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Chemicals left over from the manufacturing of stain re-pellents and other products

could be a major source of the perfluorinated compounds pres-ent in people and in the environ-ment, 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 as-sistant administrator for the Office of Prevention, Pesticides, and Toxic Substances, announced that EPA was challenging perfluorochemical manufacturers to reduce the con-centrations of these residuals from their products by 95% by 2010 and to totally eliminate them by 2015. Chemical giant DuPont Co. imme-diately accepted that challenge.

University of Toronto chem-ists Mary Joyce Dinglasan-Panlilio and Scott Mabury report the first systematic evaluation of the loose, unbound fluorinated alcohols in seven materials, including indus-trial 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 al-cohols are incorporated into and used to create the fluorinated sur-factants and polymers that are active ingredients in these con-sumer and industrial products. The residuals are found in the commercial and industrial prod-ucts because the processes used to synthesize the surfactants and polymers do not always incorpo-rate all of the fluorinated alcohols. However, these unbound residuals remain associated with the active ingredients.

PFOA (perfluorooctanoic acid)

and PFOS (perfluorooctane sul-fonate), the most common per-fluorinated chemicals, have been detected at low levels in human blood samples worldwide. These chemicals are even found in the re-mote Arctic, far from any possible sources. This is a puzzle for envi-ronmental scientists and govern-ment regulators. As a percentage of total annual production, the con-centrations of residual fluorinated alcohols reported in this new paper (0.04–4%) would yield annual fluo-rinated alcohol emissions at atmo-spheric concentrations that have been measured, the authors say.

“Because [PFOS, PFOA, and similar] compounds are not direct-ly used as commercial or industrial products, the question has always been, ‘Where do they come from?’” explains Dinglasan-Panlilio. “This

is the first systematic study that directly identifies a point source for [the fluorinated chemicals that we believe are] precursor com-pounds,” she adds.

Mabury, Ford Motor Co. chem-ist Tim Wallington, and their col-leagues had previously theorized that these volatile alcohols were the precursors to chemicals such as PFOS and PFOA. However, un-til now there were only data on in-dustrial emissions of fluorotelomer alcohols. The new analyses are the first in the peer-reviewed literature to indicate that products them-selves, not just manufacturing or application processes, are sources.

“We call perfluorinated chemi-cals ‘domestic persistent organic pollutants’ because we think that there are many sources in the home, although they have not been

Leftovers may explain perfluorinated compound puzzle

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-l-diol is not commercially available. Zonyl FSO-100 and Zonyl FSE are industrial fluo-rosurfactants 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.)

Polyfox-L-diol(0.11)

4:2 FTOH6:2 FTOH8:2 FTOH10:2 FTOHN-methyl perfluorooctane sulfonamidoethanol

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TeflonAdvance

(0.34)

ZonylFSO-100

(1.03)

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(3.80)

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rylate(0.04)

Scotchgard(0.39)

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identified,” says Environment Can-ada research scientist Tom Harner. “It is good to see that more atten-tion is being given to the question of sources and emissions of per-fluorinated 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 car-bons bonded to hydrogen. (Thus, C8F17CH2CH2OH is labeled 8:2 FTOH.)

The residuals in the industrial coating additives and the wind-shield washer fluid that the To-ronto scientists analyzed were dominated by 6:2 FTOH. In con-trast, residuals in the spray-on carpet-protector products were dominated by longer-chain alco-hols. “These different signatures might eventually provide a way to track sources,” says Harner.

To measure the unbound fluori-nated 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 addi-tives had the highest percentage of residuals; those of spray-on carpet

protectors and windshield washer fluid were lower (see figure). The scientists report the concentrations as percentages of fluorinated alco-hol 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 con-stituted 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 un-certain and that further data are necessary to determine wheth-er telomer alcohol residuals in-deed account for the amount that Dinglasan-Panlilio estimates.

According to chemical engineers familiar with fluorochemical poly-mers and other plastics, it is likely to be feasible, but perhaps expen-sive, to remove these residuals. In February 2005, U.S. fluorotelomer polymer manufacturer DuPont pledged that it would remove re-siduals from its products by Febru-ary 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

In a study published in this issue of ES&T (pp 1427–1431), a team of scientists report high concentra-tions of two sunscreen ingredients in fish tissue samples taken from rivers in northern Switzerland. The findings imply that on a hot sum-mer 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 ultravio-let (UV) radiation. When people

The cloudy side of sunscreens

Boundaries of bacterial biodiversity“We probably know more about the or-ganisms 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 Sci-ences 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 research-ers found that of the myriad param-eters 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 removalA simple new technology for quickly removing algae from freshwater could aid communities dealing with algae-clogged lakes, according to Gang Pan and his colleagues from the Chi-nese Academy of Sciences in studies published in Environmental Pollution. They demonstrate that although the technology is particularly well suit-ed 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 al-gal cells within 16 hours.

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swim, the UV filters in these prod-ucts can be transferred from their skin into lakes and streams. The chemicals also wash off in the shower and are funneled to waste-water treatment plants, where traces can escape via treated efflu-ent into the environment. Howev-er, although consumer-protection guidelines are in place for many of these UV-inhibitor products in both Europe and the U.S., regula-tory agencies have placed less em-phasis on the environmental risks that they pose.

Annual production figures for UV filters are estimated in the hundreds of metric tons, accord-ing to a previous study on the chemical contents of wastewater by the new study’s correspond-ing author Marianne Balmer. She conducted this latest study with a team of chemists at the Swiss ag-riculture department’s federal re-search station (Agroscope FAW) in Wädenswil and the Swiss Federal Laboratories for Materials Testing and Research’s Laboratory of Or-ganic Chemistry in Dübendorf.

All of the 19 fish tested in the recent study had traces of 2 of the most commonly used UV fil-ters in Europe—4-MBC (4-meth-ylbenzylidene camphor) and OC (octocrylene). Both chemicals biodegrade slowly and can bio-accumulate, according to the researchers.

Compared with another FAW study that analyzed fish from re-mote 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 (Corego-nus) and roach (Rutilus rutilus)—ranged from 20 to 170 ppb. The brown trout (Salmo trutta fario) from the rivers tested in the cur-rent 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

river fish sheds light on the envi-ronmental 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 coau-thors. “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 pharmaceuti-cals 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). Al-though the U.S. EPA does not regu-late any personal care products and 4-MBC and OC are not cur-rently 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 estab-lish a new monitoring protocol for these substances in water, he adds.

4-MBC is a known endocrine disrupter and was detected in

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 En-vironmental 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 main-tain 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 contam-inating 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

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.

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1378 n EnvironmEntal SciEncE & tEchnology / march 1, 2006

Another danger for developing frogs

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 blood-stream. “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 am-plification is not new, but Haffner and his colleagues are the first to look for evidence of this process in amphibians undergoing metamor-phosis. The choice of PCBs offered researchers a way to assess the role of solubility in contaminant ampli-fication. Haffner and his colleagues found that the degree of amplifica-tion depends on the hydrophobicity of the PCB congener. The lipid-cor-rected concentration of hydropho-bic PCBs increased over the course of metamorphosis, while the con-centration of less hydrophobic con-geners did not. They also observed that chemical structure played an independent role: Congeners with certain substitution patterns tend-ed to be less amplified, regardless of solubility.

The precipitous decline in world-wide amphibian populations over the past 30 years has led some sci-entists to refer to amphibians as “canaries in a coal mine” because their unique life cycle leaves them particularly susceptible to the ef-fects of environmental degradation. A study published in this issue of ES&T (pp 1491–1496) provides fur-ther support for that perspective.

Researchers at the University of Windsor (Canada) exposed green frog (Rana clamitans) tadpoles to a mixture of PCBs and then mea-sured whole-body concentrations of the contaminants before and during metamorphosis. The au-thors found that the metamorphos-ing tadpoles depleted their lipid reserves faster than they eliminated certain highly hydrophobic, fat-soluble PCBs—leading to as much as a 4-fold increase in the ratio of contaminant to lipid concentration. The results suggest that amphib-ians may be more susceptible to the toxic effects of hydrophobic con-taminants during metamorphosis.

Although amphibians vary in the length of their tadpole stage and the duration of metamorpho-sis, according to corresponding author G. Douglas Haffner, most frogs go through a period during

PBDEs in U.S. carsA 90-minute drive inside an auto-mobile can expose drivers and pas-sengers 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 automo-biles. The results are discussed in a report by the nonprofit Ecology Center, Toxic at Any Speed: Chemi-cals in Cars & the Need for Safe Al-ternatives. It re-ports PBDE levels in cars of up to 1.7 µg/m2, 10 times higher than those reported inside homes and com-mercial offices. PBDEs are used in automotive fabrics, armrests, floor coverings, and electronic insula-tions. The researchers found that PBDE levels were particularly high in the film that builds up on the in-ner 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 productsBecause many off-the-shelf house-hold 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 manu-facturers “green” their products. CleanGredients is now available for beta testing at GreenBlue’s website (www.greenblue.org). The first avail-able module provides information on surfactants.

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It pays to be a fat green frog. Amphibians are more susceptible to hydrophobic con-taminants during metamorphosis as lipid reserves deplete.

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“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 ef-fects of these highly lipophilic con-taminants 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, ex-press concern with certain aspects of the study’s experimental de-sign—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 recy-cling of contaminants, as research-ers 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 propor-tional lipid loss during metamor-phosis as the dosed group.

“Additional work is required to establish the toxicological signifi-cance of this finding,” cautions John Nichols, a research toxicolo-gist at the U.S. EPA, emphasiz-ing the preliminary nature of the study. Nichols adds that research-ers will need more information about amphibian metabolism and the specific course of metamor-phosis in different species. “It is of interest,” he explains, “to define the conditions under which am-

plification of chemical residues occurs and by extension to deter-mine whether this phenomenon has the potential to impact a small or large number of species.”

Haffner plans to extend his study to include common pesti-cides. He also hopes to correlate biological endpoints, such as mor-tality, to changes in lipid-corrected contaminant concentrations. But the preliminary findings with PCBs already suggest that models of am-phibian 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 organ-ism’s life history truly dominates.” —LIZZ THRALL

1380 n EnvironmEntal SciEncE & tEchnology / march 1, 2006