FACTBOX-U.S. EPA studies five ways fracking may affect water

Dec 21 (Reuters) - The U.S. Environmental Protection Agency's landmark study into the effects of hydraulic fracturing drilling technology on water supply is examining the issue from five different angles. The study, which may prove pivotal in the government's regulation of the 'fracking' technology that has unlocked generations' worth of U.S. oil and gas supplies, won't be released for public comment and peer review until 2014, but its framework was released in detail on Friday. For the full report: http://r.reuters.com/jec84t These are the five stages of the hydraulic fracturing water cycle being examined:

Water Use in Fracturing Operations

Hydraulic Potential Drinking Water Issues

Water Water Availability Acquisition Impact of water withdrawal on water quality Chemical Mixing Release to surface and ground water

(eg onsite spills and/or leaks) Chemical transportation accidents

Well Injection Accidental release to ground or surface water (eg, well

malfunctions) Fracturing fluid migration into drinking water aquifers Formation fluid displacement into aquifers Mobilization of subsurface formation materials into aquifers

Flowback and Release to surface and ground water Produced Water Leakage from onsite storage into drinking water resources

Improper pit construction, maintenance, and/or closure

Wastewater Surface and/or subsurface discharge into surface and Treatment and ground water Waste Disposal Incomplete treatment of wastewater and solid residuals

Wastewater transportation accidents

(Reporting by Jonathan Leff)