OBJECTIVETo explore the effects of occupational ethylbenzene exposure on blood neurotransmitter levels in population.

METHODSThe exposure group consisted of 246 workers occupationally exposed to ethylbenzene and the control group was composed of 122 staffs from the offices. The basic information on ethylbenzene exposure was collected by the questionnaire. The mandelic acid (MA) and phenylglyoxylic acid (PGA) in the post-working urine were measured using the high performance liquid chromatography. The levels of gamma-aminobutyric acid (GABA), dopamine (DA) and acetylcholinesterase (AchE) activity were detected by reversed phase high performance liquid chromatography, spectrofluorometry and DTNB method, respectively. The blood biochemical indexes: alanine transaminase (ALT), aspartate aminotransferase (AST), total protein (TP), albumin (ALB), alkaline phosphatase (ALP), total bilirubin (TBIL) were examined. Also the hematologic indexes: red blood cell (RBC), white blood cell (WBC), hemoglobin (HGB) and platelet (PLT) were determined.

RESULTSThe levels of MA, PGA and MA+PGA of urine in the exposed group were significantly higher than those in the control group (P < 0.05). There were no significant differences of the biochemical indexes (AST, ALT, TP, ALB, BUN, Cr, ALP and TBIL), hematologic indexes (WBC, RBC, Hb and PLT) and serum GABA between the exposure group and the control group (P > 0.05). But the serum DA [(0.21 ± 0.011) mg/L] and AChE levels [(0.321 ± 0.066) U/L] in the exposure group were significantly lower than those in the control group [(0.25 ± 0.015) mg/L, (0.583 ± 0.125) U/L], respectively (P < 0.05).

CONCLUSIONMA and PGA in urine can serve as the biomarkers of internal exposure dose. Before the obvious changes of biochemical indexes and hematologic indexes appear, the exposure to ethylbenzene can influence the blood neurotransmitter levels in workers exposed to ethylbenzene.