Correspondence/Rebuttal pubs.acs.org/est
Response to “Comment on Life Cycle Comparison of Environmental Emissions from Three Disposal Options for Unused Pharmaceuticals”
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Dr. Daughton claims that take-back programs are safer than trash disposal. This claim has no citation in his comment, and we find no evidence to support this claim in the literature. In fact, Dr. Daughton’s own previous work claims, “Few studies have ever attempted (and none has ever succeeded) in linking drug collection programs to either reductions in ambient environmental residue levels or to reductions in human poisonings”.4 Our view is that take-back programs likely increase the risk of accidental poisonings, diversion, or abuse due to stockpiling of unused medications awaiting take-back. Dr. Daughton’s previous work4,5 supports this assertion. He found that take-back programs may (1) “not succeed in efficiently capturing stored medications in a timely manner (to reduce accidental poisoning)”,5 (2) “not be an effective approach for reducing the diversion of the primary drugs of concern−controlled substances”,4 and (3) not be effective due to limited public participation.4 He also found that take-back programs result in the stockpiling of unused medication,5 which increases the potential for poisonings, diversion, and abuse.4−6 As an alternative to take-back, trash disposal is an immediate, convenient,17 and safe disposal route when it follows FDA guidelines.16 When trash disposal follows FDA guidelines18 it eliminates the safety concerns associated with take-back programs created by storage and stockpiling. Trash disposal is also better for the environment in the categories of non-API emissions considered by our paper. Dr. Daughton’s response to our paper failed to recognize that take-back disposal is likely to be less safe than trash disposal, and it did not address major inconsistencies between claims made in the comment and his own previous work, which was cited in our paper.
e appreciate the opportunity, provided by Dr. Christian Daughton’s comment1 representing the U.S. Environmental Protection Agency, to (1) elaborate on the safety implications of selecting a disposal option for unused medications and (2) clarify the methods used in our paper.2
1. SAFETY We agree with Dr. Daughton that “the primary objective for any viable [disposal] option must be to protect human health and safety”.1 The two dominant hazards from unused medications posed to public health are the risk of accidental poisoning, diversion, and abuse3−6 and the risk of environmental contamination from active pharmaceutical ingredients (APIs),3,5,6 which can have negative impacts on both human and ecosystem health.3,6−10 Our manuscript2 addressed both of these issues. In his comment, Dr. Daughton states “for most unwanted medications. . .flushing would probably contribute negligibly to the ambient aquatic levels. . .because excretion is the major source”. We agree with his own peer-reviewed research which indicated, to the contrary, that the relative contribution to environmental API emissions from unused medication is not currently known5,6,11,12 and that these emissions could have concentrations that are orders of magnitude higher than those from excretion during disposal events.11 We argue that the impact of API emissions from unused medications must be determined before Dr. Daughton can claim they are negligible, especially since APIs that undergo direct disposal can have different environmental fates and toxicological effects than APIs that are excreted.10,13 Our paper addresses this point succinctly, “If [after further research] the contribution of environmental API emissions from the disposal of unused pharmaceuticals is determined to be negligible relative to the API contributions from human and animal excretion, then toilet disposal would be the best approach. Toilet disposal has the fewest non-API emissions and is the easiest and fastest way for individuals to remove pharmaceuticals from their homes. Toilet disposal would also be viable if technology could be easily and inexpensively added to all WWTPs to render APIs and their transformation products harmless.” Therefore the main issue becomes what to do with unused medications while we learn more about their ultimate fates and impacts. New legislation is aiming to minimize the flushing of unused medications by promoting take-back programs. For instance, the Illinois Safe Pharmaceutical Disposal Act bans flushing disposal by health care institutions,14,15 and the U.S. Food and Drug Administration advises consumers to only flush certain medications if a take-back program is not available.16 If flushing is to be avoided, we pose the question of whether to trash or take-back unused medications. Our paper concludes that there is no basis to select take-back over trash when considering safety, financial, environmental, or participatory factors. © 2012 American Chemical Society
2. METHODS The comparative life cycle assessment methodology in our paper used an advanced approach to model API fate and to quantify environmental API emissions. Due to a lack of previous research on API fate, hauling, and consumer behaviors, we performed an extensive uncertainty and sensitivity analysis. For example, we considered a broad range of possible transportation behaviors, including combining errands and walking. The methods were executed such that the conclusions do not depend on the actual annual mass of unused medications. As pointed out by Dr. Daughton, neither the disposal of medical devices (e.g., sharps) nor the removal of medications placed in the trash or a take-back bin were included in our analysis. Dr. Daughton notes that our paper did not discuss mail-back programs. From the modeling and environmental perspective, mail-back programs are very similar to the take-back programs we did model (i.e., consumers pick up envelopes at a pharmacy17), and so the conclusions are the same. Mail-back programs are not better than proper trash disposal with respect Published: June 26, 2012 8521
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Environmental Science & Technology
Correspondence/Rebuttal
drugs at environmental levels on human embryonic cells. Environ. Sci. Technol. 2006, 40 (7), 2442−2447. (10) Escher, B. I.; Fenner, K. Recent advances in environmental risk assessment of transformation products. Environ. Sci. Technol. 2011, 45 (9), 3835−3847. (11) Daughton, C. G.; Ruhoy, I. S. Environmental footprint of pharmaceuticals: The significance of factors beyond direct excretion to sewers. Environ. Toxicol. Chem. 2009, 28 (12), 2495−2521. (12) Ruhoy, I. S.; Daughton, C. G. Types and quantities of leftover drugs entering the environment via disposal to sewage−Revealed by coroner records. Sci. Total Environ. 2007, 388, 137−148. (13) Cunningham, V. L. Special characteristics of pharmaceuticals related to environmental fate. In Pharmaceuticals in the Environment: Sources, Fate, Effects and Risks; Kümmerer, K., Ed.; Springer: New York, NY, 2004; p 13. (14) Safe pharmaceutical disposal act. Illinois Public Act 096−0221, 2010. http://www.ilga.gov/legislation/fulltext.asp?DocName= &SessionId=76&GA=96&DocTypeId=SB&DocNum=1919&GAID= 10&LegID=&SpecSess=&Session= (accessed May 25, 2012). (15) Garcia, M. Quinn signs bill in support of drop boxes for unused pills: Initiative aimed at keeping medicines out of water supply. Chicago Tribune [Chicago, IL] 25 Aug. 2011. http://articles. chicagotribune.com/2011-08-25/news/ct-met-prescription-drugsdisposal-la20110825_1_quinn-signs-bill-water-supply-teflon-andscotchgard (accessed May 25, 2012). (16) Disposal of Unused Medicines: What You Should Know; U.S. Food and Drug Administration: Silver Spring, MD, 2012. http://www.fda. gov/Drugs/ResourcesForYou/Consumers/ BuyingUsingMedicineSafely/EnsuringSafeUseofMedicine/ SafeDisposalofMedicines/ucm186187.htm (accessed May 25, 2012). (17) Kaye, L.; Critteden, J.; Gressit, S. Reducing Prescription Drug Misuse through the Use of a Citizen Mail-Back Program in Maine−safe Medicine Disposal for ME: A Handbook and Summary Report; University of Maine, Center on Aging: Bangor, ME, 2010. http:// www.safemeddisposal.com/documents/ MailbackProgramReportFINAL.pdf (accessed May 25, 2012). (18) How to Dispose of Unused Medicines; U.S. Food and Drug Administration: Silver Spring, MD, 2012. http://www.fda.gov/ forconsumers/consumerupdates/ucm101653.htm (accessed May 24, 2012).
to safety (due to the potential for home storage and use of unsecure residential mailboxes17), cost, and environmental emissions. Mail-back programs do involve extensive transportation processes, as do take-back programs. We agree wholeheartedly with Dr. Daughton’s final point that reducing the quantities of drugs that go unused is an efficient approach to protect human and environmental health. To this effect, our paper notes that “system improvements are needed to reduce the occurrence and impacts of API release to the environment from all sources.” Until these systems change, we find no reason to recommend take-back disposal over trash disposal since it involves home storage (creating opportunities for poisonings, abuse, and diversion) as well as the highest nonAPI emissions and costs compared to any other disposal option.
Sherri M. Cook† Nancy G. Love† Steven J. Skerlos*,†,‡ †
Department of Civil and Environmental Engineering, and Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States ‡
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AUTHOR INFORMATION
Corresponding Author
*Corresponding Author’s Contact information: Steven J. Skerlos:
[email protected]; Phone (734) 615-5253; Fax (734) 647-3170. Notes
The authors declare no competing financial interest.
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REFERENCES
(1) Daughton, C. G. Comment on “Life cycle comparison of environmental emissions from three disposal options for unused pharmaceuticals”. Environ. Sci. Technol. 2012, DOI: 10.1021/ es301975v. (2) Cook, S. M.; VanDuinen, B. J.; Love, N. G.; Skerlos, S. J. Life cycle comparison of environmental emissions from three disposal options for unused pharmaceutical. Environ. Sci. Technol. 2012, 46 (10), 5535−5541. (3) Glassmeyer, S. T.; Hinchey, E. K.; Boehme, S. E.; Daughton, C. G.; Ruhoy, I. S.; Conerly, O.; Daniels, R. L.; Lauer, L.; McCarthy, M.; Nettesheim, T. G.; Sykes, K.; Thompson, V. G. Disposal practices for unwanted residential medications in the United States. Environ. Int. 2009, 35 (3), 566−572. (4) Daughton, C. G. Drugs and the Environment: Stewardship & Sustainability; National Exposure Research Laboratory, Environmental Sciences Division, U.S. Environmental Protection Agency: Las Vegas, NV, 2010; http://www.epa.gov/nerlesd1/bios/daughton/APM2002010.pdf (accessed May 25, 2012). (5) Ruhoy, I. S.; Daughton, C. G. Beyond the medicine cabinet: An analysis of where and why medications accumulate. Environ. Int. 2008, 34 (8), 1157−1169. (6) Daughton, C. G.; Ruhoy, I. S. Green pharmacy and pharmEcovigilance: Prescribing and the planet. Expert Rev. Clin. Pharmacol. 2011, 4 (2), 211−232. (7) Hospido, A.; Carballa, M.; Moreira, M.; Omil, F.; Lema, J. M.; Feijoo, G. Environmental assessment of anaerobically digested sludge reuse in agriculture: Potential impacts of emerging micropollutants. Water Res. 2010, 44 (10), 3225−3233. (8) Kidd, K. A.; Blanchfield, P. J.; Mills, K. H.; Palace, V. P.; Evans, R. E.; Lazorchak, J. M.; Flick, R. W. Collapse of a fish population after exposure to a synthetic estrogen. Proc. Natl. Acad. Sci. U.S.A. 2007, 104 (21), 8897−8901. (9) Pomati, F.; Castiglioni, S.; Zuccato, E.; Fanelli, R.; Vigetti, D.; Rossetti, C.; Calamari, D. Effects of a complex mixture of therapeutic 8522
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