Office of Ground Water and Drinking Water November 19, 2012

MEMORANDUM

SUBJECT: Basis for Expedited Approval of Methods from 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 ASTM International. It provides the background information on why EPA is approving these methods using the expedited methods approval process. Each method is d iscussed individually below.

ASTM Method D 516

- 11 ASTM Method D 516

- 07 was approved for the analysis of s ulfate in drinking water in the expedited methods approval action that was published on November 10, 2009 (7 4 FR 57908 ). In the November 2009 acti on, ASTM Method D 516

- 07 was compared against the approved version, ASTM Method D 516

- 0 2 which is cited in the drinking water regulations at 40 CFR 14 3.4(b)

. Compare the most recent version, ASTM D516

- 11 to the approved version, noting the minor revisions associated with the expedited version :

• Section 1 .1 defines the lower range of the method as 5 mg/L instead of 1 mg/L. This is the same change made in the 2007 expedited version. The sulfate MCL defined at 40 CFR 143.3 is 250 mg/L; as such, this change in the lower limit has no bearing relative to the MCL.

• Section 1.4 incorporates a statement indicating that SI units ( t he International System of Units

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

• In Section 2, all of the separate footnotes citing individual annual books of ASTM Standards have been consolidated into a single footnote citing the ASTM website ( www.astm.org ).

• In Section 2, one of the referenced documents has been eliminated (ASTM D1192

– Specification for Equipment for Sampling Water and Steam in Closed Conduits). This reference is not necessary since a separate reference (ASTM D3370) also describes sampling water from closed conduits.

• Section 8. 5 was modified to allow the use of commercially prepared stock standard sulfate solutions

. This change was also noted in the 2007 version that was expedited.

• Section 10.1 no longer lists a 2.0 mg/L standard for the calibration curve. This same change

was n oted in the 2007 version that was expedited. Even without this standard, the calibration curve still incorporates seven standards, which is more than sufficient for a linear curve.

• Section 11.1 specifies the type of filter (0.45 μm membrane) to use with turbid samples. This same change was noted in the 2007 version that was expedited.

• Note 4 has been added which states that if dilution does not address interferences effectively, the analyst should use a different method. The methods are otherwise identic al with respect to sample collection and handling protocols, sample preparation, analytical procedure and calculation of s ulfate concentration in the sample. The precisionand bias are unchanged. Therefore, ASTM D 516

- 11 is equally as effective as the ap proved method ASTM D 516

- 02 , for determining s ulfate concentration in drinking water.

ASTM Method D 1 067

- 11 B ASTM Method D 1 06 7

- 0 6 B was approved for the determination of alkalinity in drinking water in the expedited methods approval action that was publi shed on June 24 , 20 11 ( 76 FR 37014 ). In the June 20 11 action, ASTM Method D 1 067

- 06 B was compared against the approved version, ASTM Method D 1 067

- 02 B which is cited in the drinking water regulations at 40 CFR 141.23(k)(1). Compare the most recent version, ASTM D1067

- 11 B to the approved version, noting the minor revisions associated with the expedited version :

• Added new Section 1 .6 which incorporates a statement indicating that SI units (the International System of Units

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

• In Section 2 , all of the separate footnotes citing individual annual ASTM Standards books have been consolidated into a single footnote citing the ASTM website ( w ww.astm.org )

.
• In Section 20 (Reagents), Note 5 has been added to indicate that indicators are also commercially available in prepared form

.
• Reworded the QC subsection 34.1.2.3

. The methods are otherwise identical with respect to sample collection and handling protocols, sample preparation, and analytical procedure for determination of alkalinity in the sample. The precision and bias are unchanged. Therefore, ASTM D 1067

- 11 B is equally as effective as the approved method ASTM D1067

- 02 B, for determining alkalinity in drinking water.

ASTM Method D 1293

- 12 ASTM Method D 1293

- 12 f or the analysis of pH in drinking water was compared against the approved version, ASTM Method D 1293

- 9 9 which is cited in the drinking water regulations at 40 CFR 141.2 3(k)(1)

. The following changes have been made in ASTM Method D 1293

- 12 relative to the approved version:

• Section 1.3 cites ASTM Method D6569 for more detail regarding on

- line pH measurement . This method is not approved for use in measuring pH, but cited only as a reference is not a problem.

• Section 1 .7 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.

• Added the following to the definition of pH: pH is the “negative logarithm of the hydrogen ion activity in an aqueous solution or the logarithm of the reciprocal of the hydrogen ion activity

. ”

• Added the following statement to Section 10.4: “The thermocompensator may be incorporated into the pH electrode or may be a separate probe .”

• Added the following text to Section 11.1 regarding Reference Buffer Solutions: “If traceability to NIST standard reference materials (SRMs) is required, follow exactly the NIST certificate drying, preparation, and storage instructions for the given renewal of the respective SRM buffer, and obtain the certified value from the certificate for that SRM renewal at the ap plicable temperature. Buffer solution compositions and preparations given in Sections 11.1.1 through 11.1.7 are for use with non

- NIST materials. For NIST SRMs, follow the instructions included with the SRM .”

• Modified Table 3 to incorporate recommended dr ying procedures for non

- NIST reference buffer materials.

• Added the following text to Sect. 11.1.1: “When using the NIST SRM, prepare in accordance with the current renewal certificate. For other reference materials, follow associatedinstructions or...” (remaining text in section is unchanged). This same text also prefaces Sections 11.1.2 through 11.1.7.

• Section 12.5 added the following text after discussion of calibrating with the first reference buffer: “Alternatively, follow the manufacturer’s instru ctions for calibration with the first buffer.”

• Added new Section 12.7: “Use additional portions of the second reference buffer solution, as before, until two successive readings differ by not more than + 0.02 pH units from the pHs. Alternatively, follow the manufacturer’s instructions for calibration with the second buffer.”

• Added new Section 12.8: “Interim Checks: The assembly shall be judged to be operating satisfactorily if the reading obtained for the second reference buffer solution agrees with its assigned pHs value within + 0.05 (or less) pH units.”

• Section 13.2 adds the option of using a pH electrode with integral temperature sensor.

• Added text in Section 19 discusses the use of direct pipe mounting for process pH measurement equipment.

• Added text to standardization Sect. 21 to follow the manufacturer’s instructions f or calibration (if procedural steps differ from those suggested in the method).

• Section 22 expands temperature measurement options beyond the use of a thermometer to include the use of ATC probes and pH electrodes with integral temperature sensors. The me thods 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 1293

- 12 is equally as effective as the approved method ASTM D 1293

- 99 , for determining pH in drinking water.