[Evaluation of urinary ortho-cresol as biological monitoring indicator of occupational exposure to toluene].

Objective: To investigate the feasibility of urinary ortho-cresol levels as a biological monitoring indicator for toluene exposure.

Methods: Establish pre-column derivation HPLC method to detect ortho-cresol levels in urine of human body. Ortho-cresol levels in urine of workers non-exposed and exposed to toluene was examined using this pre-column derivation HPLC method, and exposure assessment was conducted.

Results: It was shown that urinary ortho-cresol level in exposed workers was (2.61 +/- 1.94) mg/L, higher than those of control group [(0.32 +/- 0.23) mg/L, P < 0.001]. Urinary ortho-cresol level in exposed workers at the end of a workshift was higher than those before exposure to toluene, and also was correlated with the concentration of toluene to which individual exposed(r = 0.6295, P < 0.01).

Conclusion: Urinary ortho-cresol as a biological monitoring indicator for toluene exposure is feasible.