Improving Water Quality & Understanding Our Limitations
presented by: Shirley French, DCLA Member and Limnologist
This presentation was delivered on October 27th, 2020 for the members of the DCLA. It addresses an issue of great importance to all of us: the Water Quality in our Lakes. Shirley provides fact-based results and observations pertaining to what is causing the quality of our water to decline and what we might be able to do to remediate the situation.
Shirley finished an M.Sc. many decades ago from UBC where she was studying zooplankton in a marine environment. For the past 10 years she has had part time work at Queen's in the Nelson Lab where she has collected and analyzed data from lakes at the Queens Biology Station(QUBS). She also conducted her own study on Daphnia at Round Lake (QUBS) to answer some questions that she had. In 2019 she helped Allen Tian collect samples, along with other students, and that led to a workshop conducted for the Kingston Field Naturalists. Shirley had looked at the Blue Green Algae samples under the microscope to see what species were dominant in Milburn Bay while the students did their eDNA and cyanotoxin experiments. She really enjoyed working with these students since they were open to changing their preconceived ideas. It is so important in research to let the data tell you what is going on and not to let your bias come into play. "That is harder than one might think".
The DCLA would like to thank Shirley for the thorough research she did in order to arrive at this fascinating, thought provoking and sobering presentation. Please read the addendum below, provided by Shirley which is based on some questions that were asked after the video. Shirley provided responses at that time and then later, modified her answer based on some further research she conducted; like a true scientist!
This video represents the opinions of the author/speaker as of Friday January 15, 2021 and is subject to change without notice. The information contained therein is for general informational purposes only. Dog and Cranberry Lakes Association assumes no responsibility for any reliance on, misuse of, or omission of any information contained in this video; and does not warrant or make any representations regarding the information contained therein in terms of its correctness, accuracy, timeliness, reliability or any loss or damage that results from its use.
ADDENDUM to DCLA Water Quality workshop:
LPP (Lake Partner Program) sampling stations are estimates of station location. They are based on shortened latitude and longitude values provided by the LPP database.
Question: Person had heard that aluminum sulfate (AlSO4) was an effective additive for removing excess phosphates from water. Could we use this chemical addition in Dog or Cranberry Lake?
Answer (researched): The addition of AlSO4 will readily bind to phosphorus and we have excessive amounts of phosphorus in our water and sediment. The intention is for the aluminum phosphate compounds to settle into the sediment and get buried. A new application would be needed when new sources of phosphorus were to come into the lake system. Adding metals into to the environment, such as Aluminum, has three major drawbacks regarding Dog and Cranberry Lakes.
- Bioaccumulation of aluminum in fish tissues can be toxic (worldwide studies, for eg. Washington State fish kills 2008 after adding AlSO4; Catfish and Tilapia with elevated (Al) levels in Africa).
- The south end of Dog Lake and Cranberry Lake are shallow basins and therefore one of our challenges is to keep the sediment from being stirred up. Pulling out macrophytes with boat propellers and/or windy weather, readily stir up phosphorus particulates lying within/on the sediment. Therefore, aluminum compounds would be stirred up in a similar manner.
- Undetermined human health costs since some studies indicate that elevated aluminum levels can contribute to dementia and Alzheimer’s disease. A potential drinking water issue besides the concern of people eating fish.
Question: There is an embayment next to our property should I plant cattails to take up excess phosphorus?
Answer (approximately): Cattails do take up excess amounts of phosphorus (P) quite effectively therefore they are a good choice for the floating treatment platforms. However, at the end of the growing season they need to be removed from the system. Instead, I recommended willows such as our native Pussy Willow. I stated that Pussy Willows (Salix discolor) take up phosphorus and store it in their stems. As the leaves die in the fall phosphorus (P) is sent back to the stems and when the leaves decompose, much of the (P) is not therefore recycled back into the system.
Wary withdrawal: I had another look at the research paper on Willows that I was referring to in my answer above (this particular study compared Willow (P) uptake, to Poplar (P) uptake). It was a hybrid (S. discolor x S. dasyclados; pussy willow x bluestem willow) that performed best in the phosphorus experiments. However, the researchers emphasized that the willows were inconsistent in their performance and therefore no guarantee that one plant type will perform as well as the next. The Pussy Willow that was tested did not perform as well as the hybrids. So, I retract my recommendation, I do not want to mislead people to think that this is a better bioremediation plant than it may be.
- Habitat and food for wildlife
- Slows down water movement (you may not want this result), helps prevent erosion of shoreline
- Takes up phosphorus, most in the roots, next the leaves and the least in rhizomes
- This plant can take up other pollutants such as metals