Paula M. Zelanko | Geology Reports

USGS2018

Linking otolith microchemistry and surface water contamination from natural gas mining

Unconventional natural gas drilling and the use of hydraulic fracturing technology have expanded rapidly in North America. This expansion has raised concerns of surface water contamination by way of spills and leaks, which may be sporadic, small, and therefore difficult to detect. Here we explore the use of otolith microchemistry as a tool for monitoring surface water contamination from generated waters (GW) of unconventional natural gas drilling. We exposed Brook Trout in the laboratory to three volumetric concentrations of surrogate generated water (SGW) representing GW on day five of drilling. Transects across otolith cross-sections were analyzed for a suite of elements by LA-ICP-MS. Brook Trout exposed to a 0.01–1.0% concentration of SGW for 2, 15, and 30 days showed a significant ( p < 0.05) relationship of increasing Sr and Ba concentrations in all but one treatment. Analyses indicate lesser concentrations than used in this experiment could be detectable in surface waters and provide support for the use of this technique in natural habitats. To our knowledge, this is the first demonstration of how trace elements in fish otoliths may be used to monitor for surface water contamination from GW.

Environmental Pollution↗

USGS2018

Exposure to synthetic hydraulic fracturing waste influences the mucosal bacterial community structure of the brook trout (Salvelinus fontinalis) epidermis

Production of natural gas using unconventional technologies has risen as demand for alternative fuels has increased. Impacts on the environment from waste generated from these processes are largely unexplored. In particular, the outcomes of organismal exposure to hydraulic fracturing waste have not been rigorously evaluated. We evaluated the effects of exposure to surrogate hydraulic fracturing waste (HF waste) on mucosal bacterial community structure of the brook trout ( Salvelinus fontinalis ) epidermis. Brook trout are fish native to streams at risk to HF waste exposure. Here, fish were exposed to four treatments (control, 0.00%; low, 0.01%; medium, 0.10%; and high, 1.0% concentrations) of surrogate HF waste synthesized to mimic concentrations documented in the field. Epidermal mucus samples were collected and assessed 15 days post-exposure to determine if the associated bacterial community varied among treatments. We observed differences in epidermal mucosal bacterial community composition at multiple taxonomic scales among treatments. These community changes reflected compositional differences in taxa dominance and community similarity rather than losses or gains in taxonomic richness. The dominant bacterial genus that explained the greatest variation in community structure between exposed and unexposed fish was Flavobacterium . Two genera associated with salmonid diseases, Flavobacterium and Pseudomonas , were statistically more abundant in high treatments than controls. These results suggest that exposure to low levels of HF waste influences bacterial colonization and may lead to a disruption that favors bacterial populations associated with fish disease.

Pennsylvania↗