Yes! There is evidence that the genetic expression changes in the zebrafish embryos are caused by PCBs.

To confirm your experiment, you must test the water for the presence of PCBs, particularly those found in electrical transformers. To do this, you can use gas chromotography mass spectrometry or GCMS.

PCBs are a very large class of compounds. There are over 200 different PCB chemicals. They are a man-made class of chemicals and do not occur naturally. PCBs were used for lubricating and insulating electrical components because they are very fire resistant. However, because PCBs do not break down in the environment and may harm humans and wildlife, the United States stopped manufacturing PCBs in 1977. However, they are still present in older devices and in the environment.

PCBs bind to the Aryl hydrocarbon receptor (AhR) (aryl – containing an aromatic ring, hydrocarbon – containing hydrogen and carbon) When compounds bind to the AhR, the cell receives a signal to begin transforming the compounds so they can be eliminated from the body. However, this signal can also result in the production of other proteins which may negatively affect cell growth and differentiation. This can result in deformed embryos as you observed in the zebrafish experiment.

Solving the Case of the Missing Fish

Dr. Tanguay contacted Jesse and Lucy about his research findings. They were excited about finding the cause of the disappearing fish in their local river and began investigating ways to restore the contaminated area.

Why Did We Do an Animal Experiment?