Environmental News pers, and packaging; chemist. Scientists who fire-fighting ffamss ;nd study fluorinated organic other specialty compocompounds say the long nents. Other fluorinated carbon-fluorine chains organic compounds, that form the backbone including sulfonates and of these compounds sulfonamides, are found mean many are likely to in herbicides and be exceedingly persistent pesticides. in the environment. "Some fluoro-organics How PFOS accumuwill redefine persistence lates in animals such as in comparison to PCBs flesh-eating birds from and DDTs which will remote areas in the Pagenerally be considered cific Ocean is the most labile in comparison " intriguing question, Mabury says many scientists say, because PFOS is not To study the environmental effects of fluorinated surfactants. UniverThe molecules are so sity of Toronto scientists dose 16 mesocosms—10,000-liter-ponds, im- persistent because long thought to be volatile. itating an aquatic environment with PFOS. At first glance, this fluorinated hydrocarcharacteristic appears bon chains in these surto rule out the type of long-range factants create "molecular rebar", A host of more basic questions atmospheric transport through adds Stanford University chemist also remains. Litde is known about which persistent organic pollutCraig Criddle. The perfluoroalkyl the physico-chemical properties, ants such DDT volatilize in chains are stiff and very difficult such as the vapor pressure or octawarm climates and are carried by for microbes to degrade, he says. nol water partition coefficient, the winds to cooler climates adds Jennifer Field, an Oregon Fluorinated surfactants are where they precipitate State University environmental likely to exhibit a range of toxici-
LC/MS tool to help military characterize fluorinated surfactants Fluorinated surfactants are part of the groundwater contamination problems that face military bases. The surfactants are constituents of aqueous film-forming foams (AFFFs), used to fight hydrocarbon fuel fires. Although military scientists have suspected that fluorosurfactants were in contaminated groundwater plumes, they could not actually identify the compounds, because no technique existed that could isolate and analyze fluorosurfactants in samples. Scientists Cheryl Moody and Jennifer Field have been grappling with these analytical issues. In the Sept. 15 issue of ES&T, ,hey conncude ttat "liquid chromatography/mass spectrometry (LC/MS) will most likely
ously, the scientists found perfluorocarboxylate surfactants at the same three bases using gas chromatography/mass spectrometry. The analytical challenge is daunting because commercial AFFF formulations are complex proprietary mixtures whose major components include a solvent, typically a glycol ether, fluorocarbon surfactants, and hydrocarbon-based surfactants. Fluorinated surfactants contribute to the performance of AFFF as the primary fire-extinguishing chemical and as vapor sealants that prevent reignition of fuel and solvents, according to Moody and Field. Groundwater contamination at military bases stems, to a large ex-
The military comprises 75% of the AFFF market in the United States, but the chemical is also used by petrochemical companies, pharmaceutical manufacturers, airports, fire departments, and municipalities throughout the world, says Mitchell Hubert, at AFFF manufacturer Ansul, in Marriette, Wl. Besides contaminating water supplies, AFFF-laden waters can cause problems for wastewater treatment plants because they have high biological and chemical oxygen demands. At high concentrations, the surfactants turn the treatment tanks into a bubble bath, which shuts down the facility, according to Field.
prove to be the most useful tool for characterizing the compositions and concentrations of a range of perfluorinated surfactants in environmental samples." Moody, who is currently at the University of Toronto, and Field, who is at Oregon State University report quantitative identification of perfluoro-octane sulfonate in groundwater from three military bases. Previ-
tent, from fire-training exercises conducted at fire pits. Firefighters light up a cocktail of flammable fuels, then put the fire out with AFFF. The resulting liquids were either sent to a wastewater treatment plant or dumped onto the ground. To reduce contamination, the military is looking at ways to use AFFF substitutes as often as possible in training exercises.
In early August, officials from all branches of the U.S. military met at the Naval Research Laboratory in Washington, DC, to review the environmental impacts of AFFF and draft a department-wide policy on AFFF. The military has evaluated protein-based foams including products that use ox blood, but these have not proven as effective. R.R.
3 7 2 A • SEPTEMBER 1, 2000 / ENVIRONMENTAL SCIENCE & TECHNOLOGY / NEWS
