Comment on “More of EPA’s SPARC Online CalculatorsThe Need for High-Quality Predictions of Chemical Properties” We thank Arp et al. (1) for drawing attention to the need for reliable chemical property estimation software that can be downloaded or accessed free. Their comparison of the SPARC online calculator (SPARC Performs Automated Reasoning in Chemistry; http:// ibmlc2.chem.uga.edu/sparc/) (2) and the Estimation Programs Interface Suite v4.00 (EPI Suite; http:// www.epa.gov/opptintr/exposure/ pubs/episuite.htm) highlights SPARC’s utility for estimating certain parameters of interest in environmental assessment, and partitioning properties for a broad array of phases. Missing from their discussion is appreciation of the larger context in which EPI Suite exists, and of its primary intended role as a screening tool. As stated in its interface and Web site, EPI Suite is designed for quick evaluation of chemicals for exposure potential or prioritizing materials for future work. The U.S. EPA’s Office of Pollution Prevention and Toxics (OPPT) has developed or supported several such tools to help in evaluating (1) what happens to chemicals when they are used and released; (2) how workers, the general public, consumers, and the environment may be exposed; and (3) what adverse effects may result from such exposure. These tools are intended for scientists, engineers, risk assessors, and regulators familiar with chemical risk assessment principles. Their use enables assessors to consider health and safety issues when making chemical management decisions; compare product alternatives or substitute chemicals for potential risk; and identify pollution prevention and risk reduction 10.1021/es102727q
opportunities. Other OPPT tools include OncoLogic (http://www.epa. gov/oppt/sf/pubs/oncologic.htm) for predicting carcinogenicity, ECOSAR (http://www.epa.gov/ oppt/newchems/tools/21ecosar. htm) for estimating aquatic toxicity, Analog Identification Methodology (AIM) (http://aim.epa.gov), and the PBT (Persistent, Bioaccumulative, Toxic) Profiler (http://www. pbtprofiler.net/). By providing a science-based, cost-effective way to screen new chemistries, OPPT’s tools and expertise have helped industry advance green chemistry and thereby inform substitution. This entire segment of the chemical enterprise is notably absent from Arp et al.’s list of users (“researchers, students, and citizen scientists”). To help users achieve their objectives, many of the features on Arp et al.’s (1) wish list for SPARC are already available in EPI Suite. For example, EPI Suite’s predictive methods are completely transparent in the extensive help files and have been described in numerous publications. With batch processing, available for 15 years, thousands of chemicals can be processed in seconds. EPI Suite estimates many parameters of interest to health and environmental scientists that are not found in SPARC, or in some cases, even in expensive commercial software. There are also useful features available only when certain programs are run individually. For example, KOWWIN and HENRYWIN (Henry’s Law constant) allow estimation starting from analog data, yielding more accurate predictions. The next version will include external links to web-based programs and data sources including SPARC; structure entry by drawing (via a 2D chemical structure editor); better estimation for organosilicon compounds; and more. These examples show that not only does EPI Suite continue to innovate, but
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also that the voices of users are being heard. We believe that the pollution prevention community and their needs should be more widely recognized. These strongly emphasize rapid, convenient, and transparent methods for chemical screening. ROBERT BOETHLING,* CLIVE DAVIES, CATHY FEHRENBACHER, EMMA LAVOIE, LAURENCE LIBELO, AND ELIZABETH SOMMER Economics, Exposure and Technology Division, U.S. Environmental Protection Agency, Washington, DC
[email protected]. TALA HENRY National Program Chemicals Division, U.S. Environmental Protection Agency, Washington, DC PHILIP HOWARD, WILLIAM MEYLAN, LAURA MORLACCI, JAY TUNKEL, AND THOMAS WEBB SRC, Inc., North Syracuse, New York KELLY MAYO, WILLIAM WAUGH, AND MAURICE ZEEMAN Risk Assessment Division, U.S. Environmental Protection Agency, Washington, DC (1) Arp, H. P. H.; Droge, S. T. J.; Endo, S.; Giger, W.; Goss, K.-U.; Hawthorne, S. B.; Mabury, S. A.; Mayer, P.; McLachlan, M. S.; Pankow, J. F.; Schwarzenbach, R. P.; Wania, F.; Xing, B. More of EPA’s SPARC online calculatorsthe need for highquality predictions of chemical properties. Environ. Sci. Technol. 2010, 44 (12), 4400–4401. (2) Hilal, S. H.; Karickhoff, S. W.; Carreira, L. A. Prediction of Chemical Reactivity Parameters and Physical Properties of Organic Compounds from Molecular Structure Using SPARC; EPA/600/R-03/030; U.S. Environmental Protection Agency: Athens, GA, 2003.
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