ASSESSMENT OF TRACE METALS CONTAMINATION IN UPPER MISSISSIPPI RIVER USING ZEBRA 
MUSSEL (DREISSENA POLYMORPHA)

Matthew McDermott and Chulsung Kim
Department of Natural and Applied Science, Univeisty of Dubuque, Dubuque, IA 
52001

Zebra mussel (Dreissena polymorpha) has been considered as a promising 
bioindicator for the evaluation of trace metal contaminations in fresh water 
system. Efforts have been made to determine the bioaccumulation of trace metals 
in zebra mussels in the upper Mississippi River which is potentially exposed to 
abandoned lead mining areas. Five sampling sites were selected to collect zebra 
mussels covering 4 miles long along the Mississippi River shore lines. Collected 
samples were oven-dried followed by acid digestion following EPA 3050B method to 
determine various trace metals concentration such as copper (Cu), manganese 
(Mn), Iron (Fe), cobalt (Co), Nickel (Ni), Cadmium (Cd), and lead (Pb) using 
atomic absorption spectrophotometer. Results confirmed that the zebra mussel is 
a good bioindicator well representing the contamination of trace metals in fresh 
water system. Consistent amount of trace metals were detected in zebra mussel 
regardless the sampling sites except Mn and Fe. Results show that zebra mussels 
are less exposed to Co (0.56 ? 2.06 ?g/g) and Cd (0.56 ? 0.86 ?g/g) than Ni 
(3.77 ?6.29 ?g/g), Pb (4.08 ? 5.80 ?g/g) and Cu (16.80 ? 20.36 ?g/g). For Mn, 
zebra mussel at one site has relatively higher than mussels collected from four 
other sites (117.03, 122.14, 131.62, 184.30, and 381.17 ?g/g) and Fe (234.03 ? 
over 700 ?g/g) concentrations are independent on the location. Both Fe and Mn 
concentrations are high enough concerning trace metal pollution in the upper 
Mississippi River. 

Keywords: heavy metals, zebra mussel, bioindicator, Mississippi