FEATURE
European Bans on Surfactant Trigger Transatlantic Debate REBECCA RENNER
U.S. and European regulators and researchers disagree over risks of a common class of surfactants.
lkylphenol ethoxylates (APEs) are among the most widely used groups of surfactants. Worldwide, about 500,000 tons are produced annually for use in detergents, paints, pesticides, textile and petroleum recovery chemicals, metal working fluids, and personal care products (1). Nonylphenol ethoxylates are, by far, the most prevalent members of the "family." It was discovered in 1984 that APE breakdown products are more toxic to aquatic organisms than their intact precursors are, and they were banned or restricted in Europe. In 1986, Germany instituted voluntary restrictions and Switzerland banned the use of surfactants in laundry detergents. Throughout northern Europe—England, France, Germany, and the Scandinavian countries—a voluntary ban on APE use in household cleaning products began in 1995, and restrictions on industrial cleaning applications are set to follow in 2000. "The intrinsic properties of nonylphenol with respect to toxicity, persistence, and the liability to bioaccumulate have led to phase-outs," according to Hakan Bjorndal, a chemist responsible for APEs at the Swedish Environmental Protection Agency in Stockholm. "There is a general trend in Europe that the use of nonylphenol and nonylphenol ethoxylates is declining. In some countries, this is happening very fast." The Scandinavian countries, which currently consume about 5330 tons, have seen a 40% decline in APE use in the pastfiveto six years, according to Nordic Council of Ministers estimates. Recent evidence that some APE breakdown products are weakly estrogenic (see sidebar) has intensified concern over their environmental and human health effects and has spurred further regulatory concerns. Countries and organizations currently evaluating the human health or ecological risks of chemicals within the APE family include Canada, the United Kingdom, the European Union, the Organization for Economic Cooperation and Development (OECD), and the National Academy of Sciences (2). Although the nascent endocrine disrupter issue may eventually eclipse concerns about the aquatic toxicity of APEs, scientists and regulators in Europe and the United States are concerned primarily about the latter. APE breakdown products, which are acknowledged to be highly toxic to aquatic organisms, pose environmental risks because of their occurrence, persistence, and concentration.
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"Demonized" in Europe In 1987, reacting to EPAs interest in APEs, the Chemical Manufacturers Association (CMA) formed the Alkylphenol and Ethoxylates Panel 3 1 6 A • V O L . 3 1 , NO. 7, 1997/ENVIRONMENTAL SCIENCE & TECHNOLOGY / NEWS
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to conduct research on APEs. Armed with data about the toxicity and fate of APEs, the panel has been fighting European regulatory trends that have reduced APE sales. APEs "have been demonized in Europe," according to Carter Naylor, a member of the panel and a chemist with APE manufacturer Huntsman Corporation, Salt Lake City, Utah. "The formulators are feeling the losses of markets, and we have only a limited ability to turn things around there. In the U.S. we are trying to make sure that decisions are based on sound science." Research sponsored by the CMA panel may delay the proposed European ban on industrial applications of APEs. There has been no U.S. regulatory action to date. However, since 1987 EPA has been studying APEs in cooperation with CMA's panel, and this fall the agency will release draft water quality recommendations, some of which have taken two years to complete. Some industrial users and sewage treatment plant personnel will find these restrictions difficult to meet, according to state and federal regulators. An EPA draft risk assessment published last summer concluded that there is cause for concern in some U.S. rivers, and it recommends further evaluation (2) before making any decisions about possible regulations. The risk assessment will proceed to the final version after consideration of comments submitted by the CMA panel, according to Donald Rodier a scientist responsible for the assessment at EPA's Office of Prevention Pesticides and Toxic Substances in Washington D C The EPA risk assessment, deliberations on the European ban, and a new European Union risk assessment expected in draft form this summer are the venues where these issues will be resolved. APEs have been in use for more than 40 years as detergents, emulsifiers, wetting agents, and dispersing agents in household products and in agricultural and industrial applications. In the United States, industrial uses of APE encompass the largest category (55%); institutional cleaners comprise 30% of the total; and household cleaning and personal care products make up the rest (3). Most APEs enter the aquatic environment after disposal in wastewater. The primary industrial uses of APEs are for emulsion polymerization and polymer stabilization in plastics and elastomers; cleaning, spinning, weaving, and finishing of textiles; wetting agents and emulsifiers in agricultural chemicals; and pulping and deinking in the paper industry. Institutional uses of APEs are confined to cleaning products, and most are found in commercial laundry detergents, janitorial products, and vehicle cleaners. In the household market, APEs are used mainly in laundry detergents and hard-surface cleaners (3). Concerns about these surfactants arose in the early 1980s in Europe when a group of Swiss researchers
Much of the early work on APE breakdown products was done on wastewater effluents that entered Switzerland's River Glatl (Courtesy Erika Giger)
discovered a twist in their environmental fate: the surfactants were inadvertently being transformed into more toxic compounds during the biodegradation that accompanies wastewater treatment. Particularly high APE levels were measured in digested sewage sludge. The metabolites were also shown to be more persistent and more lipophilic than the parent APEs, a finding that raised concerns about bioaccumulation. Research sponsored by the CMA panel challenges each of these conclusions. The basic facts about APEs are undisputed. APEs are nonionic surfactants made up of a branchedchain alkylphenol that has been reacted with ethylene oxide to produce an ethoxylate chain (Figure 1). Commercial formulations are usually a complex mixture of homologues, oligomers, and isomers. The main alkylphenols used are nonylphenol (NP) and octylphenol (OP). Nonylphenol ethoxylates (NPEs) encompass about 80% of the world market, and octylphenol ethoxylates (OPEs) represent most of the rest (4). Biodegradation accomplished by stepwise shortening of the ethoxylate chain creates a complex soup of compounds that can be divided into three main groups: short-chain ethoxylates, alkylphenoxy carboxylic acids, and alkylphenols such as NP and OP (4). As the chain becomes shorter, the molecule becomes less soluble. The alkylphenoxy carboxylic acids and longer chain APEs are soluble in water; the shorter chain APEs, particularly NP and OP have low water solubility and tend to adsorb onto suspended solids or sediments. Most studies and regulations focus on NPEs, because these ethoxylates are the most widely used. NP one of the breakdown products, is also apVOL. 31, NO. 7, 1997/ENVIRONMENTAL SCIENCE & TECHNOLOGY / NEWS 1 3 1 7 A
Data slim on APE role in endocrine disruption There are "extremely little data available on the concentrations of APEs likely to cause adverse effects in the environment," according to John Sumpter, an endocrinologist at Brunei University in Uxbridge, U.K. "And absolutely nothing is known about exposure levels in humans or what effects, if any, this exposure might produce." Thus far, the best short-term study is by Brunei's Susan Jobling, who has shown that the threshold concentration of nonylphenol in water for vitellogenin production in male rainbow trout is approximately 10 pg/L, with inhibition of testicular growth at concentrations of >30 pg/L (13). The short-chain ethoxylates are likely to be similarly potent. Vitellogenin is a fish egg protein that is normally produced only in large amounts by female fish. Jobling's study stands out because the fish were exposed to NP via the water, and then the concentrations were measured. The concentrations spanned the range reported in the environment. She also did full dose-response evaluations to substantiate her conclusions. These features make her study easier to interpret than the more numerous in vitro tests (14) that have measured the potency of APE biodegradation products. Concerns about potential NP estrogenic activity emerged in 1991 when Ana Soto of Tufts Medical School observed that breast cancer cells, which normally proliferate only in the presence of an estrogen, exhibited the same response in plastic containers. Investigative work revealed that NP caused the growth. These concerns grew when British researchers in 1994 found that male fish placed in cages near sewage treatment discharges produced large amounts of vitellogenin. APE metabolites were suspected to be responsible for these effects. However, natural and synthetic estrogens, not APE metabolites, have now been identified as the main estrogenic chemicals in that effluent {15). "APEs are still in the frame, at least in some situations," according to Sumpter. "But I think they are probably not the major culprits in many, perhaps most, effluents." —R.R.
proximately 10 times more toxic than its ethoxylates. However, when it comes to the environmental fate of APEs, the views of European academic scientists and regulators diverge strongly from those of U.S. industrial scientists and regulators. Europeans point to extensive research showing that APE metabolites persist and bioaccumulate. U.S. industrial scientists cite other research indicating that waste treatment effectively removes APEs and that any metabolites that do enter the environment do not persist. The influential research by Walter Giger, Marijan Ahel, and co-workers at the Swiss Federal Institute for Environmental Science and Technology in Dubendorf followed APE transformation in 11 sewage treatment works in Switzerland (5). They reported that NPE removal averaged 59% (molar basis) or 70% (weight basis). Removal of dissolved organic carbon (DOC) was 57%, so NPE and DOC biodegradation rates were about the same; NPEs accounted for 4% of the DOC. They calculated an average mass balance for the NPEs and metabolites in the 11 works and found that 10 micrograms per liter (pg/L) could result in detrimental environmen-
tal effects. Emerging U.S. and international regulatory standards are about 1 pg/L. To further address the issue of biodegradation, the CMA panel has sponsored laboratory simulations of NPE biodegradation using radiocarbon-labeled NPEs in river water and activated sludge. According to results presented last November at the SETAC annual meeting in Washington, D.C., only a minor amount of NPEs and no detectable ether carboxylate breakdown products were found after 128 days, so it appeared that there were no persistent APE metabolites in the river water. But the research provoked skepticism among many European scientists. "Our field data show that the metabolites are persistent," said Geoff Brighty research manager with the U.K. Environment Agency. "For the carboxylates CMA wants to say that they readily biodegradable on the basis of tin OECD-approved test On the basis of our field data this is shocking The test doesn't mimic what goes on in the environment "
FIGURE 1
Getting to alkylphenol By attacking and shortening the hydrophilic ethoxylate chain (shown in blue), bacteria can transform alkylphenol ethoxylates into more toxic, short-chain ethoxylates, alkylphenoxy carboxylic acids, and alkylphenols. The branched structure of the hydrophobic chain (shown as R) makes it difficult to biodegrade alkylphenols. (Courtesy Michael Warhurst)
Environmental concentrations In the United States, the main source of data on the environmental concentrations of NP and its ethoxylates in rivers is the CMA panel's Thirty Rivers Study (10), although the U.S. Geological Survey (USGS) has also been monitoring APE concentrations for several years, according to Larry Barber, a USGS geochemist in Boulder, Colo. "These compounds are ubiquitous trace components in U.S. waters," according to Barber. Preliminary USGS results are compatible with the Thirty Rivers Study and indicate that U.S. sewage plants discharge effluent that contains up to 10 ug/L NP. For ethoxycarboxylates, effluent concentrations range from tens to hundreds of micrograms per liter, although 25-30 ug/L is fairly typical, he said. For the Thirty Rivers Study, the panel used EPA's River Reach File database to randomly select 30 rivers likely to have been exposed to NPEs. Three or four water samples and two or three sediment samples at each site were collected and analyzed. Water and sediment analyses are necessary because the hydrophilic ethoxylates are likely to remain in the water column and the hydrophobic NP is likely to be absorbed onto sediments. In the Thirty Rivers Study, NP and the parent ethoxylates were found in only 30% and 24% of the water samples, respectively. No water concentrations exceeded 1 ug/L. The highest concentration— 0.64 pg/L—was seen in the most contaminated river, the Grand Calumet in Indiana. The Grand Calumet's maximum sediment concentration of NP and short-chain ethoxylates was 3 parts per million (ppm), and its average concentration was 2 ppm. The next highest sediment concentration was in New York's Mohawk River which had a maximum concentration of 1.7 ppm and an average of 0.3 ppm. The average for all sediments in all the rivers was 0.16 ppm NP and 0.02 ppm NPEs. Concerns about the high concentrations of pulp and p a p e r mills on Wisconsin's Fox River also prompted the CMA panel to fund comprehensive analyses of NR short-chain ethoxylates, and carboxylates. Because there have been almost no investigations of carboxylate levels, the Fox River study provides a comprehensive and rare data set {1, 11).
Effluents from 15 paper mills and 6 publicly owned treatment works (POTWs) were sampled in the summer and winter of 1995. Concentrations were highest in the summer. Maximum NP in paper mill effluent was 28.6 pg/L, with total NPEs of 712 pg/L; 7 of the 15 mills discharged < 1 pg/L. Of the six POTWs sampled, two released < 1 pg/L, and the largest discharger released 15.9 pg/L of NP and 78.8 pg/L of NPEs. The separate study of carboxylates found the highest concentration of total carboxylates to be 1269.7 pg/L, and the highest POTW effluent concentration was 272.4 pg/L. These results indicate that APEs are a problem on the Fox River, according to David Webb, a Wisconsin Department of Natural Resources aquatic chemV0L. 31, NO. 7, 1997 / ENVIRONMENTAL SCIENCE & TECHNOLOGY / NEWS • 3 1 9 A
ist. "If you compare the toxicity data to the instream and effluent concentrations, it is likely that some effects are taking place. These may not be dramatic—there are no fish kills—but they are real."
Setting regulatory standards Regulatory agencies around the world are reaching similar conclusions about the environmental consequences of NR Denmark has introduced an environmental quality standard for NP and NPEs of 1 pg/ L. The Danish standard was based on a study for the Nordic Council of Ministers (12), which indicated that NPEs and NP are commonly found in sewage sludges, rivers, and river sediments. The study also notes that concentrations up to 1.6 milligrams per kilogram (mg/kg) have been found in fish. The 1-pg/L standard is based on a no-observed effect level on water fleas of about 20 pg/L. The U.K. Environment Agency is also planning to introduce a 1-pg/L environmental quality standard for NR according to Brighty. EPA's draft water quality criterion, which will be released for public comment in September, is likely to be between 1 and 5 pg/L, according to sources involved in preparing the draft. In the United States and the United Kingdom, these water quality recommendations are unlikely to have major effects on most discharges because significant dilutions will be available for most effluents, and thus the standards for rivers will be met, according to Brighty. But Peter Howe, an EPA Region 5 toxicologist in Chicago, believes that in some areas the criterion could have a profound effect. "There are many places in the country where streams are dominated by effluent from POTWs. These waters may not meet the standard, and then the treatment plants will have the difficult task of trying to reduce inputs from countless sources." In a separate effort, EPA's Office of Prevention, Pesticides, and Toxic Substances last summer completed a preliminary assessment of the aquatic environment's risk from NP (2). The a s s e s s m e n t concluded that some APE metabolites are persistent in the environment but appear not to bioconcentrate to any significant extent. Overall, the assessment found that NP in general does not pose a significant risk to aquatic organisms throughout the country, but there are "hot spots"—rivers such as the Grand Calumet and the Fox. The agency is working on a more detailed assessment that will evaluate the additive effects of all APEs, determine risks from pesticides containing NP, and consider the results of a full life-cycle fish test aimed at assessing endocrine disruptive effects According to Rodier a decision on possible regulatory action will notfoemade un~ til after completion of the second risk assessment toward the end of this year U.S. and European regulatory efforts have been linked by the Oslo and Paris Commission and OECD initiatives. In Europe, the work on NP and NPEs started in 1989 with the Oslo and Paris Commission, the marine convention for the protection of the northeast Atlantic. Recommendations for voluntary phase-outs were set at a ministerial meeting in 1992. At about the same time, it was proposed that NP and NPEs be added to the OECD risk reduction program. EPA opposition to this mea3 2 0 A • VOL. 31, NO. 7, 1997 / ENVIRONMENTAL SCIENCE & TECHNOLOGY / NEWS
sure led to the formation of an expert group, with Sweden and Germany as lead countries, involving EPA, CMA's panel, and academic researchers. At a meeting in Berlin in 1993, the CMA panel agreed to conduct a research program aimed at resolving differences between Europe and the United States. The results of some of this research on biodegradation were presented at the SETAC meeting in 1996. In order to consider these new results, Sweden has agreed not to expedite a complete ban on APE this year, according to Bjorndal. Because the research has failed to reconcile the different perspectives on NP and NPE, researchers with both perspectives will participate in a workshop that is being planned for this summer or early fall. Whether science can resolve these differences remains to be seen, because the crucial issues can be interpreted in two ways, observed Webb. On environmental degradation, CMA cites studies demonstrating that APEs readily biodegrade or can be efficiently treated. But field d a t a indicate that metabolites are present in significant concentrations in effluent and river water. CMA studies show that removal is very efficient, but high concentrations of APE are still found in some effluents. Although the Oslo and Paris Commission will reconsider its proposed APE ban in light of the panel's results, the European trend of phasing out APEs in favor of readily available substitutes such as alcohol ethoxylates appears likely to continue. In the United States, concerns about aquatic toxicity seem likely to lead to milder measures such as pollution prevention or source reduction efforts as opposed to APE bans.
References (1) Naylor, C. G. et al. Proceedings sf the CESIO 4th World Surfactants Congress, Barcelona, Spain; European Committee on Surfactants and Detergents: Brussels, Belgium, 1996; pp. 378-91. (2) RM-1 Risk Assessment for para-Nonylphenol. U.S. Environmental Protection Agency: Washington, DC, July 24, 1996; AR170. (3) Talmage, S. Environmental and Human Safety of Major Surfactants: Alcohol Ethoxylates ana Alkylphenol Ethoxylates; Lewis Publlshers: Boca Raton, FL, 1994. (4) Warhurst, A. M. An Environmental Assessment ofAlkylphenol Ethoxylates and Alkylphenols; Friends of the Earth Scotland: Edinburgh, Scotland, 1995. (5) Ahel, M.; Giger W.; Koch M. Water Res. 1994,26, 1111312. (6) Giger, W.; Brunner, P. H.; Schafmer, C. Science 1984,225, 623-25. (7) Giger, W. et all Water rci. Technol. 1987, 19, 449-60. (8) Di Corcia, A.; Samperi, R.; Marcomini, A. Environ. Scii Technoll.194, 28, 850-58. (9) Ahel, M.; Giger, W; ;Shafmer, C. Water Res. 1994,28,114352. (10) Weeks, J. A. et al. Proceedings of the CESIO 4th World Surfactants Congress, Barcelona, Spain; European Committee on Surfactants and Detergents: Brussels, Belgium, 1996; pp. 276-91. (11) Field, J. A.. Reed, R. L. Environ. Sci. Technol. 1996,30,354450. (12) Chemicals wiih Estrogen-Like Effects; Nordic Council of Ministers: Copenhagen, Denmark, 1996. (13) Jobling, S. et al. Environ. Toxicol. Chem. 1996, 15, 1941 202. (14) Nimrod, A. C; Benson, W. H. Crit. Rev. Toxicol. 1996,26, 335-64. (15) Desbrow, D. et al. Abstracts of Papers; Annual Meeting of the Society of Environmental Toxicology and Chemistry, Washington, DC, 1996. Rebecca Renner is a contributing editor to ES&T.
