Table 4.

Cross-cutting issues affecting seven contaminants of drinking water supplies.

Cross-cutting issue	Issue description	Evidence that contaminant impacteda
		Arsenic	Disinfection by-products	Fracking Chemicals	Lead	Nitrate	PFAS	Uranium
Aging infrastructure	Broken or leaking pipes, poor water pressure, leaded pipes		X		X
Children, childcare facilities	Contaminants known to be present in schools and childcare settings; vulnerability of children to toxic effects				X	X
Climate change	Droughts increase demand and reduce supply; wildfires and flooding contaminate source waters; higher temperatures and environmental acidification mobilize pollutants from environmental media	X	X		X
Disparities	Distributive injustices related to inequities in exposure based on income, race/ethnicity, or other factors	X			X	X	X	X
Inadequate health assessments	Based on outdated data or lacking completely	X	X	X		X	X	X
Many small systems with contamination	Limited operational and technical resources, inadequate treatment capacity	X	X	X		X	X
Numerous substances	Full identity or full toxicological characterization unavailable		X	X			X
Indigenous populations	Issues of sovereignty and distributive injustices of pollutant sources	X				X		X
Uneven enforcement	Procedural justice issues related to violations	X			X	X		X
Inadequate ccurrence data	Lack of monitoring data		X	X	X		X
Private well contamination	Chemicals known to contaminate private wells, which are unregulated	X		X	X	X	X	X

^aAn X indicates the availability of documented evidence of an effect on contaminant levels in water supplies. There may be additional impacts that are not yet well-documented.