AWRI Environmental Chemistry
Lake Macatawa, MI
A preliminary investigation of the nature and extent of sediment contamination in Lake Macatawa was performed using Sediment Quality Triad methodology. Sediment chemistry, solid-phase toxicity, and benthic macroinvertebrates were examined at 13 locations. High levels of PAH compounds were found in an area along the southern shore near a petroleum storage facility (LM-7). These levels exceeded the Probable Effect Concentrations (PECs) for current sediment quality guidelines. Sediment toxicity to amphipods (mortality) and chironomids (growth) also was observed at this location in addition to an impacted benthic community. Based on the Sediment Quality Triad, the area around LM-7 should be investigated in more detail to determine the extent of contamination and the need for remediation. With respect to the rest of the lake, significant levels of metals and organic chemicals that exceeded the PEC guidelines were not observed in surficial sediments and core samples. This suggests that from both a current and historical perspective, significant sediment contamination was not present at the locations sampled. Benthic macroinvertebrate communities throughout Lake Macatawa were found to be indicative of organically enriched conditions. Tubificids and chironomids were the dominant taxa groups at all stations. The only areas with Shannon-Weaver diversity above 2 were the control location near Pine Creek and two stations near the mouth of the Macatawa River. These locations contained a greater diversity of organisms with moderate to high pollution tolerance. The remainder of the locations in Lake Macatawa contained mostly pollution tolerant genera comprising fewer taxometric groups. Given the absence of elevated contaminant levels and sediment toxicity in the remainder of the lake, benthic community impacts appear to be related to cultural eutrophication.
Page last modified February 26, 2013