Office of Ground Water and Drinking Water January 19, 2012

MEMORANDUM

SUBJECT: Basis for Expedited Approval of Methods from Standard Methods and ASTM International

FROM: Glynda Smith Standards and Risk Management Division, Technical Support Center

TO: The Record

This memorandum documents the reviews that were conducted on new versions of methods issued by Standard Methods and ASTM International. It provides the background information on why EPA is approving these methods using the expedited metho ds approval process. Each method is discussed individually below.



### Standard Methods

Standard Method 3112 B

- 09 published online at http://www.standardmethods.org

. The published online version, 3112 B

- 99, was used as the basis for comparison because it is currently cited in the drinking water regulations at 40 CFR 141.23(k)(1) for the analysis of mercury by cold

- vapor atomic absorption spectroscopy . The updated version, 3112 B

- 09, contains only minor editorial changes relative to the approved version. Thus, the updated version is equally as effective as the approved version.

Standard Method 3125 published in the 21 st edition of Standard Methods for the Analysis of Water and Wastewater

. The version published i n the 20 th edition of Standard Methods for the Analysis of Water and Wastewater was used as the basis of comparison, because it is currently cited in the drinking water regulations at 40 CFR 141.25(a) for the analysis of uranium. The version published in the 21 st edition of Standard Methods is identical to the approved version. Thus, the 21 st edition version is equally as effective as the version published in the 20 th edition.



### ASTM International

ASTM Method D 859

- 10 ASTM Method D 859

- 05 was approved for the analysis of silica in drinking water in the expedited methods approval action that was published on June 3, 2008 (73 FR 31616). In the June 2008 action, ASTM Method D 859

- 05 was compared against the approved version, ASTM Method D 859

- 00 which is cited in the drinking water regulations at 40 CFR 141.23 (k)(1). Only two minor editorial modifications have been added to ASTM Method D859

- 10 relative to the expedited version, ASTM Method D 859

- 05:

**•** Section 1 incorporates a statement indicating that SI u nits ( t he International System of Units

- abbreviated SI from French: Système I nternational d'unités) are to be regarded as standard.

**•** Section 8.7 was modified to allow the use of commercially prepared standards.The methods are otherwise identical with respect to sample collection and handling protocols, sample preparation, analytical procedure and calculation of silica concentration in the sample. The precision and bias are unchanged. Therefore, ASTM D 859

- 10 is equally as effective as ASTM Method D 8 59

- 05 , and thus the approved method ASTM D859

- 00, for determining silica concentration in drinking water.

ASTM Method D 1179

- 10 B ASTM Method D 1179

- 04 B was approved for the analysis of fluoride in drinking water in the expedited methods approval action that was published on June 3, 2008 (73 FR 31616). In the June 2008 action, ASTM Method D 1179

- 04 B was compared against the approved version, ASTM Method D 1179

- 99 B which is cited in the drinking water regulations at 40 CFR 141.23 (k)(1). The following changes have been made in ASTM Method D 1179

- 10 B relative to the expedited version, ASTM Method D 1179

- 04 B:

**•** Section 1 incorporates a statement indicating that SI units (the International System of Units

– abbreviated SI from French: Système I nternationa l d'unités ) are to be regarded as standard.

**•** Section 2 adds two guideline references: ASTM D 4127 (Terminology Used with Ion Selective Electrodes) and ASTM D 5810 (Guide for Spiking into Aqueous Samples).

**•** Simplified and c larified text in Section 4.2. Removed the statement : “Fluoride is monitored to assure that an optimum treatment level of 1.4 to 2.4 mg/L, depending on the corresponding range of ambient temperatures of 32 to 10 o C, is maintained.” Replaced with the statement : “Fluoride is monitored t o assure that an optimum treatment level, usually near 1 mg/L, is maintained.”

**•** Expanded the Scope in Section 14.1 by adding: “Concentrated solutions of fluoroborate or fluoroboric acid, such as in electroplating wastes, should be distilled or tested using a fluoroborate ISE. Samples which contain aluminum, silica, or iron may require distillation. Anions such as chloride, bromide, iodide, sulfate, bicarbonate, nitrate, phosphate, and acetate typically do not interfere unless present at greater than 1% or more.” The cautions mentioned in the expanded scope have little bearing on drinking water samples. The threshold levels for aluminum and iron interference are significantly higher than the secondary MCLs cited at 40 CFR 143.3.

**•** Expanded the Summary in Se ction 15 by adding: “The electrode is calibrated in known fluoride solutions, and the concentrations of unknowns are determined in solutions with the same background. Samples and standards should be measured at the same temperature. Standards and sample s are diluted with an ionic strength adjustor that also minimizes possible interferences from hydroxide and low levels of aluminum and iron.” This summarizes information that is already in the Interference section.

**•** Section 11.1 allows the use of commercia lly prepared fluoride standard solutions

.
**•** Calibration Section 19.3 now describes the use of electronic spreadsheets for plotting electrode potential versus fluoride concentration. (Earlier approved versions specified manually plotting the calibration data on semilogarithmic graph paper).

**•** Section 23.6.1 was modified to remove the statement, “Fluoride is not an analyte that can be feasibly spiked into samples.” With the availability of commercially prepared solutions , matrix spikes can be performed and the section has been revised to incorporate matrix spikes accordingly. The methods are otherwise identical with respect to sample collection and handling protocols, sample preparation, and analytical procedure for determination of fluoride in the sample. The precision and bias are unchanged. Therefore, ASTM D 1179

- 10 B is equally as effective as ASTM Method D 1179

- 04 B , and thus the approved method ASTM D1179

- 99 B, for determining fluoride concentration in drinking water.ASTM Method D 5673

- 10 ASTM Method D 5 673

- 05 was approved for the analysis of uranium in drinking water in the expedited methods approval action that was published on June 3, 2008 (73 FR 31616). In th e June 2008 action, ASTM Method D 5673

- 05 was compared against the approved version, ASTM Met hod D 5673

- 03 which is cited in the drinking water regulations at 40 CFR 141.25(a). The following changes have been made in ASTM Method D 5673

- 10 relative to the expedited version, ASTM Method D 5673

- 05:

**•** Section 1 incorporates a statement indicating that SI units (the International System of Units

– abbreviated SI from French: Système I nternational d'unités ) are to be regarded as standard.

**•** In Section 4 a cross

- reference mistake has been corrected.

**•** In the Purity of Reagents subsection of Section 8.1, the method deletes the option: “other grades may be used provided it is first ascertained that the reagent is of sufficient purity to permit its use without lessening the accuracy of the determination.”

**•** In the Purity of Water subsection of Section 8.2, the method adds the statement: “Other reagent water types may be used provided it is first ascertained that the water is of sufficiently high purity to permit its use without adversely affecting the bias and pre cision of the test method.” The methods are otherwise identical with respect to sample collection and handling protocols, sample preparation, analytical procedure and calculation of uranium concentration in the sample. The precision and bias are unchanged . Therefore, ASTM D 5673

- 10 is equally as effective as ASTM Method D 5673

- 05 , and thus the approved method ASTM D5673

- 03, for determining silica concentration in drinking water.