Enhanced detection of groundwater contamination from a leaking waste disposal site by microbial community profiles

Abstract

[1] Groundwater biogeochemistry is adversely impacted when municipal solid waste leachate, rich in nutrients and anthropogenic compounds, percolates into the subsurface from leaking landfills. Detecting leachate contamination using statistical techniques is challenging because well strategies or analytical techniques may be insufficient for detecting low levels of groundwater contamination. We sampled profiles of the microbial community from monitoring wells surrounding a leaking landfill using terminal restriction fragment length polymorphism (T-RFLP) targeting the 16S rRNA gene. Results show in situ monitoring of bacteria, archaea, and the family Geobacteraceae improves characterization of groundwater quality. Bacterial T-RFLP profiles showed shifts correlated to known gradients of leachate and effectively detected changes along plume fringes that were not detected using hydrochemical data. Experimental sediment microcosms exposed to leachate-contaminated groundwater revealed a shift from a b-Proteobacteria and Actinobacteria dominated community to one dominated by Firmicutes and d-Proteobacteria. This shift is consistent with the transition from oxic conditions to an anoxic, iron-reducing environment as a result of landfill leachate-derived contaminants and associated redox conditions. We suggest microbial communities are more sensitive than hydrochemistry data for characterizing low levels of groundwater contamination and thus provide a novel source of information for optimizing detection and long-term monitoring strategies at landfill sites.

Validation of an Integrative Methodology to Assess and Monitor Reductive Dechlorination of Chlorinated Ethenes in Contaminated Aquifers

“…Results of these statistical analysis suggested that the long term monitoring of both indigenous microbial community and environmental variables significantly reduced the uncertainty about the ongoing processes occurring in the groundwater system (Imfeld et al, 2008;van der Zaan et al, 2010;Kotik et al, 2013;Shani et al, 2013;Yamazawa et al, 2014). Mouser et al (2010) indicated that the followup of a site by direct monitoring of the microbial profiles (without excessive validation by sequencing) was a useful and inexpensive tool for the long-term management of polluted aquifers.…”

Monitoring transitory profiles of leachate humic substances in landfill aeration reactors in mesophilic and thermophilic conditions

“…Even in landfills designed with protection layers, uncontrolled leachate and gas may be released due to defects of the aged liner system. Unattended leachate discharge could pose threats to nearby water bodies and groundwater resources, leading to increased organic loading, concentrated inorganic ion and nutrients, as well as elevated levels of heavy metals and xenobiotic organic compounds [1]. Furthermore, the landfill gas, mainly comprised of CH 4 , CO 2 and some nonmethane organic carbon (NMOC), could result in negative aspects associated with unpleasant odor, explosion, global warming and deleterious health effects [2].…”

Organic contaminant transport and fate in the subsurface: Evolution of knowledge and understanding

“…Mouser et al . [] proposed a strategy for detecting leachate leaks based on changes to microbial populations, which they showed occurred in both the field and laboratory. Data from this same study were used to develop a method for organizing microbial data into groupings reflecting the degree of leachate contamination [ Pearce et al ., ].…”

“…Small [1997] developed a method for using monitoring well data to assess the probability of leakage given the facility design features and the probability that an increase in a particular constituent is indicative of a leak. Mouser et al [2010] proposed a strategy for detecting leachate leaks based on changes to microbial populations, which they showed occurred in both the field and laboratory. Data from this same study were used to develop a method for organizing microbial data into groupings reflecting the degree of leachate contamination [Pearce et al, 2011].…”