Statutes, codes, and regulations
Ohio Administrative Code
Title 3745 - Ohio Environmental Protection Agency
Chapter 3745-1 - Water Quality Standards
Section 3745-1-44 - Whole effluent toxicity provisions

Ohio Admin. Code 3745-1-44

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Current through all regulations passed and filed through October 28, 2024
Section 3745-1-44 - Whole effluent toxicity provisions

[Comment: For dates of non-regulatory government publications, publications of recognized organizations and associations, federal rules and federal statutory provisions referenced in this rule, see rule 3745-1-03 of the Administrative Code.]

[Comment: See rule 3745-2-09 of the Administrative Code for whole effluent toxicity water quality based effluent limit calculation procedures.]

(A) Protection of aquatic life - whole effluent approach.
(1) An acute toxicity level of 0.3 acute units (TUa) applies outside the mixing zone to limited resource water, warmwater, exceptional warmwater, coldwater, seasonal salmonid, and modified warmwater habitat use designations in accordance with this chapter and the following equation:

TUa = 100/LC50

Where:

LC50 = the median lethal concentration as defined in rule 3745-2-02 of the Administrative Code.

(2) A chronic toxicity level of 1.0 chronic toxic units (TUc) applies outside the mixing zone to warmwater, exceptional warmwater, coldwater, seasonal salmonid, and modified warmwater habitat use designations, where:

TUc = 100/IC25 for all chronic endpoints, except that:

TUc = 100/(geometric mean of NOEC and LOEC) for survival or mortality endpoints using daphnid species when this is more restrictive than the TUc value resulting from the definition based on IC25.

(B) The chronic toxicity level does not apply to limited resource water use designations.
(C) For undesignated waters, an acute toxicity level of 0.3 TUa and a chronic toxicity level of 1.0 TUc applies outside of the mixing zone.
(D) Acute toxicity within the mixing zone is regulated by paragraph (B) of 3745-33-07 of the Administrative Code.

Ohio Admin. Code 3745-1-44

Effective: 3/20/2024
Five Year Review (FYR) Dates: 8/21/2023 and 03/06/2028
Promulgated Under: 119.03
Statutory Authority: 6111.03, 6111.041, 6111.12
Rule Amplifies: 6111.12
Prior Effective Dates: 10/31/1997, 12/30/2002, 06/07/2011, 02/06/2017