| | There is increasing concern among the agricultural community and the public about the effects of agriculture on the quality of our surface and ground waters because of news about impacts in other areas of North America. Although current agricultural practices in Alberta are less intensive than practices in many other regions of North America, information from more intensive agricultural regions can alert producers to potential problems associated with the expansion of Alberta's agricultural industry. Thus, agricultural producers can take a proactive stance toward increasing public pressure to safeguard the environment. Further, Alberta's agricultural industry market its products worldwide based on the concept of quality food produced in a clean environment. To ensure that Alberta's produce maintains positive worldwide recognition, Alberta producers must protect their natural resources.
The primary purpose of this report is to present information on the impacts of agriculture on water quality from a North American perspective. The objectives are threefold:
- to present specific examples from the primary literature of crop and livestock production practices from other regions of North American that have affected surface or ground water quality;
- to present background information on agricultural contaminants and how these contaminants are transported from agroecosystems to surface and ground waters; and
- to outline contaminant processes in lakes and rivers, and to describe the impacts of agricultural pollutants on aquatic ecosystems.
Information from this report will be developed into awareness materials for producers about potential agricultural impacts on water quality. Pollutants can harm the natural biological and chemical processes in aquatic ecosystems. Therefore, by understanding these natural processes, the cause of aquatic pollution can be linked to the effects. Furthermore, the understanding of how contaminants are transported to lakes and rivers is essential in designing and implementing land management practices to reduce pollutant loading to surface and ground waters.
Aquatic ecosystems are dynamic natural systems that respond to change, either manmade or natural. Although many Alberta lakes are naturally eutrophic from lying on top of naturally fertile soils derived from sedimentary bedrock, their productivity has likely increased from increased land development in the surrounding watersheds. High inputs of plant nutrients, such as nitrogen and phosphorus, from chemical fertilizers or livestock wastes can accelerate the eutrophication of surface waters causing lakes and rivers to experience large algal blooms and excessive aquatic weed growth. These conditions are aesthetically unpleasant, prevent recreational activities such as boating and swimming, and limit the use of water supplies for drinking purposes. In addition to inputs from the watershed, lake sediments are also a significant source of phosphorus to prairie lakes. For some prairie lakes, the lag time between increased phosphorus loads and increased algal growth and other aquatic plants may be decades. Thus, practices to reduce pollutant loads must become an integral part of land management to protect surface and ground waters.
Alberta is not immune to environmental impacts from agriculture as future expansion of the industry will place increased stress upon our natural resources. It is becoming increasingly important to sustain our natural resources for the future. Through awareness of potential impacts from agriculture and implementation of appropriate land management practices, producers can prevent potential problems before they occur.
Prepared by: Patsy Cross, Madawaska Consulting and Sandra Cooke, Conservation and Development Branch, AAFRD |
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