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Importance of Deposition Measurements in Agro-Ecosystems A Perspective from Canadian Prairie Crops
E. Poscher*, M.P. Schellenberg, J.M. Clarke,
H. Cutforth, M.R. Fernandez, and T.N. McCaig
Semiarid Prairie Agricultural Research Centre, Agriculture and Agri-Food Canada
1 Airport Road, Box 1030, Swift Current, SK S9H 3X2, Canada
| Our study examines differences in heavy metal
and metalloid concentrations in soils and crops across Saskatchewan. Western
Canada is known for production of animal and plant foods in an area largely
free of industrial and other anthropogenic sources of pollution. Therefore
incidents of higher-than-desired levels of heavy metals and metalloids
in agricultural crops are surprising but have occurred, such as the cases
of cadmium in durum wheat, flax, and sunflower, and, most recently in
2006, selenium in yellow peas. Sources of these heavy metals and metalloids
have remained unknown. It is generally assumed that these heavy metals
and metalloids were derived from the soil. Atmospheric deposition may
be another possible source for elevated heavy metals and metalloids found
in crops, as wind-borne particles, sea salt spray, volcanoes, forest fires,
energy production, mining, smelting, refining, manufacturing processes,
waste incineration, transportation, and other natural and anthropogenic
processes emit heavy metals into the atmosphere. How much of these emissions
reach our agro-ecosystems, our crops, and our food chain? Some 30 years
ago, the FAO issued a statement saying that “80% of chronic diseases
are related to pollution”, emphasizing the significance of pollutants
to environmental and human health. Ever since this FAO statement, medical
studies have shown that many chronic diseases may be metal-related, such
as auto-immune diseases, allergies, autism, cancers, inter alia. The objective
of our research study is to identify potential heavy metal point, area,
and/or line sources in agricultural production systems by surveying the
major food and feed crops including corresponding soil samples for possible
heavy metal and metalloid accumulation across the province of Saskatchewan.
The installation of four heavy metal monitoring stations in the Saskatchewan
agroecosystem is envisioned to determine atmospheric deposition of heavy
metals and metalloids onto agricultural soils and crops.
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