Bioaccumulation means an increase in the concentration of a chemical in a biological organism (fish for example) over time, compared to the chemical's concentration in the environment. Compounds accumulate in living things any time they are taken up and stored faster than they are broken down (metabolized) or excreted. HM can enter a water supply by industrial and consumer waste, or even from acidic rain breaking down soils and releasing heavy metals into streams, rivers and ground water [14].