Answer :

Bioaccumulation is the increased concentration of a pollutant from the environment that effects the first organism in the food chain. Depending upon the pollutant, bioaccumulation can effect a human if levels of the pollutant reaches a toxic state.

For instance, if a large portion of fish in an area were contaminated by a pollutant, and the humans in that area consumed this species of fish regularly, the pollutant would negatively effect the inhabitants in that area that consumed the contaminated fish. Because pollutants in fat are retained and not excreted as easily as water soluble contaminants, the contaminated fish could cause negative heath effects.
Bioaccumulation is when contaminants and poisons show up in trace amounts in producers, and then show up in increasingly higher levels as you move up the food chain. You see, when a contaminated organism is eaten, the predator recieves the contaminant. Since most organisms must eat several others to survive, this toxin accumulates. Humans are at the top of the food chain which means that the food we eat can harm us if it is tainted with something.

Hope this helps!