Comment submitted by Center for Tobacco and the Environment, San Diego State University (SDSU)

The San Diego State University (SDSU) Center for Tobacco and the Environment respectfully submits this comment in response to the U.S. Environmental Protection Agency’s draft Sixth Drinking Water Contaminant Candidate List. We urge the EPA to include both nicotine and cotinine in national drinking-water monitoring, including in future Contaminant Candidate List (CCL) evaluations and Unregulated Contaminant Monitoring Rule (UCMR) implementation. Nicotine and cotinine are known or reasonably anticipated to occur in waters that can affect public water systems. They have identifiable human and environmental sources, and the national evidence base is currently inadequate due to a lack of routine monitoring. EPA should not mistake the absence of routine monitoring data for evidence of absence. That is precisely the kind of data gap the CCL and UCMR processes are designed to correct. We recommend that EPA take the following actions: First, include nicotine and cotinine in the final CCL evaluation framework and designate them as priority tobacco-related contaminants for drinking-water-relevant monitoring. Second, include nicotine and cotinine in future UCMR monitoring so that EPA can generate nationally representative occurrence data for finished water, source water, and systems vulnerable to urban runoff, wastewater influence, septic influence, reclaimed-water recharge, or landfill leachate. Third, require sufficiently sensitive analytical methods. Monitoring should be designed to detect concentrations at ng/L and sub-ng/L levels where feasible. High detection limits would obscure meaningful environmental occurrences and make the national dataset less useful. Fourth, pair nicotine and cotinine monitoring with additional tobacco-source tracers, where feasible, such as trans-3’-hydroxycotinine, N-formylnornicotine, anabasine, or other tobacco-specific alkaloid biomarkers. This would improve source attribution and reduce ambiguity. Fifth, prioritize monitoring designs that capture temporal and geographic variability. Sampling should include storm-event conditions, dry-weather buildup periods, urban watersheds, groundwater influenced by septic or reclaimed water, and source waters downstream of dense tobacco retail, recreational, transportation, hospitality, or high-litter environments. Sixth, ensure that the monitoring covers vulnerable systems and communities. Tobacco product waste is not evenly distributed. It is often concentrated where tobacco products are sold, used, and discarded, including communities already affected by environmental hazards. National monitoring should be designed to detect these inequities rather than average them out. EPA’s drinking-water contaminant program exists to identify emerging risks before they become entrenched failures of public protection. Nicotine and cotinine are appropriate candidates for national monitoring because they are measurable, source-informative, biologically relevant, and already detected in environmental waters. The problem is not that the evidence is too weak to justify monitoring. The problem is that current monitoring is too weak to support sound national decision-making. Tobacco product waste is preventable, but prevention requires evidence. National monitoring of nicotine and cotinine would provide EPA, states, tribes, utilities, researchers, and communities with the data needed to determine where tobacco-related contaminants occur, at what concentrations, under what hydrologic conditions, and in association with which other contaminants. Without these data, the drinking-water policy will remain blind to a widespread and preventable source of chemical contamination. For these reasons, the SDSU Center for Tobacco and the Environment strongly urges EPA to add nicotine and cotinine to national drinking-water monitoring and to treat tobacco-related contamination as a legitimate emerging drinking-water concern under the Safe Drinking Water Act. Respectfully submitted, Center for Tobacco and the Environment