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Macroinvertebrate Assemblage Response to Contaminated Sediment Remediation in a Lacustuary System
Citation:
Fritz, K., M. Mills, Jim Lazorchak, AND W. Thoeny. Macroinvertebrate Assemblage Response to Contaminated Sediment Remediation in a Lacustuary System. 2018 Annual Meeting of the Society for Freshwater Science, Detroit, Michigan, May 20 - 24, 2018.
Impact/Purpose:
This long-term study assessed the potential impact of a remediation action (contaminated sediment dredging) had on the macroinvertebrate assemblage of the lower Ottawa River within the Maumee River Area of Concern.
Description:
Degradation of benthos is a common beneficial use impairments (BUI) at Great Lakes Areas of Concern (AOCs), including the Maumee River, northeastern Ohio. Ottawa River is part of the Maumee River AOC, and has been altered by urban and industrial activities. Contaminated sediment was dredged from the Lower Ottawa River Lacustuary (LORL) in 2010. Lacustuaries are transition zones where rivers flow into lakes. Macroinvertebrate were collected with multi-plate samplers from remediation and control stations before (2007 and 2009) and after dredging (2010 to 2013 and 2015). Before-After Control-Impact analysis did not detect differences in Lacustuary Invertebrate Community Index (LICI) scores or individual metrics before and after the remediation between the control and remediation stations. A higher percent abundance of collector-gatherers at remediation stations than at control stations was detected across all years. The LICI scores along the LORL fluctuated between Very Poor and Poor status. The LORL remediation has, thus far, not had a positive or negative impact on the macroinvertebrate assemblages based on the LICI scores. Further efforts, such as removal of combined sewer overflows and restoration of physical habitat, may be needed to achieve the BUI restoration goal.
