Contaminated Sediments Program
- Great Lakes Monitoring
- Monitoring and Assessment Water Quality
- Global Earth Observation System of Systems (GEOSS)
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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.
Phase II Investigation of Sediment Contamination in White Lake
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