SUMMARY: Rotifers (Brachionus koreanus) were fed fluorescent microplastic beads of 3 different sizes: 6um, 0.5um, 0.05um. The pictures in this article show how much microplastic was still left inside the rotifers right after eating, after 6 hours, 12 hours, 24 and 48 hours. The rotifers’ growth was affected (and this was dependent on the size of the beads that they ate), as well as their reproduction rates and population size (since these factors are all related). Finally, high levels of reactive oxygen species were found in the rotifers who ate the smallest beads. This in turn also increased the level of enzymes and proteins that regulated reactive oxygen species (by either forcing cell suicide or increasing inflammation).
LESSON COMMENTS: This is a great article for starting the conversation on what happens to plastic waste. How much of the plastic that we use and rinse down the sink are things that we never knew were plastic (microbeads in facewash, for example)? How aware are we of the process of plastic breaking down into smaller and smaller pieces? How much micro and nanoplastic is already inside our own bodies and cells? This paper can also be used when talking about a cell’s response to ROCs, apoptosis, even the digestive system.
Rotifers are microorganisms that are easy to find and large enough to see with a low powered microscope. Sixth through 8th grade students can do labs to find rotifers and teachers can start the discussion on how plastic waste is eaten by these animals.
When looking at water samples, it is not uncommon to find colored thread. These threads are plastic microfibers that come from textiles and they are in all bodies of water, including tap water. Combined with the rotifers, this is a really great way for students to see how prevalent plastic pollution is.
C.-B. Jeong, E.-J. Won, H.-M. Kang, M.-C. Lee, D.-S. Hwang, U.-K. Hwang, B. Zhou, S. Souissi, S.-J. Lee, and J.-S. Lee, “Microplastic Size-Dependent Toxicity, Oxidative Stress Induction, and p-JNK and p-p38 Activation in the Monogonont Rotifer (Brachionus koreanus),” Environmental Science & Technology, vol. 50, no. 16, pp. 8849–8857, 2016.