Exhaled air

Perchloroethylene in end-exhaled air Prior to last shift of workweek 5 ppm ... 

The kinetic properties of chemical compounds include their absorption and distribution in the body, theit biotransformation to more soluble forms through metabolic processes in the liver and other metabolic organs, and the excretion of the metabolites in the urine, the bile, the exhaled air, and in the saliva. An important issue in toxicokinetics deals with the formation of reactive toxic intermediates during phase I metabolic reactions (see. Section 5.3.3). 

Spirometry A test method used to evaluate lung function that measures volume of exhaled air passing through a tube during a given time. 

Oxygen masks for producing 02 in emergency situations contain potassium superoxide, K02. It reacts with C02 and H20 in exhaled air to produce oxygen ... 

Potassium superoxide is used in self-contained breathing devices for firefighters and miners. It reacts with the moisture in exhaled air to generate oxygen ... 

A self-contained breathing apparatus contains 248 g of potassium superoxide. A firefighter exhales 116 L of air at 37°C and 748 mm 1%. The volume percent of water in exhaled air is 6.2. What mass of potassium superoxide is left after the water in the exhaled air reacts with it ... 

L.6 Potassium superoxide, KC)2, is utilized in a closed-system breathing apparatus to remove carbon dioxide and water from exhaled air. The removal of water generates oxygen for breathing by the reaction 4 K02(s) + 2 H20(1) — 3 02(g) +... 

FIGURE 20 Rate of metabolism of PCL and its metabolites, determined from measurement of carbon-14 in the excreta and exhaled air of rats after implantation (s.c.) of the low molecular weight polymer. (From Ref. 53.)... 

Ethyl benzene in end-exhaled air Fluorides Prior to next shift 2 ppm Cf... 

Styrene in mixed-exhaled air Prior to next shift 40ppb Cf... 

Rapid dermal absorption of trichloroethylene is evident from a study in which peak blood and exhaled air concentrations occurred within 5 minutes after a human subject immersed one hand in a solution of unspecified trichloroethylene concentration for 30 minutes (Sato and Nakajima 1978). Studies on dermal absorption of trichloroethylene in humans, as well as animals, are complicated by the fact that exposure in these studies is usually by direct contact of the skin with the undiluted chemical. Trichloroethylene is a lipophilic solvent that defats the skin and disrupts the stratum comeum, thereby enhancing its own absorption. Thus, the rate of absorption probably increases in a nonlinear fashion with greater epidermal disruption. Although the extent of absorption through the skin may be relatively modest with normal industrial use (Sato and Nakajima 1978 Stewart and Dodd 1964), there is insufficient information to evaluate the effects of chronic, low-level exposure in hiunans, especially when multiple routes may be involved. 

Following inhalation exposure to trichloroethylene in humans, the unmetabolized parent compound is exhaled, whereas its metabolites are primarily eliminated in the urine. Excretion of trichloroethylene in the bile apparently represents a minor pathway of elimination. Balance studies in humans have shown that following single or sequential daily exposures of 50-380 ppm trichloroethylene, 11% and 2% of the dose was eliminated unchanged and as trichloroethanol, respectively, in the lungs 58% was eliminated as urinary metabolites and approximately 30% was unaccounted for (Monster et al. 1976, 1979). Exhaled air contained notable concentrations of trichloroethylene 18 hours after exposure ended because of the relatively long half-life for elimination of trichloroethylene from the adipose tissue (i.e., 3.5-5 hours) compared to other tissues (Fernandez et al. 1977 Monster et al. 1979). 

Several methods are available for the analysis of trichloroethylene in biological media. The method of choice depends on the nature of the sample matrix cost of analysis required precision, accuracy, and detection limit and turnaround time of the method. The main analytical method used to analyze for the presence of trichloroethylene and its metabolites, trichloroethanol and TCA, in biological samples is separation by gas chromatography (GC) combined with detection by mass spectrometry (MS) or electron capture detection (ECD). Trichloroethylene and/or its metabolites have been detected in exhaled air, blood, urine, breast milk, and tissues. Details on sample preparation, analytical method, and sensitivity and accuracy of selected methods are provided in Table 6-1. 

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