What type of toothpaste will affect aquatic plants the most?
Sara Yang
Sir Winston Churchill Secondary
Floor Location : M 156 V

Toothpaste is used everywhere as a product to clean our teeth. We use it at least two times daily and many dentists recommend brushing our teeth once after every meal. Not to mention how millions of people use invisalign, a product that straightens your teeth. This product asks you to brush your teeth(with toothpaste) every single time you drink any liquid with colour or sugar, and every time you eat anything before putting the invisalign back on. This product is used for 3 months-2 years and the invisalign itself has to be brushed with toothpaste every night. When I started using this product I couldn’t stop, but wonder how much extra toothpaste I am using and if the toothpaste I’m using is safe for the environment. Although the toothpaste we use goes down the drain and into ocean, it would be affecting salt watered plants and not fresh water; I decided to use freshwater plants because I only wanted to represent the effects.
In my experiment I decided to test out two of the most commonly used brands in North America (Crest and Sensodyne) and one of the most commonly used brands of toothpaste from China and Korea. What I did was I added one tsp of each product into different cups filled with water and two pieces of aquatic plant(Water Thyme). I then waited one week for the toothpaste to fully dissolve in the water and for the plants to absorb the chemicals. I was not able to make graphs for the plants before the last day of the week because taking the plants out and putting it back in may affect the end results. On the last day I took all the plants out of the cups and gently stretched the plants so that I could measure the plants. When I added the Water Thyme into the cups they were all roughly all 9 centimetres, but in the end the results clearly show what type of toothpaste is safer for the environment.
In the end, I have concluded that Crest and O-Zone(Korean brand) affected the plants the most and Sensodyne had barely any effect on the plant growth. The brands that caused most harm, not only killed the plants from top to bottom, but it also dissolved the plants into something like green, yellow slime. If I were to continue this experiment I would like to start testing out the different ingredients in toothpaste to see what type of ingredient it is that is affecting the plants so much.