The objective of this study was to determine which tailings ponds were the major sources of heavy metals in Big River (Missouri, USA); by using caged pocketbook mussels. Thirty-six pocketbook mussels of similar size were collected from sampling locations and were analyzed for lead and cadmium. Based on the results of this study, the main sources of heavy metals contamination to Big River are from the Desloge tailings pond and the ponds and chat piles located within the Flat River drainage basin. Big River also receives some heavy metal pollution from the Leadwood tailings pond, however, the contribution from this source is not as serious as from the other tailings ponds. The pocketbook mussel worked very well for this study and should work in similar studies.
