Chronic neurobehavioural effects of mercury poisoning on a group of Zulu chemical workers

Abstract

Primary objective: To assess the nature and severity of reported neurobehavioural symptoms of mercury poisoning, in a group of Zulu chemical workers (n = 16), employed by a mercury processing plant, exposed to neurotoxic levels of mercury, 5 years after exposure. Research design: A group-control design was adopted, where the exposed group was matched for age, sex, race, occupational and educational background. Method/procedures: Both groups were administered a specially selected battery of psychometric tests to measure neuropsychological functioning. Outcome and results: The exposed group had significantly impaired short term verbal and spatial memory, impaired sustained and divided attention, and impaired motor speed. They also suffered from elevated clinical levels of psychiatric symptomatology, including anxiety, depression and phobic avoidance, and neurological symptoms of tremor, weakness in the limbs, and excessive sweating. Conclusions: The exposed group suffered from varying degrees of permanent neuropsychological disability, which adversely affects their ability to work and be financially independent. Psychometric measures for monitoring cognitive symptoms are discussed.