Labile manganese in the terrestrial environment, increasing manganese deposition in soil from MMT, a gasoline additive, beside Highway 401, Ontario

grantor: University of TorontoThe study was conducted on two Hydro rights-of-way, one which crosses Highway 401 at Warden Avenue in Scarborough, and another which crosses Highway 401 at Brock Road in Pickering, Ontario. Sampling was designed to determine the degree and extent of Mn and Pb deposition in soil. Samples were collected at distances up to 160 metres form the roadside. Selected tree corings of Norway maple and White spruce were conducted. Parameters evaluated included total and exchangeable Mn and Pb, soil particle size, pH, and cation exchange capacity. Mn concentrations decreased with increasing distance from roadside. Lead concentration changed little from values reported twenty years ago, but have moved deeper into the soil, whereas Mn concentrations decreased with soil depth. Soil Mn concentrations are measurably elevated adjacent to the highway. The most likely source is Mn emitted from vehicle exhaust as a result of the combustion of MMT-containing gasoline.M.Sc