| Since the era of lead (Pb) additive to gasoline, Canadians have been more concerned about MMT use in gasoline and its effects on the Canadian environment. A number of recent publications have documented adverse health implications of MMT. However, no reports have been published on the impact of MMT on Canadian vegetation and soil. This work focused on the deposition effect of Mn from MMT source to the terrestrial environment beside the major highways in GTA, Canada. Results were compared with Pb and other trace elements such as Al, Ca, Fe, Mg, Cu, Zn, Na, and Cl− ion in order to study behavior of Mn in soil. Surface soil, subsoil, grass species, sugar maple tree core and foliage samples were collected at distances up to 40 metres from the roadside. Parameters evaluated included total and available Mn along with other trace elements, particle size, cation exchange capacity, organic matter and pH. According to the traffic density, higher Mn deposition was expected along 401 (278,560 cars/day) than 400 (47,835 cars/day). No significant difference was found in surface soil, or subsoil within 401 and 400 Barrie (E+1) site. However, significant difference was observed in grass species within 401 (Warden Avenue, E+3 and Brock Road, E+4) and 400 Barrie (E+1) site. Higher accumulation of Mn was expected on 401 urban sites but a higher level of Mn accumulation in grass species was observed at Barrie (E+1) site. No significant difference was observed in maple tree core samples or in “washed” and “unwashed” maple leaves within 400 Barrie (E+1) and King city (E+2) sites. In addition, model was developed to predict the levels of the traffic density and 15% tailpipe Mn emissions for the area studied. The Mn emission input levels were found to be so insignificant that it may take several hundred years to reach the observed output levels in surface soil. This concludes that the continuous usage of MMT in Canadian gasoline will not increase the level of Mn beside the major highways of GTA that may account toxic to the terrestrial environment as demonstrated by the study. |
