LETHBRIDGE, Alta. – Agricultural runoff may have created a few problems on the prairies but there’s no need for farmers to take all the heat when it comes to water pollution.
If an ongoing Prairie Farm Rehabilitation Administration study is correct, there is little evidence of widespread water contamination on the Prairies.
“The Prairies may be a low risk zone, they may not be,” said a water quality expert from PFRA.
Brook Harker said there is a public perception that runoff of pesticide residues from intensive agriculture is polluting streams and groundwater. Main waterways appear in good condition but the condition of small streams and lakes is uncertain.
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“We simply don’t yet know what the net effect of agriculture is on non-point water quality,” said Harker in a report. Non-point refers to action like soil erosion and pesticide runoff from ground and air applications.
Harker was one of several speakers who addressed the theme of water quality at last week’s Agricultural Institute of Canada annual meeting in Lethbridge.
Feedlots draining effluent and people using pesticides are considered prime culprits of pollution, but part of the problem stems from public assumptions that studies from the United States or Europe apply here.
People say they want their water to be absolutely pure, so it raises concerns when they hear there may be a few parts per billion of bacteria or chemicals in water, Harker said.
Scientists can detect residues at a level of one part per billion, the equivalent of one teaspoon of sugar in two Olympic-size swimming pools. They don’t know if such low levels of residue are harmful.
“We find the public is receiving very conflicting messages,” Harker said.
The PFRA study so far involves measuring levels of sediment, nitrates, phosphorus, salts and heavy metals in water. Sediment from soil erosion is significant in carrying pollutants along waterways. Phosphorus is a concern in water supplies because it’s a nutrient for the potentially toxic blue green algae.
Some studies have shown lakes including Qu’Appelle Lake, near Fort Qu’Appelle, Sask., were high in phosphorus even before agricultural settlement. Nitrates may also occur naturally at higher levels than previously assumed.
There is also concern agricultural runoff can leave deposits of fecal coliform, a bacteria that can cause dangerous illness like cryptosporidiosis, that killed 30 people in Milwaukee last year after they drank contaminated water.
There are some technical difficulties for researchers studying water quality, Harker said. There may be radically different interpretations of the data, so prairie-wide integration of research is needed.
Research beyond farm wells and municipalities, and greater understanding of how agricultural chemicals travel through water systems are also necessities.
