Neurotoxic effects in workers of the clinical thermometer manufacture plant

Occupational exposure to mercury can induce adverse health effects, and the central nervous system is the major target of its toxic action. This problem especially arises in plants involved in the manufacture of mercury-containing products, where an appropriate protection against mercury exposure is not ensured. The aim of this study was to assess health effects of mercury, especially neurotoxic effects and oral disorders, in workers employed in a clinical thermometer manufacture plant and to determine mercury concentrations in the workplace ambient air.

The study population comprised 143 workers, including 51 (35.7%) men and 92 (64.3%) women employed in the plant. Mean age in the whole group was 29 years (range, 18-55 years). It was divided into three groups: control, mercury absorption and mercury poisoning. A questionnaire-based interview was used to collect data on medical history, occupational exposure and employment. For clinical diagnosis, all subjects underwent physical, neurological and oral examinations. Mercury concentrations in the air were recorded by Hg monitoring instrument and mercury levels in collected urine samples were determined by cold vapor atomic absorption spectrophotometry.

Neurasthenic symptoms were found in 51.75% of the subjects, emotional changes in 27.27%, tremors in 11.19%, and inflammations in 21.68%. The case percentage of neurological symptoms in the control and mercury absorption groups did not show significant difference, but it was significantly higher in the mercury poisoning group.

The high occupational exposure to mercury, found in the plant and evidenced by urinary Hg concentration > or = 0.05 mg/l, can result in chronic quantitative neurotoxic effects and qualitative health changes. Therefore, constant monitoring of the work environment and checking of workers' health status should be ensured. In addition, appropriate steps should be taken to improve work conditions and promote health among the employees.