The given statement is example of the bioaccumulation.
What is phytoplanktons?
Phytoplankton, a flora of freely floating, often minute organisms that drift with water currents.
Bioaccumulation is the accumulation of contaminants by species in concentrations that are orders of magnitude higher than in the surrounding environment.
Contuining contamination of chemical leads to bioaccumulation in phytoplanktons population.
The reactants are the first two before the arrow and the products are the last two after the arrow, it is not balanced it would look like this if it was balanced:
