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Oklahoma Administrative Code (Last Updated: March 11, 2021) |
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TITLE 252. Department of Environmental Quality |
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Chapter 690. Water Quality Standards Implementation |
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Subchapter 1. Introduction |
SECTION 252:690-1-2. Definitions
Latest version.
- The following words or terms, when used in this Chapter, shall have the following meaning, unless the context clearly indicates otherwise:"Acute WET testing" means WET testing which measures short-term lethality to a specific aquatic animal test species as specified in OAC 252:690-3-29."Arithmetic mean" means the sum of the values of individual data points in a data set divided by the number of data points. This term is synonymous with arithmetic average."Background concentration" means the concentration of a substance in receiving water immediately upstream of, but not influenced by, a wastewater discharge."CAFO" means Concentrated Animal Feeding Operation."Chronic WET testing" means WET testing which measures long term lethal and sublethal effects to a specific aquatic animal test species as specified in OAC 252:690-3-29."Coefficient of variation (CV)" means, when used in the context of effluent data, the measure of an effluent distribution's variation relative to its mean. When used in the context of WET test acceptability, CV means the % variation among test replicates in either the control or the critical dilution."Conservative substance" means a substance which persists in the environment, having characteristics which are resistant to ordinary biological or biochemical degradation."Critical dilution" means an effluent dilution, expressed as a percentage, representative of the dilution afforded a wastewater discharge according to the appropriate Q*-dependent chronic mixing zone equation for chronic WET testing. The critical dilution for acute WET testing is 100%."Defensible analytical data" means data traceable to a laboratory certified for that pollutant by DEQ under OAC 252:301 or data accepted by EPA; data traceable to a municipal laboratory operated by a properly certified laboratory technician by OAC 252:710; or data generated by a state or federal agency laboratory with equivalent certification. Quality assurance procedures, including chain of custody records, shall be adequate and documentable. Quality control data required in the analytical method shall be available from the laboratory upon request."DEQ" means the Oklahoma Department of Environmental Quality."Detectable concentration" means a concentration greater than zero (0) using a ninety-nine percent (99%) probability basis."Dilution series" means a set of proportional effluent dilutions for acute or chronic WET testing based on a specified critical dilution, which is typically the next-to-highest dilution in the series."Effluent-dominated receiving stream" means a stream which receives a point source discharge greater than or equal to one-third (1/3) of its 7Q2 flow."Engineer" means professional engineer registered in the State of Oklahoma."EPA" means the United States Environmental Protection Agency."Geometric mean" means the antilog of the arithmetic average of the natural logarithms of the individual points in a data set."Intermittent toxicity" means two or more lethal or sublethal effect test failures of a routine acute or chronic WET test within any 18-month period."LC50 (lethal concentration)" means the concentration of a toxicant in an external medium that is lethal to fifty percent of the test animals for a specified period of exposure."Life of the permit" means a specific time frame from the date of the issuance of a permit until a new or renewed permit is issued."Load Allocation or LA" means the portion of a receiving water's TMDL that is attributed either to one of its existing or future nonpoint sources or to natural background sources."Log transformation" means the mathematical transformation of an observed data set which results in a data set consisting of the natural logarithms of the individual data points in the observed data set."Log-normally distributed" means a distribution of effluent data which is positively skewed."Major discharger" means an industrial facility which has a point rating greater than or equal to 80 according to the NPDES permit rating system for industrial discharges; a POTW with a design flow greater than or equal to 1 mgd; or any facility designated as such by EPA in conjunction with the state permitting authority."Mineral constituents" means chlorides, sulfates and total dissolved solids collectively."Measurable level" means a detectable concentration for which the analytical signal to noise ratio is significantly high to report a reliable single number. The measurable level corresponds to the lowest point at which the analytical calibration curve is determined based on analyses for the pollutant of concern."Municipal" means a publicly owned treatment works or facilities which are privately owned that generate only domestic waste including mobile home parks, home owner's associations, etc."Narrative water quality criterion" means statements or other qualitative expressions of chemical, physical, or biological parameters that are assigned to protect a beneficial use."Numerical water quality criterion" means concentrations or other quantitative measures of chemical, physical, or biological parameters that are assigned to protect a beneficial use."No Observed Effect Concentration-Lethal" or "NOECL" means the greatest tested effluent dilution in a WET test at and below which lethality to test organisms does not occur that is statistically different from the control (0% effluent) at the 95% confidence level."No Observed Effect Concentration-Sublethal" or "NOECS" means the greatest tested effluent dilution in a WET test at and below which a sublethal effect to test organisms does not occur that is statistically different from the control (0% effluent) at the 95% confidence level."Non-conservative substance" means a substance which undergoes significant short-term degradation or change in the environment other than by dilution."OAC" means Oklahoma Administrative Code."Once-through cooling water" means cooling water that is not recirculated."OWQS" means the Oklahoma Water Quality Standards, contained at OAC 785:45."Permit cycle" means the life of a permit from the date of issuance to the date of expiration as specifically stated on a permit, unless the expiration of the permit is extended by operation of statute, rule or agreement of the permittee and DEQ."Period of Record" means a continuous period for which a facility's effluent data is reviewed for the purposes of characterizing the effluent."Persistent toxicity" means the repeated failure of an acute or chronic WET test. If the required WET testing frequency is monthly, repeated failure occurs upon the failure of two of the three consecutive monthly tests for the same test species. If the required WET testing frequency is other than monthly, repeated failure occurs upon the failure of the required test plus one of the two monthly retests for the same test species in the ensuing two-month period."Percent mortality" means 100% minus percent survival in a WET test effluent dilution."Positively skewed" means a data distribution which is asymmetric about its arithmetic mean with a tail in the positive direction."POTW" means publically owned treatment works."Reasonable potential" means causes, or has a reasonable potential to cause or contribute to an exceedance of a water quality criterion."Robust Regression on Order Statistics (Robust ROS)" means a statistical method that computes a regression line to estimate values for non-detect data and combines these estimates with detected observations to compute sample statistics."RPF95" means the reasonable potential factor for an effluent distribution, based on a 95% probability basis, for the purpose of determining whether an effluent limitation is required."RPF95(M)" means the reasonable potential factor for an effluent distribution, based on a 95% confidence interval and 95% probability basis, and accounting for the size of the effluent data set, for the purpose of determining whether further effluent monitoring is required."Receiving water" means the water of the State to which a wastewater is discharged."Regulatory effluent flow" means the effluent flow, which is water quality criterion-dependent, used in determining reasonable potential and wasteload allocations for a substance."SMCRA" means the Surface Mining Control and Reclamation Act of 1977."Standard deviation (sx)" means the standard deviation of an untransformed data set based on a sample of size N."Standard deviation of log-transformed x (sln(x))" means the standard deviation of a log-normally transformed data set based on a sample of size N."Sublethal test failure" means the statistically significant difference (at the 95% confidence level) between reproduction or growth of the test organism at or below the chronic critical dilution after completion of an EPA approved chronic test method."T95" means the 95th percentile of the effluent temperature distribution (in EC) of sustained two-hour daily maximum effluent temperatures where effluent temperature is recorded continuously and the distribution of daily maximum effluent temperatures where temperature is recorded at discrete intervals of two hours or longer, provided that recording intervals for temperature do not exceed six hours."TDS" means total dissolved solids."TIE" means toxicity identification evaluation."TRE" means toxicity reduction evaluation."Trigger Background concentration" means the background concentration necessary to trigger reasonable potential for a substance to exceed an applicable criterion given a specified mean effluent concentration."Wasteload allocation" or "WLA" means the portion of a receiving water's TMDL that is allocated to one of its existing or future point sources of pollution."WET limit" means a WET testing limitation in the form of a NOECL, NOECS, or LC50, the exceedance of which constitutes a permit violation."WET testing" means testing for whole effluent toxicity:(A) using an effluent dilution series based on a critical dilution,(B) with a specific aquatic animal species, and(C) utilizing EPA-approved testing methods.