HYDRO25533

• Permit No: C1981022
• IBM Index Class Name: Hydrology
• Doc Date: 5/9/1994
• Doc Name: RATIONALE FOR PUBLIC NOTICE
• Permit Index Doc Type: NPDES
• Media Type: D
• Archive: No

PART I
Page lh of 19
Permit No. CO-0000132
B. MONITORING REQUIREMENTS
4. Acute WET Testing-Outfall 011 (continued)
The Division may extend the time frame for investigation where reasonable
justification exists, A request for an extension must be made in writing and
received prior to the 120 day deadline. Such request must include a
justification and supporting data for such an extension.
The permittee may use the time for,imestigation to conduct a PTI or move
directly into the TIE. A PTI consists of a brief search for possible sources of
WET, which might reveal causes of such toxicity and appropriate corrective
actions more simply and cost effectively than a formal TIE, If the PTI allows
resolution of the WET incident, the TIE need not necessarily be conducted. If,
however, WET is not identified or resolved during the PTI, the TIE must be
conducted within the allowed 120 day time frame.
Any permittee that is required to conduct a PTI/TIE investigation shall do so in
conformance with procedures identified !n the following documents, or as
subsequently updated: 1) Methods for Aquatic Toxicity Identification
Evaluations. Phase I Toxicity Characterization Procedures, EPA/600/6-91/003 Feb.
91 and 2) Methods for Acuatic Toxicity Identification Evaluations. Phase II
Toxicity Identification Procedures, EPA/600/3-88/035 Feb. 1989.
A third document in this series is Methods for Acuatic Toxicity Identification
Evaluat_io_ns, Phase III Toxicity Confirmation Procedures, EPA/600/3-88/036 Feb.
1989. As indicated by the title, this procedure is intended to confirm that the
suspected toxicant is truly the toxicant. This investigation is optional.
Within 90 days of the determination of the toxicant or no later than 210 days
after demonstration of toxicity, whichever is sooner, a control program is to be
developed and received by the Division. The program shall set down a method and
procedure for elimination of the toxicity to acceptable levels.
(e) Request For Relief
The permittee may request relief from further investigation and testing where
the toxicant has not been determined and the Division has determined suitable
treatment does not appear possible. In requesting such relief, the permittee
shall submit material sufficient to establish the following:
(i) It has complied with terms and conditions of the permit compliance
schedule for the PTI/TIE investigation and other appropriate conditions as
may have been required by the Division;
(ii) During the period of the toxicity incident it has been in compliance with.
all other permit conditions, including, in the case of a POTW,
pretreatment requirements;
Amendment 2 Issued Effective