Science Buddies: "Ask an Expert"

I am currently working on a research paper on aquatic toxicology for the IB (International Baccalaureate) Extended Essay. Although still in the planning stages, my research paper was originally going to test the effects of organic pesticide copper sulfate compared to one of its conventional pesticide counterpart, such as Bravo Ultrex by Sygenta, on Daphnia.

However, due to IB guidelines I am unable to test on Daphnia as they are considered animals and IB prohibits animal testing. My biology teacher recommended testing on protists such as algae or paramecium instead. So my questions are

1. What are some protists I could use in my research?
2. Are there any better organic and conventional pesticide combinations that would better fit my experiment?
3. How would I need to modify my experimentation methods in order to test the effects on protists? (I wouldn't be able to use the EPA test because that is tailored specifically to Daphnia.)

Thanks for any responses, Vik.

Hello,

Paramecium is a viable protist to use for this experiment and duckweed would also work. There have been many bioassays using paramecium, such as this one I found: https://www.researchgate.net/publicatio ... Pollutants
One method you could use to test the effect on paramecium is to determine the LD50- the lethal dose of 50, which is the amount of the toxin that kills 50% of the population. The pesticides you have proposed seem perfectly fine, but if you want to choose ones that are more relevant to your experiment, you could research ones that are most prevalent in aquatic systems where paramecium is found. Some additional factors you may want to consider when choosing the pesticide are its toxicity, exposure time, dose rate, and persistence in the environment.

Hope this helps in answering your questions!
~Catherine M