After prolonged warm temperatures, and with lower water levels, there are increased levels of algal growth and aquatic plants in the beach area. testing has not been performed, but visual inspections are consistent with green algae (cotton candy texture - possibly gutweed or grass kelp) and not consistent with blue-green algae (spilled paint appearance). green algae does not release toxins, although they can deplete oxygen in water causing fish kills.
if you have further observations or information, please feel free to contact me at cpcadan@gmail.com
good information is available from ottawa riverkeeper here:
https://www.ottawariverkeeper.ca/beach-closures-and-blue-green-algae/#:~:text=these%20blooms%20disappeared%20quickly%20and,late%20may%20and%20early%20october.