ArticlePublisher preview available

Fracked ecology: Response of aquatic trophic structure and mercury biomagnification dynamics in the Marcellus Shale Formation

Authors:
Christopher J. Grant at Juniata College
Christopher J. Grant
Allison Lutz at Trout Unlimited
Allison Lutz
Aaron Kulig at Temple University
Aaron Kulig
Mitchell R. Stanton
Mitchell R. Stanton
Mitchell R. Stanton
  • This person is not on ResearchGate, or hasn't claimed this research yet.
Read publisher preview
Download citation
To read the full-text of this research, you can request a copy directly from the authors.

Abstract and Figures

Unconventional natural gas development and hydraulic fracturing practices (fracking) are increasing worldwide due to global energy demands. Research has only recently begun to assess fracking impacts to surrounding environments, and very little research is aimed at determining effects on aquatic biodiversity and contaminant biomagnification. Twenty-seven remotely-located streams in Pennsylvania’s Marcellus Shale basin were sampled during June and July of 2012 and 2013. At each stream, stream physiochemical properties, trophic biodiversity, and structure and mercury levels were assessed. We used δ15N, δ13C, and methyl mercury to determine whether changes in methyl mercury biomagnification were related to the fracking occurring within the streams’ watersheds. While we observed no difference in rates of biomagnificaion related to within-watershed fracking activities, we did observe elevated methyl mercury concentrations that were influenced by decreased stream pH, elevated dissolved stream water Hg values, decreased macroinvertebrate Index for Biotic Integrity scores, and lower Ephemeroptera, Plecoptera, and Trichoptera macroinvertebrate richness at stream sites where fracking had occurred within their watershed. We documented the loss of scrapers from streams with the highest well densities, and no fish or no fish diversity at streams with documented frackwater fluid spills. Our results suggest fracking has the potential to alter aquatic biodiversity and methyl mercury concentrations at the base of food webs.
Overview map showing general location of 27 streams sampled in northwestern Pennsylvania during summer 2012 and 2013. Insets show watersheds delineated and outlined upstream of each sampling point. Blue outlined watersheds indicate study sites where hydraulic fracturing has not occurred by the time of sampling, and red outlined watersheds indicate study sites where fracking has occurred within the watershed before sampling. Watersheds with a documented frack water spill are denoted by red outline and grey striped fill pattern. For each watershed, permitted unconventional wells that were not fracked by sampling are designated by open circles, while blackened circles indicate unconventional wells that were fracked prior to sampling. Open triangles indicate permitted conventional oil wells within each watershed (see online version for color figures)
Overview map showing general location of 27 streams sampled in northwestern Pennsylvania during summer 2012 and 2013. Insets show watersheds delineated and outlined upstream of each sampling point. Blue outlined watersheds indicate study sites where hydraulic fracturing has not occurred by the time of sampling, and red outlined watersheds indicate study sites where fracking has occurred within the watershed before sampling. Watersheds with a documented frack water spill are denoted by red outline and grey striped fill pattern. For each watershed, permitted unconventional wells that were not fracked by sampling are designated by open circles, while blackened circles indicate unconventional wells that were fracked prior to sampling. Open triangles indicate permitted conventional oil wells within each watershed (see online version for color figures)
… 
Biomagnification plot of all 27 streams in Pennsylvania sampled in 2012 and 2013 grouped by the presence (F) or absence (NF) of hydraulic fracturing occurring within their watershed at time of sampling. All δ15N and log MeHg values are means of feeding group per stream and regression of biomagnification rates were done for each group: (NF: adj. R2 = 0.470, P < 0.001, n = 88), (F; adj. R2 = 0.541, P < 0.001, n = 73). The difference in y-intercepts for the F (red dashed line) and NF (blue solid line) groups is significant (P = 0.034). Red squares denote organisms from F group, while blue circles denote organisms from NF group (see online version for color figures)
Biomagnification plot of all 27 streams in Pennsylvania sampled in 2012 and 2013 grouped by the presence (F) or absence (NF) of hydraulic fracturing occurring within their watershed at time of sampling. All δ15N and log MeHg values are means of feeding group per stream and regression of biomagnification rates were done for each group: (NF: adj. R2 = 0.470, P < 0.001, n = 88), (F; adj. R2 = 0.541, P < 0.001, n = 73). The difference in y-intercepts for the F (red dashed line) and NF (blue solid line) groups is significant (P = 0.034). Red squares denote organisms from F group, while blue circles denote organisms from NF group (see online version for color figures)
… 
Boxplots of macroinvertebrate diversity indices, fish diversity, and brook trout abundance from 27 streams in Pennsylvania sampled in 2012 and 2013, grouped by the presence (F in red) or absence (NF in blue) of hydraulic fracturing occurring within their watershed at time of sampling. P-values reflect Student’s T test significance. a) Ephemeroptera, Plecoptera, and Trichoptera (EPT) macroinvertebrate richness was marginally lower for the F group (P = 0.076). b) Index for Biotic Integrity (IBI) scores for macroinvertebrates were significantly lower for the F group (P = 0.013). c) Shannon-Wiener diversity index for macroinvertebrates was not different between groups (P = 0.249), d) Simpson’s fish diversity was not different between groups (P = 0.348), and e) brook trout abundance was not significantly different between groups (P = 0.273) (see online version for color figures)
Boxplots of macroinvertebrate diversity indices, fish diversity, and brook trout abundance from 27 streams in Pennsylvania sampled in 2012 and 2013, grouped by the presence (F in red) or absence (NF in blue) of hydraulic fracturing occurring within their watershed at time of sampling. P-values reflect Student’s T test significance. a) Ephemeroptera, Plecoptera, and Trichoptera (EPT) macroinvertebrate richness was marginally lower for the F group (P = 0.076). b) Index for Biotic Integrity (IBI) scores for macroinvertebrates were significantly lower for the F group (P = 0.013). c) Shannon-Wiener diversity index for macroinvertebrates was not different between groups (P = 0.249), d) Simpson’s fish diversity was not different between groups (P = 0.348), and e) brook trout abundance was not significantly different between groups (P = 0.273) (see online version for color figures)
… 
Log MeHg concentration response to δ15N and δ13C in 27 streams (n = 414 organisms) sampled in northwestern Pennsylvania during 2012 and 2013. Six trophic groups are distinguished in the multi-dimensional plot. These include brook trout, predatory macroinvertebrates (Predators), crayfish, collector macroinvertebrates (Collector), scraper macroinvertebrates (Scraper), and shredder macroinvertebrates (Shredder). Ward’s (minimum variance) cluster analysis of the brook trout feeding group and ANOVA using standardized variables identified the clustered outgroup (circled), comprised of 11 trout from six unique streams. Red circles indicated brook trout, light blue squares squares indicate predators, orange triangles indicate crayfish, green diamonds indicate collectors, purple diamonds indicate scrapers, dark blue squares indicate shredders, and orange asterisks indicate periphyton (see online version for color figures)
Log MeHg concentration response to δ15N and δ13C in 27 streams (n = 414 organisms) sampled in northwestern Pennsylvania during 2012 and 2013. Six trophic groups are distinguished in the multi-dimensional plot. These include brook trout, predatory macroinvertebrates (Predators), crayfish, collector macroinvertebrates (Collector), scraper macroinvertebrates (Scraper), and shredder macroinvertebrates (Shredder). Ward’s (minimum variance) cluster analysis of the brook trout feeding group and ANOVA using standardized variables identified the clustered outgroup (circled), comprised of 11 trout from six unique streams. Red circles indicated brook trout, light blue squares squares indicate predators, orange triangles indicate crayfish, green diamonds indicate collectors, purple diamonds indicate scrapers, dark blue squares indicate shredders, and orange asterisks indicate periphyton (see online version for color figures)
… 
Figures - available from: Ecotoxicology
This content is subject to copyright. Terms and conditions apply.
A preview of this full-text is provided by Springer Nature.
Learn more
Content available from Ecotoxicology
This content is subject to copyright. Terms and conditions apply.
Ecotoxicology (2016) 25:1739–1750
DOI 10.1007/s10646-016-1717-8
Fracked ecology: Response of aquatic trophic structure
and mercury biomagnification dynamics in the
Marcellus Shale Formation
Christopher James Grant
1
●Allison K. Lutz
2
●Aaron D. Kulig
1
●Mitchell R. Stanton
3
Accepted: 24 August 2016 / Published online: 14 October 2016
© Springer Science+Business Media New York 2016
Abstract Unconventional natural gas development and
hydraulic fracturing practices (fracking) are increasing
worldwide due to global energy demands. Research has
only recently begun to assess fracking impacts to sur-
rounding environments, and very little research is aimed at
determining effects on aquatic biodiversity and contaminant
biomagnification. Twenty-seven remotely-located streams
in Pennsylvania’s Marcellus Shale basin were sampled
during June and July of 2012 and 2013. At each stream,
stream physiochemical properties, trophic biodiversity, and
structure and mercury levels were assessed. We used δ15N,
δ13C, and methyl mercury to determine whether changes in
methyl mercury biomagnification were related to the
fracking occurring within the streams’watersheds. While
we observed no difference in rates of biomagnificaion
related to within-watershed fracking activities, we did
observe elevated methyl mercury concentrations that were
influenced by decreased stream pH, elevated dissolved
stream water Hg values, decreased macroinvertebrate Index
for Biotic Integrity scores, and lower Ephemeroptera,
Plecoptera, and Trichoptera macroinvertebrate richness at
stream sites where fracking had occurred within their
watershed. We documented the loss of scrapers from
streams with the highest well densities, and no fish or no
fish diversity at streams with documented frackwater
fluid spills. Our results suggest fracking has the potential to
alter aquatic biodiversity and methyl mercury concentra-
tions at the base of food webs.
Keywords Aquatic ecology ●Biodiversity ●
Biomagnification ●Hydraulic fracturing ●Stable isotopes ●
Marcellus shale
Introduction
Unconventional natural gas development is on a global
increase with the potential to impact terrestrial and aquatic
ecology. Advancement of unconventional natural gas
development technologies, such as hydraulic fracturing
(fracking), are facilitating the exploitation of natural gas
reserves in many countries (Garvie & Shaw 2015),
including the United States (Entrekin et al. 2011). Despite
widespread fracking in the United States, its influence on
terrestrial and aquatic ecology is not well understood.
Current efforts have shown possibilities of groundwater
aquifer contamination (Llewellyn et al. 2015a) and forest
fragmentation (Drohan et al. 2012). Surface waters also can
be impacted by fracking through changes in physiochemical
properties (Entrekin et al. 2011), microbial communities
(Trexler et al. 2014a), and mercury (Hg) concentrations in
aquatic ecosystems (Grant et al. 2015). This is particularly
concerning, because changes in stream physio-chemistry,
microbial communities, and soluble metal concentrations
can cause cascading changes in aquatic trophic structure and
biomagnification rates (Kelly et al. 2003).
Changes in trophic structure and biomagnification rates
commonly are assessed by comparing the trophic position
of specific organisms, the length of the food chains, and
*Christopher James Grant
grant@juniata.edu
1
Juniata College, von Liebig Center for Science, Huntingdon,
PA 16652, USA
2
Biology Department, Georgia Southern University, Statesboro,
GA 30460, USA
3
Utah Division of Wildlife Resources, Vernal, UT 84078, USA
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
... While very few studies have assessed the impacts of UNGD on headwater ecosystems due to the relatively recent expansion of UNGD and limited regions with UNGD occurring in areas with headwater ecosystems, changes in water chemistry in ecosystems with UNGD activity have been identified. These changes generally correlated to the number of well pads in a watershed and included decreased stream pH, increased dissolved organic matter and mercury concentrations (Grant et al. 2015(Grant et al. , 2016. Further, streams that were disturbed by accidental spill events had dramatic decreases in pH, increases in sedimentation and metal contamination, and were lethal to all life in the stream (Papoulias et al. 2014;Grant et al. 2016). ...
... These changes generally correlated to the number of well pads in a watershed and included decreased stream pH, increased dissolved organic matter and mercury concentrations (Grant et al. 2015(Grant et al. , 2016. Further, streams that were disturbed by accidental spill events had dramatic decreases in pH, increases in sedimentation and metal contamination, and were lethal to all life in the stream (Papoulias et al. 2014;Grant et al. 2016). ...
... Studies have assessed UNGD impacts on biodiversity metrics and stream chemistry, though one measure that has yet to be evaluated is the health of native Brook trout populations that serve as keystone species in many headwater systems (King et al. 2012). Initial studies of UNGD on Brook trout populations determined that mercury concentrations in macroinvertebrates and Brook trout were higher in UNGD impacted ecosystems compared to non-impacted streams (Grant et al. 2015(Grant et al. , 2016. Additionally, exposure to saline fracking waters altered the skin microbial community on exposed trout in an experimental setting, which ultimately may have detrimental impacts on immune function for these trout (Galbraith et al. 2018). ...
Potential biomarkers of endocrine and habitat disruption identified via RNA-Seq in Salvelinus fontinalis with proximity to fracking operations in Pennsylvania headwater stream ecosystems
Article
Full-text available
  • Aug 2022
  • ECOTOXICOLOGY
Unconventional natural gas development (fracking) has been a rapidly expanding technique used for the extraction of natural gas from the Marcellus Shale formation in Pennsylvania. There remains a knowledge gap regarding the ecological impacts of fracking, especially regarding the long-term health of native Brook trout (Salvelinus fontinalis) populations. During the summer of 2015, Brook trout were sampled from twelve streams located in forested, northwestern Pennsylvania in order to evaluate the impacts of fracking on Brook trout. Four stream sites were undisturbed (no fracking activity), three had a developed well pad without fracking activity, and five had active fracking with natural gas production. Liver tissue was isolated from two to five fish per stream and underwent RNA-Seq analysis to identify differentially expressed genes between ecosystems with differing fracking status. Data were analyzed individually and with samples pooled within-stream to account for hierarchical data structure and variation in sample coverage within streams. Differentially expressed and differentially alternatively spliced genes had functions related to lipid and steroid metabolism, mRNA processing, RNA polymerase and protein regulation. Unique to our study, genes related to xenobiotic and stress responses were found as well as potential markers for endocrine disruption and saline adaptation that were identified in watersheds with active fracking activity. These results support the utility of RNA-Seq to assess trout health and suggest detrimental impacts of fracking on sensitive trout populations.
View
... For example, SGD threatens to deplete surface water quantity, alter stream flows, and contaminate surface and ground water in a variety of ways including increasing suspended sediments, turbidly, salinity, and contamination from hydraulic fracturing fluid (Entrekin et al., 2011;Ziemkiewicz & He, 2015). In addition, SGD has been linked to higher levels of mercury in surface waters and in macroinvertebrates (Grant et al., 2015(Grant et al., , 2016. However, surprisingly little is known about the changes to aquatic and terrestrial assemblages and ecosystems (Souther et al., 2014). ...
... Likewise, Keller et al. (2017) in the same area of Pennsylvania found no effect of pad density at relatively low levels (< 0.5 pads/km 2 ) on fish, salamanders, and crayfish. However, Wood et al. (2016) and Grant et al. (2016) found statistically lower quality macroinvertebrate characteristics (i.e., lower genus richness of Ephemeroptera, Plecoptera, and Trichoptera, fewer intolerant taxa, and more tolerant taxa) in forested headwater streams impacted by SGD. Johnson et al. (2015) also found more tolerant taxa in streams closer to well pads, but flood-level flows the following year mitigated that pattern. ...
... Considering hydrological characteristics of streams for water withdrawals (i.e., greater allowances on larger systems, pass-by flow on smaller systems) that may be more resistant to influences of SGD is also important (Johnson et al., 2015;Shank & Stauffer, 2015). Since SGD has similar effects on stream ecosystems as other landscape disturbances, making use of simple best management practices, for example with road construction and sediment management, may significantly reduce or eliminate impairment to streams due to active SGD in central Appalachia (Grant et al., 2016;Johnson et al., 2015). While the threat of sedimentation and other disturbances continues with active construction of unconventional gas infrastructure, threats of water quality contamination will continue also. ...
Patterns in benthic macroinvertebrate assemblages in an active region of unconventional shale-gas development in the western Appalachian Plateau of West Virginia, USA
Article
Full-text available
diverged in similarity downstream compared to upstream of impacts in the first and last years of the study when SGD activity was elevated. Assemblage divergence was related to variation in water quality. Indicator species analysis linked a few key taxa to un-impacted conditions in the first year of the study; tolerant taxa were indicators for impacted conditions later in the study. Our study links SGD to weak negative changes in water quality and benthic macroin-vertebrates, which may have negative consequences to food quality for wildlife that rely on aquatic prey within forested systems.
View
... Decreased stream pH values at F+ streams relative to F-streams are believed to be the result of hydraulic fracturing activities. While watershed characteristics such as wetlands and conifer stands have the ability to significantly decrease stream pH (St. Louis et al. 1994), previous research on these same streams indicated no differences between such characteristics of F+ and F-streams used in this study Lutz et al. 2015;Grant et al. 2016). Others have shown that hydraulic fracturing uses a number of acidic agents and solutions during the extraction of natural gasses (Kharka et al. 2013), and that these agents can reach nearby streams through leaking equipment and impoundments, lateral blowouts and seepage, as well as backflow into the wellhead (Kargbo et al. 2010;Warner et al. 2013). ...
... scrapers) would be the first to disappear (Barbour et al. 1998). Further, lowered stream pH increases solubility of other contaminants, potentially leading to increased bioaccumulation of toxins in higher trophic order fish (Jardine et al. 2013;Grant et al. 2016). ...
Fracked Fish? Effects of Unconventional Natural Gas Extraction on Wild Brook Trout
Article
  • Sep 2017
Unconventional natural gas development and hydraulic fracturing are increasing across the United States due to global energy demands. Research has only recently begun to assess hydraulic fracturing impacts to streams, and very little study has aimed at determining effects on wild trout populations. During June and July 2012-2016, we sampled 32 remotely-located streams in Pennsylvania's Marcellus Shale basin containing Brook Trout Salvelinus fontinalis. At each stream, pH, fish assemblages, and Brook Trout abundance were assessed. All streams either had experienced hydraulic fracturing (F+, n=19) or not yet experienced hydraulic fracturing (F-, n=13) within their watersheds at the date of sampling. Stream pH was significantly lower at F+ sites than F-sites (p=0.009), and was negatively correlated with well pad density (r=-0.495, p<0.001) and well density (r=-0.387, p=0.003). Brook Trout abundance (r=0.266, p=0.005) and fish diversity (r=0.5715, p<0.001) were positively correlated with pH, while fish diversity was negatively correlated with well pad density (r=-0.704, p<0.001) and well density (r=-0.462, p<0.001). Our results suggest that hydraulic fracturing has the potential to affect stream pH, fish assemblages, and wild Brook Trout in their native habitat. Better management strategies (with respect to hydraulic fracturing) are needed to ensure the conservation of wild trout.
View
... Hydraulic fracturing (fracking), which has become one of the region's top extractive industries, causes hydrological changes that can decrease dissolved oxygen, increase deposition of fine sediment, and increase water temperatures (Entrekin et al., 2011;Kiviat, 2013). While there is no research addressing how fracking affects functional diversity of fish communities, spills from fracking sites have been documented to impact fish and macroinvertebrate community compositions (Grant, 2016). Based on results from our study, we recommend further research to understand how fracking may impact fish functional diversity across the region. ...
Fish Community Responses to Environmental and Anthropogenic Conditions in West Virginia
Thesis
Full-text available
  • Aug 2023
While Appalachia is among the oldest region in the world, Central West Virginia watersheds have been impacted by anthropogenic stressors, including extractive mining and timber harvest industries, as well as urban development and agriculture, damns, fracking, mining, and land cover use. This study aims to understand how natural environmental and human altered gradients impact affect diversity of fish communities in streams and rivers throughout Central Appalachia. The first chapter aims to provide insights into the impact of the 2016 low head dam removals on taxonomic and functional fish communities in the West Fork River, West Virginia and the potential benefits and challenges associated with this type of restoration effort. Between September and October 2022, boat electroshocking surveys were conducted on the West Fork River in sites that were previously impounded and sites that are currently impounded by low head dams. Additionally, one year of pre-removal data exists for sport fish species from the summer of 2015. Results from multivariate analysis indicate that current impounded sites and free flowing sites have statistically significant distinct taxonomic and trophic fish communities. Free flowing sites were associated with overall higher taxonomic richness, as well as species abundance of recreational importance including spotted bass, smallmouth bass, and channel catfish. Further, we calculated functional richness indices for the modern impounded and free flowing sites (FRic, FEve, and FDiv). Results from ANOVA comparing indices at the two categories of sites suggest that FRic is higher at free-flowing sites. The second chapter of this study focuses on how environmental filtering from natural and anthropogenic conditions effect functional diversity (FD) of fish communities of mid-order streams. Using morphological traits, FD indices (FRic, FEve, and FDiv) were calculated for each site and evaluated using Bayesian Regression techniques. Our results showed that FD of fish communities are influenced by both natural and human altered environmental conditions, including stream temperature, dissolved oxygen mg/L, turbidity, and percent developed landcover in the catchment. Evidence from this study suggests that enhancing natural flow conditions, especially in highly developed watersheds, is essential for conserving biodiversity and quality of fisheries in West Virginia.
View
... Non Commercial Use threat to all forms of aquatic life in comparison to organic contamination (Szoszkiewicz et al., 2006;Hamidian, Atashgahi, and Khorasani, 2014), which caste less harmful consequences on biota (Szoszkiewicz et al., 2006;Arul et al., 2016); but these are dealt with high biomagnification properties of tolerant aquatic plants (Szoszkiewicz et al., 2006;Abbas, Ahmed, and Tariq, 2013;Bind, Goswami, and Prakash, 2018;Singh et al., 2019;Grant et al., 2016;Harguinteguy, Cirelli, and Pignata, 2014). Thus, unlike organic pollutants, metal toxins are tough to eliminate from ecosystems by itself (Alahuhta et al., 2018). ...
Genus Schizothorax in the Northwestern Himalayas
Chapter
  • Jun 2022
Schizothorax is morphologically, meristically, and economically a very viable and valuable fish genus of Kashmir valley. Wide diversity bolstered with a high market demand makes it a very dynamic entity in the research realms. Schizothorax is intrinsically an herbivore growing to an appreciable 500 odd millimeters in length. It is an abounding source of protein, low saturated fatty acids with a significant omega-3 fatty acid content besides some minerals. However, the genus’ reported attrition is attributed to the gross trespassing of the fish ecosystem by humans through a range of means. The vital cogs accelerating this reported recession in fish numbers is primarily the use of pesticides, the introduction of exotic fish species, construction of dams, and eutrophication of water bodies. Eutrophication, a multipronged factor, has rendered a powerful jolt to aquatic ecosystems impacting the fish at large. There is an urge to redress the decline from the cardinals by comprehensive introspection while chalking out SOPs associated with chemicals, fish conservation methods, and breeding techniques to replenish the dwindling genus from the valley.
View
... Non Commercial Use threat to all forms of aquatic life in comparison to organic contamination (Szoszkiewicz et al., 2006;Hamidian, Atashgahi, and Khorasani, 2014), which caste less harmful consequences on biota (Szoszkiewicz et al., 2006;Arul et al., 2016); but these are dealt with high biomagnification properties of tolerant aquatic plants (Szoszkiewicz et al., 2006;Abbas, Ahmed, and Tariq, 2013;Bind, Goswami, and Prakash, 2018;Singh et al., 2019;Grant et al., 2016;Harguinteguy, Cirelli, and Pignata, 2014). Thus, unlike organic pollutants, metal toxins are tough to eliminate from ecosystems by itself (Alahuhta et al., 2018). ...
View
... Non Commercial Use threat to all forms of aquatic life in comparison to organic contamination (Szoszkiewicz et al., 2006;Hamidian, Atashgahi, and Khorasani, 2014), which caste less harmful consequences on biota (Szoszkiewicz et al., 2006;Arul et al., 2016); but these are dealt with high biomagnification properties of tolerant aquatic plants (Szoszkiewicz et al., 2006;Abbas, Ahmed, and Tariq, 2013;Bind, Goswami, and Prakash, 2018;Singh et al., 2019;Grant et al., 2016;Harguinteguy, Cirelli, and Pignata, 2014). Thus, unlike organic pollutants, metal toxins are tough to eliminate from ecosystems by itself (Alahuhta et al., 2018). ...
View
View
Inland Waters—Rivers: Land Use and Water Quality
Chapter
  • Jan 2021
Land use and land cover (LULC) such as agriculture, urbanization, and natural resource extraction are major determinants of water quality worldwide. Shifts from natural landscapes to anthropogenic LULC drive chemical, physical, and biological aspects of water quality through alterations in catchment hydrology, sedimentation and fluvial geomorphology, habitat structure, nutrient availability, and contaminant pollution. These alterations affect the abundances and diversity of aquatic biota in many ways. Conservation approaches including riparian buffers and restoration of streams and wetlands can partially mitigate the effects of LULC change. However, water protection policies and novel management approaches are needed to safeguard water resources in the face of human population growth, climate change, and landscape conversion.
View
Streamwater Chemistry
Chapter
  • Mar 2021
Chemical variation among streams is primarily governed by the type and composition of rocks in the drainage, and by the amount and chemical composition of precipitation. In addition, human activities can significantly influence the chemical composition of rivers and streams, indirectly by changing land use and the chemical composition of precipitation, and directly by the input of agricultural, industrial, and domestic waste. This chapter focuses on the dissolved major ions (Ca2+, Na+, Mg2+, K+, HCO3-, SO42-, Cl-) and gases (O2 and CO2). Exchange with the atmosphere maintains both gases at close to their equilibrium concentrations in solution, although photosynthesis and respiration have noticeable effects in highly productive systems, and pollution in the form of excessive organic waste can deplete O2 levels. Important causes of pollution of fresh waters includes salinization due to salts used to melt ice from roads and faulty irrigation practices, increased acidity from mine drainage and fossil fuel use, legacy contaminants such as PCBs and DDT, and emerging chemicals of concern such as pharmaceuticals and personal care products, and plastic. Where pollutants occur at sufficient concentrations, their presence is detectable in organism tissue and may significantly limit populations.
View
View
View
Evaluating a groundwater supply contamination incident attributed to Marcellus Shale gas development
Article
Full-text available
  • May 2015
Significance New techniques of high-volume hydraulic fracturing (HVHF) are now used to unlock oil and gas from rocks with very low permeability. Some members of the public protest against HVHF due to fears that associated compounds could migrate into aquifers. We report a case where natural gas and other contaminants migrated laterally through kilometers of rock at shallow to intermediate depths, impacting an aquifer used as a potable water source. The incident was attributed to Marcellus Shale gas development. The organic contaminants—likely derived from drilling or HVHF fluids—were detected using instrumentation not available in most commercial laboratories. More such incidents must be analyzed and data released publicly so that similar problems can be avoided through use of better management practices.
View
Marcellus and mercury: Assessing potential impacts of unconventional natural gas extraction on aquatic ecosystems in northwestern Pennsylvania
Article
Full-text available
  • Apr 2015
  • J ENVIRON SCI HEAL A
Mercury (Hg) is a persistent element in the environment that has the ability to bioaccumulate and biomagnify up the food chain with potentially harmful effects on ecosystems and human health. Twenty-four streams remotely located in forested watersheds in northwestern PA containing naturally reproducing Salvelinus fontinalis (brook trout), were targeted to gain a better understanding of how Marcellus shale natural gas exploration may be impacting water quality, aquatic biodiversity, and Hg bioaccumulation in aquatic ecosystems. During the summer of 2012, stream water, stream bed sediments, aquatic mosses, macroinvertebrates, crayfish, brook trout, and microbial samples were collected. All streams either had experienced hydraulic fracturing (fracked, n = 14) or not yet experienced hydraulic fracturing (non-fracked, n = 10) within their watersheds at the time of sampling. Analysis of watershed characteristics (GIS) for fracked vs non-fracked sites showed no significant differences (P > 0.05), justifying comparisons between groups. Results showed significantly higher dissolved total mercury (FTHg) in stream water (P = 0.007), lower pH (P = 0.033), and higher dissolved organic matter (P = 0.001) at fracked sites. Total mercury (THg) concentrations in crayfish (P = 0.01), macroinvertebrates (P = 0.089), and predatory macroinvertebrates (P = 0.039) were observed to be higher for fracked sites. A number of positive correlations between amount of well pads within a watershed and THg in crayfish (r = 0.76, P P P P P = 0.02), and macroinvertebrate taxa richness (r = −0.60, P = 0.01) were negatively correlated with the number of well pads within a watershed. Further investigation is needed to better elucidate relationships and pathways of observed differences in stream water chemistry, biodiversity, and Hg bioaccumulation, however, initial findings suggest Marcellus shale natural gas exploration is having an effect on aquatic ecosystems.
View
The Energy-Water Nexus: Potential Groundwater-Quality Degradation Associated with Production of Shale Gas
Article
Full-text available
  • Dec 2013
Oil and natural gas have been the main sources of primary energy in the USA, providing 63% of the total energy consumption in 2011. Petroleum production, drilling operations, and improperly sealed abandoned wells have caused significant local groundwater contamination in many states, including at the USGS OSPER sites in Oklahoma. The potential for groundwater contamination is higher when producing natural gas and oil from unconventional sources of energy, including shale and tight sandstones. These reservoirs require horizontally-completed wells and massive hydraulic fracturing that injects large volumes (up to 50,000 m(3)/well) of high-pressured water with added proppant, and toxic organic and inorganic chemicals. Recent results show that flow back and produced waters from Haynesville (Texas) and Marcellus (Pennsylvania) Shale have high salinities (>= 200,000 mg/L TDS) and high NORMs (up to 10,000 picocuries/L) concentrations. A major research effort is needed worldwide to minimize all potential environmental impacts, especially groundwater contamination and induced seismicity, when producing these extremely important new sources of energy. (C) 2012 The Authors. Published by Elsevier B.V.
View
Assessing Impacts of Unconventional Natural Gas Extraction on Microbial Communities in Headwater Stream Ecosystems in Northwestern Pennsylvania
Article
Full-text available
  • Nov 2014
Hydraulic fracturing and horizontal drilling have increased dramatically in Pennsylvania Marcellus shale formations, however the potential for major environmental impacts are still incompletely understood. High-throughput sequencing of the 16S rRNA gene was performed to characterize the microbial community structure of water, sediment, bryophyte, and biofilm samples from 26 headwater stream sites in northwestern Pennsylvania with different histories of fracking activity within Marcellus shale formations. Further, we describe the relationship between microbial community structure and environmental parameters measured. Approximately 3.2 million 16S rRNA gene sequences were retrieved from a total of 58 samples. Microbial community analyses showed significant reductions in species richness as well as evenness in sites with Marcellus shale activity. Beta diversity analyses revealed distinct microbial community structure between sites with and without Marcellus shale activity. For example, operational taxonomic units (OTUs) within the Acetobacteracea, Methylocystaceae, Acidobacteriaceae, and Phenylobacterium were greater than three log-fold more abundant in MSA+ sites as compared to MSA- sites. Further, several of these OTUs were strongly negatively correlated with pH and positively correlated with the number of wellpads in a watershed. It should be noted that many of the OTUs enriched in MSA+ sites are putative acidophilic and/or methanotrophic populations. This study revealed apparent shifts in the autochthonous microbial communities and highlighted potential members that could be responding to changing stream conditions as a result of nascent industrial activity in these aquatic ecosystems.
View
Environmental Chemistry and Toxicology of Mercury
Book
  • Jan 2012
The book that looks at mercury's impact on the planet today. Recent research by the EPA has concluded that one in six women of childbearing age have unsafe levels of mercury in their bodies, which puts 630,000 newborn babies each year at risk of neurological impairment. Mercury poses severe risks to the health of animals and ecosystems around the world, and this book provides the essential information that anyone interested in environmental sciences should know about the fundamentals of the entire mercury cycle. Comprised of four parts that present an overview of mercury in the environment, mercury transformations, transport, and bioaccumulation and toxicology, each chapter of Environmental Chemistry and Toxicology of Mercury includes the basic concepts of the targeted subject, a critical review of that subject, and the future research needs. This book explains the environmental behavior and toxicological effects of mercury on humans and other organisms, and provides a baseline for what is known and what uncertainties remain in respect to mercury cycling. The chapters focus on the fundamental science underlying the environmental chemistry and fate of mercury. This work will be invaluable to a wide range of policy experts, environmental scientists, and other people requiring a comprehensive source for the state of the science in this field.
View
View
Shale gas development and community response: perspectives from Treaty 8 territory, British Columbia
Article
  • Jul 2015
Northeast British Columbia (BC), Canada, is the site of a fast-growing shale gas industry that is a cornerstone of the current provincial government's economic policy. In this paper, we explore the perspectives of local First Nations (members of Treaty 8) regarding governance of this industry, focusing in particular on the experiences of the Fort Nelson First Nation (FNFN). Based on findings from 15 in-depth interviews with staff from four Treaty 8 First Nations, the Treaty 8 Tribal Association, oil and gas companies, and the Government of BC, we argue that current governance processes fail to adequately protect the environment and treaty rights. We also explore the diverse tactics that the FNFN is using to gain influence over shale gas development within its territories as the Nation seeks to achieve “balanced development” that protects the local ecology and treaty rights while maximising local economic benefits. Through an array of tactics and collaboration with diverse actors, the FNFN has been partially successful in challenging industry's social license to operate and has brought the provincial government back to the table to negotiate new decision-making arrangements on a “government to government” basis. Still, the regulation and management of a fast-paced global industry are a vast burden for a small community to bear. The FNFN's work has also shown the need for further research on how local efforts for equitable and environmentally sustainable approaches to shale gas regulation can be scaled up, institutionalised, and used to create political opportunities in other contexts.
View
Linking aquatic and terrestrial food webs – Odonata in boreal systems
Article
  • Jul 2012
1. It is increasingly realised that aquatic and terrestrial systems are closely linked. We investigated stable isotope variations in Odonata species, putative prey and basal resources of aquatic and terrestrial systems of northern Mongolia during summer. 2. In permanent ponds, δ13C values of Odonata larvae were distinctly lower than those of putative prey, suggesting that body tissue comprised largely of carbon originating from isotopically light carbon sources. Presumably, prey consumed during autumn and winter when carbon is internally recycled and/or methanotrophic bacteria form an important basal resource of the food web. In contrast, in a temporary pond, δ13C values of Odonata larvae were similar to those of putative prey, indicating that their body carbon originated mainly from prey species present. 3. Changes in δ15N and δ13C values between larvae and adults were species specific and reflected differential replacement of the larval isotopic signature by the terrestrial diet of adult Odonata. The replacement was more pronounced in Odonata species of permanent ponds than in those of the temporary pond, where larvae hatched later in the year. Replacement of larval carbon varied between tissues, with wings representing the larval isotopic signature whereas thoracic muscles and eggs reflected the δ15N and δ13C values of the terrestrial diet of adults. 4. The results suggest that because of their long larval development, Odonata species of permanent ponds carry the larval signature, which is partly replaced during their terrestrial life. Terrestrial prey forms the basis for egg production and thus the next generation of aquatic larvae. In temporary ponds, in contrast, Odonata species rely on prey from a single season, engage in a prolonged aquatic phase and hatch later, leaving less time to acquire terrestrial prey resources for offspring production. Stable isotope analysis provided important insights into the food webs of the waterbodies and their relationship to the terrestrial system.
View