 0.32 parts of 2,4,6-trinitrotoluene per million parts of water (ppm) and in soil at up to 13,000 ppm. We have no data on levels in air or foods. 2,4,6-Trinitrotoluene can be taken up by plants from contaminated soil and is probably present in the air as a result of disposal by burning at military sites. Therefore, intake of air and homegrown fruits and vegetables by people living near military sites may also be sources of exposure to 2,4,6-trinitrotoluene.
Worker exposure to 2,4,6-trinitrotoluene is possible as a result of its use in the production of bombs and grenades. Most workplace exposure results from breathing in 2,4,6-trinitrotoluene dust or vapor and contact with dust on the skin.
Pathways for 2,4,6-Trinitrotoluene in the body
2,4,6-Trinitrotoluene rapidly and completely enters your body when you breathe in air or drink water that is contaminated with this chemical. We have no information on how much 2,4,6-trinitrotoluene enters your body when it gets on your skin. We do know that it enters your body more slowly through the skin than when it is taken into your mouth. 2,4,6-Trinitrotoluene in your blood travels throughout your body to all of your organs. When 2,4,6-trinitrotoluene reaches your liver, it breaks down and changes into several different substances. Not all of these substances have been identified, and we do not know whether they are harmful or not. Most of these substances travel in your blood until they reach your kidneys and then leave your body in your urine. Studies in animals show that almost all of the 2,4,6-trinitrotoluene that enters the body breaks down and leaves the body in the urine within 24 hours.
Health effects of 2,4,6-Trinitrotoluene
You should know that one way to learn whether a chemical will harm people is to determine how the body absorbs, uses, and releases the chemical. For some chemicals, animal testing may be necessary. Animal testing may also help identify such health effects as cancer or birth defects. Without laboratory animals, scientists would lose a basic method for getting information needed to make wise decisions that protect public health. Scientists have the responsibility to treat research animals with care and compassion. Scientists must comply with strict animal care guidelines because laws today protect the welfare of research animals.
Additionally, there are vigorous national and international efforts to develop alternatives to animal testing. The efforts focus on both in vitro and in silico approaches and methods. For example, the National Toxicology Program (NTP) at the National Institute of Environmental Health Sciences (NIEHS) created the NTP Interagency Center for the Evaluation of Alternative Toxicological Methods (NICEATM) in 1998. The role of NICEATM is to serve the needs of high quality, credible science by facilitating development and validation—and regulatory and public acceptance—of innovative, revised test methods that reduce, refine, and replace the use of animals in testing while strengthening protection of human health, animal health and welfare, and the environment. In Europe, similar efforts at developing alternatives to animal based testing are taking place under the aegis of the European Centre for the Validation of Alternative Methods (ECVAM).
Workers involved in the production of high explosives experienced many harmful health effects as a result of exposure to 2,4,6-trinitrotoluene at their jobs. These effects included disorders of the blood, such as anemia, and abnormal liver function. However, the levels of 2,4,6-trinitrotoluene in the workplace air at the time these effects were seen ranged from less than 0.01 to 1.49 milligrams of 2,4,6-trinitrotoluene per cubic meter of air (mg/m³). Some of the concentrations measured are higher than the level currently allowed in the workplace (0.5 mg/m³). Similar effects on the blood and the liver have been observed in animals that either breathed or were fed 2,4,6-trinitrotoluene. In addition, studies show that animals force- fed 2,4,6-trinitrotoluene for an intermediate-duration (from 15–364 days) may have enlargement of the spleen and other harmful effects on the immune system. When people have prolonged skin contact with 2,4,6-trinitrotoluene, they may develop an allergic reaction of the skin to this chemical, such as itching and irritation. In addition, long-term exposure to 2,4,6-trinitrotoluene has been associated with the development of cataracts in people.
No information is available to indicate whether 2,4,6-trinitrotoluene causes birth defects. However, studies in animals that were treated with high doses of 2,4,6-trinitrotoluene have shown that it can cause serious effects on the male reproductive system. The available information for determining whether 2,4,6-trinitrotoluene causes cancer in humans is inadequate. However, rats that ate 2,4,6-trinitrotoluene for long periods developed tumors of the urinary bladder. Based on this study with rats, EPA has classified 2,4,6-trinitrotoluene in Group C, a possible human carcinogen.
Medical tests for exposure to 2,4,6-Trinitrotoluene
There are tests to determine if you have been exposed to 2,4,6-trinitrotoluene. These tests measure 2,4,6-trinitrotoluene or its breakdown products in your blood and urine and have been used to test exposed workers. Detection of the breakdown products in your urine is a clear indication that you have been exposed. The complex and expensive equipment needed to perform these tests is generally available only at specialized laboratories. Another simpler, but less specific, test of 2,4,6-trinitrotoluene exposure is a change in the color of your urine to amber or deep red. This change results from the presence of breakdown products and may indicate that you have been exposed to 2,4,6-trinitrotoluene. None of these tests can predict whether a person exposed to 2,4,6-trinitrotoluene will experience any health effects related to the exposure.
Further Reading
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