ABSTRACT
This chapter reviews the full complement of regulations and regulatory guidance thresholds for 1,4-dioxane, with an emphasis on the derivation of water quality standards. The 1996 Safe Drinking Water Act amendments require that Environmental Protection Agency issue a new list of no more than 30 unregulated contaminants to be monitored by public water systems under the Unregulated Contaminant Monitoring Rule (UCMR). A number of events would have to transpire before 1,4-dioxane could be regulated with a federal Maximum Contaminant Level (MCL). Firstly, identification of 1,4-dioxane as a possible health concern in US drinking water has been completed with the data collected in UCMR3. Secondly, the US Environmental Protection Agency (USEPA) must determine whether an opportunity exists to reduce public health risks by regulation using the agency's human health risk assessments, which determine potential drinking water exposure risks and standards. 1,4-dioxane and other solvent stabilizer compounds are not regulated by USEPA, except for epichlorohydrin, which has an MCL goal of zero.
