12 Va. Admin. Code § 5-590-378 - Radiological monitoring

A. The location of sampling points, the radionuclides measured in community waterworks, the frequency, and the timing of sampling within each compliance period shall be established or approved by the department. The department may increase required monitoring where necessary to detect variations within the waterworks. Failure to comply with the sampling schedules in this section will require public notification pursuant to 12VAC5-590-540 A 3.

B. The owner of a community waterworks shall conduct monitoring to determine compliance with the PMCLs listed in Table 340.4 and 12VAC5-590-388 in accordance with this section.

1. Monitoring requirements for gross alpha particle activity, radium-226, radium-228, and uranium.

a. The owner shall conduct initial monitoring to determine compliance with the PMCLs listed in Table 340.4 for gross alpha particle activity, radium-226, radium-228, and uranium. For the purposes of monitoring for gross alpha particle activity, radium-226, radium-228, uranium, and beta particle and photon radioactivity in drinking water, "detection limit" is defined as specified in Table 378.1.

(1) Applicability and sampling location for an existing community waterworks or its sources. The owner using groundwater, surface water, or both groundwater and surface water shall sample at every entry point to the distribution system that is representative of all sources being used under normal operating conditions. The owner shall collect each sample at the same entry point unless conditions make another sampling point more representative of each source.

(2) Applicability and sampling location for a new community waterworks or its sources. A new community waterworks or a community waterworks that uses a new source water shall begin to conduct initial monitoring for the new source water within the first quarter after initiating use. The owner shall conduct more frequent monitoring when directed by the department in the event of possible contamination or when changes in the distribution system or treatment processes occur that may increase the concentration of radioactivity in the finished water.

b. Initial monitoring. The owner shall conduct initial monitoring for gross alpha particle activity, radium-226, radium-228, and uranium as follows:

(1) The owner shall collect four consecutive quarterly samples at all entry points.

(2) For gross alpha particle activity, uranium, radium-226, and radium-228 monitoring, the department may waive the final two quarters of initial monitoring for an entry point if the results of the samples from the previous two quarters are below the detection limit as defined by and as specified in Table 378.1.

(3) If the average of the initial monitoring results for an entry point is above the PMCL, then the owner shall collect and analyze quarterly samples at that entry point until the owner has results from four consecutive quarters that are at or below the PMCL, unless the owner enters into another schedule as part of a formal compliance agreement with the department.

c. Reduced monitoring. The department may allow the owner to reduce the future frequency of monitoring from once every three years to once every six or nine years at each entry point, based on the following criteria:

(1) If the average of the initial monitoring results for each contaminant (i.e., gross alpha particle activity, uranium, radium-226, or radium-228) is below the detection limit as specified in Table 378.1, then the owner shall collect and analyze for that contaminant using at least one sample at that entry point every nine years.

(2) For gross alpha particle activity, combined radium, and uranium, if the average of the initial monitoring results for each contaminant is at or above the detection limit as specified in Table 378.1, but at or below half of the PMCL, then the owner shall collect and analyze for that contaminant using at least one sample at that entry point every six years.

(3) For gross alpha particle activity, combined radium, and uranium, if the average of the initial monitoring results for each contaminant is above half the PMCL but at or below the PMCL, then the owner shall collect and analyze at least one sample at that entry point every three years.

(4) The owner shall use the samples collected during the reduced monitoring period to determine the monitoring frequency for subsequent monitoring periods (e.g., if a waterworks entry point is on a nine-year monitoring period, and the sample result is above half the PMCL, then the next monitoring period for that entry point is three years).

(5) If the owner has a monitoring result that exceeds the PMCL while on reduced monitoring, then the owner shall collect and analyze quarterly samples at that entry point until the results from four consecutive quarters are below the PMCL, unless the waterworks enters into another schedule as part of a formal compliance agreement with the department.

d. Compositing. To fulfill quarterly monitoring requirements for gross alpha particle activity, radium-226, radium-228, or uranium, the owner may composite up to four consecutive quarterly samples from a single entry point if analysis is done within a year of the first sample. The department will treat analytical results from the composited sample as the average analytical result to determine compliance with the PMCLs and the future monitoring frequency. If the analytical result from the composited sample is greater than half the PMCL, then the department may direct the owner to collect additional quarterly samples before allowing the owner to sample under a reduced monitoring schedule.

e. A gross alpha particle activity measurement may be substituted for the required radium-226 measurement provided that the measured gross alpha particle activity does not exceed 5 pCi/L. A gross alpha particle activity measurement may be substituted for the required uranium measurement provided that the measured gross alpha particle activity does not exceed 15 pCi/L. The gross alpha measurement shall have a confidence interval of 95% (1.65 [SIGMA], where [SIGMA] is the standard deviation of the net counting rate of the sample) for radium-226 and uranium. When an owner uses a gross alpha particle activity measurement instead of a radium-226 or uranium measurement, the gross alpha particle activity analytical result will be used to determine the future monitoring frequency for radium-226 or uranium. If the gross alpha particle activity result is less than the detection limit as specified in Table 378.1, then half the detection limit will be used to determine compliance and the future monitoring frequency.

2. Monitoring requirements for beta particle and photon radioactivity. To determine compliance with the PMCL in Table 340.4 for beta particle and photon radioactivity, an owner shall monitor at a frequency as follows:

a. The owner (using surface water or groundwater sources) designated by the department as vulnerable shall sample for beta particle and photon radioactivity. The owner shall collect quarterly samples for beta emitters and annual samples for tritium and strontium-90 at each entry point to the distribution system, beginning within one quarter after being notified by the department. A waterworks already designated by the department shall continue to sample until the department evaluates and either reaffirms or removes the designation.

(1) If the gross beta particle activity minus the naturally occurring potassium-40 beta particle activity at an entry point has an RAA (computed quarterly) less than or equal to 50 pCi/L (screening level), then the department may reduce the frequency of monitoring at that entry point to once every three years. The owner shall collect all samples required in subdivision B 2 a of this section during the reduced monitoring period.

(2) For a waterworks in the vicinity of a nuclear facility, the department may allow the owner to utilize environmental surveillance data collected by the nuclear facility instead of monitoring at the waterworks entry point, where the department determines the data is applicable to a particular waterworks. In the event that there is a release from a nuclear facility, the owner who is using surveillance data shall begin monitoring at the waterworks entry point in accordance with subdivision B 2 a of this section.

b. The owner (using a surface water, a groundwater source, or both) designated by the department as utilizing waters contaminated by effluents from nuclear facilities shall sample for beta particle and photon radioactivity. The owner shall collect quarterly samples for beta emitters and iodine-131 and annual samples for tritium and strontium-90 at each entry point to the distribution system, beginning within one quarter after being notified by the department. The owner of a waterworks already designated by the department as using waters contaminated by effluents from nuclear facilities shall continue to sample until the department evaluates and either reaffirms or removes the designation.

(1) Quarterly monitoring for gross beta particle activity shall be based on the analysis of monthly samples or the analysis of a composite of three monthly samples. The former procedure, analysis of monthly samples, is recommended.

(2) For iodine-131, a composite of five consecutive daily samples shall be analyzed once each quarter. As directed by the department, more frequent monitoring shall be conducted when iodine-131 is identified in the finished water.

(3) Annual monitoring for strontium-90 and tritium shall be conducted by means of the analysis of a composite of four consecutive quarterly samples or analysis of four quarterly samples. The latter procedure, analysis of monthly samples, is recommended.

(4) If the gross beta particle activity minus the naturally occurring potassium-40 beta particle activity at a sampling point has an RAA (computed quarterly) less than or equal to 15 pCi/L (screening level), then the department may reduce the frequency of monitoring at that sampling point to every three years. The owner shall collect all samples required in subdivision B 2 b of this section during the reduced monitoring period.

(5) For a waterworks in the vicinity of a nuclear facility, the department may allow the owner to utilize environmental surveillance data collected by the nuclear facility instead of the monitoring at the waterworks entry point, where the department determines the data is applicable to a particular waterworks. In the event that there is a release from a nuclear facility, the owner who is using surveillance data shall begin monitoring at the waterworks entry point in accordance with subdivision B 2 b of this section.

c. The owner of a waterworks designated by the department to monitor for beta particle and photon radioactivity cannot apply to the department for a waiver from the monitoring frequencies specified in subdivision B 2 a or B 2 b of this section.

d. The owner may analyze for naturally occurring potassium-40 beta particle activity from the same or equivalent sample used for the gross beta particle activity analysis. The owner is allowed to subtract the potassium-40 beta particle activity value from the total gross beta particle activity value to determine if the screening level is exceeded. The potassium-40 beta particle activity shall be calculated by multiplying elemental potassium concentrations (in mg/L) by a factor of 0.82.

e. If the gross beta particle activity minus the naturally occurring potassium-40 beta particle activity exceeds the appropriate screening level, then an analysis of the sample shall be performed to identify the major radioactive constituents present in the sample and the appropriate doses shall be calculated and summed to determine compliance with the PMCL for beta particles and photon radioactivity. Doses shall also be calculated and combined for measured levels of tritium and strontium to determine compliance.

f. The owner shall monitor monthly at each entry point that exceeds the PMCLs listed in Table 340.4 beginning the month after the exceedance occurs. The owner shall continue monthly monitoring until the waterworks has established, by a rolling average of three monthly samples, that the PMCL is being met. The owner who establishes that the PMCL is being met shall return to quarterly monitoring until the requirements set forth in subdivision B 2 a (1) or B 2 b (4) of this section are met.

3. General monitoring requirements for radionuclides.

a. The department may require more frequent monitoring than specified in subdivisions B 1 and B 2 of this section or may require confirmation samples at the department's discretion. The results of the initial and confirmation samples shall be averaged for use in compliance determinations.

b. The owner shall monitor at the time designated by the department during each compliance period.

c. The department has the discretion to delete results of obvious sampling or analytic errors.

d. Table 378.1 provides the minimum detection limits for radiological analyses.

TABLE 378.1 Minimum Detection Limits for Radiological Analyses
CONTAMINANT	DETECTION LIMIT (pCi/L unless otherwise noted)
Gross alpha	3
Gross beta	4
Cesium-134	10
Iodine-131	1
Radium-226	1
Radium 228	1
Strontium-89	10
Strontium-90	2
Tritium	1,000
Uranium	1 (µg/L)

Notes

12 Va. Admin. Code § 5-590-378

Derived from Virginia Register Volume 37, Issue 20, eff. 6/23/2021.

Statutory Authority: §§ 32.1-12 and 32.1-170 of the Code of Virginia.