The Canadian Environmental Assessment Agency says there are more than 1,000 potentially toxic metals and compounds in Lake Ontario’s water, and they are spread across thousands of square kilometres.
And that includes contaminants found within the sediments and sediment-bearing rock layers that make up the lake’s bottom, said the agency’s water quality scientist, Mike Leung.
“I think there are some potentially toxic substances in the lake,” he said in an interview.
“They are scattered throughout the bottom layer, and it would be really interesting to know what those are and how they got there.”
The federal government and environmental groups have been asking for a full-scale environmental assessment of Lake Erie, and Leung said it was essential to determine the extent to which contaminants are present.
The EPA is working on the report.
“What we know now is that there are about 1,600 different contaminants in the bottom of Lake Ontario,” he told The Globe and Mail.
“We know that they are dispersed across the bottom, and there are other contaminants that are not in the lakes bottom, but they are all dispersed in the sediment.”
The EPA estimates that about 4,000 of the contaminants were detected in Lake Huron’s waters in 2015.
Leung is the lead researcher for that study, which he is calling the “Lake Huron water contaminants assessment.”
The lake’s sediments, and their contents, are an important part of the analysis.
Leong said the lake sediments are so heavily contaminated that it is hard to identify what contaminants are there.
“There are quite a lot of different things that are in there,” he explained.
“So what we can do is take samples and look at what the contaminants are, and then we can then determine if they are present in the groundwater or the surface water, but also in the water that’s in the ground and in the soil and in those that are suspended up in the air.”
That’s really the key.
“The toxicology team will be looking at a variety of sources of contaminants, and the agency says they will be analyzing the lake through the sediment analysis.”
Lake HurON is one of the largest bodies of water in the United States, and its size makes it difficult to clean up. “
And we are trying to figure out what those contaminants are.”
Lake HurON is one of the largest bodies of water in the United States, and its size makes it difficult to clean up.
Leulong said that since the 1980s, Lake HurON has seen significant development of the area around it, and pollution levels have increased.
“The lake itself is pretty small, so it doesn’t really affect the way we measure things,” he noted.
“In terms of the toxicological tests, they are very sensitive to the type of water that you are trying for, so you really have to look at that.”
Lake Erie’s lake is also one of Canada’s largest freshwater lakes.
Leang said there are hundreds of lakes in Ontario that are comparable to Lake Hurons, and Lake Hurontas unique characteristics are also one that makes it hard to clean.
“It is one that’s a little bit more complicated,” he admitted.
“Its a very unique environment, and so the contaminants that we are getting are very different from the contaminants in Lake Ontarians.”
“It’s really important that we do a full, comprehensive assessment of the lake and its sediment and the contaminants and to see if there are any other contaminants.”
The agency says that once a full environmental assessment is completed, the results will be sent to the provincial and federal governments.
“The results will then be submitted to the Minister of Environment,” Leong explained.
The Lake Huronian Water Quality Assessment is scheduled to be released in September 2019.