DEQ-CFW_00004295

Subject: GW standards versus MCLs
Date: Thu, 15 Dec 2005 12:52:07 -0500
From: Jessica Miles <j essica. miles@ncmail. net>
To: luanne williams <Iuanne.williams@ncmail. net>
In response to your inquiry, and after consultation with our attorney, I provide the
following.
It is our opinion that it would be extremely ill advised for the state to have a groundwater
standard that is higher than an MCL (maximum contaminant level) federal drinking water
standard. This situation would allow an event where a waste permittee would be allowed
to release a chemical into the environment at a level higher than the regulated MCL
(regardless of any particular study or evidence that suggests the level is "safe"). If the
release then contaminated a public water system source, the result would be an MCL
violation and enforcement action against the water system, as well as expense in
removing the contamination or developing a new source, transferring the clean up burden
unfairly to the water system. There is no provision in the Safe Drinking Water Act
(SDWA) that provides for the state to have less stringent standards. In fact, were the
state to proceed with activities that resulted in less stringent standards than the federal,
EPA would be required to initiate proceeding against the state to withdraw primary
enforcement authority ("primacy") for the SDWA program. No groundwater standard in
North Carolina should be set above an MCL under the SDWA for any contaminant.
If DHHS believes they have information that could lead to an increase in the MCL, that
information should be provided to EPA along with an explanation. EPA does perform
rule reviews on contaminant standards on regular intervals. If EPA relaxed the current
standard in the face of new data indicating higher levels are safe, then at that time, our
program would have no objection.
Please let me know if you need additional information.
Jessica G. Miles, PE., CPM, Chief
North Carolina Public Water Supply Program
DEQ-CFW-00004295