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The Health Effects Institute has attempted to explore and list the knowledge gaps
that remain concerning potential human health risks from shale gas extraction and
fracking. These fall under the three broad categories of (1) risk sources, (2) transport
pathways, and (3) exposed populations (HEI 2019). Each is described in the paragraphs that follow.
Risk Sources Little is known about the probability of environmental releases of
hazardous materials from unconventional, fracked well sites. Risk of release varies
over time and between locations because of differences in geology, changes in
meteorological conditions, and the adoption of different practices by different operators. It can also change due to technological innovations, changing regulations, and
operator response to community concerns. For a true risk assessment, the uncertainty needs to be replaced with a probability function that defines the likelihood,
composition, magnitude, frequency, and duration of releases. This will help quantify the potential for emissions or leakage/spills from different stages in the shale
gas development process.
Environmental monitoring of risk sources would be simplified if some indicator
chemicals, such as methane in air or TDS in water could be used as predictors of
other releases. Long-term emission trends from sources could be monitored with
ground-based or satellite historical observations. The mechanism by which a chemical is released into the air or water must be better understood, be it operational,
accidental, or illegal.
Transport Pathways Variations in local conditions such as meteorology, topography, geochemistry, and hydrology can affect the movement of frack chemicals in air
and water. Some conditions vary over time intervals ranging from hourly to seasonally, and control how gases, vapors and liquids might move from a well site to
expose a nearby population. It is critically important to obtain pre-drilling baseline
data, especially on air and groundwater to distinguish fracking chemicals from other
natural and anthropogenic sources.
An intervention on a transport pathway can stop human populations from being
exposed to potential fracking health risks. For example, keeping a leaking toxic
chemical from trickling into a stream that is used for drinking water will prevent
many health impacts. Closing a vent to stop VOCs from entering the air during a
temperature inversion can prevent the build-up of smog and ozone. In order for this
to work however, the transport pathways must first be identified. If released chemicals can be contained and kept away from vulnerable populations, health risks will
be reduced substantially.
Exposed Populations This is perhaps the most complicated assessment of the three
categories of human health risks. Different behaviors can have a substantial influence on how individuals react to potential exposure to frack chemicals. Smoking,
alcohol consumption, use of certain drugs, poor eating habits, vitamin deficiencies
and many other factors can affect how a person reacts to a chemical. Although one
might expect the rig workers to be the primary exposed group because they are
8 Impacts to Human Health and Ecosystems
The Health Effects Institute has attempted to explore and list the knowledge gaps
that remain concerning potential human health risks from shale gas extraction and
fracking. These fall under the three broad categories of (1) risk sources, (2) transport
pathways, and (3) exposed populations (HEI 2019). Each is described in the paragraphs that follow.
Risk Sources Little is known about the probability of environmental releases of
hazardous materials from unconventional, fracked well sites. Risk of release varies
over time and between locations because of differences in geology, changes in
meteorological conditions, and the adoption of different practices by different operators. It can also change due to technological innovations, changing regulations, and
operator response to community concerns. For a true risk assessment, the uncertainty needs to be replaced with a probability function that defines the likelihood,
composition, magnitude, frequency, and duration of releases. This will help quantify the potential for emissions or leakage/spills from different stages in the shale
gas development process.
Environmental monitoring of risk sources would be simplified if some indicator
chemicals, such as methane in air or TDS in water could be used as predictors of
other releases. Long-term emission trends from sources could be monitored with
ground-based or satellite historical observations. The mechanism by which a chemical is released into the air or water must be better understood, be it operational,
accidental, or illegal.
Transport Pathways Variations in local conditions such as meteorology, topography, geochemistry, and hydrology can affect the movement of frack chemicals in air
and water. Some conditions vary over time intervals ranging from hourly to seasonally, and control how gases, vapors and liquids might move from a well site to
expose a nearby population. It is critically important to obtain pre-drilling baseline
data, especially on air and groundwater to distinguish fracking chemicals from other
natural and anthropogenic sources.
An intervention on a transport pathway can stop human populations from being
exposed to potential fracking health risks. For example, keeping a leaking toxic
chemical from trickling into a stream that is used for drinking water will prevent
many health impacts. Closing a vent to stop VOCs from entering the air during a
temperature inversion can prevent the build-up of smog and ozone. In order for this
to work however, the transport pathways must first be identified. If released chemicals can be contained and kept away from vulnerable populations, health risks will
be reduced substantially.
Exposed Populations This is perhaps the most complicated assessment of the three
categories of human health risks. Different behaviors can have a substantial influence on how individuals react to potential exposure to frack chemicals. Smoking,
alcohol consumption, use of certain drugs, poor eating habits, vitamin deficiencies
and many other factors can affect how a person reacts to a chemical. Although one
might expect the rig workers to be the primary exposed group because they are
8 Impacts to Human Health and Ecosystems