Rules & Regulations of the State of Tennessee
Title 0400 - Environment and Conservation
Subtitle 0400-45 - Division of Water Resources
Chapter 0400-45-01 - Public Water Systems
Section 0400-45-01-.11 - RADIONUCLIDE SAMPLING
Universal Citation: TN Comp Rules and Regs 0400-45-01-.11
Current through September 24, 2024
(1) For the purpose of monitoring radioactivity concentrations in drinking water, the required sensitivity of the radioanalysis is defined in terms of a detection limit. The detection limit shall be that concentration which can be counted with a precision of plus or minus 100 percent at the 95 percent confidence level (1.96 sigma where sigma is the standard deviation of the net counting rate of the sample.)
(a) To determine compliance with
gross alpha particle activity, radium-226, radium-228 and uranium the detection
limit shall not exceed the concentration in the Table to this subparagraph.
Detection Limits for Gross Alpha Particle Activity, Radium-226, Radium-228, and Uranium
| Contaminant | Detection Limit |
| Gross alpha particle activity | 3pCi/L |
| Radium-226 | 1pCi/L |
| Radium-228 | 1pCi/L |
| Uranium | 1/10 the MCL |
(b) To determine compliance with beta
particle and photon activity the detection limit shall not exceed the
concentrations listed in the following table.
Detection Limits for Man-made Beta Particle and Photon Emitters
| Radionuclide | Detection Limit |
| Tritium | 1000pCi/L |
| Strontium-89 | 10pCi/L |
| Strontium-90 | 2pCi/L |
| Iodine-131 | 1pCi/L |
| Cesium-134 | 10pCi/L |
| Gross beta | 4pCi/L |
| Other radionuclides | 1/10 of the applicable limit |
(2) To judge compliance with the maximum contaminant levels listed in paragraph (5) of Rule 0400-45-01-.06 averages of data shall be used and shall be rounded to the same number of significant figures as the maximum contaminant level for the substance in question.
(3) The Department has the authority to determine compliance or initiate enforcement action based upon analytical results or other information compiled by their sanctioned representatives and agencies.
(4) Monitoring and compliance requirements for gross alpha particle activity, radium -226, radium 228, and uranium.
(a)
Community water systems (CWSs) must conduct initial monitoring to determine
compliance with radium-226 and 228, gross alpha particle activity and uranium
activity by December 31, 2007. For the purposes of monitoring for gross alpha
particle activity, radium-226, radium-228, and uranium and beta particle
activity and photon activity in drinking water "detection limit" is defined as
in paragraph (3) of this rule.
1.
Applicability and sampling location for existing community water systems or
sources. All existing CWSs using ground water, surface water or systems using
both ground and surface water (hereafter referred to as systems) must sample at
every entry point to the distribution system that is representative of all
sources being used (hereafter called a sampling point) under normal operating
conditions. The system must take each sample at the same sampling point unless
conditions make another sampling point more representative of each source or
the Department has designated a distribution system location, in accordance
with item 2(ii)(III) of this subparagraph.
(i)
Applicability and sampling location for new community water systems or sources.
All new CWSs or CWSs that use a new source of water must begin to conduct
initial monitoring for the new source within the first quarter after initiating
use of the source. CWSs must conduct more frequent monitoring when ordered by
the Department in the event of possible contamination or when changes in the
distribution system or treatment processes occur which may increase the
concentration of radioactivity in finished water.
2. Initial monitoring: Systems must conduct
initial monitoring for gross alpha particle activity, radium-226, radium-228,
and uranium as follows:
(i) Systems without
acceptable historical data, as defined below, must collect four consecutive
quarterly samples at all sampling points before December 31, 2007.
(ii) Grandfathering of data: The Department
may allow historical monitoring data collected at a sampling point to satisfy
the initial monitoring requirements for that sampling point, for the following
situations.
(I) To satisfy initial monitoring
requirements, a community water system having only one entry point to the
distribution system may use the monitoring data from the last compliance
monitoring period that began between June 2000 and December 8, 2003.
(II) To satisfy initial monitoring
requirements, a community water system with multiple entry points and having
appropriate historical monitoring data for each entry point to the distribution
system may use the monitoring data from the last compliance monitoring period
that began between June 2000 and December 8, 2003.
(III) To satisfy initial monitoring
requirements, a community water system with appropriate historical data for a
representative point in the distribution system may use the monitoring data
from the last compliance monitoring period that began between June 2000 and
December 8, 2003, provided that the Department finds that the historical data
satisfactorily demonstrates that each entry point to the distribution system is
expected to be in compliance based upon the historical data and reasonable
assumptions about the variability of contaminant levels between entry points.
The Department must make a written finding indicating how the data conforms to
these requirements.
(iii) For gross alpha particle activity,
uranium, radium-226, and radium-228 monitoring, the Department may waive the
final two quarters of initial monitoring for a sampling point if the results of
the samples from the previous two quarters are below the detection
limit.
(iv) If the average of the
initial monitoring results for a sampling point is above the MCL, the system
must collect and analyze quarterly samples at that sampling point until the
system has results from four consecutive quarters that are at or below the MCL,
unless the system enters into another schedule as part of a formal compliance
agreement with the Department.
3. Reduced monitoring: The Department may
allow community water systems to reduce the future frequency of monitoring from
once every three years to once every six or nine years at each sampling point,
based on the following criteria:
(i) 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 specified in this rule, the system must collect and analyze for
that contaminant using at least one sample at that sampling point every nine
years.
(ii) For gross alpha
particle activity and uranium, if the average of the initial monitoring results
for each contaminant is at or above the detection limit but at or below 1/2 the
MCL, the system must collect and analyze for that contaminant using at least
one sample at that sampling point every six years. For combined radium-226 and
radium-228, the analytical results must be combined. If the average of the
combined initial monitoring results for radium-226 and radium-228 is at or
above the detection limit but at or below 1/2 the MCL, the system must collect
and analyze for that contaminant using at least one sample at that sampling
point every six years.
(iii) For
gross alpha particle activity and uranium, if the average of the initial
monitoring results for each contaminant is above 1/2 the MCL but at or below
the MCL, the system must collect and analyze at least one sample at that
sampling point every three years. For combined radium-226 and radium-228, the
analytical results must be combined. If the average of the combined initial
monitoring results for radium-226 and radium-228 is above 1/2 the MCL but at or
below the MCL, the system must collect and analyze at least one sample at that
sampling point every three years.
(iv) Systems must use the samples collected
during the reduced monitoring period to determine the monitoring frequency for
subsequent monitoring periods (e.g., if a system's sampling point is on a nine
year monitoring period, and the sample result is above 1/2 MCL, then the next
monitoring period for that sampling point is three years).
(v) If a system has a monitoring result that
exceeds the MCL while on reduced monitoring, the system must collect and
analyze quarterly samples at that sampling point until the system has results
from four consecutive quarters that are below the MCL, unless the system enters
into another schedule as part of a formal compliance agreement with the
Department.
4.
Compositing: To fulfill quarterly monitoring requirements for gross alpha
particle activity, radium-226, radium-228, or uranium, a system 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 composite as the average analytical result to determine
compliance with the MCLs and the future monitoring frequency. If the analytical
result from the composited sample is greater than 1/2 MCL, the Department may
direct the system to take additional quarterly samples before allowing the
system to sample under a reduced monitoring schedule.
5. 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 a system uses a
gross alpha particle activity measurement in lieu of a radium- 226 and/or
uranium measurement, the gross alpha particle activity analytical result will
be used to determine the future monitoring frequency for radium-226 and/or
uranium. If the gross alpha particle activity result is less than detection,
1/2 the detection limit will be used to determine compliance and the future
monitoring frequency.
(b) Monitoring and compliance requirements
for beta particle and photon radioactivity. To determine compliance with the
maximum contaminant levels for beta particle and photon radioactivity, a system
must monitor at a frequency as follows:
1.
Community water systems (both surface and ground water) designated by the
Department as vulnerable must sample for beta particle and photon
radioactivity. Systems must collect quarterly samples for beta emitters and
annual samples for tritium and strontium-90 at each entry point to the
distribution system (hereafter called a sampling point), beginning within one
quarter after being notified by the Department. Systems already designated by
the Department must continue to sample until the Department reviews and either
reaffirms or removes the designation.
(i) 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 50 pCi/L (screening level), the
Department may reduce the frequency of monitoring at that sampling point to
once every 3 years. Systems must collect all samples required in part 1 of this
subparagraph during the reduced monitoring period.
(ii) For systems in the vicinity of a nuclear
facility, the Department may allow the CWS to utilize environmental
surveillance data collected by the nuclear facility in lieu of monitoring at
the system's entry point(s), where the Department determines if such data is
applicable to a particular water system. In the event that there is a release
from a nuclear facility, systems which are using surveillance data must begin
monitoring at the community water system's entry point(s) in accordance with
part 1 of this subparagraph.
2. Community water systems (both surface and
ground water) designated by the Department as utilizing waters contaminated by
effluents from nuclear facilities must sample for beta particle and photon
radioactivity. Systems must 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 (hereafter called a sampling point), beginning
within one quarter after being notified by the Department. Systems already
designated by the Department as systems using waters contaminated by effluents
from nuclear facilities must continue to sample until the Department reviews
and either reaffirms or removes the designation.
(i) 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 is
recommended.
(ii) For iodine-131, a
composite of five 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 four
consecutive quarterly samples or analysis of four quarterly samples. The latter
procedure is recommended.
(iv) If
the gross beta particle activity beta 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 15 pCi/L, the Department may
reduce the frequency of monitoring at that sampling point to every 3 years.
Systems must collect all samples required in part 2 of this subparagraph during
the reduced monitoring period.
(v)
For systems in the vicinity of a nuclear facility, the Department may allow the
CWS to utilize environmental surveillance data collected by the nuclear
facility in lieu of monitoring at the system's entry point(s), where the
Department determines if such data is applicable to a particular water system.
In the event that there is a release from a nuclear facility, systems which are
using surveillance data must begin monitoring at the community water system's
entry point(s) in accordance with part 2 of this subparagraph.
3. Community water systems
designated by the Department to monitor for beta particle and photon
radioactivity can not apply to the Department for a waiver from the monitoring
frequencies specified in part 1 or 2 of this subparagraph.
4. Community water systems may analyze for
naturally occurring potassium-40 beta particle activity from the same or
equivalent sample used for the gross beta particle activity analysis. Systems
are 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 must be calculated by
multiplying elemental potassium concentrations (in mg/L) by a factor of
0.82.
5. For community water
systems, if the gross beta particle activity minus the naturally occurring
potassium-40 beta particle activity exceeds the screening level, an analysis of
the sample must be performed to identify the major radioactive constituents
present in the sample and the appropriate doses must be calculated and summed
to determine compliance with part (5)(b)1 of Rule 0400-45-01-.06, using the
formula in part (5)(b)2 of Rule 0400-45-01-.06. Doses must also be calculated
and combined for measured levels of tritium and strontium to determine
compliance.
6. Community water
systems must monitor monthly at the sampling point(s) which exceed the maximum
contaminant level in subparagraph (5)(c) of Rule 0400-45-01-.06 beginning the
month after the exceedance occurs. Systems must continue monthly monitoring
until the system has established, by a rolling average of 3 monthly samples,
that the MCL is being met. Community water systems who establish that the MCL
is being met must return to quarterly monitoring until they meet the
requirements set forth in subparagraph 1(ii) or 2(i) of this
subparagraph.
(c)
General monitoring and compliance requirements for radionuclides.
1. The Department may require more frequent
monitoring than specified in subparagraphs (a) and (b) of this paragraph, or
may require confirmation samples at its discretion. The results of the initial
and confirmation samples will be averaged for use in compliance
determinations.
2. Each public
water systems shall monitor at the time designated by the Department during
each compliance period.
3.
Compliance: Compliance the radionuclide MCLs will be determined based on the
analytical result(s) obtained at each sampling point. If one sampling point is
in violation of an MCL, the system is in violation of the MCL.
(i) For systems monitoring more than once per
year, compliance with the MCL is determined by a running annual average at each
sampling point. If the average of any sampling point is greater than the MCL,
then the system is out of compliance with the MCL.
(ii) For systems monitoring more than once
per year, if any sample result will cause the running average to exceed the MCL
at any sample point, the system is out of compliance with the MCL
immediately.
(iii) Systems must
include all samples taken and analyzed under the provisions of this Rule in
determining compliance, even if that number is greater than the minimum
required.
(iv) If a system does not
collect all required samples when compliance is based on a running annual
average of quarterly samples, compliance will be based on the running average
of the samples collected.
(v) If a
sample result is less than the detection limit, zero will be used to calculate
the annual average, unless a gross alpha particle activity is being used in
lieu of radium-226 and/or uranium. If the gross alpha particle activity result
is less than detection, 1/2 the detection limit will be used to calculate the
annual average.
4. The
Department has the discretion to delete results of obvious sampling or analytic
errors.
5. If the MCL for
radioactivity set forth in paragraph (5) of Rule 0400-45-01-.06 is exceeded,
the operator of a community water system must give notice to the Department
pursuant to Rule 0400-45-01-.20 and to the public as required by Rule
0400-45-01-.19.
Authority: T.C.A. §§ 68-221-701 et seq. and 4-5-201 et seq.
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