P-360 SEVERITY OF PARKINSONISM ASSOCIATED WITH ENVIRONMENTAL MANGANESE EXPOSURE

Abstract

Abstract Introduction Workers exposed to manganese can develop impaired cognitive and motor function, manifesting primarily as parkinsonism. The effects of exposure to lower, environmental levels are unclear. Methods We investigated the motor effects of exposure to ambient manganese from a ferromanganese smelter in South Africa. Two groups of adults (> 40 years) participated from 2016 to 2020: 621 living near the smelter and 95 from an unexposed area. All were examined by a movement disorders specialist, using the Unified Parkinson Disease Rating Scale motor subsection part 3 (UPDRS3). All participants completed accelerometry-based kinematic (ABK) and grooved pegboard (GP) tests. Airborne PM2.5-Mn was measured in both areas. We compared performances between the two groups, using linear regression. Results The mean PM2.5-Mn concentration near the smelter was 203 ng/m3 in 2016-2017; 20 times higher than the 10 ng/m3 measured in 2020 in the unexposed area. UPDRS3 scores were 6.6 (95% CI 5.2-7.9) points higher in the exposed than the unexposed participants. Mean angular velocity for finger-tapping on the ABK test (degrees/second) was slower in the exposed than the unexposed participants: 74.9, 95% CI 48.7-101.2, and 82.6, 95% CI 55.2-110.1 for the dominant and non-dominant hand, respectively. Discussion We showed that exposure to low manganese levels is associated with parkinsonian motor dysfunction. Occupational health practitioners should be aware of the potential for workers to develop neurological health effects at low exposure levels of manganese. Conclusion The current OEL for manganese should be investigated, taking into account the findings from this and other similar studies.