Gas well drillers tapping into the deep Marcellus Shales add up to 54 substances, some of them toxic, to the water they use to fracture that rock and release the gas.
And the state Department of Environmental Protection doesn't know what chemicals, metals and possibly radioactive elements are in the waste water that is pushed out of the wells. It is discharged into the state's waterways including the Monongahela River, from which 350,000 people get their drinking water.
"That's the bigger issue. They don't have an analysis of what's in the waste water they're pulling out," said Dr. Conrad Dan Volz, assistant professor in the Graduate School of Public Health at the University of Pittsburgh. "What they're putting into the wells can chemically change and be added to underground, and no one is saying how much arsenic, manganese, cobalt, chromium and lead is in the stuff. Depending on the concentration, it could be a hazardous waste."
Each well drilled into the Marcellus Shales, which lie at least a mile deep beneath parts of Pennsylvania, New York, West Virginia and Ohio, uses up to 4 million gallons of water to fracture the rock and release natural gas. The chemicals are added to the "frac" water that is pumped into the wells under high pressure to reduce friction in the pipe and allow the water to flow more freely into the rock layers.
Among the chemical additives are formaldehyde, a human carcinogen; various acids; a variety of petroleum compounds and several pesticides that are toxic to fish and other aquatic life. Many of the chemicals, depending on their concentrations, can also cause human skin, eye and nose irritations, and damage kidney, heart, liver and lung function.
Much of that frac water -- about 40 percent of the total used -- is pushed back to the surface by the gas released from the shale, and it must be disposed of.
"Yes, we're concerned," said Mark Hartle, chief of aquatic resources for the Pennsylvania Fish and Boat Commission. "And we're more concerned with the recovered fluids from the wells than with the water they use to do the fracing initially. The problem is, we're not sure what they're ending up with so we don't know the constituents of the discharges."
Lou D'Amico, executive director of the Independent Oil & Gas Association of Pennsylvania, said frac water chemical concentrations are low and treatment facilities are removing much of the metals and dissolved solids from the waste water.
"Companies are committed to huge investments to treat the waste water, because without that we're out of business," Mr. D'Amico said. "We're very aware of all the environmental and public concerns, and our mission is to develop the Marcellus shale as an economic benefit to Pennsylvania and in an environmentally sensitive way."
He said drilling and fracing companies are doing a wide-ranging survey of the waste water, also known as "flow-back water," to show it is not a health hazard.
Tom Rathbun, a DEP spokesman, said the department also is doing a chemical analysis of the waste water, a study that should be done by the first of the year.
"We have a general idea but want to know for sure," Mr. Rathbun said. "If it's different, we will make the necessary adjustments.
"I don't think they've been doing enough Marcellus Shales drilling so far to make a difference," Mr. Rathbun said. "But the gas industry needs to come up with a way to deal with this. A couple of companies want to do on-site water treatment, and others are looking at different recycling technologies."
He said there are now only about 20 active Marcellus Shales gas wells. But there has been drilling activity at more than 300 in Pennsylvania, and another 250 have been issued state permits.
The drilling and water discharges have attracted the attention of the U.S. Environmental Protection Agency.
"It is an issue that's been on our radar for a while and currently a matter we're looking into," said Dave McGuigan, associate director of EPA's regional office of permits and enforcement. "The question is what is in [well waste water] and what are the treatment facilities doing with it."
Some of the waste water is taken to DEP-approved municipal sewer authorities that dilute it with their regular effluent before discharging it into a river or stream. Some is trucked to one of the state's six industrial water treatment facilities, where metals, oils and some dissolved solids are removed but where waste salts are a disposal problem exacerbated by the volume of the waste water.
"The salts are the biggest issue right now and the most expensive thing to remove from the highly concentrated brines," said Paul Hart, president of Pennsylvania Brine Treatment Inc., who owns three of the state's six industrial treatment facilities and wants to build six more.
Mr. Hart criticized the DEP for slow action on permit applications for new treatment facilities, for regulating the well water as waste, which limits the ability of drillers and treatment facilities to recycle it, and for failing to determine the composition of the waste water.
"The Marcellus has wide variations in the amount of iron, barium and salt, and we need to know the high and low marks so we can treat it and we're still determining that," he said. "Right now we don't know as much as we'd like to know."
The drilling companies provide the DEP with lists of chemicals they add to the water but not the amounts of specific mixtures, claiming that is proprietary information.
Four of the chemical compounds are complex pesticides that scientific assessments have determined are "very toxic to fish." One, 2.2-Dibromo-3-nitrilopropionamide, retards fetal development in rabbits.
The pesticides are added to the drill water to stop the growth of algae in temporary holding ponds and tanks built next to the drilling pads. Algae and other "biofilms" can foul pumps used to push the water underground and into the shale.
None of those chemicals should be discharged directly into surface water such as the Monongahela River, said Dr. Volz, who is studying the effects of pollutants in the rivers.
"If there's enough biocide to kill algae, by the looks of this bromated compound there's enough to do damage to fish," Dr. Volz said. "Throwing it in the water is just crazy."
He said formaldehyde, which is a human carcinogen, "is always a concern," but any risk is impossible to assess without knowing its concentration.
In addition to the pesticides, the chemicals added to the well "fracing" water include acids to dissolve cement around the pipe casings and open perforations in the pipe for the water to flow through and into the shale formation; friction reducers to make pumping easier; and additives to keep clay from reducing the flow of the released gas.
Different pumping companies use different frac-fluid recipes and formulas and different combinations and amounts of those chemicals.
A report on the chemical additives requested by DEP's Bureau of Oil & Gas Management and prepared for the Independent Oil & Gas Association of Pennsylvania states that care and controls are used to prevent the frac chemicals and chemical water solutions from contaminating surface and ground water near the wells. The report also notes that water in the Marcellus Shales contains high concentrations of dissolved solids, making it unsuitable as a drinking, agricultural or industrial water supply.
The DEP and public water suppliers have said the high TDS levels are not a health concern. But David Dzombeck, an environmental engineering professor at Carnegie Mellon University, said without knowing the chemical composition of the dissolved solids, that's hard to confirm.
Don Hopey can be reached at 412-263-1983.