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Phase II Investigation of Sediment Contamination in White Lake
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GL975368-01-0 -
February 2004
EPA-905-R-04-001
View the Report (2,568kb)
Disclaimer
The U.S. Environmental Protection Agency through its Great Lakes
National Program Office funded the project described here under
Grant GL-975207 to Grand Valley State University. It has not
been subjected to Agency review and therefore does not
necessarily reflect the views of the Agency, and no official
endorsement should be inferred.
Reference
herein to any specific commercial products, process or service
by trade name, trademark, manufacturer or otherwise, does not
necessarily constitute or imply its endorsement, recommendation,
or favoring by the United States Government. The views and
opinions of the authors expressed herein do not necessarily
state or reflect those of the United States Government, and
shall not be used for advertising or product endorsement
purposes. |
Executive Summary
A Phase II investigation of the nature and extent of sediment
contamination in White Lake was performed. Sediment chemistry,
solid-phase toxicity, and benthic macroinvertebrates were examined
at 21 locations. Since chromium was previously identified as the
major contaminant in the sediments, experiments were conducted to
determine the accumulation of the metal in zebra mussels,
macrophytes, and chironomids. In addition, three core samples were
evaluated using radiodating and stratigraphy to assess sediment
stability and contaminant deposition. High levels of chromium were
found to cover a majority of the lake bottom and to extend 8 km from
Tannery Bay. All locations sampled west of Tannery Bay exceeded the
Probable Effect Concentration (PEC). Most of the chromium was found
in the top 51 cm of the core samples. High concentrations of PCBs
were found near the outfall of the former Occidental/Hooker Chemical
facility. These levels also exceeded PEC guidelines. Sediment
toxicity was observed in the east bay area and at the
Occidental/Hooker Chemical outfall. Toxicity near the
Occidental/Hooker Chemical outfall was probably due to the presence
of PCBs. No obvious toxicant was present in the sediments from the
east bay. While no relationship was previously observed for total
chromium and amphipod toxicity, a significant correlation was found
for the organically bound fraction and the metal. Elevated levels of
organic chromium were found in archived sediments from Tannery Bay.
Benthic macroinvertebrate communities throughout White Lake were
found to be indicative of organically enriched conditions. The
locations in the east bay were significantly different than
reference sites, as indicated by a shift to chironomids that were
predators and sprawlers. Chironomid populations in the remainder of
the lake were burrowers and detritivores. Higher densities of
nematodes and reduced tubificids populations were associated with
the stations with elevated chromium levels (> 400 mg/kg). The metal
also was correlated with an increase in the trophic status of
chironomid populations. Chromium accumulation was observed in
chironomid populations throughout White Lake. In addition,
macrophytes and zebra mussels in Tannery Bay were observed to
accumulate the metal in their tissue.
All of the stratigraphy cores showed uniform levels of chromium
deposition in the top 10 - 15 cm. This pattern suggested that a
constant source of chromium was present in White Lake. A standard
exponential decay pattern was absent in the lower sections of the
cores, indicating that historical changes in sedimentation were
caused by episodic events. These data coupled with chromium
contour maps and the generalized circulation pattern of the lake
were used to elucidate the fate and transport of the metal. The
proximity to the drowned rivermouth currents at the Narrows and the
wind induced resuspension in the bay provided conditions that
facilitated the advection and dispersion of a sediment plume 8 km
from its source. Higher concentrations of chromium were found in
the three deep deposition basins (300-500 mg/kg). In contrast, the
PCBs discharged by the Occidental/Hooker Chemical outfall remained
within 100 m of the outfall pipe. The depth of the discharge (15 m)
plus the depositional nature of the discharge zone acted to confine
the contaminants to a small area. The removal of contaminated
sediments in Tannery Bay and the Occidental/Hooker outfall were
completed by October 2003. Both remedial actions are essential for
the recovery of White Lake. Remediation at Tannery Bay removed the
ongoing source of chromium contamination while dredging the
Occidental/Hooker outfall reduced the amount of bioaccumulative
compounds in the lake.
For further information regarding this report, contact:
Dr. Marc Tuchman
U. S. Environmental Protection Agency
Great Lakes National Program Office
77 West Jackson Boulevard
Chicago, Illinois 60604-3590
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