A couple of weeks ago we wrote a story about the release of partially treated gas drilling wastewater into Pennsylvania’s rivers. The post highlighted an Associated Press analysis of data covering July 2009 through June 2010 and mentioned a new state rule that requires newly-built wastewater plants to meet higher treatment standards.

We wanted to know if those new standards are being met, so we asked the Department of Environmental Protection when any new plants might be built. Later that night, a spokeswoman for the DEP sent us a chart showing that a couple of dozen are planned or proposed. She also pointed out that two of about 20 existing plants on the list already meet the new regulations.

But that list was incorrect. In fact, only one plant satisfies the regulations. The other one listed is not yet built, and not even fully permitted, according to Larry Mostoller, president and CEO of Somerset Regional Water Resources, the company building the facility. (Jamie Legenos, the DEP spokeswoman, said that labeling this plant operational was a clerical mistake.)

Legenos could not give us an estimate of how long it may be before more plants are online. Mostoller said his plant could be operating by the summer of 2012. Another plant he is building, which he said is fully permitted and took two and a half years to get approved, should be running within a year.

Former DEP Secretary John Hanger, who left the department this week with the out-going governor, said focusing on when or how many plants may go online misses the big picture: that the state’s drinking water is safe and that gas drilling is producing far less wastewater than originally predicted, because drillers are reusing most of their wastewater. He said a monitoring network in rivers and drinking-water facilities ensures that contaminants do not reach high levels.

“This is why we can tell you that every drop of water that goes to a tap meets the standard,” he said. “And if it didn’t we would immediately notify the public.”

The regulations were updated in August to require all new and expanding facilities treating oil and gas wastewater to remove Total Dissolved Solids (TDS), a measure of dissolved organic and inorganic materials such as salts and minerals, down to a concentration of 500 milligrams per liter (other industries have a higher limit).

Many of the state’s waterways suffer from high TDS levels that have harmed aquatic life and have occasionally contributed to health concerns at some drinking-water facilities, according to the official Pennsylvania Bulletin, where the new regulations were published. It says 17 drinking-water intakes on the Monongahela River are subject to high levels of one contaminant, “which result in increased risks of bladder cancer.” It also says TDS levels have contributed to a “shift in biotic communities” in some of the state’s rivers. The effects of TDS on human health depend on its components.

The EPA sets a guideline of 500 mg per liter for TDS as a “secondary standard,” meaning it may have aesthetic or cosmetic effects, such as tooth discoloration, but the agency lets states decide whether to enforce that guideline, which is included in the Safe Drinking Water Act.

Hanger said the Pennsylvania law sets its “trigger” at 375 mg per liter, so if TDS levels exceed that point downstream, DEP can compel any plant to reduce or halt its discharges. We were unable to verify with the department that this trigger applies to existing oil and gas wastewater facilities. Legenos pointed us to language applying the trigger to other industries and to a general statement that the law guarantees levels will not rise above 500 mg per liter.

John Baillie, senior attorney at the environmental group PennFuture, which worked to pass the regulations, said he’s not aware of a trigger in the law that applies to existing oil and gas wastewater facilities. He said the DEP does have the broad authority to limit wastewater discharges if the department decides they are contributing to pollution.

Hanger said the regulations allow the DEP to guarantee that Pennsylvania’s drinking water meets the EPA standard. But that doesn’t mean that the state’s waterways are in the clear.

“I think it’s fair to say in some cases they are less stressed and in some cases they’re probably about in the same position,” he said, compared to when TDS levels spiked in the Monongahela in 2008, corroding equipment at a steel mill and a power plant. “Problems on Monongahela have not gone away, but they’ve been less severe.”

The Monongahela’s TDS problem can’t be blamed entirely on gas drilling. Hanger said the water’s TDS content was high even before it entered the state, having passed through heavy mining areas in West Virginia. Runoff from mining and other industries contributes to TDS levels, although gas wastewater has particularly high concentrations of these salts and minerals.

The bulletin says other Pennsylvania rivers also have a limited ability to sustain new discharges containing high TDS levels.

Some have questioned whether the new rules go far enough to fully protect the state’s waterways. The regulation instructs the department to monitor levels as monthly averages and to allow for temporary spikes, which can be caused not only by increased discharges but also by low water levels. In its public comment on an early draft of the rule, the environmental group Delaware Riverkeeper said that fluctuations in TDS levels can harm aquatic life.

Still, the new regulations were largely recognized as a victory for environmentalists.

“They weren’t as strong as first proposed, but that’s always the case,” said Jan Jarrett, PennFuture’s president and CEO. “Generally speaking we think that now that they’re in place and they’re in force, they’re adequate to protect the streams from the TDS.”