NR 252.0365(3)(g)1.1. Optional iterative procedure to verify the reasonableness of the estimated MDL and calculated MDL of subsequent MDL determinations. NR 252.0365(3)(g)2.2. If this is the initial attempt to compute MDL based on the estimated MDL in par. (a), take the MDL as calculated in par. (f), spike in the matrix at the calculated MDL and proceed through the procedure starting with par. (d)1. NR 252.0365(3)(g)3.3. If the current MDL determination is an iteration of the MDL procedure for which the spiking level does not permit qualitative identification, report the MDL as that concentration between the current spike level and the previous spike level which allows qualitative identification. NR 252.0365(3)(g)4.4. If the current MDL determination is an iteration of the MDL procedure and the spiking level allows qualitative identification, use S2 from the current MDL calculation and S2 from the previous MDL calculation to compute the F ratio. then compute the spooled standard deviation by the following equation:
respike at the last calculated MDL and process the samples through the procedure starting with par. (d).
NR 252.0365(3)(g)5.5. Use the Spooled as calculated in subd. 3. to compute the final MDL according to the following equation: MDL=2.681 (Spooled)
where 2.681 is equal to t (12, 1-a=.99)
NR 252.0365(3)(g)6.6. The 95% confidence limits for MDL derived in subd. 4. are computed according to the following equations derived from percentiles of the chi squared over degrees of freedom distribution. MDLLCL=0.72 MDL
MDLUCL=1.65 MDL
where LCL and UCL are the lower and upper 95% confidence limits respectively based on 14 aliquots.
NR 252.0365(4)(4) Reporting. The analytical method used shall be specifically identified by number or title and the MDL for each analyte expressed in the appropriate method reporting units. If the analytical method permits options which affect the method detection limit, these conditions shall be specified with the MDL value. The sample matrix used to determine the MDL shall also be identified with the MDL value. Report the mean analyte level with the MDL. If a laboratory standard or a sample that contained a known amount analyte was used for this determination, report the mean recovery and indicate if the MDL determination was iterated. If the level of the analyte in the sample matrix exceeds 10 times the MDL of the analyte in reagent water, do not report a value for the MDL. NR 252.0365(5)(5) Reference. Glaser, J.A., Foerst, D.L., McKee, G.D., Quave, S.A., and Budde, W.L., “Trace Analysis for Wastewaters,” Environmental Science and Technology, 15, 1426 (1981). NR 252.0365(6)(6) Table of students’ T-values at the 99% confidence level. NR 252.0365 HistoryHistory: Cr. Register, May, 2001, No. 545, eff. 6-1-01; correction in (3) (e) made under s. 35.17, Stats., Register November 2024 No. 827. NR 252.04NR 252.04 Applicability of sulfide pretreatment standards. NR 252.04(1)(1) A POTW receiving wastewater from a facility subject to this chapter may require more stringent pretreatment standards for sulfide than those established by this chapter without EPA approval. NR 252.04(2)(2) The pretreatment standards for sulfide established by this chapter will not apply if the POTW receiving wastewater from a facility subject to this chapter certifies in writing with explanation of relevant factors considered, in accordance with the provisions of sub. (3) that the discharge of sulfide from the facility does not interfere with the operation of the POTW. In making this determination, the POTW shall consider all relevant factors including but not limited to the following: NR 252.04(2)(a)(a) The presence and characteristics of other industrial wastewaters which can increase or decrease sulfide concentrations, pH, or both. NR 252.04(2)(b)(b) The characteristics of the sewer/interceptor collection system which either minimize or enhance opportunities for release of hydrogen sulfide gas. NR 252.04(2)(c)(c) The characteristics of the receiving POTW’s headworks, preliminary and primary treatment systems, and sludge holding and dewatering facilities which either minimize or enhance opportunities for release of hydrogen sulfide gas.
