Environmental exposure to manganese in air: Associations with cognitive functions

• 186 adult residents of two towns environmentally exposed to manganese in air.
• Modeled mean average air-Mn exposures over 10 years range from 0.01 to 6.32 μg/m3.
• Cognitive function was assessed with comprehensive neuropsychological screening test battery.
• Increased air-Mn levels inversely related to working/visuospatial memory and verbal skills.

Manganese (Mn), an essential element, can be neurotoxic in high doses. This cross-sectional study explored the cognitive function of adults residing in two towns (Marietta and East Liverpool, Ohio, USA) identified as having high levels of environmental airborne Mn from industrial sources.Air-Mn site surface emissions method modeling for total suspended particulate (TSP) ranged from 0.03 to 1.61 μg/m3 in Marietta and 0.01–6.32 μg/m3 in East Liverpool. A comprehensive screening test battery of cognitive function, including the domains of abstract thinking, attention/concentration, executive function and memory was administered. The mean age of the participants was 56 years (±10.8 years). Participants were mostly female (59.1) and primarily white (94.6%). Significant relationships (p < 0.05) were found between Mn exposure and performance on working and visuospatial memory (e.g., Rey-O Immediate β = −0.19, Rey-O Delayed β = −0.16) and verbal skills (e.g., Similarities β = −0.19).Using extensive cognitive testing and computer modeling of 10-plus years of measured air monitoring data, this study suggests that long-term environmental exposure to high levels of air-Mn, the exposure metric of this paper, may result in mild deficits of cognitive function in adult populations.