Okla. Admin. Code § 252:740-3-3 - Sampling for whole effluent toxicity testing

(a) Discharges with overlapping mixing zones may be combined, at the discretion of the permitting agency, and whole effluent toxicity tests may be required on the combined effluent. Samples shall be combined in proportion to the flow for each outfall. If some of the discharges are not toxic, combining discharges may allow intermittent instream toxicity if the discharge rates fluctuate. In these cases, combined discharge testing will be disallowed. If the outfall originates from a lagoon with a retention time greater than 24 hours, composite samples may not be necessary. The permitting agency may determine that a grab sample near the discharge is sufficient.

(b) The toxicity test must be initiated within 36 hours after sample collection. No sample may be held for more than 72 hours prior to use.

Notes

Okla. Admin. Code § 252:740-3-3

Adopted by Oklahoma Register, Volume 40, Issue 6, December 1, 2022, eff. 10/25/2022 Adopted by Oklahoma Register, Volume 40, Issue 24, September 1, 2023, eff. 9/15/2023