> March 29, 2005

VIA ELECTRONIC AND REGULAR U.S. MAIL

Water Docket in the EPA Docket Center

Environmental Protection Agency

Mail Code 4101T

1200 Pennsylvania Ave., NW

Washington, DC 20460

Attention: Docket ID No. OW-2004-0037

To Whom It May Concern:

The Northeast Ohio Regional Sewer District hereby provides comments on
the *Draft National Whole Effluent Toxicity (WET) Implementation
Guidance Under the NPDES Program* released for public review and comment
on December 28, 2004.

The Association of Metropolitan Sewerage Agencies (AMSA) has expressed
its longstanding concern about numeric whole effluent toxicity (WET)
limitations implemented on a pass/fail basis for determining NPDES
permit compliance. We endorse the comments submitted by AMSA in this
regard. We concur that WET testing is a useful tool in evaluating the
potential impact of an effluent on a receiving water's biota. However,
even the U.S. Court of Appeals for the D.C. Circuit, in its December 10,
2004 decision, acknowledged, "The ratified WET tests are not without
their flaws."

Because of these "flaws," we, and AMSA, support a WET implementation
approach in which NPDES permit compliance is based upon a permittee's
actions to prevent or eliminate toxicity, rather than on a measured
value that may be beyond the permittee's ability to control. U.S. EPA
had recognized the validity of this concern in the preamble to the
November 19, 2002 WET Test Methods Final Rule: "EPA policy states that
'EPA does not recommend that the initial response to a single exceedance
of a WET limit, causing no known harm, be a formal enforcement action
with a civil penalty.' EPA policy suggests additional testing is an
appropriate initial response to a single WET limit exceedance." 67 FR
69968.

We are disappointed that the draft Guidance, by not promoting an
implementation approach like that advocated by AMSA, leaves this concern
insufficiently addressed. Regardless, we submit the following comments
on the Guidance as drafted:

We appreciate that the draft Guidance has provided an option of
expressing the monthly chronic WET limit as a median rather than as an
average in "low-flow dilution situations." This reflects a correct
recognition by the Agency that, as a numeric WET limitation approaches
1.0 chronic toxicity units (TU~c~), the probability of the WET
limitation being exceeded by a single WET test result greatly increases
independent of real effluent toxicity. Because this is a function of the
numeric magnitude of the effluent limitation rather than receiving water
conditions, and because WET limitations this low can be established for
policy or other reasons not directly related to water quality, we urge
the Agency to expand this option's availability beyond "low-flow
dilution situations" to include all cases where chronic numeric WET
limitations approach 1.0 TU~c~.

For the median option to be beneficial as intended, at least three
chronic WET tests will need to be performed within the averaging period.
This many chronic WET tests within one month will pose a virtually
insurmountable challenge to some laboratories. Many will not be able to
overcome the difficulties associated with scheduling this many
additional tests. Conducting consecutive, or even overlapping, tests
while maintaining sufficient, viable populations of test organisms will
be infeasible for some laboratories and, particularly for the public
sector, will strain already limited resources. To ease these
laboratories' burden and make the justified median option more
practicable, we urge the Agency to provide that the averaging period for
compliance with a low chronic WET limitation may be extended to beyond a
single month in duration. At the very least, the Guidance should include
an explicit recognition that the averaging period need not constitute a
calendar month. In addition, whether the average or the median is the
basis for compliance, different numbers of tests should be allowed for
different species (e.g., three tests for *C. dubia* and one test for *P.
promelas*) within the averaging period. This would further ease the
strain on laboratories. The Agency should also recognize that, under
such circumstances, it may be necessary and is appropriate to use more
than one qualified laboratory.

Furthermore, we cannot agree with an additional, permittee-specific
requirement for three-species screening where the permitting authority
has already determined that routine testing of two properly-selected
test species is protective. We are not aware of any consideration
specific to using the median for determining compliance that would
necessitate such an additional requirement.

In Section 4.14, the draft Guidance states, "If an effluent is known to
contain residual chlorine at levels which may result in unacceptable
toxicity in-stream, *in situ* testing is recommended." We believe that
the Guidance should clarify that *in situ* WET testing would be
redundant and is not necessary wherever chemical monitoring is performed
to determine the adequacy of effluent dechlorination.

Finally, where environmental data enable a weight-of-evidence approach
to reasonable potential (RP), such an approach is not only warranted but
necessary for appropriately determining the need for WET limitations.
In-stream biological survey data demonstrating the presence or absence
of adverse effects of an effluent on aquatic life -- directly measuring
the receiving water's ecological condition -- are superior to solely
considering variable results from WET tests performed in the laboratory.
The environmental data ought not to be ignored in RP determinations. The
Guidance should offer the weight-of-evidence approach as an alternative
to its current RP approach which is rigidly based on statistics with
safety factors compensating for uncertainty. The weight-of-evidence
approach would provide the very kind of WET implementation flexibility
which the D.C. Circuit U.S. Court of Appeals assumed in, and relied on
for, its December 2004 decision:

> "The role of state permitting authorities ... should allay the
> concern, which petitioners express, that the correlation between
> laboratory toxicity and instream impacts grows weaker at lower levels
> of toxicity."
>
> "Individual dischargers \[should\] remain free to challenge their
> permits, on a case-by-case basis, if they believe that local
> authorities are regulating at a level that poses only a minimal risk
> to aquatic life."

Thank you for providing this opportunity to comment. If any
clarification is necessary, please do not hesitate to contact Keith Linn
of my staff at <LinnK@neorsd.org> or (216) 641-6000.

> Sincerely,
>
> Erwin J. Odeal
>
> Executive Director
>
> Northeast Ohio Regional Sewer District

kjl

cc: NEORSD Senior Staff Team

NEORSD Regulation & Permits Advisory Committee

Association of Metropolitan Sewerage Agencies