One researcher from Aurora College, Mike Palmer, has been involved in research about how sunlight transforms toxic arsenic found in groundwater into a less-toxic form.
The lead researcher, Marc Amyot from L’Université de Montréal, had the idea that drove the study eight years ago. While the data collection was slow going at first, in the last two years the research really started to pick up, Amyot said.
“We started the research a long time ago, it was just an idea in my head,” he said. “Whenever we had the occasion of collecting some waters that were of interest, we did it, and then we did the experiments on the side.”
There were a total of six researchers involved on the project.
Palmer said he got involved from working on similar projects in the past. He said they did a seasonal investigation of what was happening in lakes but they couldn’t get at the process behind arsenic transforming into a less-toxic form which was what Amyot was researching.
“Under ice, you can have pretty large increase in arsenic and kind of the change in the form of arsenic that happens under ice, but what we also noticed was a large increase in ice and this rapid transition back to this less-toxic form in spring.”
Amyot said there are two forms of arsenic (As) found in the water, arsenite or As+3 – the more toxic variety – and arsenate or As+5, which is less toxic and less mobile.
Amyot knows that arsenic is an important issue in Northern Canada, particularly in the lens of a changing climate.
He added, “with climate change, you have changes in rainfall and hydrology and permafrost dying, so there are a lot of things happening in the North and it’s important to look at how these changes will affect the movement of toxic arsenic in the environment.”
Amyot said there has been research in the past using light to transform arsenic to clean drinking water in Bangladesh, so he and the research team applied those findings to the Northern environment. It’s the first study of its kind to look at light can modify the form of arsenic in Northern Canada.
They took samples from water around Yellowknife from Handle Lake, Baker Creek, Lower Martin Lake and Long Lake but they also grabbed samples from water in Northern Quebec as well.
They observed that when the arsenic was in the dark there were no changes and when it was in the light the changes happened very quickly, “in a matter of hours,” Amyot said.
“In the samples that were kept under light, there was a lot happening and it was happening very fast,” he said. “After that, we looked at the what can increase the speed of this process and what can decrease it.”
Amyot said the research is just in the phases of lab-based research the “powerful process” was impressive was to see, “like the fact that you keep it in the dark, you see nothing, but when you put it under a light you see very fast oxidation, it was very impressive.”
Palmer appreciated how the team’s research “really adds a piece to the puzzle of understanding about how lakes recover from arsenic pollution in the Yellowknife area.”
Amyot said the next step is to go back and look at the lakes, repeating the exposure to solar radiation in the lake itself instead of using samples, which will help them answer the big question, which is “is the process really important in the labs or in was it only important in the lab?”
“We know our understanding of how lakes recover is really built on a lot of different studies and so it is important that we have field-based investigations (to) measure things how they are,” Palmer said, noting sometimes there is difficulty repeating processes in the field.
Though Amyot doesn’t expect this process to be used in the short-term in Yellowknife, he says the process could be a way to clean up the water in some places with arsenic for different remediation projects in other countries, like Bangladesh.
Palmer said, “when we want to understand how lakes recover, we have to understand how lakes recover naturally in the system that we live in.”
He added, “once we understand the components of the things that are controlling recovering in these lakes and maybe we can can think about specific remediation options – where we can enhance these processes and remove some of these processes that isn’t helpful in terms of recovery for lakes.”
Amyot said “the real value of the work it is really targeted in helping people predict how arsenic changes forms in the environment. It was not really designed to clean up the water, it’s not exactly the same purpose.”