Flame Retardants Contaminants in Wastewater

California’s “Voice of Biosolids,” Greg Kester, put out the word last week in an email to his biosolids colleagues that WERF had issued its RFP to study three special compounds in biosolids. He asked us to pass this word along to you, and so I do:“Developing Exposure and Toxicity Data for Priority Trace Organics in Biosolids,” Request for Proposal (RFP) No. TOBI2R15.

WERF’s new RFP specifically addresses three compounds. These are: polybrominated diphenyl ethers (PDBEs), Azithromycin, and Ciprofloxacin. The first, the subject of this commentary, you may recognize as a “BFR,” or Brominated Flame Retardant, with a growing list of environmental and human health, causing EPA to issue an “Action Plan.” The other two are antibiotics, the first known as a “world bestseller” and the second among a powerful class known as “the last resort.” After a series of WERF reports, first in 2010 Trace Organic Chemicals in Biosolids-Amended Soils: State-of-the-Science Review, followed by the 2012 report Gathering Unpublished Data on Compounds Detected in Biosolids , WERF has identified these three compounds as the highest of the high priorities for follow up study.

I was particularly intrigued in WERF’s special interest today in PBDEs. I heard of PBDEs in biosolids first in 2001, 14 years ago. PBDEs were largely abandoned as a flame retardant 10 years ago, in 2004. And now this year, 2015, WERF is commissioning a special study of the eco-toxicity of PBDEs in biosolids. Do we act fast, or what?

PBDEs have been a concern of mine for a while. I remember the specific moment I first heard uttered that phrase “polybrominated diphenyl ethers.” It was out of the mouth of Rhonda Bowen in Ocean City, Maryland, in July 2001, on the outside deck, overlooking the Atlantic Ocean, with a beer on the table in front of me, at the close of a biosolids session of the Chesapeake Water Environment Association conference.

Rhonda had gotten a call on that deck from the Hampton Roads Sanitation District Executive Director saying that the public affairs director needed to field a reporter’s call in response to an article in Nature by a researcher at Virginia Institute of Marine Sciences, Rob Hale, based on work that he had published in Environmental Science & Technology. This letter associated (wrongly we felt, then and now) measurements of PBDEs in land-applied biosolids with measurements of PBDE in stream sediments. You will recall from my commentary a few weeks back that Dr. Hale still seems to be confused about the plausibility of exposure pathways involving biosolids, as evidenced by the article in Chemical and Engineering News (March 2, 2015, “Persistence Pays Off…”).

But my surprise at the current WERF project is attributable to a journal article that had caught my attention a couple months back involving, not PBDEs, but the high-volume chemical class that had replaced PBDEs as flame retardants. These are chemicals called “organophosphorus flame retardants,” or “OFRs.” Ten years after these compounds became used in furniture and clothing chemists we seem only now to begin searching and finding these OFRs in wastewater influent. What is more, they are not benign from a human health or environment problem.

Here are a couple articles pertinent to this emerging story.

It starts with California, where many well-intentioned regulations start. The NRDC explains in its article, Toxic Chemicals in Our Couches, that California chose to protect its citizens from cigarettes falling onto couches with this result: “For decades, an ineffective flammability standard, California's TB 117, has resulted in the foam inside our sofas, recliners, and love seats being saturated with pounds of toxic flame retardants. …TB 117 became a default standard for furniture sold across the country.” PBDEs were the chemical used to achieve this standard, worldwide, for many years.

But by 2004, concerns with PBDE prompted change. According to Key Flame Retardant Law is About to Change – Updated: “…due to mounting health concerns …its manufacturer voluntarily ceased production in 2004…. Since then, TDCPP and Firemaster 550 have been the primary flame retardants used by furniture manufacturers to comply with TB 117.  TDCPP was also recently found to be prevalent in a wide variety of children’s products, such as nursing pillows, changing pads, and car seats.” TDCPP is tris (1,3-dichloro-2-propyl) phosphate, one of several compounds classified as chlorinated organophosphate flame retardants, or OFRs.
With this change, the world may have gone from the proverbial frying pan into the fire. New Details on Organophosphate Flame Retardants: Exposure in Men Appears Stable over Time is a 2014 article that concludes: “Both TDCPP and TPP (triphenyl phosphorus) are widely used, and a limited number of animal studies suggest that both compounds may be carcinogenic, neurotoxic, or reproductive toxicants. Despite the potential for health effects, very few human studies of either flame retardant have been published to date….”

Is TDCPP a problem for wastewater treatment? The answer to this brings me to the paper I came across in my recent science wanderings: “Organophosphorus Flame Retardants and Plasticizers in Swedish Sewage Treatment Plants.” The answer is YES! But for biosolids, the “good news” is that it passes through in the effluent and not into the biosolids. Here is the conclusion: “The organophosphorus compounds (OPs)[of which TDCPP is a specific type] studied were poorly removed from the wastewater; especially the chlorinated OPs tended to pass through the STPs without being removed or degraded… Of the total amount of OPs reaching the STPs annually, 49% is degraded, 50% (27 tons) is emitted to the recipients, and only 1% ends up in the sludge.”

How do OPs get into wastewater? In an Environmental Health Perspectives article, New Details on Organophosphate Flame Retardants, we learn: “Indoor dust is known to be a significant source of exposure to PBDEs, and the new study suggests it may also be an important source of exposure to TDCPP….” This jibes with the other recent study, Flame Retardant Transfers from U.S. Households (Dust and Laundry Wastewater) to the Aquatic Environment, which concluded: “[OFRs] were present at the highest concentrations in both dust and laundry wastewater, making up 72% of total flame retardant mass in dust and 92% in laundry wastewater. Comparison of flame retardant levels in WWTP influents to estimates based on laundry wastewater levels indicated that laundry wastewater may be the primary source to these WWTPs.”

Is it good news that these flame retardants are not a big deal in biosolids? Not if you step back and look at what may be emerging as an eco-toxicity issue no less concerning than that of PBDEs, and maybe more so. The emerging research on exposures suggest that OFR-laden dust leads to dermal absorption through skin, to respiration through inhalation and to oral intake contaminated food – all three. In a sort of troubling irony, world health may have been better off when PBDEs were used as flame retardants, because at least they ended up relatively well-bound in biosolids. The issue of PBDEs is still relevant for us in biosolids, because so many furniture cushions still give off PBDEs, but they will subside, and the world is changing focus to these other compounds.

How is it that the issue of flame retardants has gotten so out of control? I wonder if we, the environmental stewards in the wastewater profession, ought to have been more proactive in watching for “compounds of emerging concern” in our influent flows, instead of waiting until others sounded the alarm? If we had taken on such a role, we might have early-on witnessed the PBDE contaminants, and then afterwards the increasing influx of TDCPP. Yes, that would have required that we delve into the hard task of controlling influent quality to protect biosolids use and to protect aquatic life; that is our job, isn’t it? Yes, these are chemicals outside our traditional purview, but they are well within the realm of our commitment to the environment.

But, we missed the opportunity to be the ones to have sounded the alarm on flame retardants.