n-Nitrosodiphenylamine is an orange-brown or yellow solid. It evaporates slowly to the air and can attach to dust particles and travel with the wind. It can dissolve in water and attach to soil. It breaks down to other substances, but we do not know whether these substances are harmful to humans. We have not found n-nitrosodiphenylamine in drinking water, foods, or in the air we breathe. However, it is in the water and soil near some hazardous waste sites. We do not know whether n-nitrosodiphenylamine is found in the air near hazardous waste sites or in food grown near such sites.
We do not know if n-nitrosodiphenylamine occurs naturally in the environment, but some scientific evidence suggests that tiny organisms too small to be seen without the aid of a microscope (that is, microorganisms) can make it. It can be man-made and is used to make such rubber products as tires. It is sometimes used to make other chemicals. In the early 1980s, most United States rubber manufacturers replaced it with other chemicals. Only one manufacturer in the U.S. produces n-nitrosodiphenylamine.
Pathways in the body
n-Nitrosodiphenylamine can enter the environment by evaporating to the air from waste sites. Also, it can leak into the ground from waste sites and dissolve into the groundwater and surface water. Industrial discharge releases n-nitrosodiphenylamine into water. n-Nitrosodiphenylamine can also bind to soil. In laboratory tests, most n-nitrosodiphenylamine disappears from water and soil within several weeks. Organisms that live in the water take it up to a limited degree. We do not know if land animals or plants take it up. It is believed that the chemical breaks down to other products. We do not know what the breakdown products are or if they are harmful to humans. However, it has not been found in the drinking water, food, or air with which you would normally come in contact.
There is no available information to show that n-nitrosodiphenylamine exists in the soil, air, food, or water with which you would normally come in contact. You are not, therefore, likely to be exposed to it.
Workers who were or are involved in the production or use of n-nitrosodiphenylamine may have been exposed to the chemical. Occupational data from 1981 to 1983 show that an estimated 1,093 workers employed at 137 plants might have been exposed to it. Today, since only one company makes it, fewer workers are exposed. Current exposure may also include contact with n-nitrosodiphenylamine at hazardous waste sites. It has been found in 3.6% of underground water samples and 0.7% of aboveground water samples taken at hazardous waste sites.
Pathways in the body
Substances can generally enter your bloodstream if you breathe them in the air, eat or drink them, or get them on your skin. We do not know if n-nitrosodiphenylamine can enter your body through the lungs. Evidence from animal studies shows that n-nitrosodiphenylamine enters the bloodstream after animals swallow water or food containing it. This information suggests that it is likely to enter your body if you are exposed to it by mouth. Animal studies also suggest that n-nitrosodiphenylamine can enter your body if it gets on your skin. If you live near a hazardous waste site, n-nitrosodiphenylamine could enter your body if you drink water containing it or possibly if you breathe it in the air. Children could also be exposed by eating or touching dirt that has n-nitrosodiphenylamine in it. If you work with n-nitrosodiphenylamine, you could be exposed to it by breathing small particles of it in the air or getting it on your skin. Animals break n-nitrosodiphenylamine down into other substances that can also harm their health. We expect that humans break it down by similar means.
An animal study showed that some n-nitrosodiphenylamine rapidly leaves the body in urine. Some probably also leaves the body in feces. It probably leaves the human body in a similar manner. We do not how long it takes for all n-nitrosodiphenylamine to leave the body.
It is most likely to enter your body if you come into contact with it in air, water, or soil at hazardous waste sites containing it.
We do not have enough information to know how n-nitrosodiphenylamine will affect your health.
We know very little about the health effects of exposure to n-nitrosodiphenylamine in animals, except that swallowing large doses can cause death. Animals given n-nitrosodiphenylamine in their diets for long periods developed swelling, cancer of the bladder, and changes in body weight. We do not know whether these effects would occur in humans. We also do not know if it can affect pregnancy or cause birth defects. EPA considers n-nitrosodiphenylamine to be a possible cancer-causing substance in humans because of the health effects seen in some animals. The International Agency for Research on Cancer (IARC) concluded that there are not enough data to determine whether n-nitrosodiphenylamine causes cancer in humans. IARC also concluded that there is limited evidence indicating that n-nitrosodiphenylamine causes cancer in experimental animals.
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).
There are no tests available to determine if you have been exposed to n-nitrosodiphenylamine. There are tests to detect n-nitrosodiphenylamine and its breakdown products in the blood and urine of exposed animals, but these tests have not been used for testing people routinely. Tests that are used to indicate the presence of chemical substances in living organisms support the practice of biomonitoring.
Disclaimer: This article is taken wholly from, or contains information that was originally published by, the Agency for Toxic Substances and Disease Registry. Topic editors and authors for the Encyclopedia of Earth may have edited its content or added new information. The use of information from the Agency for Toxic Substances and Disease Registry should not be construed as support for or endorsement by that organization for any new information added by EoE personnel, or for any editing of the original content.