Xylene: its toxicity, measurement of exposure levels, absorption, metabolism and clearance

Validation of an HPLC–MS/MS method for the simultaneous determination of phenylmercapturic acid, benzylmercapturic acid and o-methylbenzyl mercapturic acid in urine as biomarkers of exposure to benzene, toluene and xylenes

“…Currently, no evidence exists to suggest that toluene and xylenes are carcinogenic. Nevertheless, exposure to high concentrations of these compounds can induce changes in the central nervous system and other neurotoxic effects [3][4][5]. The metabolism of these aromatic compounds has been thoroughly investigated [6][7][8].…”

A physiologically based toxicokinetic model of inhalation exposure to xylenes in Caucasian men

“…The TLV-TWA for xylenes was set at 100 ppm to protect nearly all workers exposed from adverse health effects. However, airborne concentrations are not the best indicator of body burden, since physiological effects of organic solvents are more directly related to the amount of toxicant within the body (Langman, 1994). This study, as well as many others, showed that even among equivalently exposed subjects, actual body burden may vary up to 10-fold (Jang and Droz, 1997;Pierce et al, 1996a).…”

“…This work further illustrated that the toxicokinetics and actual body burden of airborne solvents varies among equivalently exposed individuals. While our study was done with healthy Caucasian men exposed at rest, additional inter-individual variability is expected with women, different ethnic groups, working conditions, and those with pathological variables (Langman, 1994;and Jang and Droz, 1997). For these reasons, airborne concentrations are imprecise indicators of the actual toxicological dose and duration of internal exposure.…”

“…Chronic occupational exposure has been associated with subjective findings of depression, fatigue, headache, anxiety, feeling of drunkenness, and sleep disorders. Langman (1994) found that chronic exposure was also linked to anemia, leukopenia, electrocardiogram abnormalities, dyspnea, and cyanosis.…”

“…However, actual body burden may vary greatly among equivalently exposed workers due to individual differences in the dose received (caused by differences in ventilation rates), as well as differences in the absorption, metabolism, and distribution of the toxicant. These differences in toxicokinetics are related to many population variables including genotype, body size and composition, gender, life style factors such as alcohol consumption and smoking, and nutritional and health status (Langman, 1994;Pierce et al, 1998). Biological indicators of exposure, such as toxicant levels in the blood or metabolite levels in the urine, reflect these individual differences (Pierce et al, 1998).…”