On this page:


for lead, from deep warm

aeration, to ensure food safety

before feeding to any child.

Who is liable if fish not tested?

Aeration risk hypotheses:


I served as a member of RM Council's volunteer Killarney Lake Action Committee, providing positive critique during the three years of its hired UM scientist research project to investigate lake phosphorus origins and removal. Then in mid-summer 2017, I wrote all members and mayor with the following discussion relating to their apparent intention to conduct deep lake aeration (... and was then no longer invited to their meetings):

Toxins in Lake Bottoms?

We would be wise to assume the bottoms of lakes may now contain every enduring toxic substance brought by humans. There is thermometer mercury, lead from gasoline, batteries, paints, buckshot and fishline weights, cadmium from tires and fertilizer contamination, bluestone copper, DDT, dioxin, asphalt benzene, gasoline preservatives, asbestos fibers, plastic microfibers, and perhaps antibiotics, synthetic estrogen hormones and natural cyanobacter neurotoxins also in its sediment, all in unknown hotspots at unpredictable concentrations.

It is impossible to use spot sampling of the bottom sediment to ascertain the possible presence of random high concentration hot spots for pollutants. Nor would testing of a few bottom samples for whether oxygenation might release low hazard copper from sediment, be predictive of release of any other more hazardous substances from bottom sediment or organic matter as a consequence of the aeration proposal to add oxygen, heat energy and turbulence via pressurized aeration of the deep lake bottom.

Released pollutants via deep bottom aeration might make the fish not safe to eat.

The wells in town and for about 2 miles to the north are shallow, some were never pumped dry during the 1930's, and the fields internally drain downwards as evidenced by lack of marshes and the natural depressions in fields which in most years can be annually cropped without cutting drainage ditches. As recent as 40 years ago it was mostly oak forest, with oak favoured possibly due to its taproot reaching into the unlimited waters at shallow depth. Killarney Lake might possibly be considered to be a continuous body of water of about three miles diameter, under the town and under the farms to the north. I presume the open water portion may be where the ice age glacier gouged out the rocky hill on its south. This suggests that the town could be considered a floating island on a layer of porous sand/stone inert to reactivity with toxins and nutrients which leach into it, possibly contiguous via springs into the adjacent lake.

When the oak forests to the north were dozed and burned, the depressions for several years were of white soil, maybe ash, in the bottoms which I remember observing as peculiar, but now those depressions are dark black, suggesting the excess nutrients within the white powder have leached down into the aquifer. Fertilizer dealers have had many phosphorus spills over the years. The ground at the coal depot was continuous black through the year. Every home burned imported nutrient-rich wood or coal, and the ashes obviously scattered in backyards for the first half century, as was any liquid garbage just dumped along the back fence, just as did the equipment dealers and repair shops with especially hazardous substances during the early decades. All of the cleaners and solvents and dyes and paints and polishes and pesticides sold in hardware stores have been spilled in town with its surface drains and natural permeable soil draining into the subterranean aquifer likely contiguous with the adjacent lake. For 135 years.

Links to scientific research futher down this page.

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Advertisement Sept 7, 2018:

Analyze all Dead Fish

15 months ago I advised Council's lake committee and mayor of risk of deep lake aeration releasing pollutants from bottom sediment and organic matter. Every dead or unhealthy fish should now be tested for possibility of toxic heavy metals or asbestos fibers etc, and if one is discovered then aeration be ordered to halt and a remediation plan such as aggressive biomass harvest be implemented.

Photograph and put fish in a double freezer bag marked as "hazardous" and refrigerate, for analysis for Pb Cd As Al etc in Winnipeg at Maxxam Lab or ALS Lab or Central Testing Lab. Have reports copied to Manitoba Water Stewardship mws@gov.mb.ca and minsdev@leg.gov.mb.ca, and to local Council info@killarney.ca and to this newspaper, and immediately warn all local fishers.

Testing is URGENT and our avoidance or delay legally negligent.
If your confidentiality is required, I could arrange for analysis.
www.GrantRigby.ca   M.Sc. Food

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Request for Regulation

To: Manitoba Government June 29, 2018
Minister of Sustainable Development (Environment), Minister of Municipal Relations, Minister of Health. Copy: Assoc of Manitoba Municipalities

Lakes belong to all Canadians.
The Municipal Council for the lands adjacent to Killarney Lake has initiated transformation of its ecology by installing air hoses under its greatest depth to bubble air (adding oxygen and heat energy). The stated intent is to "decompose the (ancient) organic matter on the bottom", releasing substances (phosphorus and modern contaminants such as lead, plastic microfibers) into the water. Increasing fish life is presumed the likely beneficial result. The risks include toxins accumulating in fish, and earlier cyanobacteria toxins in water, unpredictably altered from historical. For waterways such as the Pelican River below Ninette into Pembina River, nutrients and toxins from aeration get flushed down to lower lakes to Lake Winnipeg.

Proposed Lake Aeration Regulations:

  1. Living biomass must be harvested and removed in phosphorus amount exceeding the phosphorus potentially released from the bottom organic matter, to recapture its nutrients and hopefully the toxins historically safely sequestered in it.
  2. Fish must not be eaten until continuous testing for all possible toxins confirms 100% food safety.
  3. Cyanobacteria neurotoxin levels must be analysed at all beaches daily and the tourism public warned proactively via signage and website.
  4. Cost of the aeration works, operation, analyses etc. must not be borne by general taxpayer to more than 50% of total costs to governments, with most of total governments' costs recovered by special assessment of benefiting local hospitality and retail businesses serving the sport fishing community.
  5. A democratic lakeshore resident owners association be established, to help provide wiser, more children-focused, balanced local governance for every recreational lake.

Thank you for consideration of appropriate provincial government oversight of lake aeration projects, especially to protect children swimmers and fish eaters from risk of toxins ingestion.

Grant Rigby M.Sc. Food, local farmer www.grantrigby.ca

Consult public sector lake scientists. Harvest cattails.
Search: scholar.google.caKeywords:cyanobacterialake

(The above was placed as an advertisement in Killarney guide newspaper.)

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To: Residents of Killarney Turtle Mountain
(sent via general mail to all on April 11, 2018)

Where should you authorize the "bubblers" be put in your lake?

Evidence to consider: "Two of the five lakes at Fort Whyte Alive have been aerated for several years, and the one with the longest period of aeration is also the most eutrophic, with massive amounts of Aphanizomenon (cyanobacteria) at times" - lake scientist at U. Manitoba.

Visser et al. 2016 "Artificial mixing to control cyanobacterial blooms: a review." Built on review of over 100 peer-reviewed scientific articles, they concluded "A change from cyanobacterial dominance to green algae and diatoms can be observed if the imposed mixing is strong enough to keep the cyanobacteria entrained in the turbulent flow..." Aeration bubbling directly under the neurotoxin-producing blue-green cyanobacteria blooms was the most energy efficient method of mixing the waters to kill them. You can read this easily via: scholar.google.ca, search for "visser cyanobacteria", then click on "since 2014". (UM engineering scientist forwarded this article to aid our considerations.)

The massive rain storm I observed from my farm in July 2016, travelling from NW to SE over long narrow Pelican Lake, might have flushed it clean as the front of fresh new water of different density moved along it from NW to SE pushing much of the floating algae, cyanobacteria, dissolved toxins etc. out its river exit. But we cannot conclude with certainty that the rain event was the primary cause of perceived improvements in water clarity and fish life, because humans had implemented an aeration treatment that they are convinced was the primary cause.

After a few summers of aeration treatment, the phosphorus levels remained high, and both ends of Pelican Lake were still ordered closed to swimming due to cyanobacteria in 2017, at the same time as were Killarney Lake and Rivers Reservoir. But Killarney Lake starts with much higher phosphorus that many scientists correlate with promoting cyanobacteria, yet has no river exit to drain away organisms, toxins and nutrients, and is below an industrial town over a shallow aquifer contiguous with the lake, resupplying it with the fertilizer nutrients and many toxins spilled in town over the last 138 years.

The Risk in Council's decision: Copied from www.healthylake.ca, the Killarney Lake Action Committee's brochure states the "addition of oxygen is to facilitate more decomposition of the organic matter on the bottom". But its decomposition releases more nutrients such as phosphorus and also sequestered toxins that are currently safely contained in that bottom organic matter, such as plastic microfibers and lead from gasoline exhaust via town gutters, buckshot and fishing weights. The unanswered question: Why position aeration bubblers on the deepest bottom to maximally oxygenate the lake, most distantly from toxin-producing blue-green cyanobacteria blooms, and risk predictable biological release from old organic matter of its phosphorus and its safely sequestered toxins, back into biologically-active lake waters, to then bio-concentrate up the food chain into fish eating families?

I participated on the KLAC committee for about three years. Thanks for that opportunity to assist. This letter fulfills my responsibility to stimulate the best planning to protect children from neurotoxins. Further action is the responsibility of each reader. More discussion is at www.GrantRigby.ca

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Scientific Studies

Dr. Richard Grosshans' research work:

Cattail (Typha spp.) biomass harvesting for nutrient capture and sustainable bioenergy for integrated watershed management 2014

Some of Canadian lake scientist Dr. Diane Orihel's research work:

Internal phosphorus loading in Canadian fresh waters: a critical review and data analysis 2017


Many physical, chemical, and biological processes in freshwater ecosystems mobilize the nutrient phosphorus (P) from sediments, which in turn may contribute to the formation of harmful algal blooms. Here, we critically reviewed internal P loading in Canadian fresh waters to understand the geographic patterns and environmental drivers of this important process. From 43 publications, we consolidated 618 estimates of internal P loading from Canadian freshwater ponds, lakes, reservoirs, and coastal wetlands (n = 70). Expressed in terms of total P, short-term gross rates in sediment samples (Lgross) ranged from -27 to 54 mg·m-2·day-1 (n = 461), while long-term net rates in whole ecosystems (Lnet) ranged from -1694 to 10 640 mg·m-2·year-1 (n = 157). The main environmental drivers of this variation were oxygen, pH, geology, and trophic state. Internal P loading tended to be higher during the open-water season and most prominent in small prairie lakes. Priorities for future research on internal P loading should include resolving methodological problems, assessing the relative importance of different mechanisms, examining the influence of anthropogenic activities, and quantifying rates in understudied ecosystems.

Reducing phosphorus to curb lake eutrophication is a success 2016

The "nutrient pump:" Iron-poor sediments fuel low nitrogen-to-phosphorus ratios and cyanobacterial blooms in polymictic lakes 2015

High microcystin concentrations occur only at low nitrogen-to-phosphorus ratios in nutrient-rich Canadian lakes 2012

Dr. Bill Paton (deceased) of Brandon University reported to us that they had earlier discovered for one lake (maybe Blue Lake in Duck Mtn?), that cyanobacteria was restricted by availability of iron supplied into the lake by springs. (The nitrogenase enzyme in nitrogen-fixing cyanobacteria requires an iron atom.)

Some recent work by others:

Iron limitation effects on nitrogen-fixing organisms with possible implications for cyanobacterial blooms 2018

Persistency of artificial aeration at hypertrophic Lake Tuusulanjärvi: A sociohistorical analysis 2017


With present-day scientific evidence challenging the efficiency of artificial aeration as an effective restoration method for eutrophicated lakes, our sociohistorical investigation traces the reasons for the persistent support for this method in Finland, where about one hundred lakes are subject to this treatment. Our study employed the concepts of technological path and aeration frame to analyze the extensive restoration and aeration history of the hypertrophic Tuusulanjärvi in southern Finland. Continuously aerated since 1972, it has the longest history of aeration in Finland. Qualitative analysis of documentary and archival sources revealed that the longstanding preference for aeration in the context of increasing scientific controversy was based on its functional versatility and seemingly unproblematic applicability in regard to shifting emphasis and goal setting of restoration. Additionally, the stability of the aeration frame has been supported by the practical and emotional attachment of local residents to lake restoration, particularly aeration, and finally the problems and contradicting interests related to alternative restoration methods.

The actual role of oxygen deficit in the linkage of the water quality and benthic phosphorus release: Potential implications for lake restoration 2017

Artificial mixing to control cyanobacterial blooms: a review. 2016