Breath benzene

Benzene causes problems in the blood. People who breathe benzene for long periods may experience harmful effects in the tissues that form blood cells, especially the bone marrow. 

An exhaled breath VOC of concern is benzene. The exhaled breath of smokers exhibited mean benzene concentrations of 14-50 pg/m, compared to 1-8 pg/m for non-smokers (Brugnone et al., 1989 Wallace et al., 1987 Reidel et al., 1996), and immediate smoking can elevate breath benzene concentrations to 90- 220 pg/m (Wallace, 1989 Brown and Knott, 1997). Assuming a breathing rate of 6 litres/minute and a worst case exhaled breath benzene concentration of 50 pg/m, a smoker may exhale 18 pg/h of benzene into building air even where smoking does not occur for a 20-m room with a ventilation rate of 0.35 h" and no pollutant sinks, this would lead to an equilibrium benzene concentration of 2.6 pg/m. Similar calculations could be made for many of the exhaled VOCs described earlier provided it is known that the compounds are endogenous, e.g., for isoprene at an exhaled breath concentration of 600 pg/m, indoor air con-... 

Animal studies have shown low birth weights, delayed bone formation, and bone marrow damage when pregnant animals breathed benzene. 

WEL 8-hour TWA Ippm. This excellent solvent is seldom used today because of its toxic effects. It may be inhaled or absorbed via the skin and is readily absorbed by fatty tissues. A large proportion of benzene which enters the body is stored in the bone marrow which may be damaged, causing anaemia or more rarely leukaemia. Benzene is altei chemically in the body and then excreted in the mine. For exposures about the WEL, blood benzene is a useful measmement. For lower exposures, breath benzene is suitable. Urinary excretion as a phenol test is no longer recommended. 

Figure 6.13 Illustration of (a) rocking, (b) twisting, (c) scissoring and (d) wagging vibrations in a CH2 group. Also shown are (e) the torsional vibration in ethylene, (f) the ring-breathing vibration in benzene and (g) the inversion, or umbrella, vibration in ammonia...

Determine the action level in pg/iiv for an 80 kg person with a life expectancy of 70 years exposed to benzene over a 15-year period. The "acceptable risk is one incident of cancer per 1 million persons or lO ". Assume a breathing (intake) rate of 15 m /d and an absorption factor of 75%. The potency factor for benzene is 1.80 (mg/kg-d)." ... 

Because benzene is a constitute of gasoline and some other fuels, and because it is so volatile, virtually all of us are exposed, almost continuously, to a certain level in the air we breathe. In some cases, because of fuel leaks and spills, ground waters and surface waters have become contaminated with benzene. What can be said about the threats to health, if any, we all face from these relatively low levels of exposure through our environment ... 

Benzene is shipped in tank cars, tank trucks, barges, and drums. Transfers from one vessel to another are in dosed systems because benzene is a poisonous substance with acute toxic effects. It ll kill you in 5—10 minutes if you breathe too much. Red DOT flammable liquid labels are required. 

Methods for Determining Biomarkers of Exposure and Effect. Exposure to 1,4-dichloro-benzene may be evaluated by measuring the levels of this compound in blood, breath, milk, and adipose tissue, and by measuring the level of 2,5-dichlorophenol, a metabolite of 1,4-dichlorobenzene, in urine (Bristol et al. 1982 Erickson et al. 1980 Jan 1983 Langhorst and Nestrick 1979 Pellizzari et al. 1985). Sensitive analytical methods are available for measurements in blood. Development of methods with improved specificity and sensitivity for other tissues and breath would be valuable in identifying individuals with low-level exposure. Development of standardized procedures would permit comparison of data and facilitate the study of correlations between exposure and measured levels biological samples. Interlaboratory studies are also needed to provide better performance data for methods currently in use. 

Wallace, L.A. Pellizzari, E.D. (1986) Personal air exposure and breath concentrations of benzene and other volatile hydrocarbons for smokers and nonsmokers. Toxicol Lett., 35, 113-116... 

Raman spectra of adsorbed species, when obtainable, are of great importance because of the very different intensity distributions among the observable modes (e.g., the skeletal breathing frequency of benzene) compared with those observed by infrared spectroscopy and because Raman spectra of species on oxide-supported metals have a much wider metal oxide-transparent wavenumber range than infrared spectra. Such unenhanced spectra remain extremely weak for species on single-crystal surfaces, but renewed efforts should be made with finely divided catalysts, possibly involving pulsed-laser operation to minimize adsorbate decomposition. Renewed efforts should be made to obtain SER and normal Raman spectra characterizing adsorption on surfaces of the transition metals such as Ni, Pd, or Pt, by use of controlled particle sizes or UV excitation, respectively. 

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