Canadian lakes in toxin crisis

15 August 2012

Press reports this week paint a disturbing picture of conditions in all provinces of Canada.  The following excerpt appeared yesterday, dominating the headlines in several papers and journals across the country.

Ottawa, Ontario (August 14, 2012) – Nutrient pollution, one of the greatest threats to our freshwater resources, is responsible for the algal blooms that blanket our lakes and waterways in summer months. Large blooms of cyanobacteria (‘blue green algae’) can cause fish kills, increase the cost of drinking water treatment, devalue shoreline properties, and pose health risks to people, pets, and wildlife. A new paper just published in the Canadian Journal of Fisheries and Aquatic Sciences shows that microcystin, a toxin produced by cyanobacteria, is present in Canadian lakes in every province.

This study is the first to report on microcystin prevalence at a national scale–data from 246 bodies of water across Canada were collected. The authors determined that water quality was most at risk in lakes with the highest concentrations of nutrients. Nutrient-rich lakes and reservoirs, particularly in central Alberta and southwestern Manitoba, proved to have highest toxin concentrations, though all regions in Canada contained lakes that reached microcystin levels of concern.

The survey found nearly 10 per cent of the 256 lakes surveyed had microcystin levels that exceeded Canadian guidelines, even for recreational use.

“Harmful algae blooms are a growing problem worldwide. The more we look, the more we find,” remarked international water expert Dr. Stephen Carpenter, Director of the Center for Limnology at the University of Wisconsin-Madison, “Orihel and colleagues help define the conditions when we would expect highly toxic freshwater. These insights make it possible to focus management and research on the highest-risk situations.”  

“This study addresses an issue that has important health consequences, but also highlights the importance of both the underlying basic science and monitoring programs essential to determine environmental changes,” says Don Jackson, Co-Editor of the Canadian Journal of Fisheries and Aquatic Sciences.

The situation in Canada mirrors that present in many countries right now. China has recently admitted that more than 40% of its rivers are severely polluted and 80% of its lakes are eutrophic!  Here in South Africa. where around 40% of our major dams are eutrophic (we have no lakes worth mentioning), a small group of scientists is about to enter into yet another debate about how to address the burgeoning problem of eutrophication.  A review of this situation will appear in Droplets in the next few days.  As the senior author of the Canadian study observed:

We need to get serious about water quality in these lakes. This is now a human health concern across Canada.” [I am] urging landowners and agricultural producers to take responsibility for the water quality in their own lakes. Improving sewage treatment and restoring natural lakeside vegetation are two moves that would go a long way to reducing microcystin risk, [she] suggested.

Moving to the US, two beaches have been closed at Chautauqua in New York State and Black Lake (also in NY I think) has been placed off limits.  In Texas, Lake LBJ on the lower Colorado River has an algal bloom problem and not-so Crystal Lake has been closed for the remainder of the season, for the same reason.

In the UK, Grovelands Park Lake (North London) also contains potentially-toxic algae.

Finally, a day or so ago I mentioned the mysterious dog death illness in the UK – this in relation to the mysterious death of some deer.  Well, here is an update on what is now termed ‘fatal dog illness’.



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