Top 10 Articles

LS-Studio
GayRomeo
Justus_Dahinden
Mercedes Benz OM601
Diyanet İşleri Başkanlığı
Radically 25
Ral color system
RTLnow.de
New concept
Electromagnetic compatibility

News:

N-Nitrosodimethylamine

Not to be confused with MDMA.
N-Nitrosodimethylamine
IUPAC name N,N-Dimethylnitrous amide
Other names Dimethylnitrosamine
N,N-Dimethylnitrosamine
Abbreviations DMN, DMNA
Identifiers
CAS number [62-75-9]
PubChem 6124
SMILES CN(C)N=O
Properties
Molecular formula C2H6N2O
Molar mass 74.08 g mol-1
Appearance yellow liquid
Density 1.005 g/cm³
Boiling point

152 °C, 425 K, 306 °F
Solubility in water 29 g/100 ml (20 °C)
Hazards
R-phrases R26 R27 R28 R45 R61
Flash point 61 °C
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)
Infobox disclaimer and references

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.[1] At high doses, it is a "potent hepatotoxin that can cause fibrosis of the liver" in rats.[2] The induction of liver tumors in rats after chronic exposure to low doses is well-documented.[3] Its toxic effects on humans are inferred from animal experiments but not well-established experimentally.

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.[4] Finally, NDMA is found at low levels in numerous items of human consumption including cured meat, fish, beer, and tobacco smoke [4] 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.[5]

References

  1. ^ Andrzejewski et al. (10 June 2005). "The hazard of N-nitrosodimethylamine (NDMA) formation during water disinfection with strong oxidants". Desalination 176 (1-3): 37–45. doi:10.1016/j.desal.2004.11.009. 
  2. ^ George et al. (2001). "Dimethylnitrosamine-induced liver injury in rats: the early deposition of collagen". Toxicology 156 (2-3): 129–38. doi:10.1016/S0300-483X(00)00352-8. 
  3. ^ Peto, R. et al. (December 1, 1991). "Dose and Time Relationships for Tumor Induction in the Liver and Esophagus of 4080 Inbred Rats by Chronic Ingestion of N-Nitrosodiethylamine or W-Nitrosodimethylamine". Cancer Research (51): 6452–6469. 
  4. ^ a b Najm, Issam; Trussell, R. Rhodes (February 2001). "NDMA Formation in Water and Wastewater". Journal AWWA 93 (2): 92–99. 
  5. ^ William A. Mitch; Jonathan O. Sharp; R. Rhodes Trussell; Richard L. Valentine; Lisa Alvarez- Cohen; David L. Sedlak (2003). "N-Nitrosodimethylamine (NDMA) as a Drinking Water Contaminant: A Review". Environmental Engineering Science 20 (5): 389–404. doi:10.1089/109287503768335896. 

External links

The original article is from Wikipedia. To view the original article please click here.
Creative Commons Licence

 
Custom Search