The relative magnitude of phosphorus sources for small, oligotrophic lakes in Ontario, Canada

Dillon, P. J.
Reid, R. A.
Evans, H. E.
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Ontario Ministry of the Environment

Mass balances for total phosphorus (TP) were measured for a minimum of 9 years in 8 lakes located near the southern boundary of the Canadian Precambrian Shield in Ontario. The lakes ranged from having no shoreline development to having intensive development. Potential inputs of TP from anthropogenic activities ranged from 0% (in the undeveloped lakes) to about 60% of the TP load. In all the lakes, internal sources of TP were small (generally less than 10% of the total TP load). Atmospheric deposition was a major source of TP (approximately 21 mg/m2/yr) in those lakes with small catchments relative to lake area. Export of TP from the watershed was important in those lakes with large catchment: lake area ratios.

Ontario Ministry of the Environment
Other O.M.E. Environmental Reports
phosphorus, nutrients, total phosphorus, mass balance, anthropogenic inputs, catchment input, precipitation input, internal input, sewage disposal system