N-Nitrosodimethylamine

N-Nitrosodimethylamine (NDMA), also known as dimethylnitrosamine (DMN), is a semi-volatile organic chemical, produced as by-product of several industrial processes and present at very low levels in certain foodstuffs, especially those cooked, smoked, or cured. NDMA is water-soluble, yellow in color, and has little or no taste and odor. It is toxic to the liver and other organs and is a probable human carcinogen. It is also used to create cancer in rats for cancer research. N-Nitrosodimethylamine (NDMA), also known as dimethylnitrosamine (DMN), is a semi-volatile organic chemical, produced as by-product of several industrial processes and present at very low levels in certain foodstuffs, especially those cooked, smoked, or cured. NDMA is water-soluble, yellow in color, and has little or no taste and odor. It is toxic to the liver and other organs and is a probable human carcinogen. It is also used to create cancer in rats for cancer research. NDMA is a yellow, oily liquid with a faint, characteristic odor and a sweet taste. It is an industrial by-product or waste product of several industrial processes, such as manufacturing of unsymmetrical dimethylhydrazine (UDMH), which is a component of rocket fuel that requires NDMA for its synthesis. Of more general concern, water treatment by 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, tobacco smoke and as an impurity in pharmaceuticals. It is, however, unlikely to bioaccumulate. N-Nitrosodimethylamine is highly toxic, especially to the liver, and is a known carcinogen in lab animals. The EPA classifies NDMA as a probable human carcinogen. The US Environmental Protection Agency has determined that the maximal admissible concentration of NDMA in drinking water is 7 ng/L. The EPA has not yet set a regulatory maximal 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'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 range breaks the N–N bond and can thus be used to degrade NDMA. Additionally, reverse osmosis is able to remove approximately 50% of NDMA. It is classified as an extremely hazardous substance in the United States as defined in Section 302 of the U.S. Emergency Planning and Community Right-to-Know Act (42 U.S.C. 11002) and is subject to strict reporting requirements by facilities that produce, store, or use it in significant quantities. Several incidents in which NDMA was used to intentionally poison another person have garnered media attention. In 1978, a teacher in Ulm, Germany was sentenced to life in prison for trying to murder his wife by poisoning jam with NDMA and feeding it to her. Both the wife and the teacher later died from liver failure. In 1978, Steven Roy Harper spiked lemonade with NDMA at the Johnson family home in Omaha, Nebraska. The incident resulted in the deaths of 30-year-old Duane Johnson and 11-month-old Chad Shelton. For his crime, Harper was sentenced to death but committed suicide in prison before his execution could be carried out. In the 2013 Fudan poisoning case, Huang Yang, a postgraduate medical student at Fudan University, was the victim of a poisoning in Shanghai, China. Huang was poisoned by his roommate Lin Senhao, who had placed NDMA into the water cooler in their dormitory. Lin claimed that he only did this as an April Fool's joke. He received a death sentence and was executed in 2015. Additionally in 2018, NDMA was used in an attempted poisoning at Queen's University.