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The Rural Voice, 1980-08, Page 5Our polluted Great Lakes How much does agriculture add to the problem? BY HERB SHOVELLER When discussions of water pollution arise it seems we are most inclined to identify the sources in large centres where paper production, mining and smelting, high urban concentrations or other industrial complexes are prominent. These centres are described as point sources because they are easy to identify and a great deal of attention was directed at rectifying their contributions to pollution. Recently, however, there has been a growing awareness of the contribution to water quality deterioration from non -point sources. Specifically, it is concerned with water pollution as a result of agricultural practices. The growing awareness of pollution from farming activities was at least partially inspired by the work of the International Reference Group on Great Lakes Pollution From Land Use Activities (PLUARG), which conducted its work under the auspices of the International Joint Commission (LJC) which is based in Windsor. INDIVIDUALLY SMALL SOURCES Reports from PLUARG,which initiated its studies in the fall of 1977 and ended formally about a year later, say "nonpoint pollution differs from that of industrial plants and municipal sewage treatment plants (point sources) in that the former results from a large number of diffuse sources often producing individually small, but cumulatively significant, quantities of pollution." The contribution of nonpoint sources is especially significant in the agriculturally rich region of southwestern Ontario which borders on three of the Great Lakes, Huron, Erie and Ontario. For measures of nonpoint loads in the Great Lakes, it was discovered that cropland was the major source. This can be attributed to two causes. First is the high density of row crops in the area and the second is the fine grained clay soils which are common in the southern part of the province and in several of the northern American states. Both of these factors, if not carefully attended, result in soil erosion and poor drainage of land. Through erosion a variety of agricultural wastes from livestock, fertilizers, pesticides and insecticides make their way into the water system and much of it eventually ends up in the lakes. Hans Feldman, who farms in Wallace township in the north of Perth County, has been interested in the problem of erosion since well before groups like PLUARG focussed greater attention on it. "Pollution can be cleaned up one way or another, at a cost," he says, "but erosion is an ongoing process. You can't avoid erosion, but you can limit it. "The biggest source of pollution is too huge a concentration of Hans Feldman, who devoted a great deal of time to Investigating the erosion problem, looks over one of the PLUARG reports. (Photo by Shoveller) THE RURAL VOICE/AUGUST 1980 PG. 3