n-Nitrosodi-n-propylamine is a yellow liquid at room temperature that does not dissolve in water and evaporates slowly. It is a man-made chemical made in small amounts for use in research. There is no evidence that n-Nitrosodi-n-propylamine exists naturally in soil, air, food, or water. Small amounts of n-Nitrosodi-n-propylamine are produced as a side reaction during some manufacturing processes, as a contaminant in some commonly available weed killers (dinitroaniline-based), and during the manufacture of some rubber products. When exposed to sunlight, n-Nitrosodi-n-propylamine usually does not last for more than a day. Without sunlight (e.g., in water deeper than sunlight reaches or in subsurface soil) n-Nitrosodi-n-propylamine breaks down slowly. It takes between 14 and 80 days for one-half of any certain amount of n-Nitrosodi-n-propylamine to break down when it is released to the subsurface soil.
Persons may be exposed to n-Nitrosodi-n-propylamine by eating foods treated with nitrite preservatives (e.g., cheeses, cured meats) and drinking certain alcoholic beverages. n-Nitrosodi-n-propylamine forms in the stomach during digestion of nitrite-treated foods and foods that contain certain amines, particularly di-n-propylamine. Amines occur in some medicines and in a variety of foods. Levels of n-Nitrosodi-n-propylamine found in food and alcoholic beverages range between 0.03 parts per billion (ppb) in fried, salt- preserved fish to 30 ppb in cheese. The general population may be exposed to n-Nitrosodi-n-propylamine in cigarette smoke.
Workers making molded rubber products have been exposed to levels of n-Nitrosodi-n-propylamine in workroom air that were measured in parts of compound per trillion parts (ppt) of air. Workers applying contaminated weed killers may also be exposed to extremely low (ppt) levels of n-Nitrosodi-n-propylamine. At this time, n-Nitrosodi-n-propylamine has been found in at least 1 of 1177 hazardous waste sites on the National Priorities List (NPL) in the United States. Workers and the general population at these sites could possibly be exposed to this compound by skin contact, breathing, and eating contaminated items.
Pathways in the body
n-Nitrosodi-n-propylamine can enter the body when a person breathes air that contains n-Nitrosodi-n-propylamine, or eats food or drinks water contaminated with n-Nitrosodi-n-propylamine.
n-Nitrosodi-n-propylamine is not likely to get into your body unless you eat certain foods, drink alcoholic beverages, or are exposed to it at a waste disposal site by breathing n-Nitrosodi-n-propylamine vapors. It is likely that n-Nitrosodi-n-propylamine can enter the body by direct skin contact with wastes, pesticides, or soil that contains it. Experiments with animals suggest that if n-Nitrosodi-n-propylamine enters the body, it will be broken down into other compounds and will leave the body in the urine.
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).
The effects of short- or long-term exposures to n-Nitrosodi-n-propylamine on human health have not been studied. Little is known about the health effects of short exposures to n-Nitrosodi-n-propylamine in experimental animals except that eating or drinking certain amounts of this chemical can cause liver disease and death. Long-term exposure of experimental animals to n-Nitrosodi-n-propylamine in food or drinking water causes cancer of the liver, esophagus, and nasal cavities. Although human studies are not available, the animal evidence indicates that it is reasonable to expect that exposure to n-Nitrosodi-n-propylamine by eating or drinking could cause liver disease and cancer in humans. It is not known whether other effects, such as birth defects, occur in animals or could occur in humans exposed to n-Nitrosodi-n-propylamine by eating or drinking. It is also not known whether exposure to n-Nitrosodi-n-propylamine by breathing contaminated air or contact with the skin can affect the health of animals or humans. Liver disease and cancer due to exposure to n-Nitrosodi-n-propylamine by breathing or skin contact are, however, a possibility and a health concern.
The presence of n-Nitrosodi-n-propylamine in blood and urine can be measured by chemical analysis, but this analysis is not usually available at your doctor's office and has not been used to test for human exposure or to predict possible health effects.
Levels of exposure
As discussed above, no information is available on the health effects of n-Nitrosodi-n-propylamine in people. In animals, liver injury and death have been seen from short-term exposure to levels of 308 parts of n-Nitrosodi-n-propylamine per million parts of food (ppm) and above.
- The Agency for Toxic Substances and Disease Registry
- Interagency Coordinating Committee on the Validation of Alternative Methods
- European Centre for the Validation of Alternative Methods
- Institute for Laboratory Animal Research
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