Explain what happens to contaminants and environmental pollution (such as mercury) as you move down and up the ecological pyramid (what is this called?).
Biomagnification is the term
If you go up in the ecological pyramid, you see that synthetic contaminants, heavy metals and metalloids are in higher concentration in living organisms.
According to Medical Dictionary, biomagnification is: "The increasing concentration of a substance, such as a toxic chemical, in the tissues of organisms at successively higher levels in a food chain".
As far as I know, there is no term used as acronym of biomagnification.