Environmental and biological monitoring of exposure to mercury and assessment of its effects on neurobehavioral disorders; A case-control study among workers in a unit of petroleum industry

Introduction: Mercury, in different form can induce adverse effects on various organs especially central nervous system. The aim of this study was to determine concentration of mercury in inhalation and urine of the exposed worker and to investigate the prevalence of probable neurobehavioral disorders. Material and Method: The present case-control study was conducted among workers of a unit in a petroleum industry. The study population consisted of 52 workers as case and 63 workers as control groups. The mercury concentration in air and urine was measured according to NIOSH 6009 standard and using the cold vapor atomic absorption spectrophotometer (CV-AAS). Demographic data and neurobehavioral disorders were collected using a self-reported questionnaire. Pearson correlation coefficient, multiple regression tests and SPSS v24 were used to analyze the data. Result: Air concentration of mercury was 0.062 ± 0.0014 mg/m3 which was higher than the recommended threshold by NIOSH and ACGIH. In addition, there was a significant difference between urinary concentration of mercury in the case (37.73 ± 13.01 µg/g cratinine) and control (5.93 ± 4.76 µg/g cratinine) groups (p=0.03 6). Based on the multivariate logistic regression model, significant relationships were found between memory loss, sleep disturbance, and urine mercurial concentrations and, between memory loss, moody, muscle weakness and air mercurial concentration. Conclusion: The values of Hg in blood and urine workers who worked in investigated unit were significantly higher than recommended threshold values. In addition, the Hg concentration in urine was related to some of neurobehavioral disorders.