Environmental t News C
hemicals left over from the manufacturing of stain repellents and other products could be a major source of the perfluorinated compounds present in people and in the environment, according to a new study published in this issue of ES&T (pp 1447–1453). This research was published online on the same day that the U.S. EPA’s Susan Hazen, acting assistant administrator for the Office of Prevention, Pesticides, and Toxic Substances, announced that EPA was challenging perfluorochemical manufacturers to reduce the concentrations of these residuals from their products by 95% by 2010 and to totally eliminate them by 2015. Chemical giant DuPont Co. immediately accepted that challenge. University of Toronto chemists Mary Joyce Dinglasan-Panlilio and Scott Mabury report the first systematic evaluation of the loose, unbound fluorinated alcohols in seven materials, including industrial paint and polish additives, consumer carpet-protector sprays, and windshield washer fluid. The perfluorinated compounds are residuals, unwanted chemicals left over from the manufacturing processes by which fluorinated alcohols are incorporated into and used to create the fluorinated surfactants and polymers that are active ingredients in these consumer and industrial products. The residuals are found in the commercial and industrial products because the processes used to synthesize the surfactants and polymers do not always incorporate all of the fluorinated alcohols. However, these unbound residuals remain associated with the active ingredients. PFOA (perfluorooctanoic acid)
Percent of total residuals measured
Leftovers may explain perfluorinated compound puzzle 4:2 FTOH 6:2 FTOH 8:2 FTOH 10:2 FTOH N-methyl perfluorooctane sulfonamidoethanol
100 80 60 40 20 0
PolyfoxL-diol (0.11)
Teflon Advance (0.34)
Zonyl FSO100 (1.03)
Zonyl FSE (3.80)
Motomaster 8:2 Windshield MethacWasher rylate (0.36) (0.04)
Scotchgard (0.39)
In recent tests, scientists recorded the proportions of residual unbound fluorinated alcohols released by different consumer products. Teflon Advance is a carpet stain repellent for home use, as is 3M’s Scotchgard Rug and Carpet Protector (please note that 3M withdrew this formulation from the market several years ago). Polyfox-ldiol is not commercially available. Zonyl FSO-100 and Zonyl FSE are industrial fluorosurfactants that can be incorporated into paints, polishes, and other coatings. Motomaster Windshield Washer with Teflon is an automotive windshield washer fluid. The 8:2 methacrylate is a monomer analyzed for comparison with the other products. (The overall percentages of residuals released are shown below each product’s name.)
and PFOS (perfluorooctane sulfonate), the most common perfluorinated chemicals, have been detected at low levels in human blood samples worldwide. These chemicals are even found in the remote Arctic, far from any possible sources. This is a puzzle for environmental scientists and government regulators. As a percentage of total annual production, the concentrations of residual fluorinated alcohols reported in this new paper (0.04–4%) would yield annual fluorinated alcohol emissions at atmospheric concentrations that have been measured, the authors say. “Because [PFOS, PFOA, and similar] compounds are not directly used as commercial or industrial products, the question has always been, ‘Where do they come from?’” explains Dinglasan-Panlilio. “This
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is the first systematic study that directly identifies a point source for [the fluorinated chemicals that we believe are] precursor compounds,” she adds. Mabury, Ford Motor Co. chemist Tim Wallington, and their colleagues had previously theorized that these volatile alcohols were the precursors to chemicals such as PFOS and PFOA. However, until now there were only data on industrial emissions of fluorotelomer alcohols. The new analyses are the first in the peer-reviewed literature to indicate that products themselves, not just manufacturing or application processes, are sources. “We call perfluorinated chemicals ‘domestic persistent organic pollutants’ because we think that there are many sources in the home, although they have not been © 2006 American Chemical Society
protectors and windshield washer fluid were lower (see figure). The scientists report the concentrations as percentages of fluorinated alcohol to dry mass of the material. The authors note that according to industry estimates, 11–14 million kg of telomer alcohols are produced annually. If unbound residuals constituted just a few percent of this amount, their emissions would be at least 100,000 kg annually. “Based on our data, it appears that residuals are a significant source,” says Dinglasan-Panlilio. “Hence, removing them would make a significant impact on the environment,” she adds. However, Harner and other experts caution that these assumptions are uncertain and that further data are necessary to determine whether telomer alcohol residuals indeed account for the amount that Dinglasan-Panlilio estimates. According to chemical engineers familiar with fluorochemical polymers and other plastics, it is likely to be feasible, but perhaps expensive, to remove these residuals. In February 2005, U.S. fluorotelomer polymer manufacturer DuPont pledged that it would remove residuals from its products by February 2006. EPA on January 23 asked DuPont and seven other chemical companies with operations in the U.S. to work to eliminate residuals in their products. —REBECCA RENNER
The cloudy side of sunscreens In a study published in this issue of ES&T (pp 1427–1431), a team of scientists report high concentrations of two sunscreen ingredients in fish tissue samples taken from rivers in northern Switzerland. The findings imply that on a hot summer day, chances are that if people are wearing sunscreen, it’s also
likely to be in their drinking water or fish dinner. Many of the lotions, lip balms, and other cosmetics that we slather on to protect us from the deleterious effects of too much sun exposure contain chemical compounds that absorb ultraviolet (UV) radiation. When people
News Briefs Boundaries of bacterial biodiversity
“We probably know more about the organisms in the deepest ocean trenches than we know about the organisms living in the soil in our backyards,” says Noah Fierer of the University of Colorado. In a paper published in the Proceedings of the National Academy of Sciences U.S.A. (2006, 103, 626–631), Fierer and Robert Jackson of Duke University analyzed 98 soil samples from various locations and ecological niches throughout North and South America, looking for links between environmental conditions and bacterial diversity. The researchers found that of the myriad parameters considered, only soil pH seemed to correlate with microbial diversity, which diminished as the soils moved from near-neutral to acidic pH levels.
Quick, cheap method for algae removal
A simple new technology for quickly removing algae from freshwater could aid communities dealing with algaeclogged lakes, according to Gang Pan and his colleagues from the Chinese Academy of Sciences in studies published in Environmental Pollution. They demonstrate that although the technology is particularly well suited for emergency removal of toxic cyanobacteria, it also may provide a long-term strategy for permanently remediating algae-clogged lakes. The new approach mixes local sediments and clays with chitosan to grab hold of the algae via flocculation and drag the unwanted plants to the bottom. In a test at Lake Taihu in eastern China, spraying low levels (25 mg/L) of 10% chitosan-modified local soils into a test enclosure removed 99% of the algal cells within 16 hours.
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identified,” says Environment Canada research scientist Tom Harner. “It is good to see that more attention is being given to the question of sources and emissions of perfluorinated compounds,” he adds. Other scientists contacted for this story echoed his views. Fluorinated alcohols include fluorotelomer alcohols, which are volatile and are often denoted by the number of carbons bonded to fluorine and the number of carbons bonded to hydrogen. (Thus, C8F17CH2CH2OH is labeled 8:2 FTOH.) The residuals in the industrial coating additives and the windshield washer fluid that the Toronto scientists analyzed were dominated by 6:2 FTOH. In contrast, residuals in the spray-on carpet-protector products were dominated by longer-chain alcohols. “These different signatures might eventually provide a way to track sources,” says Harner. To measure the unbound fluorinated alcohols, Dinglasan-Panlilio dispersed the fluorinated material in water. This process forced the volatile alcohols into the air, where they were trapped for analysis via gas chromatography combined with mass spectrometry. Most of the unbound fluorinated alcohols escaped from the products in about 2 days. The industrial coating additives had the highest percentage of residuals; those of spray-on carpet
swim, the UV filters in these products can be transferred from their skin into lakes and streams. The chemicals also wash off in the shower and are funneled to wastewater treatment plants, where traces can escape via treated effluent into the environment. However, although consumer-protection guidelines are in place for many of these UV-inhibitor products in both Europe and the U.S., regulatory agencies have placed less emphasis on the environmental risks that they pose. Annual production figures for UV filters are estimated in the hundreds of metric tons, according to a previous study on the chemical contents of wastewater by the new study’s corresponding author Marianne Balmer. She conducted this latest study with a team of chemists at the Swiss agriculture department’s federal research station (Agroscope FAW) in Wädenswil and the Swiss Federal Laboratories for Materials Testing and Research’s Laboratory of Organic Chemistry in Dübendorf. All of the 19 fish tested in the recent study had traces of 2 of the most commonly used UV filters in Europe—4-MBC (4-methylbenzylidene camphor) and OC (octocrylene). Both chemicals biodegrade slowly and can bioaccumulate, according to the researchers. Compared with another FAW study that analyzed fish from remote Swiss mountain lakes, the river fish accumulated much higher concentrations of both chemicals. Lipid-weight-based concentrations of 4-MBC in the lake species—whitefish (Coregonus) and roach (Rutilus rutilus)— ranged from 20 to 170 ppb. The brown trout (Salmo trutta fario) from the rivers tested in the current study had concentrations ranging from 50 to 1800 ppb. OC was mostly absent in the lake fish but was found in the river fish at concentrations from 40 to 2400 ppb. The nearly 10-fold difference in concentrations among lake and
JUPITERIMAGES
Environmentalt News
Both Europe and the U.S. have consumer-protection guidelines for many UV-inhibitor products, such as sunscreen lotions, lip balms, and cosmetics. However, regulatory agencies are well behind the curve on the environmental risks they pose.
river fish sheds light on the environmental transport and fate of these chemicals. “The study shows that UV filters were present in fish from rivers that receive inputs of wastewater,” says Hans-Rudolf Buser, one of the report’s coauthors. “One might argue, therefore, that aerial transport is not a major pathway for the presence, or the distribution, of UV filters in the environment and fish.” The Swiss government’s work takes research on pharmaceuticals and personal care products (PPCPs) in the environment to the next level in the U.S., says Dana Kolpin, a hydrologist with the U.S. Geological Survey (USGS). Although the U.S. EPA does not regulate any personal care products and 4-MBC and OC are not currently on USGS’s monitoring list, Kolpin says that Balmer’s work will help USGS decide how to prioritize further study on specific PPCPs. USGS is modifying its sediment analysis method to include some UV inhibitors and will soon establish a new monitoring protocol for these substances in water, he adds. 4-MBC is a known endocrine disrupter and was detected in
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human milk in a 1997 study in Germany, according to Margret Schlumpf, a toxicologist at the University of Zurich’s Group for Reproductive, Endocrine, and Environmental Toxicology, which researches the health effects of UV filters. In studies with rats, Schlumpf has shown that some UV filters, including 4-MBC at levels as low as 7 mg per kg of body weight each day, can alter reproductive function and affect birth weight and postnatal survival rates. The significantly higher concentrations in river fish reported in the new study are shocking, she says, and will help further her research. But industry sources maintain that UV filters do not produce harmful endocrine-disruption effects. Industry studies on the health impacts and environmental fate of both 4-MBC and OC, which are currently under review by EU officials, have shown that there is no risk of these chemicals contaminating the food chain at harmful levels, according to Gerald Renner, director of science and research at the European Cosmetic Toiletry and Perfumery Association. —TASHA EICHENSEHER
News Briefs
Another danger for developing frogs
It pays to be a fat green frog. Amphibians are more susceptible to hydrophobic contaminants during metamorphosis as lipid reserves deplete.
A 90-minute drive inside an auto mobile can expose drivers and passengers to the same amount of PBDEs (polybrominated diphenyl ethers) that they would come into contact with by spending 8 hours indoors, according to the first study to look for PBDEs inside automobiles. The results are discussed in a report by the nonprofit Ecology Center, Toxic at Any Speed: Chemicals in Cars & the Need for Safe Alternatives. It reports PBDE levels in cars of up to 1.7 µg/m2 , 10 times higher than those reported inside homes and commercial offices. PBDEs are used in automotive fabrics, armrests, floor coverings, and electronic insulations. The researchers found that PBDE levels were particularly high in the film that builds up on the inner surface of automobile windows, according to the study. The array of PBDE compounds in these films was notable for including relatively low levels of the Deca flame retardant. Because Deca was the predominant PBDE congener in the dust inside the cars, this finding suggests that Deca could be breaking down inside automotive interiors to create some of the other, lighter-weight PBDE compounds.
Database helps green cleaning products
Because many off-the-shelf household cleaning products contain toxic ingredients, the U.S. EPA’s Design for the Environment program has teamed with the GreenBlue Institute, a nonprofit organization, to create a searchable database to help manufacturers “green” their products. CleanGredients is now available for beta testing at GreenBlue’s website (www.greenblue.org). The first available module provides information on surfactants.
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PBDEs in U.S. cars
which they stop feeding, relying upon their internal lipid stores for energy. As lipids are lost, chemical concentrations in the remaining fat increase—in a process known as contaminant amplification—and formerly sequestered contaminants may be pushed into the bloodstream. “The old adage is that it’s survival of the fattest,” explains Haffner. “As long as the chemicals are associated with the fat, they’re not able to reach key target sites.” The concept of contaminant amplification is not new, but Haffner and his colleagues are the first to look for evidence of this process in amphibians undergoing metamorphosis. The choice of PCBs offered researchers a way to assess the role of solubility in contaminant amplification. Haffner and his colleagues found that the degree of amplification depends on the hydrophobicity of the PCB congener. The lipid-corrected concentration of hydrophobic PCBs increased over the course of metamorphosis, while the concentration of less hydrophobic congeners did not. They also observed that chemical structure played an independent role: Congeners with certain substitution patterns tended to be less amplified, regardless of solubility. G. DOUGL AS HAFFNER
The precipitous decline in worldwide amphibian populations over the past 30 years has led some scientists to refer to amphibians as “canaries in a coal mine” because their unique life cycle leaves them particularly susceptible to the effects of environmental degradation. A study published in this issue of ES&T (pp 1491–1496) provides further support for that perspective. Researchers at the University of Windsor (Canada) exposed green frog (Rana clamitans) tadpoles to a mixture of PCBs and then measured whole-body concentrations of the contaminants before and during metamorphosis. The authors found that the metamorphosing tadpoles depleted their lipid reserves faster than they eliminated certain highly hydrophobic, fatsoluble PCBs—leading to as much as a 4-fold increase in the ratio of contaminant to lipid concentration. The results suggest that amphibians may be more susceptible to the toxic effects of hydrophobic contaminants during metamorphosis. Although amphibians vary in the length of their tadpole stage and the duration of metamorphosis, according to corresponding author G. Douglas Haffner, most frogs go through a period during
Environmentalt News “I think it’s a great paper,” says Bruce Pauli, a wildlife biologist at the Canadian Wildlife Service. “If you’re looking at the potential effects of these highly lipophilic contaminants on amphibians, then it’s a good idea to look at them over the course of metamorphosis, where they’re mobilized and where they may make it to receptor sites and cause toxicity.” According to Pauli, previous studies have given only a “snapshot” of contaminant levels in amphibians at metamorphosis, not a picture of changes over time. Other researchers, however, express concern with certain aspects of the study’s experimental design—in particular, the decision to place control and dosed tadpoles in the same tank, separated only by mesh dividers, and differences in the preparation of control and dosed food. Haffner argues that the use of a single tank provides a
mechanism to determine the recycling of contaminants, as researchers were able to monitor control organisms’ uptake of PCBs from the water. Although he concedes that the treatment of the dosed food increased its fat content and, as a result, the lipid levels of the dosed tadpoles, he notes that the control group showed the same proportional lipid loss during metamorphosis as the dosed group. “Additional work is required to establish the toxicological significance of this finding,” cautions John Nichols, a research toxicologist at the U.S. EPA, emphasizing the preliminary nature of the study. Nichols adds that researchers will need more information about amphibian metabolism and the specific course of metamorphosis in different species. “It is of interest,” he explains, “to define the conditions under which am-
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plification of chemical residues occurs and by extension to determine whether this phenomenon has the potential to impact a small or large number of species.” Haffner plans to extend his study to include common pesticides. He also hopes to correlate biological endpoints, such as mortality, to changes in lipid-corrected contaminant concentrations. But the preliminary findings with PCBs already suggest that models of amphibian toxicology are inadequate if they do not take into account the upheavals of metamorphosis. “We define hazards based on persistence, bioaccumulation, and toxicity . . . and we’re talking about chemical properties,” says Haffner. “What we tend to miss is the importance of the organism’s life history—and here is a case where the organism’s life history truly dominates.” —LIZZ THRALL
