Nose-only exposure system

Thomson EM, Williams A, Yauk CL et al (2009) Impact of nose-only exposure system on pulmonary gene expression. Inhalation Toxicol 21(suppl l) 74-82... 

Bide and Risk (2000) exposed outbred male GDI (SD) BR rats, outbred male GDI (ICR) BR mice, and outbred male (HA) BR guinea pigs to NaCl aerosols containing entrained VX in a nose-only inhalation system for an exposure time of 12 min. Observed LC/50 values are summarized in Table 6.3. 

The apparatus consisted of a U-shape glass volatilization pipe preheated to a designed temperature, a nose-only exposure unit containing six mice, a glass wool trap (packed with 0.5 g of glass wool fiber) that sequestered the vaporized test compound, and a vacuum system that created negative pressure and pulled the air through the... 

The data in Figures 2.12-2.14 suggest that the systemic penetration of C(-)P(-)-soman during nose-only exposure is very rapid, since this stereoisomer can be measured in blood at 30 s after starting the exposure. Moreover, the... 

Irregular respiration was observed in both male and female rats after a 4-hour nose-only inhalation exposure to aerosolized endosulfan (Hoechst 1983a). In both male and female rats, dyspnea was observed at the lowest concentrations tested (12.3 and 3.6 mg/m for males and females, respectively). Autopsies of the rats that died revealed dark-red, pinhead-sized foci on the lungs. It is unclear whether these effects represent direct effects of inhaled endosulfan on respiratory tissues or whether they are secondary to central nervous system effects on respiratory function. No treatment-related effects were... 

Heck et al. (1985) determined the fate of inhaled formaldehyde in the human. Four men and two women were exposed to a 1.9 0.06 ppm air concentration of formaldehyde in a large walk-in chamber for 40 minutes. Shortly before and shortly after the exposure, venous blood samples were taken from each person (each person served as his/her own control) and the blood was analyzed for formaldehyde content. Mean venous blood formaldehyde concentrations in humans prior to exposure showed a blood concentration of 2.6 H0.41 g/g of blood. Individual variability was markedly present. Immediately after a 40-minute exposure, mean blood concentration of formaldehyde was 2.77 0.28 g/g of blood. There was no significant difference between pre- and postexposure blood concentrations of formaldehyde at the formaldehyde air concentrations tested in this study, most likely indicating rapid metabolism and/or local absorption in the respiratory tract mucosa rather than systemic absorption into the blood. In the same report by Heck et al. (1985), the fate of inhaled formaldehyde was determined in the rat. Male Fischer 344 rats were placed in a nose-only inhalation chamber and exposed to a 14.4 2.4 ppm air concentration of formaldehyde for 2 hours, were sacrificed, and a venous blood sample was collected and analyzed for formaldehyde content. Unexposed control rats had a mean formaldehyde... 

Troop exposure to these materials could result from leaking DF containers, accidents that disrupt packaging, spills at production or storage facilities, or accidents during transport. Because DF and DC are relatively volatile compounds, the primary route of exposure is expected to be the respiratory system. However, ingestion also results from inhalation exposures in animals and could occur in humans. DF and DC vapors have a pungent odor and may cause severe and painful irritation of the eyes, nose, throat, and lungs. Data provided are for DF only, DC has similar properties. 

A small residence can even act as a shield. An individual can turn off the air circulation system (or switch it to recirculation mode), and close vents, windows, and doors to create a barrier that will help prevent contaminated smoke or other airborne debris from entering the home. Because a building may not always be nearby in the event of a terrorist attack, shielding could be provided from another object such as a car (with the vents closed), a folded handkerchief over the nose and mouth, or any object that reduces the potential of exposure. The shield does not have to be sophisticated it only needs to be effective. 

The toxic properties of xylene isomers are similar to toluene or ethylbenzene. The target organs are the central nervous system, eyes, gastrointestinal tract, kidneys, liver, blood, and skin, which, however, are affected only at high levels of exposure. In humans its exposure may cause irritation of the eyes, nose, and throat, headache, dizziness, excitement, drowsiness, nausea, vomiting, abdominal pain, and dermatitis. The irritation effects in humans may be felt at a concentration of 200 ppm in air, while exposure to 10,000 ppm for 6-8 hours may be fatal. 

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