The purpose of this rulemaking is to make revisions that would allow the Department of Environmental Quality (DEQ) to use improvements in analytical technology implemented since the Ground Water Quality Rule was promulgated in 1997 to identify the subset of coliform bacteria more likely to be harmful to human health. The proposed revisions augment the ground water quality standards for bacteria by adding standards for fecal coliform and Escherichia coli (E. coli) bacteria.
The proposed standard for both fecal coliform and E. coli bacteria is less than one viable colony or less than one colony forming unit/100 ml as determined by any EPA approved method. This standard is based on comments received from the state health lab during negotiated rulemaking. The state health lab indicated that test results for bacteria may be reported three ways: as zero, presence or absence, or less than one. A standard of less than one would satisfy all three reporting options. In addition, DEQ proposes to remove the reference to Subsection 200.01.c. from Subsection 400.02.a.iii. The reference to Subsection 200.01.c. is no longer correct due to revisions made to Section 200 in 2003.
In the preliminary draft for negotiated rulemaking, DEQ proposed to remove the standard for total coliform bacteria to eliminate redundancy due to the proposed addition of standards for fecal coliform and E. coli bacteria. However, during the negotiated rulemaking process, DEQ received comments in favor of maintaining the current total coliform standard due to its widespread use, both historically and currently. As proposed, the numerical ground water quality standard for bacteria will become a two-step process. The first step will be to screen the sample for bacteria using total coliform testing. If the primary ground water quality standard of 1 colony forming unit/100 ml for total coliform is exceeded, an additional analysis for fecal coliform or E. coli would be conducted to determine if the bacteria are likely to be harmful to human health. Laboratory tests currently in use can identify E. coli or fecal coliform when total coliform bacteria are present in the sample.
This phased implementation approach would eliminate the redundancy in the rule caused when standards for fecal coliform and E. coli are added, while maintaining the total coliform standard. It also allows DEQ to fulfill statutory requirements by requiring an action – testing for fecal coliform or E. coli - when a standard is exceeded. More importantly, the proposed rule change enables DEQ and other agencies to focus resources on those sites where bacterial impacts are the result of fecal contamination and are more likely to pose a threat to human health.
Domestic well owners and the public at large may be interested in this rulemaking. After consideration of public comments, DEQ intends to present the final proposal to the Board of Environmental Quality in October 2006 for adoption of a pending rule. The rule is expected to be final and effective upon the adjournment of the 2007 legislative session if approved by the Legislature.
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