Oklahoma Administrative Code
Title 252 - Department of Environmental Quality
Chapter 690 - Water Quality Standards Implementation
Subchapter 3 - Point Source Discharges
Section 252:690-3-14 - Requirements specific to numeric criteria for toxic substances for the Fish and Wildlife propagation beneficial use

(a) Background assumed zero. DEQ will assume zero background levels for direct discharges of once through cooling water.

(b) Hardness or pH dependent criteria. Where a criterion for a pollutant is hardness or pH-dependent, DEQ will add hardness or pH monitoring, as appropriate, to the background monitoring requirements.

(c) Representative of low flow conditions in streams. The permittee shall collect background samples as close to low flow conditions as possible in streams.

(d) Background data from a previous permit. DEQ will not use background data referenced in the fact sheet or statement of basis of a previous permit unless the data is defensible analytical data.

(e) Background monitoring. Where toxicity-based effluent limitations for a substance are established in a permit and a complete background data set meeting the requirements of OAC 252:690-3-11 is not available, background monitoring of the limited substance is required. This requirement does not apply where the background shall be considered equal to zero in accordance with OAC 252:690-3-14(a), where Q* $ 0.333, or where the 7Q2 of the receiving stream is assumed to be 1 cfs.