Impaired neuromotor functions in hospital laboratory workers exposed to low levels of organic solvents

Abstract

Solvents are ubiquitous in industrial societies in a wide range of processes, and long-term exposure to these organic compounds may impair neuromotor functions such as equilibrium function. However, there is limited knowledge of effects on posture and gaze control after organic solvent exposures below workplace threshold limit values. The aim of this study was to evaluate the consequences of low-level co-exposure to organic solvents on balance and gaze control in hospital laboratory workers. Twelve hospital laboratory female subjects mainly exposed to toluene and ethanol, with median exposure duration of 24 years, and 12 non-exposed female controls were submitted to posturography and oculomotricity testings including sensory organization and motor control tests and saccade and smooth pursuit tests. Although current measured exposure values to toluene and ethanol were much below workplace threshold limit values (current median exposure levels of 32.5 mg/cubic meter and 39.9 mg/cubic meter, respectively), exposed workers displayed a weaker balance and a less precise gaze control. They presented, on the one hand, a reduced ability to resolve sensorial conflict situations compared to controls, particularly when situations were managed by the vestibular information, and, on the other hand, longer saccadic reaction time. Organic solvents might have an impact on vestibular pathways involved in postural control and exert a depressant central pathway effect implicated in the management of oculomotor response. Evaluating balance control in sensory conflicting situations and saccadic reaction time is proposed as a way to reveal subclinical neurotoxicological effects due to low-level exposure to organic solvents.

Effect of Chronic and Subchronic Organic Solvents Exposure on Balance Control of Workers in Plant Manufacturing Adhesive Materials

“…Few studies investigated effects of chronic exposure to volatile organic solvents on balance control through posturography, which is now recognized as a useful technique to assess neurotoxic effects on CNS (Ledin et al 1991;Kuo et al 1996;Yokoyama et al 1997;Iwata et al 2005;Vouriot et al 2005b;Herpin et al 2008). While most studies have shown that chronic exposure close to or higher than workplace threshold limit values led to balance disorders, the additive neurotoxic effects after a weeklong exposure, defined here as subchronic, are, to our knowledge, less understood.…”

Solvent Use in Private Research Laboratories in Japan: Comparison with the Use in Public Research Laboratories and on Production Floors in Industries

“…Nevertheless, the use of chloroform may require attention 4,14,15,23) because this solvent is commonly used in laboratories but only on rare occasions on production floors ( Table 1). The descriptions of solvent application in histology laboratories would be expected to be simple 16,17,21,22) because xylenes, toluene or the combination of them would be the only solvents used in this field of study 6) . Overall, therefore, it was not possible to examine if the observations as summarized in Table 1 could be confirmed through a literature survey.…”

Use of organic solvents in large research institutions in Japan

“…In contrast, use of xylenes in histology laboratories were reported by Gunson et al [6] and Purdie et al [8], suggesting that xylenes are commonly used in histopathology laboratories in medical fields, as in the present cases (Table 4). In addition, Herpin et al [7] reported that laboratory technicians in charge of 'anatomy sample preparation for microscopic analysis' were exposed to toluene and ethyl alcohol.…”

“…Nevertheless, information on the solvent use has been reported only on limited occasions and usually as a simple compilation of solvent names [5][6][7][8][9][10] with no further details such as use prevalence. In the present study, seven large research institutions were studied for solvent use in laboratories.…”