NR 149.48(3) (3)LOQ.
NR 149.48(3)(a)(a) A laboratory shall establish the LOQ for all tests performed except for those exempted from an LOD under sub. (2) (a).
NR 149.48(3)(b) (b) The LOQ shall meet the regulatory limits required by the covered programs.
NR 149.48 Note Note: Exemptions to LOQ requirements for specific compounds are provided on the Wisconsin department of natural resources laboratory accreditation program website.
NR 149.48(3)(c) (c) Except for ICP and ICP/MS single point initial calibrations, the LOQ shall be established as 10/3 the LOD or at the concentration of the lowest standard in the initial calibration. For ICP and ICP/MS, when single point initial calibrations are utilized, the LOQ shall be established as 10/3 the LOD or at the “lower limit of quantitation.”
NR 149.48 Note Note: The “lower limit of quantitation” is referenced in SW-846 6010C, 6010D, 6020A, and 6020B.
NR 149.48(3)(d) (d) The LOQ shall be greater than the LOD.
NR 149.48(4) (4)Reporting limits.
NR 149.48(4)(a)(a) Reporting limits are reserved for those analytes exempted under sub. (2) (a) and shall be established based on a test's sensitivity and the intended use of the data.
NR 149.48(4)(b) (b) For biochemical oxygen demand and carbonaceous biochemical oxygen demand, the minimum reporting limit is 2 mg/L which is based on a 300 mL sample volume. When no dilution is equal to 300 mL, the reporting limit shall be adjusted based on the lowest dilution reported.
NR 149.48(4)(c) (c) For total suspended solids, the reporting limit shall be determined using the following formula: Reporting Limit (mg/L) = 1000 / (sample volume filtered in mL).
NR 149.48(5) (5)Method blank.
NR 149.48(5)(a)(a) The laboratory shall process method blanks along with and under the same conditions, including all sample preparation steps, as the associated samples in a preparation batch.
NR 149.48 Note Note: Method blanks are not required for analysis of pH, alkalinity, acidity, conductivity, and solids determinations.
NR 149.48(5)(b) (b) The laboratory shall process method blanks at a frequency of at least one per preparation batch up to 20 environmental samples. When samples are analyzed by methods that do not require a preparation step before analysis, a method blank shall be analyzed at the frequency of one per analytical batch up to 20 environmental samples.
NR 149.48(5)(c) (c) Whenever the concentration of the method blank contains analytes of interest greater than the LOD, the laboratory shall evaluate the nature of the interference and its effect on each sample in a preparation batch.
NR 149.48(5)(d) (d) The acceptance criteria for method blanks are analyte and sample specific and are established based on the highest of any of the following:
NR 149.48(5)(d)1. 1. The LOD.
NR 149.48(5)(d)2. 2. Five percent of the regulatory limit for that analyte.
NR 149.48(5)(d)3. 3. Ten percent of the measured concentration in the sample.
NR 149.48(6) (6)LCS.
NR 149.48(6)(a)(a) Unless otherwise exempted by this subsection, the laboratory shall process an LCS at a frequency of at least one sample per preparation batch up to 20 environmental samples, along with and under the same conditions as the associated samples in a preparation batch. These conditions shall include all sample preparation steps, except for leaching procedure extractions.
NR 149.48 Note Note: TCLP leachates for metals analysis are fortified after the leaching step is completed and before acid preservation.
NR 149.48(6)(b) (b) The laboratory shall fortify the LCS for the biochemical oxygen demand and carbonaceous biochemical oxygen demand tests with a mixture of glucose-glutamic acid as specified in approved methods of analysis. The LCS shall be processed at a frequency of at least one sample per analytical batch for a laboratory that analyzes more than 20 samples per week. A laboratory that analyzes fewer than 20 samples per week shall analyze one LCS per week.
NR 149.48(6)(c) (c) The laboratory is not required to process an LCS for tests for which analyzing a fortified sample is impossible or impractical.
NR 149.48 Note Note: An LCS need not be analyzed for the following tests: pH, solids determinations, chlorophyll a, and color.
NR 149.48(6)(d) ( d) The LCS shall be fortified with the analytes specified by method, regulation, or covered program or all reported analytes, except as allowed in par. (e).
NR 149.48(6)(e) (e) For analyses of polychlorinated biphenyls, the laboratory shall fortify an LCS with at least one aroclor per preparation batch. For other tests that determine analytes with responses that encompass more than one chromatographic peak, as in the case of toxaphene and chlordane, the laboratory may fortify an LCS with a single multi-peak analyte per preparation batch. The laboratory shall ensure that all multi-peak analytes detectable by a method are fortified in an LCS at least once every year that any of those analytes are reported at a detectable concentration.
NR 149.48(6)(f) (f) When the method, regulation, or covered program do not specify control limits, the laboratory shall evaluate LCS recoveries and generate in-house control limits, following exclusion of outliers with a statistical technique and using the mean plus or minus 3 times the sample standard deviation. Annually, the laboratory shall review its generated in-house control limits and update those limits whenever the performance characteristics change.
NR 149.48(6)(g) (g) In lieu of using generated in-house control limits for the LCS, the laboratory may opt to use the CCV standard limits.
NR 149.48(7) (7)Selectivity. The laboratory shall establish procedures to confirm the detections of organic analytes determined by technologies that, unlike mass spectrometry or diode array liquid chromatography, do not provide a positive unique identification when a covered program requires it or when the history of a sample source does not suggest the likely presence of the detected analyte.
NR 149.48(7)(a) (a) The laboratory shall develop and document acceptance criteria, which consider retention time shifts, for chromatographic retention time windows.
NR 149.48(7)(b) (b) The laboratory shall document acceptance criteria for mass spectral tuning.
NR 149.48 History History: CR 17-046: cr. Register February 2021 No. 782, eff. 6-29-21; correction in (2) (e), (3) (a), (4) (a) made under s. 35.17, Stats., Register February 2021 No. 782.
NR 149.50 NR 149.50 Technology requirements. The purpose of this section is to establish minimum requirements that can significantly affect data quality but are not always clearly or consistently addressed in all approved methods.
NR 149.50 Note Note: The Department will take the applicability of these requirements into consideration when there are new approved methods or advancements in technology.
NR 149.50(1) (1)Oxygen demand assays (BOD or CBOD).
NR 149.50(1)(a) (a) The environmental conditions for the analysis of biochemical oxygen demand and carbonaceous biochemical oxygen demand shall be 17 to 23 °C.
NR 149.50(1)(b) (b) When dissolved oxygen meters are calibrated using a water-saturated air or air-saturated water standard, the laboratory shall verify concentrations in mg/L of those standards by comparing those concentrations to the dissolved oxygen theoretical saturation point. The measured concentration shall be at or near the theoretical saturation point.
NR 149.50(1)(c) (c) The laboratory shall use the theoretical saturation point, based on temperature and barometric pressure, on each day of analysis to assess supersaturation.
NR 149.50 Note Note: When barometric pressure and temperature measurement features are available on the DO meter, they should be taken from the DO meter.
NR 149.50(1)(d) (d) The laboratory shall properly treat supersaturated samples before an initial dissolved oxygen measurement is performed.
NR 149.50(1)(e) (e) When the laboratory uses pipets to deliver sample volumes, the tips shall be manufactured to be wide-bore.
NR 149.50(1)(f) (f) When the laboratory analyzes multiple method blanks and glucose-glutamic acid standards in an analytical batch, each method blank and glucose-glutamic acid standard analyzed shall be assessed individually and associated to the entire analytical batch unless individual method blanks and individual glucose-glutamic acid standards are clearly documented to be traceable to specific groups of 20 samples.
NR 149.50(1)(g) (g) The laboratory shall seed disinfected samples and nitrogenous demand inhibited samples.
NR 149.50(1)(h) (h) The laboratory may not add nitrogenous demand inhibitor to the glucose-glutamic acid standard, to seed material, or method blanks.
NR 149.50(1)(i) (i) The laboratory shall use sample volumes for dilutions that are sufficient to expect 2 mg/L depletion in at least one dilution.
NR 149.50(1)(j) (j) When equipment with multiple dissolved oxygen probes is employed, the laboratory shall calibrate each probe. Sample records shall be traceable to the probe used.
NR 149.50(1)(k) (k) The laboratory shall calibrate dissolved oxygen probes on each day of use.
NR 149.50(1)(L) (L) The laboratory shall use local barometric pressure which has not been adjusted to sea level.
NR 149.50(1)(m) (m) When determining residual chlorine, a minimum detection capability of 0.1 mg/L shall be met.
NR 149.50(2) (2)Colorimetric or turbidimetric.
NR 149.50(2)(a) (a) Except for inverse chemistries, the laboratory shall use calibration blanks in the initial calibration of colorimetric or turbidimetric analyses, and those calibration blanks shall be assigned the measured response.
NR 149.50 Note Note: High range chemical oxygen demand and hexavalent chromium are two tests where inverse chemistries are utilized.
NR 149.50(2)(b) (b) When closed vials are digested using block digesters for total phosphorus, the laboratory shall perform the digestion at 150 ± 2 °C for a minimum of 30 minutes.
NR 149.50(2)(c) (c) When the laboratory uses sulfide strips, the sulfide strips shall have a minimum detection capability of 10 mg/L.
NR 149.50(2)(d) (d) The laboratory may not dilute samples after the color reagent has been added to the samples.
NR 149.50(2)(e) (e) The laboratory shall process hexavalent chromium standards the same as samples.
NR 149.50(3) (3)Electrometric assays (i.e. ion-selective electrode). When the laboratory performs electrometric assays, the laboratory shall perform an initial calibration on each day of analysis.
NR 149.50(4) (4)Gravimetric assays – residue (solids).
NR 149.50(4)(a) (a) The laboratory may not use Buchner funnels or Gooch crucibles for determination of total suspended solids or total dissolved solids.
NR 149.50(4)(b) (b) When the laboratory uses pipets to deliver sample volumes for total solids and total suspended solids, the pipet tips shall be manufactured to be wide-bore.
NR 149.50(5) (5)Gravimetric assays – oil & grease as hexane extractable materials (HEM).
NR 149.50(5)(a) (a) When using the solid phase extraction technique, the laboratory may not allow polar solvents to contact the sample.
NR 149.50(5)(b) (b) The laboratory shall use activated silica gel for silica gel-treated determinations.
NR 149.50(6) (6)Titrimetric or potentiometric titration assays. When standardization is required by method, the laboratory shall standardize all titrants monthly, unless all the following are met:
NR 149.50(6)(a) (a) Unused titrant is never poured back into the original container.
NR 149.50(6)(b) (b) Titrants shall always be protected from light.
NR 149.50(6)(c) (c) LCS recovery control limits shall be set at 90 to 110%, or tighter, and recovery is achieved.
NR 149.50(7) (7)Nondispersive IR or microcoulometry.
NR 149.50(7)(a) (a) For total organic carbon determinations, the laboratory shall perform an inorganic carbon removal check with each analysis batch.
NR 149.50(7)(b) (b) For aqueous samples with results greater than or equal to the LOQ, the laboratory shall perform duplicate injections until the relative percent difference is 10% or less.
NR 149.50(8) (8)Ion chromatography (IC). The width of the retention time window that the laboratory uses to make identifications shall be based upon measurements of actual retention time variations of standards over the course of a day unless analyst experience provides for another defensible procedure.
NR 149.50(9) (9)Flame atomic absorption spectrophotometry (FLAA).
NR 149.50(9)(a)(a) The laboratory shall perform at least two consecutive readings for all samples, standards, and quality control samples, and the laboratory shall use the average for calculating results.
NR 149.50(9)(b) (b) When sample concentrations are greater than the LOQ, the laboratory shall use a control limit of 10% or less for the relative percent difference between replicate aspirations.
NR 149.50(9)(c) (c) The laboratory shall include the same acid types and concentrations in calibration standards as those used in samples.
NR 149.50(10) (10)Graphite furnace atomic absorption spectrophotometry (GFAA).
NR 149.50(10)(a) (a) The laboratory shall use at least two firings for all samples, standards, and quality control samples.
NR 149.50(10)(b) (b) When sample concentrations are greater than the LOQ, the laboratory shall use a control limit of 10% or less for the relative standard deviation of replicate firings.
NR 149.50(10)(c) (c) When elements are measured at wavelengths lower than 200 nm, the laboratory shall analyze the samples with an instrument equipped with Zeeman background correction or equivalent.
NR 149.50(10)(d) (d) The laboratory shall include the same acid types and concentrations in calibration standards as those used in samples.
NR 149.50(11) (11)Cold vapor atomic absorption spectrophotometry (CVAA). The laboratory shall ensure that potassium permanganate is present after the two-hour digestion for Hg, or the sample shall be redigested using a smaller sample amount until potassium permanganate remains. Instead, the laboratory could choose to add more potassium permanganate to the affected samples and method blank and digest for an additional two hours.
NR 149.50(12) (12)Inductively coupled plasma emission spectrophotometry (ICP).
NR 149.50(12)(a)(a) The laboratory shall perform a spectral interference identification study before performing any sample analysis using the following single element standards: Ag, Al, As, B, Ba, Be, Ca, Cd, Ce, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, Pb, Sb, Se, SiO2, Sn, Sr, Ti, Tl, V, and Zn. When other interferences have been identified, the laboratory shall perform appropriate spectral interference identification studies for those interferences. The laboratory shall analyze the interfering elements to identify potential interelement interferences for each mode and wavelength used. This requirement applies to each instrument used for analysis.
NR 149.50(12)(b) (b) The concentration of single element standards used in the spectral interference identification study shall be at or greater than the maximum concentrations encountered in samples.
NR 149.50(12)(c) (c) At the beginning of each analysis day, the laboratory shall verify that interference corrections and background corrections are working properly through the analysis of interference check standards. The interference check standards shall include all the identified interferences at the maximum concentrations encountered in samples.
NR 149.50(12)(d) (d) Interference correction is only valid to the concentration tested in the spectral interference identification study. Samples with interferences present greater than the concentrations tested shall be reanalyzed at a dilution, or if the instrument is capable, the laboratory may analyze a single element standard at the level in the sample to demonstrate that the apparent concentration is less than the LOQ; if it is not less than the LOQ, the interelement correction factors may be updated, and all of the associated data can be reprocessed.
NR 149.50(12)(e) (e) When reporting results to the LOD, the concentration of each non-spiked target element in the interference check standard shall be less than 10/3 their corresponding LOD.
Published under s. 35.93, Stats. Updated on the first day of each month. Entire code is always current. The Register date on each page is the date the chapter was last published.