Regulatory Policy Implications of 1,4-Dioxane - Environmental Investigation and Remediation - page 462

Water utility managers may not be inclined to authorize analyses that extend beyond compli-
ance requirements because the information obtained may present risk communication challenges.
Informing consumers of the presence of a contaminant like 1,4-dioxane in drinking water is
loaded with problems, as consumers typically do not appreciate that there can be a safe level for
any synthetic or industrial chemical, particular one whose chemical name sounds very similar to
the substantially more toxic group of compounds called dioxins. * A water utility may have an impec-
cable record of full compliance with all statutory requirements, but the utility's well-deserved
image with its consumers can be damaged when they publicize the discovery of an unregulated
contaminant.
In addition to facing a signii cant public information challenge, water utilities operated by local
governments may be faced with responding to political leaders who call for action to address the
perceived risk from the discovery. Consequently, substantial sums of public funds are being
expended to address emerging contaminants with treatment or purchasing alternative water supplies
before there is consensus on the threshold of risk for the contaminant and long before a regulatory
standard is adopted. As proi led in Chapter 6, state 1,4-dioxane action levels range from 3 μg/L in
California to 85 μg/L in Michigan, underscoring the lack of consensus. In the absence of well-dei ned
federal or state regulatory guidance on emerging contaminants, local water utilities are left to decide
whether they should follow the precautionary principle and test, publicize, and treat emerging con-
taminants. State and federal programs such as the UCMRs are intended to i ll this void; however,
the number of chemicals potentially present in groundwater withdrawn from wells in urban, indus-
trial, or agricultural areas is so large that it is virtually unmanageable.
Water utility managers are seemingly faced with a lose-lose proposition when it comes to testing
for emerging contaminants. The Groundwater Ambient Monitoring and Assessment (GAMA)
program provides a solution by arranging for state government and federal contractors to perform
testing on public water supply wells for ultra-trace levels of regulated contaminants and for emerg-
ing contaminants. † Yet some water utilities are also inclined to resist cooperation with the GAMA
program for the same reason for which they are not inclined to do the testing themselves: commu-
nicating the presence of contaminants, even at ultra-trace levels, can lead to public distrust of a
water system that satisi es all statutory requirements.
The solution may lie in developing risk communication programs that include stakeholder
involvement before, during, and after the testing for emerging contaminants or ultra-trace levels of
regulated contaminants is performed. Outreach programs to educate the interested public and local
journalists are essential to ensuring that the data are understood in its proper context. The outreach
programs can include public meetings with appearances by state ofi cials with regulatory authority
over the water utility to allow questions to be answered by an informed but disinterested party. If
water utilities are to succeed at fuli lling their collective mission of serving healthy, safe water, it is
necessary to proactively explore all aspects of the water quality and to deal forthrightly with the
information thus obtained.
While water utilities may face challenges when analyzing for 1,4-dioxane and other emerging
contaminants, they may also derive secondary benei ts in addition to improved protection of drink-
ing water quality. For example, using laboratory analyses to identify all detectable compounds can
inform water treatment plant operators of the possible presence of dimethylamine and dithiocar-
bamate, which can lead to formation of nitroso-dimethyl amine upon chlorination during the
treatment of drinking water. The detection of 1,4-dioxane can provide early warning that the well
is capturing contamination from a solvent release site and that chlorinated solvents (most likely
1,1-dichloroethylene) are likely to follow.
* For example, the dioxin compound known as 2,3,7,8-tetrachlorodibenzo-p-dioxin, also called 2,3,7,8,-TCDD, has a
federal MCL of 3 × 10 −8 mg/L, that is, 0.00003 μg/L or 30 parts per quadrillion.
† For many VOCs, the GAMA program uses a reporting limit of 5 ng/L, i.e. i ve parts per trillion. For 1,4-dioxane testing
in limited areas, the GAMA program used a reporting limit of 0.15 μg/L.