150
A detailed USGS study was carried out on 25 different small watersheds in the
Marcellus Shale gas development area of Pennsylvania to evaluate geochemical and
biological effects on streams (Mumford et al. 2020). The intent of this project was
to comprehensively test the hypothesis that quantifiable, significant links exist
between increased density of shale gas development and greater amounts of
fracking- associated chemical compounds in stream water, with associated negative
impacts to aquatic ecosystems.
Measurements were made over a period of 2 years to account for the seasonal
variability of geochemical parameters, and numerous watersheds were sampled to
cover a cross-section of shale gas development intensity. The USGS investigation
found that no statistically significant relationship exists between the presence or
absence of fracked shale wells and any specific chemicals in the streams, including
those recognized as oil and gas “indicators.” The results showed no significant
effects on the microbial or benthic macroinvertebrate communities either (Mumford
et al. 2020).
Several factors may account for the difference in the findings of the Brantley
et al. (2014) Penn State investigation, which did find some stream impacts from
fracking, and the USGS study by Mumford et al. (2020) which did not find any
impacts statistically associated with Marcellus wells. The USGS study was done
randomly over a large area to obtain a statistically significant sample across a gradient of Marcellus Shale development activity. The Penn State investigation was
focused on watershed impacts from reported incidents of spills associated with
Marcellus Shale wells and fracking. Also, the Penn State study was carried out prior
to 2014 during the tail end of the fracking boom in Pennsylvania. The USGS work
was done 5 years later under much less frantic drilling schedules and with far more
experienced rig crews who were presumably less prone to accidents.
In any event, these types of investigations provide a framework for assessing the
intensity of environmental impacts from the anthropogenic development of natural
resources, and suggest an approach for conducting statistically-valid studies that
control variability across land regions and through time. Substantial natural variability in stream chemistry and biota with the seasons and with sampling location
shows the importance of collecting baseline data prior to the start of fracking activities in a watershed. The natural geochemical and biological variability of headwater
streams must be established before the impacts of fracking can be isolated and
measured.
Trying to separate the effects of an anthropogenic activity like fracking from
natural spatial and temporal variability in water chemistry and biology is a major
challenge. It is more complicated in places like Pennsylvania or Ohio where a long
history of legacy anthropogenic activities affect streams. Everything from railroad
construction to coal mining has left impacts that may mask or mimic any signal
from fracking against the natural background. The type of comprehensive, integrated study performed by Mumford et al. (2020) is required to understand the
effects of fracking and shale gas development on watersheds at regional scales.
Fracking is used offshore to improve the performance of conventional wells.
Although there have been no documented impacts to marine life or ecosystems so
8 Impacts to Human Health and Ecosystems
A detailed USGS study was carried out on 25 different small watersheds in the
Marcellus Shale gas development area of Pennsylvania to evaluate geochemical and
biological effects on streams (Mumford et al. 2020). The intent of this project was
to comprehensively test the hypothesis that quantifiable, significant links exist
between increased density of shale gas development and greater amounts of
fracking- associated chemical compounds in stream water, with associated negative
impacts to aquatic ecosystems.
Measurements were made over a period of 2 years to account for the seasonal
variability of geochemical parameters, and numerous watersheds were sampled to
cover a cross-section of shale gas development intensity. The USGS investigation
found that no statistically significant relationship exists between the presence or
absence of fracked shale wells and any specific chemicals in the streams, including
those recognized as oil and gas “indicators.” The results showed no significant
effects on the microbial or benthic macroinvertebrate communities either (Mumford
et al. 2020).
Several factors may account for the difference in the findings of the Brantley
et al. (2014) Penn State investigation, which did find some stream impacts from
fracking, and the USGS study by Mumford et al. (2020) which did not find any
impacts statistically associated with Marcellus wells. The USGS study was done
randomly over a large area to obtain a statistically significant sample across a gradient of Marcellus Shale development activity. The Penn State investigation was
focused on watershed impacts from reported incidents of spills associated with
Marcellus Shale wells and fracking. Also, the Penn State study was carried out prior
to 2014 during the tail end of the fracking boom in Pennsylvania. The USGS work
was done 5 years later under much less frantic drilling schedules and with far more
experienced rig crews who were presumably less prone to accidents.
In any event, these types of investigations provide a framework for assessing the
intensity of environmental impacts from the anthropogenic development of natural
resources, and suggest an approach for conducting statistically-valid studies that
control variability across land regions and through time. Substantial natural variability in stream chemistry and biota with the seasons and with sampling location
shows the importance of collecting baseline data prior to the start of fracking activities in a watershed. The natural geochemical and biological variability of headwater
streams must be established before the impacts of fracking can be isolated and
measured.
Trying to separate the effects of an anthropogenic activity like fracking from
natural spatial and temporal variability in water chemistry and biology is a major
challenge. It is more complicated in places like Pennsylvania or Ohio where a long
history of legacy anthropogenic activities affect streams. Everything from railroad
construction to coal mining has left impacts that may mask or mimic any signal
from fracking against the natural background. The type of comprehensive, integrated study performed by Mumford et al. (2020) is required to understand the
effects of fracking and shale gas development on watersheds at regional scales.
Fracking is used offshore to improve the performance of conventional wells.
Although there have been no documented impacts to marine life or ecosystems so
8 Impacts to Human Health and Ecosystems