Airborne manganese particulates and methylcyclopentadienyl manganese tricarbonyl (MMT) at selected outdoor sites in Montreal

This study aims to assess the atmospheric concentrations of methylcyclopent adienyl manganese tricarbonyl (MMT), respirable manganese (Mn-R) and total manganese (Mn-T) in certain specific microenvironments and to provide an es timation of human exposure to Mn-R. Sampling was carried out in five microe nvironments: a gas station, an underground car park, downtown Montreal, nea r an expressway and near an oil refinery. The samples were collected using Gil-Air portable pumps during three days and were analyzed by instrumental neutron activation analysis (INAA). The mean concentrations of Mn-R, Mn-T a nd MMT were 0.036 mu g m(-3), 0.103 mu g m(-3) and 0.005 mu g m(-3) respect ively. The MndMn, ratios vary from 25% to 43% (mean 35%) while the MMT/Mn-T ratios averaged about 5%. Furthermore, the mean concentration of the Mn-R measured near the expressway (0.053 mu g m(-3)) is similar to the United St ates Environmental Protection Agency (U.S. EPA) reference concentration (Rf C=0.05 mu g m(-3)). The average daily environmental exposure dose to Mn, is estimated at 0.010 mu g kg(-1) d(-1) and its contribution to the multimedi a exposure (air, food and water) is low. The overall results show a lack of potential exposure to MMT and substantial concentrations of Mn, near an ex pressway. (C) 1999 Inter Press, Inc.