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Preliminary Investigation of the Extent of Sediment
Contamination in Muskegon Lake
Executive Summary
A preliminary investigation of the nature and extent of sediment
contamination in Muskegon Lake was performed using Sediment Quality
Triad methodology. Sediment chemistry, solid-phase toxicity, and
benthic macro-invertebrates were examined at 15 locations. In
addition, three core samples were evaluated using radiodating and
stratigraphy to assess sediment stability and contaminant
deposition. High levels of cadmium, copper, chromium, lead, and
mercury were found in the Division Street Outfall area. These levels
exceeded the Probable Effect Concentrations (PECs) for current
sediment quality guidelines. Most of the heavy metals were found in
the top 80 cm of the core samples. Deeper layers of contamination
were found only near the former Teledyne foundry and down stream
from Ruddiman Creek. High concentrations of PAH compounds were found
at a lakeshore industrial area formerly occupied by a manufactured
gas facility, an iron foundry, commercial shipping docks, a rail
yard, and a coal storage facility. These levels also exceeded PEC
guidelines. Sediment toxicity was observed at two stations in the
Division Street Outfall area and at the lakeshore industrial site.
These locations had the highest concentrations of metals and PAH
compounds respectively. Benthic macro-invertebrate communities
throughout Muskegon Lake were found to be indicative of organically
enriched conditions. The locations in the Division Street Outfall
area were significantly different than reference sites with respect
to fewer numbers and a smaller population of detritivores.
Sediment Quality Triad diagrams were prepared and significant
correlations were obtained between chemistry and toxicity and
chemistry and diversity (p < .01). Toxicity and diversity also were
positively correlated (p < .05). Based on the results of this
investigation, the Division Street Outfall and the location down
gradient from the lakeshore industrial site are priority areas for
further investigation and potential remediation due to adverse
ecological effects, toxicity, and high contaminant levels.
Stratigraphy and radiodating analyses conducted on sediment cores
provided important information related to depositional history.
Ruddiman Creek appears to have a significant influence on the
deposition of heavy metals in the southwestern part of Muskegon
Lake. A peak in metals deposition was found that corresponded to the
100+ year flood that occurred in 1986. The historical deposition was
considerably higher than current rates. The deep zone off the Car
Ferry Dock was not found to be an area that accumulates sediments.
High inventories of 210Pb were found near the bottom of this 80 cm
core, indicating active mixing and movement of sediments. The
presence of elevated metals in the deeper strata plus the high 210Pb
inventories suggest that contaminated sediments are moved from the
eastern part of Muskegon Lake to this location where they are mixed
and made available for resuspension by the currents traveling along
the old river channel. The core from the Division Street Outfall
showed relatively stable sediments in the top 20 cm followed by a
stable zone of heavy accumulation after 1960. Based on these results
it is apparent that the removal of contaminated sediments from
Ruddiman Creek and the lagoon would reduce the loading of heavy
metals to western Muskegon Lake. The areas of high sediment
contamination in the eastern part of the lake also appear to be
mixed and subject to transport.
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