Current through Register 2024 Notice Reg. No. 38, September 20, 2024
(a) Each community
and nontransient-noncommunity water system (system) shall comply with the
primary MCLs in table 64443 and use the DLRs for reporting monitoring results:
Table 64443
Radionuclide Maximum Contaminant Levels (MCLs) and
Detection Levels for Purposes of Reporting (DLRs)
|
Radionuclide
|
MCL
|
DLR
|
| Beta/photon emitters |
4 millirem/year annual |
Gross Beta |
| dose equivalent to the
total | particle activity: |
| body or any internal organ | 4
pCi/L |
| Strontium-90 |
8 pCi/L |
2 pCi/L |
|
(= 4 millirem/yr dose to bone marrow) |
|
| Tritium |
20,000 pCi/L |
1,000 pCi/L |
|
(= 4 millirem/yr dose to total body) |
|
(b)
Each system designated by the State Board as vulnerable to contamination by
nuclear facilities and/or a determination of vulnerability by a source water
assessment, as defined in section
64401.57, shall monitor to
determine compliance with the MCLs in Table 64443, as follows:
(1) Beginning within one quarter after being
notified by the State Board that the system is vulnerable, quarterly for
beta/photon emitters and annually for tritium and strontium-90 at each water
source, or every entry point to the distribution system that is representative
of all sources being used under normal operating conditions, and shall conduct
all monitoring at the same sample site(s) unless a change is approved by the
State Board, based on a review of the system and its historical water quality
data;
(2) For quarterly monitoring,
during the same month (first, second or third) of each quarter during each
quarter monitored; and
(3) If the
gross beta particle activity minus the naturally-occurring potassium-40 beta
particle activity at a sampling site has a running annual average less than or
equal to 50 pCi/L (screening level), reduce monitoring to a single sample for
beta/photon emitters, tritium and strontium-90 once every three years
(compliance monitoring period).
(c) Each system designated by the State Board
as utilizing waters contaminated by effluents from nuclear facilities on the
basis of analytical data and/or a Source Water Assessment, shall:
(1) Beginning within one quarter after being
notified by the State Board of the above designation, monitor on an ongoing
basis pursuant to subparagraphs (A) through (C) at each sampling site:
(A) For beta/photon emitters, quarterly by
analyzing three monthly samples and averaging the results or by analyzing a
composite of three monthly samples;
(B) For iodine-131, quarterly by analyzing a
composite of five consecutive daily samples, unless the State Board has
directed the system to do more frequent monitoring based on a detection of
iodine-131 in the sampled water; and
(C) For strontium-90 and tritium, annually by
analyzing four quarterly samples and averaging the results or by analyzing a
composite of four quarterly samples.
(2) If the gross beta particle activity minus
the naturally-occurring potassium-40 beta particle activity at a sampling site
has a running annual average (computed quarterly) less than or equal to 15
pCi/L (screening level), reduce the frequency of monitoring to a single sample
for beta/photon emitters, iodine-131, strontium-90 and tritium once every three
years (compliance monitoring period).
(d) If the gross beta particle activity minus
the naturally-occurring potassium-40 beta particle activity exceeds a system's
screening level pursuant to Subsection (b)(3) or (c)(2):
(1) The sample shall be analyzed to identify
the primary radionuclides present and the doses shall be calculated and summed
to determine compliance with the MCL for beta particle/photon radioactivity;
and
(2) Except for strontium-90 and
tritium for which the MCLs provide the average annual concentrations assumed to
produce a total body or organ dose equivalent to 4 millirem/year, the
concentration of manmade radionuclides shall be calculated on the basis of 2
liters per day drinking water intake using the 168 hour data list in "Maximum
Permissible Body Burdens and Maximum Permissible Concentrations of
Radionuclides in Air and in Water for Occupational Exposure," NBS (National
Bureau of Standards) Handbook 69 as amended August 1963, U.S. Department of
Commerce. (See Title 40, Code of Federal Regulations, section
141.66(d)(2).)
(e) If a
system analyzes for naturally-occurring potassium-40 beta particle activity
from the same or equivalent samples used for the gross beta particle activity
analysis, the potassium-40 beta particle activity shall be calculated by
multiplying elemental potassium concentrations (in mg/L) by a factor of 0.82
pCi/mg.
(f) A system required to
monitor under this section may use environmental surveillance data (collected
by the nuclear facility to detect any radionuclide contamination) in lieu of
monitoring, subject to the State Board's determination that the data is
applicable to the system based on a review of the data and the hydrogeology of
the area. In the event that there is a release of radioactivity or radioactive
contaminants from the nuclear facility, a system using environmental
surveillance data shall begin the monitoring in paragraph (b)(1) or (c)(1)(A)
through (C), whichever is most applicable.
(g) If a sample result is greater than an
MCL:
(1) Compliance shall be determined as
follows:
(A) At each sampling site, based on
the analytical results for that site. Any confirmation sample result shall be
averaged with the initial result.
(B) Using all monitoring results collected
under this article during the previous 12 months, even if more than the minimum
required number of samples was collected.
(C) By a running annual average of four
consecutive quarters of sampling results where quarterly monitoring is
required, or by an annual sample when applicable for tritium and strontium-90.
Averages shall be rounded to the same number of significant figures as the MCL
for which compliance is being determined.
1.
If any sample result will cause the annual average at any sample site to exceed
the MCL, the system shall be out of compliance immediately after being notified
of the result;
2. If a system has
not analyzed the required number of samples, compliance shall be determined by
the average of the samples collected at the site during the most recent 12
months; and
3. If a sample result
is less than the DLR in 64443, zero shall be used to calculate the annual
average.
(D) If the
system can provide documentation that a sample was subject to sampling or
analytical errors, the State Board may invalidate the result based on its
review of the documentation, the sampling result, and the historical sampling
data.
(E) Each system shall ensure
that the laboratory analyzing its samples collected for compliance with this
article calculates and reports the sample-specific Minimum Detectable Activity
at the 95% confidence level (MDA95) along with the
sample results. The MDA95 shall not exceed the DLR and
is calculated as described in ANSI N42.23 Measurement and Associated
Instrumentation Quality Assurance for Radiobioassay Laboratories, Appendix
A.7.6. (September 10, 1995).
(2) If a sample has a gross beta/photon
radioactivity level greater than the MCL:
(A)
A system shall monitor monthly beginning the month after receiving a result
greater than the MCL and continue monthly monitoring until an average of three
consecutive monthly sample results does not exceed the MCL;
(B) The system shall then monitor quarterly
until the average of four consecutive quarterly sample results does not exceed
the MCL; and
(C) Subsequently, the
system shall conduct the monitoring in paragraph (b)(1) or (c)(1)(A) through
(C), whichever is most applicable.
1. New NOTE
filed 12-7-84 (Register 84, No. 49).
2. Amendment of subsection (c)
filed 10-7-88; operative 1-1-89 (Register 88, No. 42).
3. Amendment
of subsections (b) and (c), and renumbering of Table 5 to Table 4 filed
11-22-88; operative 12-22-88 (Register 88, No. 51).
4. Repealer and
new section filed 5-12-2006; operative 6-11-2006 (Register 2006, No.
19).
5. Change without regulatory effect amending subsections
(b)-(b)(1), (c)-(c)(1), (c)(1)(B), (f) and (g)(1)(D) and amending NOTE filed
6-2-2015 pursuant to section
100, title 1, California Code of
Regulations (Register 2015, No. 23).
6. Amendment of subsection (b)
filed 6-17-2021; operative 7-1-2021 pursuant to Government Code section
11343.4(b)(3)
(Register 2021, No. 25). Transmission deadline specified in Government Code
section
11346.4(b)
extended 60 calendar days pursuant to Executive Order
N-40-20.
Note: Authority cited: Sections
116271,
116325,
116350
and
116375,
Health and Safety Code. Reference: Sections
116275,
116365
and
116385,
Health and Safety Code; and Section 141.66(d)(2), Title 40, Code of Federal
Regulations.
