N-Nitrosodimethylamine
Encyclopedia
N-Nitrosodimethylamine (NDMA), also known as dimethylnitrosamine (DMN), is a semi-volatile
organic chemical
that is highly toxic
and is a suspected human carcinogen
. The US Environmental Protection Agency has determined that the maximum admissible concentration of NDMA in drinking water
is 7 ng L−1. The EPA has not yet set a regulatory maximum contaminant level (MCL) for drinking water. At high doses, it is a "potent hepatotoxin
that can cause fibrosis
of the liver
" in rats. The induction of liver tumors in rats after chronic exposure to low doses is well documented. Its toxic effects on humans are inferred from animal experiments but not well-established experimentally.
NDMA appears to have a very strong affinity as a poison for the liver and at least one case of poisoning in humans is reported. NDMA is water-soluble, colorless, and has at best a weak taste and odor. In the incident reported by New Yorker writer Berton Roueché
, a jealous former boyfriend spiked lemonade with NDMA, which he had acquired while working at a cancer research center. At the time of writing, this substance was in common use in the laboratory to induce cancer in mice for study. The incident resulted in the death of an 11-month-old male child and a 30-year old man from, ultimately, massive liver damage. In the victims, NDMA produced very characteristic lesions in the liver, rapidly declining platelet count, and highly elevated SGOT levels. Other symptoms included headache, fever, vomiting, abdominal pain, scattered intradermal hemorrhage, lethargy, nausea, and diarrhea.
NDMA is an industrial by-product or waste product of several industrial processes. It first came to attention as a groundwater
contaminant in California
in 1998 and 1999 at several sites that produced rocket fuel. Manufacturing of unsymmetrical dimethylhydrazine (UDMH), which is a component of rocket fuel that requires NDMA for its synthesis, proved to be the culprit in these cases. Of more general concern, water treatment
via chlorination
or chloramination
of organic nitrogen-containing wastewater can lead to the production of NDMA at potentially harmful levels. Further, NDMA can form or be leached during treatment of water by anion exchange resins. Finally, NDMA is found at low levels in numerous items of human consumption including cured meat, fish, beer, and tobacco smoke It is, however, unlikely to bioaccumulate.
NDMA's contamination of drinking water is of particular concern due to the minute concentrations at which it is harmful, the difficulty in detecting it at these concentrations, and to the difficulty in removing it from drinking water. It does not readily biodegrade, adsorb, or volatilize. As such, it cannot be removed by activated carbon
and travels easily through soils. Relatively high levels of UV
radiation in the 200 to 260 nm breaks the N-N bond and can thus be used to degrade NDMA. Additionally, reverse osmosis
is able to remove approximately 50% of NDMA.
Volatility (chemistry)
In chemistry and physics, volatility is the tendency of a substance to vaporize. Volatility is directly related to a substance's vapor pressure. At a given temperature, a substance with higher vapor pressure vaporizes more readily than a substance with a lower vapor pressure.The term is primarily...
organic chemical
Organic chemistry
Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, composition, reactions, and preparation of carbon-based compounds, hydrocarbons, and their derivatives...
that is highly toxic
Toxin
A toxin is a poisonous substance produced within living cells or organisms; man-made substances created by artificial processes are thus excluded...
and is a suspected human carcinogen
Carcinogen
A carcinogen is any substance, radionuclide, or radiation that is an agent directly involved in causing cancer. This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes...
. The US Environmental Protection Agency has determined that the maximum admissible concentration of NDMA in drinking water
Drinking water
Drinking water or potable water is water pure enough to be consumed or used with low risk of immediate or long term harm. In most developed countries, the water supplied to households, commerce and industry is all of drinking water standard, even though only a very small proportion is actually...
is 7 ng L−1. The EPA has not yet set a regulatory maximum contaminant level (MCL) for drinking water. At high doses, it is a "potent hepatotoxin
Hepatotoxin
A hepatotoxin is a toxic chemical substance that damages the liver.It can be a side-effect of medication, or found naturally, as microcystins, or in laboratory environments....
that can cause fibrosis
Cirrhosis
Cirrhosis is a consequence of chronic liver disease characterized by replacement of liver tissue by fibrosis, scar tissue and regenerative nodules , leading to loss of liver function...
of the liver
Liver
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...
" in rats. The induction of liver tumors in rats after chronic exposure to low doses is well documented. Its toxic effects on humans are inferred from animal experiments but not well-established experimentally.
NDMA appears to have a very strong affinity as a poison for the liver and at least one case of poisoning in humans is reported. NDMA is water-soluble, colorless, and has at best a weak taste and odor. In the incident reported by New Yorker writer Berton Roueché
Berton Roueché
Berton Roueché was a medical writer who wrote for The New Yorker magazine for almost fifty years. He also wrote twenty books including Eleven Blue Men , The Incurable Wound , Feral , and The Medical Detectives...
, a jealous former boyfriend spiked lemonade with NDMA, which he had acquired while working at a cancer research center. At the time of writing, this substance was in common use in the laboratory to induce cancer in mice for study. The incident resulted in the death of an 11-month-old male child and a 30-year old man from, ultimately, massive liver damage. In the victims, NDMA produced very characteristic lesions in the liver, rapidly declining platelet count, and highly elevated SGOT levels. Other symptoms included headache, fever, vomiting, abdominal pain, scattered intradermal hemorrhage, lethargy, nausea, and diarrhea.
NDMA is an industrial by-product or waste product of several industrial processes. It first came to attention as a groundwater
Groundwater
Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of rock formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock...
contaminant in California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
in 1998 and 1999 at several sites that produced rocket fuel. Manufacturing of unsymmetrical dimethylhydrazine (UDMH), which is a component of rocket fuel that requires NDMA for its synthesis, proved to be the culprit in these cases. Of more general concern, water treatment
Water treatment
Water treatment describes those processes used to make water more acceptable for a desired end-use. These can include use as drinking water, industrial processes, medical and many other uses. The goal of all water treatment process is to remove existing contaminants in the water, or reduce the...
via chlorination
Chlorination
Chlorination is the process of adding the element chlorine to water as a method of water purification to make it fit for human consumption as drinking water...
or chloramination
Chloramination
Chloramination is the treatment of drinking water with a chloramine disinfectant. Both chlorine and small amounts of ammonia are added to the water one at a time which react together to form chloramine , a long lasting disinfectant...
of organic nitrogen-containing wastewater can lead to the production of NDMA at potentially harmful levels. Further, NDMA can form or be leached during treatment of water by anion exchange resins. Finally, NDMA is found at low levels in numerous items of human consumption including cured meat, fish, beer, and tobacco smoke It is, however, unlikely to bioaccumulate.
NDMA's contamination of drinking water is of particular concern due to the minute concentrations at which it is harmful, the difficulty in detecting it at these concentrations, and to the difficulty in removing it from drinking water. It does not readily biodegrade, adsorb, or volatilize. As such, it cannot be removed by activated carbon
Activated carbon
Activated carbon, also called activated charcoal, activated coal or carbo activatus, is a form of carbon that has been processed to make it extremely porous and thus to have a very large surface area available for adsorption or chemical reactions.The word activated in the name is sometimes replaced...
and travels easily through soils. Relatively high levels of UV
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...
radiation in the 200 to 260 nm breaks the N-N bond and can thus be used to degrade NDMA. Additionally, reverse osmosis
Reverse osmosis
Reverse osmosis is a membrane technical filtration method that removes many types of large molecules and ions from solutions by applying pressure to the solution when it is on one side of a selective membrane. The result is that the solute is retained on the pressurized side of the membrane and...
is able to remove approximately 50% of NDMA.