Toluene level

Several authors have pointed out that the urinary excretion of hippurate is a poor indicator of exposure to toluene at 200 ppm [760 mg/m ] or lower (Jonai Sato, 1988 Too et al., 1991 Pierce et al., 1996). Therefore, data on ethnic differences in hippurate or cresol excretion in urine at these low exposure levels (e.g., Inoue et al., 1988) are of doubtful significance. Toluene level in expired air may be a more reliable parameter (Foo et al., 1991). Although at the level of the individual, data on urinary hippurate cannot be reliably used to estimate low toluene exposures, they can be used at the group level to establish whether at a certain location the toluene exposure remained below a particular threshold (Lauwerys, 1983). 

Sullivan and Conolly (1988) compared toluene levels in the blood of Sprague-Dawley rats after inhalation w ith those seen after subcutaneous or oral administration. They concluded that, at low- exposure levels, subcutaneously administered toluene better mimics steady-state levels observed after inhalation exposure, while at high exposures, oral dosage gives satisfactory results. However, orally administered toluene was more rapidly eliminated, presumably because of first-pass oral metabolism. 

Sullivan, M.J. Conolly, R.B. (1988) Comparison of blood toluene levels after inhalation and oral administration. Environ. Res., 45, 64-70... 

It is interesting to note that an article in the Buffalo Courier Express dated September 23, 1978 headlined "Study Shows Canal Air Beats L.A." tried to put exposure levels in perspective by comparing data for basement benzene and toluene levels with atmospheric concentrations in Los Angeles, as posted in the office of a Dr. Philip Taylor, then on-site director for the state Health Department. 

The level of toluene (a flammable hydrocarbon) in a storage tank may fluctuate between 10 and 400 cm from the top of the tank. Since it is impossible to see inside the tank, an open-end manometer with water or mercury as the manometer fluid is to be used to determine the toluene level. One leg... 

Benignus, V.A., K.E. Mueller, C.N. Barton, and J.A. Bittikoffer. 1981. Toluene levels in blood and brain of rats during and after respiratory exposure. Toxicol. Appl. Pharmacol. 61 (3) 326-334. 

Six studies were found that quantified toluene concentrations. The countries that reported these observations included Germany, Russia, Finland and Singapore. In general, lOL toluene levels are lower than those reported in the literature. 

Some published data are difficult to interpret. For example, 26 men were exposed in tanks and holds of two merchant vessels being painted (solvents) and sprayed with mala-thion 20% and pyrethrin 1.5%, with piperonyl butoxide in toluene. They showed losses of concentration, unawareness of danger and unconsciousness at toluene levels estimated as 10,000 to 12,000 ppm and up to 30,000 ppm below waist level. Additive effects of the neurotoxic insecticides were not discussed. 

By using the developed toluene contamination model and the ORR parameter relations obtained from experiments at ppm levels, we numerically studied the cell performance degradation when the toluene inlet concentration was at ppb levels, which closely resembled normal indoor and outdoor toluene levels [20]. One could also estimate the degree of cell performance degradation at a certain contaminant level and current density. 

Toluene is a common solvent, and is used in model glues. Most toxicity in humans from exposure to toluene is from glue-sniffing or accidental exposure in the workplace. These incidents rarely provide information as to the amount to which someone was exposed. In this example, we are interested in ingestion of toluene. For example, take a case where toluene-contaminated groundwater was used as a drinking water supply and we want to be sure that the toluene levels are below those that could cause toxic effects in humans. There is not sufficient data for humans to establish a safe concentration or dose for this type of exposure. 

Toluene levels of 19,000 ppm are lethal after a short exposure period [197]. Concentrations of 800-1,000 ppm cause severe poisoning [197, 239], those of 50-100 ppm produce faintness, nausea, drowsiness, lassitude and headaches [197, 239]. Such concentrations are not present in the environment [13]. 

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