The statement you provided is actually False.
Biomagnification refers to how toxic substances accumulate in organisms at higher trophic levels, leading to higher concentrations in top predators. However, the last part of your statement incorrectly states that top predators have "increasingly lower concentrations of these substances." In reality, top predators have higher concentrations of these substances due to their position in the food chain, as they consume multiple prey that have already accumulated the toxins.
So, the correct responses to your statement would be:
False.