R 325.10730 Radionuclides; monitoring requirements for beta particle and photon radioactivity; applicability.

Rule 730. (1) To determine compliance with the maximum contaminant levels in R 325.10603(2)(c) for beta particle and photon radioactivity, a community water supply, also considered a "water supply" or "supply" in this rule, designated by the department as either vulnerable or utilizing water contaminated by effluents from nuclear facilities, shall sample for beta particle and photon radioactivity. The department's designation shall be based on monitoring data, environmental surveillance data collected in the vicinity of nuclear facilities, or source water assessments. (2) Beginning within 1 quarter after being notified of the department's designation and continuing until the department reviews and either reaffirms or removes the designation, a supply shall collect samples at each entry point to the distribution system, known as sampling point, under both of the following provisions: (a) For a vulnerable supply, quarterly samples for beta emitters and annual samples for tritium and strontium 90. (b) For a supply utilizing waters contaminated by effluents from nuclear facilities, quarterly samples for beta emitters and iodine 131 and annual samples for tritium and strontium 90. A supply shall monitor and analyze the samples under all of the following provisions: (i) Quarterly monitoring for gross beta particle activity shall be based on the analysis of monthly samples or the analysis of a composite of 3 monthly samples. (ii) For iodine 131, a composite of 5 consecutive daily samples shall be analyzed once each quarter. As ordered by the department, more frequent monitoring shall be conducted when iodine 131 is identified in the finished water. (iii) Annual monitoring for strontium 90 and tritium shall be conducted by means of the analysis of a composite of 4 consecutive quarterly samples or analysis of 4 quarterly samples. (3) All of the following provisions apply for gross beta particle activity: (a) A supply may analyze for naturally occurring potassium 40 beta particle activity from the same or equivalent sample used for the gross beta particle activity analysis. A supply may subtract the potassium 40 beta particle activity value from the total gross beta particle activity value to determine if the screening level in subdivision (b) of this subrule 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. (b) If the gross beta particle activity minus the naturally occurring potassium 40 beta particle activity at a sampling point has a running annual average, computed quarterly, less than or equal to a screening level of 50 pCi/L for a vulnerable supply or 15 pCi/L for a supply utilizing waters contaminated by effluents from nuclear facilities, then the department may reduce the frequency of monitoring at that sampling point to once every 3 years. During the reduced monitoring period, a supply shall collect the same type of samples required in subrule (2)(a) of this rule for a vulnerable supply or subrule (2)(b) of this rule for a supply utilizing water contaminated by effluents from nuclear facilities. (c) If the gross beta particle activity minus the naturally occurring potassium 40 beta particle activity exceeds the appropriate screening level in subdivision (b) of this subrule, 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 R 325.10603(2)(c)(i), using the formula in R 325.10603(2)(c)(ii). Doses shall also be calculated and combined for measured levels of tritium and strontium to determine compliance. (4) For a supply in the vicinity of a nuclear facility, the community water supply may utilize environmental surveillance data collected by the nuclear facility instead of monitoring at the supply's entry point or points, where the department determines that the data is applicable to a particular water supply. If there is a release from a nuclear facility, then a supply which uses surveillance data shall begin monitoring at the community water supply's entry point or points under subrule (2)(a) or (b) of this rule. (5) A community water supply designated by the department to monitor for beta particle and photon radioactivity shall not apply to the department for a waiver from the monitoring frequencies specified in subrule (2)(a) or (b) of this rule. (6) A supply shall monitor monthly at the sampling point or points that exceed the maximum contaminant level in R 325.10603(2)(c) beginning the month after the exceedance occurs. The supply shall continue monthly monitoring until the supply has established, by the average of results from any 3 consecutive months, that the MCL is being met. A supply that establishes that the MCL is being met shall return to quarterly monitoring until it meets the requirements set forth in subrule (3)(b) of this rule.