responsiveness summary to public comments - US Environmental ...

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Because EPA disapproved the omission of specifically named waterbodies, EPA put out
for public notice and comment an amendment to Missouri’s 2002 Section 303(d) list that
includes the waterbodies and pollutants added by EPA. EPA received the following comments
regarding the listing of those waterbodies:
General Comments Regarding EPA’s Evaluation of Consent Decree Waterbodies:
Comment:
1. Three letters of comment that EPA received regarding the listing of 13 out of the 26
Attachment B waters, contended that EPA’s Community Tolerance Index (CTI) is fundamentally
flawed. Commenters said the single metric approach is not appropriate and only considers
tolerance, and does not consider relative abundance among tolerance groups, as do other
tolerance based metrics. MDNR’s Visual/Benthic reference key is not an appropriate level of
taxonomic resolution to impose accurate tolerance values. The Visual/Benthic Surveys provided
a rapid and inexpensive method for screening large numbers of waterbodies for obvious water
quality problems and to determine where more intensive monitoring is needed. Visual/Benthic
Surveys consist of small amounts of chemical data, qualitative sampling of invertebrates or fish,
and visual observations of streams, and therefore, are Level One data, according to the State’s
2002 Listing Methodology. MDNR uses only Level Two or higher data to list waterbodies. The
impairment scoring cut-off value of 6.5 was not explained by EPA and appears to be arbitrary.
The Visual/Benthic Survey lacks proper QA/QC. EPA was quoted as having said in earlier
correspondence with the State that “it was not clear whether or not benthic macro-invertebrates
and fish are being identified at the survey sites by a qualified taxonomist, with samples verified
in the lab with appropriate changes made for misidentification. One commenter added that it
believes the differences of CTI values between waterbodies on either side of the 6.5 cutoff value
are insignificant and that the CTI values are contradictory to the stated evaluation for determining
the quality of the flow in a stream and is, therefore, not a valid application of the testing data.
2. One commenter asserted that the visual/benthic surveys do not indicate impairment.
For instance, EPA’s justification for listing waters include: “large amounts of algae” (commonly
occurs in even pristine streams due to edaphic and hydrologic variables); “slight turbidity” (this
occurs in all streams including the most pristine streams in the state); “elevated conductance” (is
a measure of dissolved solids, but no exceedence of the state total dissolved solids (TDS) or
sulfate + chloride standard data was provided); and “reduced aquatic diversity” (East Honey
Creek and Sandy Creek were placed on the list for poor aquatic diversity but McCarty Creek,
which had virtually the same aquatic life, was not listed because EPA judged it had acceptable
AQL diversity).
3. It was asserted that EPA made several decisions regarding attainment of Missouri’s
general water quality criteria based on observations made by MDNR field personnel that cannot
be supported by any factual evidence or measurements, and that other specific waterbody