The 50,000-gallons-a-day of hydraulic fracturing wastewater trucked from gas drilling fields in Pennsylvania for treatment and disposal in Baltimore County’s Back River last year may have contained a pesticide that can be fatal to oysters and aquatic life, according to the Maryland Department of the Environment.
But this pesticide, called DBNPA (or 2,2-dibromo-3-Nitrilopropionamide), was likely removed when the wastewater was treated in the Back River Wastewater Treatment Plant, the state agency said. “We do not think that there was any risk to Back River, the (Chesapeake) Bay, or oysters,” a spokesman for the state agency, Jay Apperson, wrote in an email.
Harry Campbell, senior scientist in the Chesapeake Bay Foundation's Pennsylvania office, said the agency's conclusions about this pesticide appear to be correct. "The question remains, however, whether this type of treatment is good enough to remove the myriad of other chemicals and contaminants in the fluids," Campbell said. "Toxicity testing of this treated wastewater, before discharged into the Bay or anywhere else, would begin to shed light on that question."
Drilling companies pump millions of gallons of water laced with sand, acid, and chemicals into shale formations to fracture the rock and release natural gas. They often use pesticides, also known as “biocides,” to prevent the growth of bacteria that could clog up the well, according to the Pennsylvania Department of Environmental Protection.
Dr. Conrad "Dan" Volz, Director of the University of Pittsburgh School of Public Health's Center for Healthy Environments and Communities, said secondary treatment of fracking wastewater by sewage plants should remove some of the DBNPA, but he has no data to indicate whether all of it is removed. "We do know these plants are not really set up to remove toxic substances," Dr. Volz said. "Secondary treatment in a sewage plant should not be the primary treatment for biocides."
Last week, Bay Daily asked the Maryland Department of the Environment about pesticides in hydraulic fracturing wastewater. For a few months last year, 50,000 gallons a day of wastewater was trucked from Pennsylvania’s drilling fields to an industrial treatment plant in Baltimore called Clean Harbors, which then sent the effluent to the Back River Wastewater Treatment Plant. Millions of gallons of fracking wastewater are trucked all over the region for disposal and recycling.
The question was spurred by a Bay Daily reader named Dr. Ronald Bishop, a biochemist at the State University of New York, Oneanta, who has been collecting data on hydraulic fracturing wastewater.
“Do folks in the Chesapeake Bay region know that the biocides used in gas drilling and fracturing fluids often include DBNPA?” Dr.Bishop wrote to Bay Daily last week. “So what, you think? These compounds are lethal to Bay oysters at concentrations below their chemical detection limits!”
The Pennsylvania Department of Environmental Protection's official list of known chemical components of hydraulic fracturing fluids does, in fact, list DBNPA. An EPA report on the pesticide concluded that it poses a "high risk to aquatic organisms,” including oysters. But the report also says that when a wastewater treatment plant treats the effluent, the pesticides would be “sufficiently degraded to adequately mitigate the risk" to aquatic organisms, according to the EPA report.
The wastewater sent to the Clean Harbors plant last year for treatment was then sent to the Back River Waste Water Treatment Plant, for a second round of treatment, before discharge to the river, according to the Maryland Department of the Environment.
“This treatment would have adequately treated any DBNPA that might have been present in the original wastewater,” the MDE spokesman wrote in his email. “In addition, it would have been diluted dramatically by the sewage and further diluted when it was discharged to surface water.”
By Tom Pelton
Chesapeake Bay Foundation
Posted below is the full text of MDE's emailed response of March 8, 2011, to my four questions about pesticides in hydraulic fracturing wastewater. My questions are in BOLD, and MDE's responses follow.
Tom, answers to your questions are provided below, but we want to make sure you understand the regulatory structure here. The State issues permits for discharges to surface water, including discharges of treated effluent from WWTPs. These WWTPs, especially in urban areas, receive wastewater from commercial and industrial facilities as well as from residences. The Pretreatment Program is the mechanism by which these non-residential discharges are managed by the WWTPs. Baltimore City regulates Clean Harbors’ discharge to its WWTP through the City’s pretreatment program. If you want specific information about how the City does this, you should ask the City. Ralph Cullison would be a good place to start.
1) Was MDE aware that hydraulic fracturing fluids often contain DBNPA and DBAN?
We are aware that the Pennsylvania Department of Environmental Protection has compiled a list of chemicals used by hydraulic fracturing companies in Pennsylvania and that the list includes DBNPA. We will be reviewing the additives that applicants for drilling and hydraulic fracturing permits in Maryland propose to use.
2) Does MDE consider this a risk to Back River or Bay oysters?
We do not think that there was any risk to Back River, the Bay, or oysters. The wastewater that Clean Harbors pretreated was sent to the Back River WWTP, where it underwent further treatment, along with all the other wastewater, before discharge. This treatment would have adequately treated any DBNPA that might have been present in the original wastewater. In addition, it would have been diluted dramatically by the sewage and further diluted when it was discharged to surface water.
The EPA study of DBNPA, Reregistration Eligibility Decision (RED) 2,2-dibromo-3- Nitrilopropionamide (DBNPA), EPA 738-R-94-026, stated on page 21 “After evaluating available data and consultations between Agency Offices (Office of Pesticide Programs, Office of Water, and the Office of Pollution Prevention and Toxics), the Agency has determined that aquatic risk concerns for all uses of DBNPA, except single flow-through cooling systems, may be adequately mitigated by secondary biological treatment of waste water.” To put this in simpler language, EPA considered all the toxicology information, including the data on oysters, and determined that if the wastewater was treated by a WWTP with secondary biological treatment, the resulting wastewater would not contain sufficient DBNPA to harm oysters or other aquatic life.
3) Did Clean Harbors test the waste water (before or after) for DBNPA or DBAN?
We do not have this information, but as noted above, the DBNPA would have been treated adequately in the Back River WWTP.
4) Did Clean Harbors or the Back River WWTP treat the waste water to remove DBNPA or DBAN?
Regardless of what treatment Clean Harbors provided, the treatment at the Back River WWTP was effective to remove DBNPA. The EPA document referenced above, at Appendix G, page 3, states that wastewater containing DBNPA can be discharged to wastewater treatment plants without pretreatment because the biological degradation readily occurs in the WWTP.
Deputy Director, Office of Communications
Maryland Department of the Environment
1800 Washington Boulevard
Baltimore, MD 21230