Assessment of personal exposure to manganese in children living near a ferromanganese refinery

Abstract

Airborne exposure to manganese (Mn) can result in neurologic effects. Stationary air sampling is the traditional technique to assess Mn exposure for communities, yet may not accurately reflect children's personal exposure. The goal of the study was to characterize personal exposure to Mn and PM2.5 in a cohort of children ages 7–9years residing near a ferromanganese refinery.A subset of children living in non-smoking households ages 7–9 enrolled in the Marietta Community Actively Researching Exposure Study during March–June 2009 and 2010 were invited to participate. Blood and hair were collected and analyzed for Mn. Participants wore a PM2.5 sampler (Personal Modular Impactor) for 48h. TWD was based on time spent at home and school and the distance of each from the refinery. Stationary outdoor air sampling was conducted 8km from the refinery using a Harvard-type PM2.5 impactor. The relationship between personal Mn exposure and TWD was examined by multiple regression adjusting for stationary air Mn concentration, wind speed and direction, and precipitation.Complete personal air sampling data were collected on 38 children. TWD ranged from 4.7km to 28.5km with a mean distance of 11.1 (4.7sd) km. Mn concentration in personal air samples ranged from 1.5ng/m3 to 54.5ng/m3 (geometric mean, 8.1ng/m3). TWD was a significant predictor of natural log personal air Mn concentration (lnMn) with an associated decrease of 0.075lnMn for each km TWD (p<0.05, 95% CI −0.13 to −0.01). Personal Mn exposures were positively associated with stationary air Mn levels and inversely associated with wind speed.A child's location (home and school) relative to the refinery is a significant predictor of personal Mn exposure. Wind speed is also an important contributor to personal Mn exposure.