Michael Zwicky Hauschild

Chemical Footprints: Thin Boundaries Support Environmental Quality Management

Quality Management E impacts of rising global chemical emissions are neither known nor globally regulated, while impacts of single chemicals and mixtures can currently be demonstrated and assessed locally or on a landscape scale (e.g., ref 3). In response, we developed and outlined a novel vision on chemical footprinting to support communication and decisions promoting safe chemical management at all spatial scales. Further, we presented case studies showing typical steps and results obtained with the method. However, in their Letter “Footprints and Safe Operation Space: Walk the Line?”, Pfister and Raptis’ (P&R) raised concerns about our view and proposed life cycle assessment methods as an alternative solution. We reply to P&R, recommending that the footprint approach is sound and that we need multiple, not just one approach to work toward chemical safety. P&R’s concerns partly relate to the limited details in our Viewpoint. These concerns are addressed in cited case studies. For example, P&R refer to the need to address temporal aspects that were, in fact, addressed using multimedia environmental chemical modeling as one approach. We disagree with P&R that our approach legitimizes pollution: our approach helps to judge impacts and to compare safe chemical management options, observing that emissions occur and tend to grow while dilution options are not endless. While we have made progress with chemical footprinting, we acknowledge that many scientific challenges remain and we need multiple approaches. And beyond science, we must design how footprinting can serve safe global chemical governance (e.g., ref 8). We firmly believe that our viewpoint outlines a way to reach a point on the horizon where we have safe global governance of chemicals. We disagree with P&R that footprinting delivers bad decision support. They stated that “the planetary boundary [is] not a thin but a very broad line”, on which “we might appear to always be walking [...], almost independently of the level of pollution”. We advocate the opposite. Since the 1980s, scientists have provided a basis for deriving and implementing chemical boundaries for single chemicals, via species sensitivity distribution modeling and other approaches. These science-based boundaries are thin lines, while predicted impacts of single chemicals could and can be predicted only with uncertainty. Nonetheless, management actions triggered by comparing predicted or observed concentrations with these established environmental quality criteria have resulted in reduced chemical impacts. The most hazardous chemicals have been banned, and the most hazardous situations have been contained. Our footprint can similarly assist with choosing the safest management option, and can be compared to boundaries designed to be safe. Waiting for the ideal method would leave room for an unnecessary increase in hazard(s). Our viewpoint urges collaboration among many disciplines, including management sciences. Reasoning back from a (shared) point on the horizon−following the adage of “design, then ref ine”−we draw on approaches from risk assessment, ecology, life cycle assessment and other fields. We submit that chemical footprinting is one way forward to provide sound decision support from the local to the global scale to achieve chemical safety. Leo Posthuma*,† Anders Bjørn‡ Michiel C. Zijp†,∥ Morten Birkved‡ Miriam L. Diamond Michael Z. Hauschild‡ Mark A. J. Huijbregts Christian Mulder† Dik Van de Meent†,∥ †RIVM, Centre for Sustainability, Environment and Health, P.O. Box 1, 3720BA Bilthoven, The Netherlands ‡DTU Management Engineering, Quantitative Sustainability Assessment, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark Dept Earth Sciences, 22 Russell Street, University of Toronto, Toronto, M5S 3B1, Canada Dept Environmental Science, Institute for Water and Wetland Research, Radboud University, 6525AJ Nijmegen, The Netherlands