Grade 9 Science Journal (2022)

In Grassy narrows, ON (80 km north of Kenora, ON) residents are among the most mercury contaminated waters in the entire province. For generations the residents of these lands have relayed on fishing by Clay Lake which has been extremely contaminated with mercury after a dump of 10tonnes in the 1960’s. Now the average meal of walleye is 15x the daily tolerable intake for adults and 40x the limit for adolescents, pregnant women and children.

Residents of Grassy Narrows have been rightfully frustrated and worry as they claim there has been no action taken towards making their waters once more, safe. It was common for families to fish for and eat the fish in their river, though that is now dangerous to practice.

Here as we head up the trophic levels, the amount of mercury increases by biomagnification; phytoplankton turn the inorganic mercury- organic, which then sticks to the proteins in the organisms, causing an increase as each organism needs more of the last to sustain itself. As the Zooplankton consume plants and phytoplankton, which are then consumed by small fish like trout, by the time we reach the walleye it has about 90x the legally safe consumption amount of mercury. This likely causes an up-rise in walleye population that cannot be consumed.

The mercury pollution here is entirely caused artificially and was preventable. Human activity has made these waters inhabitable to any species that are affected by mercury and lowered the carrying capacity by- quite a bit. The lack of fish being eaten is also likely to throw the environment out of balance.

The environment here is slowly dying due to the extreme exposure, as the clay tends to absorb and contain large amounts of mercury, preventing species from returning it to an organic state.

References;

• https://www.thestar.com/news/canada/2016/11/23/grassy-narrows-residents-eating-fish-with-highest-mercury-levels-in-province.html
• https://oceanservice.noaa.gov/facts/plankton.html#:~:text=Most%20zooplankton%20eat%20phytoplankton%2C%20and,%2C%20right%2C%20and%20blue%20whales.
• https://a-z-animals.com/blog/what-do-walleye-eat-their-5-favorite-foods/#:~:text=Walleyes%20are%20a%20member%20of%20the%20perch%20family.&text=Walleye%20eat%20a%20diet%20that,dawn%20as%20they%20are%20nocturnal.
• https://www.michigan.gov/dnr/education/michigan-species/fish-species/walleye#:~:text=Diet%3A,are%20early%20morning%20and%20evening.
• https://www.lakescientist.com/lake-facts/fish/northern-pike/#:~:text=Newly%20spawned%20Northern%20Pike%20are,or%20other%20land%2Droaming%20carnivores.
• https://www.anglersatlas.com/place/726722/clay-lake#:~:text=Which%20fish%20can%20I%20catch,caught%20here%20are%20Yellow%20Perch.
• https://nereusprogram.org/works/why-is-there-so-much-mercury-in-marine-food-webs-plankton-communities-are-the-first-step-in-bioaccumulation/#:~:text=Zooplankton%20ingest%20phytoplankton%2C%20along%20with,slowly%20than%20they%20ingest%20it.
• https://teachforcanada.ca/en/wp-content/uploads/2017/09/Grassy-Narrows-2019-update.pdf