Atrazine is used extensively in Canada as a pre- and post-emergence weed control agent, primarily for corn but also for rapeseed. Photo: Adobe Stock, Faustasyan .
Atrazine is used extensively in Canada as a pre- and post-emergence weed control agent, primarily for corn but also for rapeseed. Photo: Adobe Stock, Faustasyan.

Atrazine, widely used as a weedkiller, is known to have harmful effects on aquatic wildlife and presents a risk to human health by altering the action of certain hormones. According to Health Canada, it (or its dealkylated metabolites) is one of the most frequently detected pesticides in surface and well water. Health Canada’s maximum acceptable concentration for atrazine in drinking water is 0.005 mg/L. Contamination has been reported in British Columbia, Nova Scotia, Prince Edward Island, Quebec, Ontario and Saskatchewan.

In a study published recently in Water Research, a team of researchers led by Institut national de recherche scientifique (INRS) professor Patrick Drogui compares various processes used to degrade atrazine. The team demonstrates that photo-electro-Fenton (PEF), a hybrid process, is particularly effective for removing low concentrations of atrazine and its byproducts in surface water sampled from agricultural areas. The study marks the first use of PEF in these conditions.

According to a press release, the researchers used a combination of electrochemical, photochemical, and photoelectrochemical processes together in a single reactor. The results were conclusive: over 99% of the atrazine was eliminated after 15 minutes of treatment. After 45 minutes of treatment, the byproducts were all in concentrations lower than the detection limit in synthetic samples. In surface water, anywhere from 96% to 100% of the byproducts were eliminated. The team was even able to observe each phase of degradation for the atrazine byproducts.

“These days, the challenge is to develop low cost industrial technologies that can be used to treat large volumes of water and simultaneously remove micropollutants like pesticides and their metabolites, which can be more toxic than the original compounds,” coauthor of this study Professor Patrick Drogui said.

Researchers say that although PEF is a clean, effective technology, it will take some more work to combine it with a biological treatment process in a water treatment plant and make it more energy efficient. Further research is needed to get a better understanding of how the atrazine degradation mechanisms identified in the study function in the presence of organic matter.

The study is published in Water Research under the title “Removal of atrazine and its byproducts from water using electrochemical advanced oxidation processes.

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