# 40 CFR 61.207 - Radium-226 sampling and measurement procedures.

*n*

*1*represent the number of samples taken.

*n*

*1*samples in accordance with the analytical procedures described in 40 CFR part 61, appendix B, Method 114.

*x*

*1*and

*s*

*1*are expressed in pCi/g.

*x** is expressed in pCi/g.

*x*

*1*and

*x** calculated in paragraphs paragraphs (a)(3) and (4) of this section, determine which of the following conditions will be met:

*x*

*1*< 10 pCi/g and

*x** ≤ 10 pCi/g; phosphogypsum may be removed from this area of the stack for distribution in commerce pursuant to § 61.204.

*x*

*1*, < 10 pCi/g and

*x** > 10 pCi/g, the owner or operator may elect to follow the procedures for further sampling set forth in paragraph (c) of this section:

*x*

*1*≥ 10 pCi/g; phosphogypsum shall not be removed from this area of the stack for distribution in commerce pursuant to § 61.204.

*n*

*2*shall be rounded upwards to the next whole number. The number of additional samples needed is

*n*

*A*=

*n*

*2*−

*n*

*1*.

*n*

*A*, which shall also be taken at regularly spaced intervals across the surface of the location on the stack from which phosphogypsum will be removed.

*n*

*A*additional samples in accordance with the analytical procedures described in 40 CFR part 61, appendix B, Method 114.

*n*

*2*radium-226 concentrations by joining this set of

*n*

*A*concentrations with the

*n*

*1*concentrations previously measured. Use the formulas in paragraph (a)(3) of this section, substituting the entire set of

*n*

*2*samples in place of the

*n*

*1*samples called for in paragraph (a)(3) of this section, thereby determining the mean,

*x*

*2*, and standard deviation,

*s*

*2*, for the entire set of

*n*

*2*concentrations.

*x*

*2*, for

*x*

*1*, the recalculated standard deviation,

*s*

*2*, for

*s*

*1*, and total sample size,

*n*

*2*, for

*n*

*1*.

*x*

*2*for

*x*

*1*.

**Title 40 published on 2014-07-01**

no entries appear in the Federal Register **after** this date.

**Title 40 published on 2014-07-01**

The following are **ALL** rules, proposed rules, and notices (chronologically) published in the Federal Register relating to *40 CFR 61* **after** this date.

GPO FDSys XML | Text type regulations.gov FR Doc. 2014-17135 RIN 2060-AP26 EPA-HQ-OAR-2008-0218 FRL-9914-06-OAR ENVIRONMENTAL PROTECTION AGENCY Proposed rule; extension of comment period. Written comments on the proposed rule published on May 2, 2014 (79 FR 25388) must be received on or before October 29, 2014. 40 CFR Part 61 The Environmental Protection Agency is announcing an extension of the public comment period for the Notice of Proposed Rulemaking (NPRM) requesting public comment and information on revisions to the EPA's “National Emission Standards for Radon Emissions from Operating Mill Tailings”. The EPA published the NPRM on May 2, 2014 in the Federal Register , which included a request for comments on or before July 31, 2014. The purpose of this action is to extend the public comment period an additional 90 days.