The Movie Chemist
Microplastics, BPA, environment in the series ‘Siren’
There is always a balance in film and TV show to present a consistent story while maintaining enough scientific reality to keep it believable. This balance is often very difficult to achieve. The script writer has to make a choice between the drama of the story and the correctness of the science. If the science is not believable or logical the story falls apart. I was expecting this to be the case on a recent episode of Siren (S3/E7 Northern Exposure) where there was a discussion of the effects of microplastics on those from the water. I was happy to find they actually did a good job of balancing the story with the science.
The microplastics are harmful to the Alaskan mermaids and prevented the chosen ones from being able to transform into a male in order to procreate. This was attributed to BPA (Bisphenol A) in the plastics since “all plastics contain BPA”. The remedy was to clean the water with a ferrofluid made from magnetic iron powder and vegetable oil. It seemed inconceivable that all plastics release BPA and it was hard to envision how the ferrofluid can clean an ocean.
The mention of BPA and plastics is what drew my interest to this scene. Not all plastics contain or decompose down to BPA. The BPA was responsible for disrupting the reproductive system in the mermaids… back to reality, BPA is a suspected endocrine disrupter, meaning that it takes the place of natural hormones. It is possible for BPA to make it impossible for aquatic species to procreate. BPA is not a naturally occurring material but has become ubiquitous in the environment. It enters the environment along several different channels: manufacturing, waste, breakdown of some plastics like polycarbonates and epoxies. BPA as measured has increased in surface waters and is now above the level of what is termed “Predicted No Effect Concentration” (PNEC) in Canada, the European Union and Japan. This is based on information compiled on global assessment of BPA in the environment [Corrales, J., Kristofco, L. A., Steele, W. B., Yates, B. S., Breed, C. S., Williams, E. S., & Brooks, B. W. (2015). Global Assessment of Bisphenol A in the Environment: Review and Analysis of Its Occurrence and Bioaccumulation. Dose-response : a publication of International Hormesis Society, 13(3), 1559325815598308. https://doi.org/10.1177/1559325815598308] In this case the script writer exaggerated the source of the BPA but got the effects correct.
The second part of the scene in Siren focused on cleaning up the microplastics by mixing the water with oil and magnetite. Magnetite is a magnetic form of iron oxide. Robb, Ben and Maddie seemed to have trouble finding magnetite which is a little farfetched as Magnetite can be found in refrigerator magnets, beach sand and cassette or video tapes. The cleanup procedure initially seemed a little farfetched but was actually shown to be possible by an 18-year-old boy from Ireland, Fiona Ferreira. With this idea, he won the Google Science Fair. The idea is sound and works on a small scale but will it work on a larger scale? That’s definitely a possibility. The script writer here used unproven but plausible science in the story. Since the science is unproven, there is more freedom in its use.
Siren just finished its third season with episode 10 on Thursday May 28 on FreeForm. The whole series is currently streaming on Hulu.