Sample containers, tobacco smoke

Excluding tobacco and tobacco smoke (lf f3), the largest known human exposure to N-nitrosamines is in the industrial sector (4). The area or process air samples containing the largest amount of nitrosamines are in a tire factory, NMOR at the 250 yg/m level (5, a leather tannery, NDMA at the 47 ]xg/wr level (jy, and a rocket fuel factory, NDMA at the 36 yg/m level (7). 

Thousands of tonnes of methyl chloride are produced naturally every day, primarily in the oceans. Other significant natural sources include forest and brush fires and volcanoes. Although the atmospheric budget of methyl chloride can be accounted for by volatilization from the oceanic reservoir, its production and use in the manufacture of silicones and other chemicals and as a solvent and propellant can make a significant impact on the local atmospheric concentration of methyl chloride. It has been detected at low levels in drinking-water, groundwater, surface water, seawater, effluents, sediments, in the atmosphere, in fish samples and in human milk samples (Holbrook, 1993 United States National Library of Medicine, 1998). Tobacco smoke contains methyl chloride (lARC, 1986). 

The most highly developed and validated method for sampling volatile A-nitrosamines from tobacco smoke employs an aqueous buffered solution (pH 4.5 citrate-phosphate) with 2.10 M ascorbic acid contained in several impingers connected in series. Ascorbic acid is added to the solution as a nitrosating inhibitor to prevent the formation of artifact A-nitrosamines from the... 

Nickel normally occurs at very low levels in the environment, and therefore, very sensitive methods are needed to detect nickel in most environmental samples. You may be exposed to nickel by breathing air, drinking water, eating food, or smoking tobacco containing nickel. 

Estimates of daily exposure to benzene from urban or suburban air range from 180 to 1300 /ig/person/day.1112 Urban air concentrations of the other aromatic hydrocarbons are similar to those of benzene and the vast majority of exposure of the general population to these other aromatic hydrocarbons will be due to road transport or solvent-containing products rather than food. A 1995 survey of these compounds in samples from the UK Total Diet Study showed that average dietary exposures to benzene and related compounds from food in the UK are low, and very much lower than estimated exposure from active smoking of tobacco or intakes from air by urban dwellers.13 The mean dietary exposure to benzene was estimated to be in the range 0.9-2.4 /ig/person/day. 

Roemer, E. and U. Hackenberg Mouse skin bioassay of smoke condensates from cigarettes containing different levels of cocoa Food Addit. Contam. 7 (1990) 563-569. Roeraade, J. and C.R. Enzell Tobacco chemistry. 14. Sampling, concentration, and examination of tobacco headspace vapors J. Agr. Food Chem. 20 (1972) 1035-1039. 

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