PNNL

Abstract

Coal combustion accounts for 40% of the world’s electricity and generates more than a billion tons of coal combustion products (CCP) annually, half of which end up in landfills and impoundments. CCP contains mixtures of chemicals and metals that can be mobile in the environment and impact the quality of surface waters and potable groundwater. In this investigation, water samples from 14 coal combustion management sites across 4 physiographic regions in the U.S., paired with background and down-gradient groundwater samples, were analyzed for the emergence of microbiological and chemical patterns that could be indicative of diagnostic signatures of background groundwater, CCP porewater, and CCP influenced groundwater if present downgradient of the site. 16S rRNA gene amplicon diversity across CCP management sites was high. 95% of amplicon sequence variants (ASVs) were observed infrequently (only 1 sample) and in low relative abundance (ASV average = 0.002%). Ordination plots revealed significant differences (p