Moving Beyond the Term “Contaminants of Emerging Concern”
2021; Wiley; Volume: 40; Issue: 6 Linguagem: Inglês
10.1002/etc.5022
ISSN1552-8618
Autores Tópico(s)Pesticide and Herbicide Environmental Studies
ResumoEnvironmental Toxicology and ChemistryVolume 40, Issue 6 p. 1527-1529 Points of ReferenceFree Access Moving Beyond the Term “Contaminants of Emerging Concern” Jerry Diamond, Corresponding Author Jerry Diamond jerry.diamond@tetratech.com orcid.org/0000-0001-7257-1652 Tetra Tech, Owings Mills, Maryland, USA Address correspondence to jerry.diamond@tetratech.comSearch for more papers by this authorG. Allen Burton Jr., G. Allen Burton Jr. School for Environment and Sustainability and Department of Earth & Environmental Science, University of Michigan, Ann Arbor, Michigan, USASearch for more papers by this author Jerry Diamond, Corresponding Author Jerry Diamond jerry.diamond@tetratech.com orcid.org/0000-0001-7257-1652 Tetra Tech, Owings Mills, Maryland, USA Address correspondence to jerry.diamond@tetratech.comSearch for more papers by this authorG. Allen Burton Jr., G. Allen Burton Jr. School for Environment and Sustainability and Department of Earth & Environmental Science, University of Michigan, Ann Arbor, Michigan, USASearch for more papers by this author First published: 22 February 2021 https://doi.org/10.1002/etc.5022AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Following the publication of the Kolpin et al. (2002) landmark study, the term contaminants of emerging concern (CECs) has become increasingly popular as a catchall for various chemicals measured in the environment that are not regulated and therefore not typically monitored by federal, state, or local environmental agencies. These chemicals are considered “emerging” in the sense that we, as scientists, know very little about most of them, and certainly do not have enough information as to whether some of these CECs are or should be a concern and perhaps regulated. This ambiguity is reflected in how different researchers categorize CECs. In a cursory literature review examining studies over the past 20 yr, we found that between 9 and 40 groups of chemicals have been identified as CECs in individual studies (e.g., Daughton and Ternes [1999] identified 17 groups of emerging chemicals that only included pharmaceuticals and personal care product chemicals). The number of chemicals in each group appears to be growing over time as more chemicals are detected and increasingly finer distinctions are made in chemical groupings by researchers. The only characteristic that CECs share in common is that they are currently unregulated, and some believe they have the potential to cause adverse effects. Thus, CEC is an artificial classification that doesn't strike us as either meaningful or useful for environmental decision-making. As a case in point, some water utilities, resource agency staff, the public, and even some researchers have been known to request data for “CECs” for a site or a project, as if CECs comprised a standardized list of chemicals. Other researchers have noted similar issues regarding the term CECs (e.g., Sauvé and Desrosiers 2014). How do we take the thousands of unregulated chemicals (and their degradation products) reported in United States surface waters and identify which of these are truly a concern? To answer this question, it is educational to examine how a chemical arrived at the state of being a real concern. Triclosan, which is used as an antimicrobial agent in various consumer products, was first reported in some treated wastewater effluents and surface waters in the late 1990s (Kolpin et al. 2002) even though it has been in use in hospitals in the United States and elsewhere since the 1970s and has been widely incorporated into consumer products since the 1980s. Triclosan became an emerging contaminant because we could now detect lower concentrations in surface waters than before and it is widespread. The intended use of triclosan as an antimicrobial could have potential effects on biota and people (Bedoux et al. 2011). The widespread incorporation of triclosan into many personal care products used by millions of households and the “down the drain” fate of these products were key considerations in escalating the concern over triclosan. Human health concerns over triclosan, particularly potential cross-resistance to antibiotics, was a major consideration when both the European Union and the United States banned triclosan in certain consumer products. Thus, this CEC had a wealth of supporting data (i.e., a weight-of-evidence) demonstrating several reasons to be a concern. If in fact, CECs take the path noted for triclosan, in which many years and extensive resources are needed to confirm a chemical is truly a concern, how is it possible to address the thousands of chemicals considered to be CECs? Many assessments have approached this challenge by targeting specific chemical groups (e.g., pyrethroid or nicotinamide pesticides), chemicals with similar intended use (e.g., antimicrobials, synthetic hormones, surfactants), type of source (e.g., agricultural watersheds, wastewater treatment effluents), intended biological effects (e.g., biocide, pesticide), a predetermined list of priority chemicals (e.g., Diamond et al. 2011), or those with alarming chemical characteristics, if known (e.g., high bioaccumulation potential). All these approaches could miss many chemicals that we currently do not recognize as having potential effects on biota or people. Also, currently unknown or undescribed chemicals (such as chemical degradation products) are generally not addressed. Another less frequently used strategy is linking exposure and effects to determine chemicals of concern. Assessment tools for this strategy target chemical toxicity mechanisms using diagnostic organism and population measures. These tools are also capable of distinguishing the relative effects of chemicals versus other types of stressors (e.g., Brack et al. 2015; Water Environment & Reuse Foundation 2017). Biomolecular tools indicating the presence of other types of mechanisms of action are actively being developed and refined, which will help address a large universe of chemicals (LaLone et al. 2017). Organism and population characteristics along with exposure tools are capable of distinguishing endocrine-disrupting chemical exposure in fish and other types of chemical exposures, some of which may be caused by unregulated chemicals (Water Environment & Reuse Foundation 2017; Kidd et al. 2019). Targeted chemical analysis of water, biota, and other relevant media based on biological results can help identify types of chemicals of concern as well as perhaps the likely candidate chemicals themselves. These frameworks are mostly retrospective, that is, monitoring and analysis results are fed into the framework, often using a weight-of-evidence approach, to determine whether a concern exists. Many researchers have suggested that there is an even greater need for frameworks and approaches that can be used prospectively as well (Posthuma et al. 2017). A path forward in the assessment of unregulated chemicals should address mixtures, because chemicals rarely if ever occur singly in aquatic systems. Exposure-effects–driven tools can address mixture effects, and then follow-up chemical analysis can be used to identify the specific chemicals that may be responsible for the observed effects. The path forward should also bundle chemicals by their fate and intended uses, which can help inform where the chemicals are likely to be transported, and how biota or people would be exposed if at all. The intended use of chemicals can in some cases provide useful information as to their fate and transport and therefore their potential concern, as evidenced in the triclosan example. Figure 1 depicts a framework that groups chemicals by their fate properties coupled with their intended use to help inform which types of chemicals are likely to be transported and available for exposure, and therefore whether there is a potential concern for biota as well as people. The intended uses and fate properties of chemical groups drive the framework, to help identify groups of chemicals that may be of most concern, pending information regarding the potential level of exposure and effects. A similar logic has been reported by other researchers (e.g., Nilsen et al. 2019) to convey how chemicals could be evaluated as groups rather than individually. This framework could work prospectively as well as retrospectively by knowing the intended use and fate of a particular group of chemicals. “Fate” as used in Figure 1 includes probable transport pathways for the chemical group. We believe this is important because it gives us clues as to the likelihood that biota would be exposed to the chemicals. This framework might also help identify those groups of chemicals for which exposure and effects information may be lacking or ambiguous and therefore high priority for further monitoring and research. Figure 1Open in figure viewerPowerPoint Conceptual flow diagram for identifying chemicals (particularly currently unregulated chemicals) that are either low or high priority as a concern to aquatic biota and perhaps people. We would argue that the use of CECs as a term serves to continue a chemical-by-chemical approach with relatively little attention given to the chemical mixtures that largely occur in aquatic systems. An exposure-effects–driven approach such as we have outlined is likely to be more effective in identifying chemical mixtures of concern, the conditions under which they may be a concern, and the types of aquatic biota that should be targeted as being most at risk so that appropriate management actions can be identified. REFERENCES Bedoux G, Roig B, Thomas O, Dupont V, Le Bot B. 2011. Occurrence and toxicity of antimicrobial triclosan and by-products in the environment. Environ Sci Pollut Res 19: 1044– 1065. CrossrefCASPubMedWeb of Science®Google Scholar Brack W, Altenburger R, Schüürmann G, Krauss M, Lopez Herraez D, van Gils J, Slobodnik J, Munthe J, Gawlik BM, van Wezel A, Schriks M, Hollender J, Tollefsen KE, Mekenyan O, Dimitrov S, Bunke D, Cousins I, Posthuma L, van den Brink P, Lopez de Alda M, Carcelo D, Faust M, Kortenkamp A, Scrimshaw M, Ignatova S, Engelen G, Massmann G, Lemkine G, Teodorovic I, Walz K-H, Dulio V, Jonker MTO, Jager F, Chipman K, Falciani F, Liska I, Rooke D, Zhang X, Hollert H, Vrana B, Hilscherova K, Kramer K, Neumann S, Hammerbacher R, Backhaus T, Mack J, Segner H, Escher B, de Aragao Umbueiro G. 2015. The SOLUTIONS project: Challenges and responses for present and future emerging pollutants in land and water resources management. Sci Total Environ 503–504: 22– 31. CrossrefCASPubMedWeb of Science®Google Scholar Daughton C, Ternes T. 1999. Pharmaceuticals and personal care products in the environment: Agents of subtle change? Environ Health Perspect 107: 907– 938. CrossrefCASPubMedWeb of Science®Google Scholar Diamond J, Latimer H, Thornton K, Munkittrick K, Kidd K, Bartell S. 2011. Prioritizing contaminants of emerging concern for ecological screening assessments. Environ Toxicol Chem 30: 2385– 2394. Wiley Online LibraryCASPubMedWeb of Science®Google Scholar Kidd K, Servos M, Hecker M, Gagné F. 2019. A screening approach to assess the impacts of municipal wastewaters on aquatic systems—Research conducted 2013–2015. Canadian Water Network, Waterloo, ON, Canada. [cited 2019 October]. Available from: http://www.cwn-rce.caGoogle Scholar Kolpin D, Furlong E, Meyer M, Thurman E, Zaugg S, Barber L, Buxton H. 2002. Pharmaceuticals, hormones, and other organic wastewater contaminants in U.S. streams, 1999–2000: A national reconnaissance. Environ Sci Technol 36: 1202– 1211. CrossrefCASPubMedWeb of Science®Google Scholar LaLone CA, Ankley GT, Belanger SE, Embry MR, Hodges G, Knapen D, Munn S, Perkins EJ, Rudd MA, Villeneuve DL, Whelan M, Willett C, Zhang X, Hecker M. 2017. Advancing the adverse outcome pathway framework—An international horizon scanning approach. Environ Toxicol Chem 36: 1411– 1421. Wiley Online LibraryCASPubMedWeb of Science®Google Scholar Nilsen E, Smalling K, Ahrens L, Gros M, Miglioranza K, Pico Y, Schoenfuss H. 2019. Critical review: Grand challenges in assessing the adverse effects of contaminants of emerging concern on aquatic food webs. Environ Toxicol Chem 38: 46– 60. Wiley Online LibraryCASPubMedWeb of Science®Google Scholar Posthuma L, Brown C, de Zwart D, Diamond J, Dyer S, Hamer M, Holmes C, Marshall S, Burton A. 2017. Simplifying environmental mixtures–an aquatic exposure-based approach via land use scenarios. Environ Toxicol Chem 37: 715– 728. Wiley Online LibraryWeb of Science®Google Scholar Sauvé S, Desrosiers M. 2014. A review of what is an emerging contaminant. Chem Central J 8: 15. CrossrefPubMedWeb of Science®Google Scholar Water Environment & Reuse Foundation. 2017. Testing and refinement of the trace organics screening tool. Project CEC6R12. Final Report. Alexandria, VA, USA. Google Scholar Volume40, Issue6June 2021Pages 1527-1529 FiguresReferencesRelatedInformation
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