Hi to all!
Water samples were taken last week from Lake Rosalind and Marl Lake.
The results are posted in the chart below with conditions at time of sampling. The lakes are listed by the flow of water thru the lake system (from LR-2 in Lake Rosalind to Marl Lake’s second lake (ML-2)
|
Lake |
Clarity (m) |
Temp (℉) |
Toxin ( µg ) |
|
LR-2 |
3.2 |
75.0 |
1.02 |
|
LR-1 |
2.0 |
79 |
2.05 |
|
ML-1 |
3.0 |
80 |
1.32 |
|
ML-2 |
3.3 |
81.5 |
1.74 |
In order to assist residents in understanding the chart above, Rick Kalte has offered the following explanation:
"A µg is a microgram or one millionth of a gram. µg/L would then refer to a millionth of a gram of the toxin in 1 litre of water...very small units and extremely small amount of toxin. To make it more visual, if you took one drop of toxin and added that drop to an olympic sized swimming pool, the pool would now have 1 microgram of toxin per litre of water (1.0 µg/L). This would be similar to the same concentration in the second lake with the testing results noted above."
The Canadian Drinking Water Standard for microcystin toxins is 1.5 µg/L and below.
The Candadian Recreational Standard for microcystin toxin was changed from 20 µg/L to 10µg/L in 2022.
The weather conditions have been inconsistent with downpours, windy days and completely still days. The wind shifts during the day cause the scums to move back and forth. It is imperative that you check your swim area before entering the water for recreation or allowing pets into the lake.
More conclusions about these results will be forwarded to residents when the Algae Identification tests are completed. At this point it is hard to draw any conclusions regarding the Algae ID although it would appear that the biochar is doing a good job of mopping up the toxins. Biochar can absorb the toxins released when the cells die but not when they are still active in the cells. The lifespan of a B-G algae cell is about 12 hours which means that there should be lots of toxins in the water IF most of the algae is blue-green. In the past, we have had toxin numbers of more than 6 with blooms that were not as significant as we are seeing right now so there is most definitely something happening to the toxins and one conclusion could point to the biochar bags.
**** Disclaimer
It is important to note that these tests represent results from specific testing for microcystin and DO NOT provide broader results for other tests on bacteria, virus or parasitic pathogens. These tests are taken from designated locations on a specific date and time with the possibility of fluctuations in results in other areas of the lake and on other days. The test results are offered as a guide for information purposes only.
The Lake Rosalind/Marl Lake Water Quality Committee bears no responsibility for resident action (swimming, drinking) as a result of these testing reports.
Residents are reminded to keep pets and children out of the water when blue green algae scums are present or water clarity falls below 1m. All residents are advised to never use lake water as a drinking source.