M2 PM Non-Point Source Pollution and TMDLs
Monday, 14 November 2005: 1:50 PM - 5:30 PM in Ballroom 2

(DRO-1117-733955) Detection of high variability in organochlorine and PCB concentrations in water of the Detroit River using a long term mussel biomonitoring data base.

Drouillard, K¹, Haffner, G¹, Leadley, T¹, ¹ Great Lakes Institute for Environmental Research, University of Windsor, Windsor, Ontario, Canada

ABSTRACT- Calibrated freshwater mussel (Elliptio complanata) biomonitors were deployed at six locations in the Detroit River during the open water season over the period of 1996 to 2003. This large temporal data set (n= 544 samples) was interpreted along with additional spatial biomonitoring and sediment quality surveys performed throughout the entire Detroit River during 1999 and 2002. Both mussel biomonitors and sediment surveys identified similar near-shore contaminated regions within the Detroit River indicating that on-going loadings of PCBs to water continue to occur within this system. A toxicokinetic model was used to interpret time-accumulated residues measured in mussel tissues at individual sites and years. Although lipid normalization removed a portion of the site- and time-specific individual variation in mussel exposures, steady state correction of time-accumulated mussel residues failed to remove within site and within-year variation for the majority of cases. There were only a few exceptions (sites and years) where non-steady state, lipid-normalized contaminant residues in mussels followed the expected uptake trajectory predicted by the bioaccumulation model under a condition of constant water concentrations. The above variation was not likely due to artifacts in field deployed mussel toxicokinetic parameters since field validation of mussel PCB elimination kinetics showed comparable results with laboratory toxicokinetic data. These observations implicate considerable variation in PCB water concentrations in the Detroit River during the open water season. Thus, monthly water sampling as routinely performed by high-volume water extraction monitoring programs in this system may be inadequate to characterize PCB loads in the Detroit River

Key words: biomonitor, PCBs, bioaccumulation, water contamination