The Role of Toxicological Science in Meeting the Challenges and Opportunities of Hydraulic Fracturing

Abstract

We briefly describe how toxicology can inform the discussion and debate of the merits of hydraulic fracturing by providing information on the potential toxicity of the chemical and physical agents associated with this process, individually and in combination. We consider upstream activities related to bringing chemical and physical agents to the site, on-site activities including drilling of wells and containment of agents injected into or produced from the well, and downstream activities including the flow/removal of hydrocarbon products and of produced water from the site. A broad variety of chemical and physical agents are involved. As the industry expands this has raised concern about the potential for toxicological effects on ecosystems, workers, and the general public. Response to these concerns requires a concerted and collaborative toxicological assessment. This assessment should take into account the different geology in areas newly subjected to hydraulic fracturing as well as evolving industrial practices that can alter the chemical and physical agents of toxicological interest. The potential for ecosystem or human exposure to mixtures of these agents presents a particular toxicological and public health challenge. These data are essential for developing a reliable assessment of the potential risks to the environment and to human health of the rapidly increasing use of hydraulic fracturing and deep underground horizontal drilling techniques for tightly bound shale gas and other fossil fuels. Input from toxicologists will be most effective when employed early in the process, before there are unwanted consequences to the environment and human health, or economic losses due to the need to abandon or rework costly initiatives.Disclaimer: Any statements, opinions, or conclusions contained herein do not necessarily represent the opinions, statements, or conclusions of EPA, NIEHS, NIH, or the U.S. Government.

A Framework for Identifying Organic Compounds of Concern in Hydraulic Fracturing Fluids Based on Their Mobility and Persistence in Groundwater

“…6 Previous studies of potential drinking water contamination by fracturing fluids have focused on characterizing the toxicity of the individual compounds, 11−14 with consideration of environmental exposure potential for only a limited number of compounds 9,13,14 and not mixtures. 15 The variety of compounds hinders baseline groundwater monitoring due to analytical limitations of a comprehensive analysis of possible constituents. 16 Effective groundwater monitoring should focus on constituents most likely to be present.…”

Unconventional shale gas development: challenges for environmental policy and EA practice

“…However, unconventional shale gas development has significant environmental burden with serious implications for human and ecological health in the medium and long-term (e.g. Goldstein et al 2014). The dramatic growth of unconventional shale gas development in the last decade and a half has been accompanied by public protests (Long 2008) and civil suits (King et al 2012), with hydraulic fracturing bans or moratoria imposed in various jurisdictions, e.g.…”

Air Concentrations of Volatile Compounds Near Oil and Gas Production: A Community-Based Exploratory Study

“…Sources of variability of air emissions and concentrations of VOCs and other pollutants near UOG sites include: (1) the spatial variability of UOG operations; (2) the discontinuous use of equipment such as diesel trucks, glycol dehydrators, separators, and compressors during preparation, drilling, hydraulic fracturing, well completion, and other stages; (3) the composition of shale and other formations and the specific constituents of the drilling and hydraulic fracturing fluids used on-site (which can influence the makeup of produced or flowback water stored in pits and tanks); (4) intermittent emissions from venting, flaring, and leaks; (5) the shifting location, spacing, and intensity of well pads in response to market conditions, improvements in technology, and regulatory changes; (6) the effects of wind, complex terrain, and microclimates; and (7) considerable differences among states in permitting, leak detection and repair, and other requirements [10,16,[23][24][25]. Wind, for example, can influence outdoor and indoor concentrations of air pollutants.…”