Last month the US Environmental Protection Agency (EPA) released a Progress Report on the Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources. The report does not offer conclusions at this point, but it does provide status updates on the 18 different research activities covered in the study.

Study results, including findings from individual research projects, are expected to be released in 2014. The final results are intended to provide the public and policymakers with scientific knowledge for decision making. The study itself has been structured as a scientific investigation and will not offer any policy recommendations; immediate regulatory changes are unlikely once it is issued.

What are the goals of the study? According to the EPA, the overall purpose of the study is to assess potential impacts of hydraulic fracturing on drinking water resources and identify driving factors that could affect the severity and frequency of impacts. It does not evaluate best management practices or new technologies. It is not a risk assessment, nor does it address all issues of environmental concern.

The EPA's research approach includes analysis of existing data, scenario evaluations, laboratory studies, toxicity assessment, and case studies. Research is focused on the following five primary research questions:

• Water acquisition:What are the possible impacts of large volume water withdrawals from ground and surface waters on drinking water resources?
• Chemical mixing: What are the possible impacts of hydraulic fracturing fluid surface spills on or near well pads on drinking water resources?
• Well injection: What are the possible impacts of the injection and fracturing process on drinking water resources?
• Flowback and produced water: What are the possible impacts of flowback and produced water surface spills on or near well pads on drinking water resources?
• Wastewater treatment and waste disposal: What are the possible impacts of inadequate treatment of hydraulic fracturing wastewater on drinking water resources?

Some preliminary data released The Progress Report provides preliminary data on some projects, including a list of chemicals used in hydraulic fracturing fluids and those detected in flowback and produced water. It provides initial data and maps on water availability in the Susquehanna River and Upper Colorado River Basins. It also provides chemical concentration data from initial samples of surface waters downstream from two wastewater treatment facilities in Pennsylvania and from retrospective case study sites.

Specific research areas After our review of the Progress Report, we feel several research areas will likely generate valuable information in the final report:

• Service company data on 333 wells sites from 9 different companies provides one of the biggest opportunities for insight. Data collected on water volumes, operations, and source locations will help assess the stress on different types of water resources and the amount of disposal capacity needed. Data collected on well construction, depth, and pressure will help assess consistency and robustness of well integrity. Since much of the data is confidential, it is uncertain how EPA will aggregate it in the final report.\
• Scenarios model hypothetical situations in both subsurface and surface contaminant transport and in watershed-level water availability. The subsurface modeling is likely to make a significant contribution in assessing which pathways are most likely to cause contamination. The detailed time scale granularity of the water availability modeling will help assess the potential for short term demand to exceed availability in certain areas.
• Case studies will provide several opportunities to track issues both retrospectively and prospectively at different sites facing potential groundwater contamination issues. The retrospective studies were chosen based on criteria such as proximity of population and drinking water supplies, evidence of impaired water quality, and health and environmental concerns. Extensive water sampling should generate valuable data for analysis.

Changes made to study The progress report shows that research is generally following the schedule and objectives listed in the study plan issued in November 2011. However, one major change is the exclusion of two secondary research questions associated with geochemical interactions between fracturing fluids and rock formations. Since the US Department of Energy, and academic intuitions are conducting similar analyses, EPA is discontinuing this research.

A major addition to the study is the analysis of FracFocus data. The EPA has already collected data from January 2011 to February 2012, and data from the following year will be collected. Although FracFocus data is publicly available, information can only be downloaded for one well at a time. EPA's aggregation and analysis will help to draw meaningful conclusions on industry trends related to water acquisition and chemical usage.

Areas needing more research After review of the report, we believe that there are some key research gaps that may make it difficult to develop conclusions in the final report. Although acknowledged by the EPA in the study plan, we are disappointed that the following topics were not included in this study.

• The surface spill analysis uses incomplete data sets and only includes those spills on or near the well site. It excludes spills related to transportation, which accounts for a significant portion of surface spills.
• Under the treatment and disposal area, only treatment and release of wastewater to surface waters is studied. However, the majority of wastewaters are disposed in underground injection wells, and a significant amount of concern is related to this practice and potential induced seismicity.
• While the study's toxicity assessment rigorously analyzes the relative concentrations of chemicals in hydraulic fracturing fluid and provides initial estimates of threshold "safe" levels, the EPA does not plan to develop complete dose-response curves needed for a full risk assessment and address potential health effects on humans.

Next steps EPA will continue hosting technical roundtables and workshops throughout 2013. The results and any findings from the 18 research projects will be issued in separate peer-reviewed journals or EPA publications in 2014, with final conclusions issued in a summary report in late 2014. EPA will continue to post updates on the study's website.

This article was published by S&P Global Commodity Insights and not by S&P Global Ratings, which is a separately managed division of S&P Global.