Indiana Administrative Code
Title 327 - WATER POLLUTION CONTROL DIVISION
Article 8 - PUBLIC WATER SUPPLY
Rule 2 - Drinking Water Standards
Section 2-10.2 - Monitoring frequency for radioactivity; community water systems
Universal Citation: 327 IN Admin Code 2-10.2
Current through September 18, 2024
Authority: IC 13-13-5; IC 13-14-8-7; IC 13-14-9; IC 13-18-3; IC 13-18-16
Affected: IC 13-18
Sec. 10.2.
(a) Monitoring requirements for gross alpha particle activity, radium-226, radium-228, and uranium in CWS are as follows:
(1) Initial monitoring requirements for CWSs
are as follows:
(A) CWSs must conduct initial
monitoring to determine compliance with section 9 of this rule by December 31,
2007. Unless exempted under subdivision (2) or reduced under clause (D),
systems must collect four (4) consecutive quarterly samples at all sampling
points before December 31, 2007.
(B) For the purposes of monitoring for gross
alpha particle activity, radium-226, radium-228, and uranium in drinking water,
"detection limit" is as described in section 10.1(c) of this rule.
(C) Applicability and sampling location shall
be according to the following:
(i) Every
existing CWS or source using ground water or surface water or a system using
both ground and surface water (to be known as "system" for purposes of this
section) must sample at every entry point to the distribution system that is
representative of all sources being used (to be known as "sampling point" for
purposes of this section) 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.
(ii) Every new CWS or source or CWS that uses
a new source of water must conduct initial monitoring for the new source within
the first quarter after initiating use of the source.
(iii) A system must conduct more frequent
monitoring when ordered by the commissioner 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 finished
water.
(D) The
commissioner may waive the final two (2) quarters of initial monitoring for a
sampling point if the results of the samples from the previous two (2) quarters
are below the detection limit.
(E)
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 (4) 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 commissioner.
(2) The commissioner may allow historical
monitoring data, that which is collected at a sampling point between June 1,
2000, and December 8, 2003, to satisfy the initial monitoring requirements for
that sampling point in the following situations:
(A) A CWS having only one (1) entry point to
the distribution system may use its acceptable historical monitoring data from
the latest sampling conducted during the specified period.
(B) A CWS 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 latest sampling
conducted during the specified period.
(3) Sampling after completion of the initial
monitoring specified in subdivision (1) is once every three (3) years unless
reduced by the commissioner as follows:
(A) If
the average of the initial monitoring results for each contaminant (gross alpha
particle activity, uranium, radium-226, or radium-228) is below the detection
limit specified in section 10.1 of this rule, the system must collect and
analyze for at least one (1) sample for that contaminant at that sampling point
every nine (9) years.
(B) 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
one-half (1/2) the MCL:
(i) the system
must collect and analyze at least one (1) sample for that contaminant at that
sampling point every six (6) years; and
(ii) 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 one-half (1/2) the MCL, the system must collect and
analyze at least one (1) sample for radium-226 and radium-228 at that sampling
point every six (6) years.
(C) Systems must use the samples collected
during the most recent monitoring period to determine the monitoring frequency
for subsequent monitoring periods. For example, if a system's sampling point is
on a nine (9) year monitoring period and the sample result is above one-half
(1/2) the MCL, then the next monitoring period for that sampling point is
three (3) years.
(D) If a system
has a monitoring result that exceeds the MCL while sampling less frequently
than quarterly, the system must collect and analyze quarterly samples at that
sampling point until the system has results from four (4) consecutive quarters
that are below the MCL unless the system enters into another schedule as part
of a formal compliance agreement with the commissioner.
(4) To fulfill quarterly monitoring requireme
nts for gross alpha particle activity, radium-226, radium-228, or uranium, a
system may composite up to four (4) consecutive quarterly samples from a single
entry point if analysis is done within one (1) year of the first sample. The
commissioner will treat analytical results from the composited sample as the
average analytical result to determine compliance with the MCLs and to
determine the future monitoring frequency. If the analytical result from the
composited sample is greater than one-half (1/2) the MCL, the commissioner
may direct the system to take additional quarterly samples before allowing the
system to sample once every three (3) years.
(5) A gross alpha particle activity
measurement may be substituted for the required:
(A) radium-226 measurement provided that the
measured gross alpha particle activity does not exceed five (5) pCi/l;
and
(B) uranium measurement
provided that the measured gross alpha particle activity does not exceed
fifteen (15) pCi/l. The gross alpha measurement shall have a confidence
interval of ninety-five percent (95%) (1.65 F, where F 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 instead of the
measurement for radium-226 or uranium, or both, the gross alpha particle
activity analytical result will be used to determine the future monitoring
frequency for radium-226 or uranium, or both. If the gross alpha particle
activity result is less than detection, one-half (1/2) the detection limit
will be used to determine compliance and the future monitoring
frequency.
(b) For purposes of monitoring for beta particle and photon radioactivity in drinking water, "detection limit" is as described in section 10.1(c) of this rule. To determine compliance with the MCLs in section 10 of this rule for beta particle and photon radioactivity, a system must comply with monitoring and sampling frequency requirements as follows:
(1) CWSs (both surface and ground
water) designated by the commissioner 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 sampling
point beginning within one (1) quarter after being notified by the commissioner
of the designation. Designated systems must continue to sample until the
commissioner reviews and either reaffirms or removes the designation. 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 fifty (50) pCi/l (screening level), the
commissioner may reduce the frequency of monitoring at that sampling point to
once every three (3) years. A system must continue to collect all other samples
required by this subdivision during the reduced monitoring period.
(2) CWSs (both surface and ground water)
designated by the commissioner as utilizing waters contaminated by effluents
from nuclear facilities must sample for beta particle and photon radioactivity.
A system designated under this subdivision 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 beginning within one (1) quarter
after being notified by the commissioner of the designation. A system
designated as using waters contaminated by effluents from a nuclear facility
must continue to sample until the commissioner reviews and either reaffirms or
removes the designation. The following monitoring and frequency of sampling
requirements apply to vulnerable systems:
(A)
Quarterly monitoring for gross beta particle activity shall be based on the
analysis of monthly samples or the analysis of a composite of three (3) monthly
samples. The former is recommended.
(B) For iodine-131, a composite of five (5)
consecutive daily samples shall be analyzed once each quarter. At the direction
of the commissioner, more frequent monitoring shall be conducted when
iodine-131 is identified in the finished water.
(C) Annual monitoring for strontium-90 and
tritium shall be conducted by analysis of a composite of four (4) consecutive
quarterly samples or analysis of four (4) quarterly samples. The latter
procedure is recommended.
(D) 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 fifteen (15) pCi/l (screening
level), the commissioner may reduce the frequency of monitoring at that
sampling point to once every three (3) years. Systems must collect all samples
required in this subdivision during the reduced monitoring period.
(3) CWSs 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 eighty-two
hundredths (0.82).
(4) If the gross
beta particle activity minus the naturally occurring potassium-40 beta particle
activity exceeds the appropriate 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 section 10 of this rule using the formula in that section.
Doses must be calculated and combined for measured levels of major radioactive
constituents, tritium, and strontium to determine compliance.
(5) A system must monitor monthly at the
sampling point or points that exceed the MCL in section 10 of this rule
beginning the month after the exceedance occurs. A system must continue monthly
monitoring until the system has established, by a rolling average of three (3)
monthly samples, that the MCL is being met. A system that reestablishes
compliance with the MCL must return to quarterly monitoring until the
requirements set forth in subdivision (1) or (2)(D) are met.
(c) The following general monitoring and compliance requirements for radionuclides apply:
(1) The commissioner has the discretion to
require:
(A) more frequent monitoring than
specified in subsections (a) and (b); or
(B) confirmation samples. The results of the
initial and confirmation samples shall be averaged for use in compliance
determinations.
(2) A
CWS shall monitor at the time designated by the commissioner during each
compliance period.
(3) The
following shall be used to determine whether a CWS is in compliance with
sections 9 through 10 of this rule:
(A)
Analytical results obtained at each sampling point must meet the applicable
requirements of sections 9 through 10 of this rule. If one (1) sampling point
is in violation of an MCL, the system is in violation of the MCL.
(B) 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 running annual average of any sampling point is greater
than the MCL, then the system is out of compliance with the MCL.
(C) For systems monitoring more than once per
year, if any single 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.
(D) A system must
include all samples taken and analyzed under this section in determining
compliance even if that number is greater than the minimum required.
(E) If a system does not collect all required
samples when compliance with the MCL is based on a running annual average of
quarterly samples, compliance will be based on the running average of the
samples collected.
(F) If a sample
result is less than the detection limit, zero (0) shall be used to calculate
the annual average, unless a gross alpha particle activity is being used
instead of radium-226 or uranium, or both. If the gross alpha particle activity
result is less than detection, one-half (1/2) the detection limit will be
used to calculate the annual average.
(4) The commissioner has the discretion to
delete results of obvious sampling or analytic errors.
(5) If the MCL for radioactivity set forth in
sections 9 through 10 of this rule is exceeded, the operator of a CWS must give
notice to the commissioner under section 13 of this rule and to the public as
required by
327 IAC
8-2.1-7 through
327
IAC 8-2.1-16.
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