BIOACCUMULATION OF VARIOUS ELEMENTS IN AQUATIC AND TERRESTRIAL MACROINVERTEBRATES NEAR AN ACTIVE NORTH CAROLINA COAL-ASH POND

Macroinvertebrates are an integral part of the food web. They link terrestrial and aquatic ecosystems, and are important indicators of stream health. Coal ash is a by-product of coal combustion that may contain many potentially toxic elements including arsenic, cadmium, chromium, and selenium, which in turn can have negative effects on macroinvertebrate communities through chemical stress and reproductive failure. Aquatic, predatory terrestrial (specifically, spiders), and non-predatory terrestrial macroinvertebrates were collected using kicknets, sweepnets, and flying-intercept traps at two independent streams near the coal-ash pond of an active coal-fired power plant in NC, and at two hydrologically disconnected ‘control’ streams. Sample collection took place from May 2015 through September 2015, and in June 2016. The macroinvertebrates and spiders were processed using a modified EPA 3052 method for total digestion of biota, and analyzed for cadmium, chromium, lead, and selenium using inductively coupled plasma mass spectrometry (ICP-MS). Concentrations of all elements in aquatic macroinvertebrates at the two streams near the coal ash pond were higher than the those found in samples collected at the control sites. Concentrations of all elements in non-predatory terrestrial invertebrates at contaminated sites were equivalent to those found at the control sites, but markedly lower than values determined in aquatic and predatory macroinvertebrates from the same sites. There was no noticeable correlation between element concentrations in predatory vs. aquatic macroinvertebrates. These preliminary data suggest that these elements may be accumulating in biota near the coal ash ponds. Future research includes studies involving segregated sampling of aquatic macroinvertebrates and evaluation of potential toxic element bioaccumulation higher in the food web.