HYDRO29812

• Permit No: C1981041
• IBM Index Class Name: Hydrology
• Doc Date: 6/8/1992
• Doc Name: RATIONAL FOR PUBLIC NOTICE POWDERHORN COAL CO
• Permit Index Doc Type: NPDES
• Media Type: D
• Archive: No

Part I
Page lh of 19
Permit No. CO-0027146
8. MONITORING REQUIREMENTS
6. WET Preliminarv Toxicitv Investigation (continued)
If the preliminary toxicity investigation identifies a probable
toxicant and/or a probable source of toxicity, the permittee shall
submit, as part of its final report results, written notification to
chat effect co the Division. Within 30 days of completing the
preliminary toxicity investigation, the permittee shall submit (dace
of receipt) for the Division's approval a control program to control
effluent toxicity, and shall proceed to implement such plan within 7
days following receipt of written approval from the Division.
If no probable explanation for toxicity is identified in the 15-day
preliminary toxicity investigation, a Phase I Toxicity Reduction
Evaluation (TRE) is required. The permittee shall notify the
Division, as part of its final report, of its intent to proceed with
the Phase I TRE.
If toxicity disappears during the preliminar;+ toxicity investigation,
the permittee shall submit written no cification co that effect to the
Division. The Division may require the permittee Co cunduct
accelerated testing to 3emonstrate the continued absence of toxicity.
If, after comoleting any Division directed accelerated testing, no
acute conicity is found *_c exis-, the permittee shall resume normal
quarterly testing.
7. WET Phase i iRE
The Phase I TRE performed by the permittee shall be in general
accordance with Methods for Tcxicity Reduction Evaluations Phase I
Toxicitv Characterization Procedures (September, 1988) published by
EPA, or in accordance with procedures approved by the Division. If
only one species demonstrated toxicity during accelerated casting,
then chat species alone may be used in the Phase I TRE. The permittee
has 45 days from the submission (dace of receipt) of the final report
on the preliminary toxicity investigation co complete the Phase I TRE
and submit (date of receipt) a report to the Division on the results
of the study.
If the Phase I TRE identifies a probable toxicant and/or a probable
source of toxicity, the permittee shall submit written notification to
that effect co the Division as part of the report. Within 30 days of
submission (dace of receipt) of the Phase I TRE, the permittee shall
submit (dace of receipt) for the Division's approval a control program
co control WET, and shall proceed to implement such plan within 7 days
following receipt of written approval from the Division.
If the Phase I TRE fails to identify a probable toxicant and/or a
probable source of toxicity, the permittee shall notify the Division
of its findings and proceed with the Phase II TRE.