Ohio Administrative Code › Title 3745 - Ohio Environmental Protection Agency › Chapter 3745-81 - Primary Drinking Water Rules › Section 3745-81-26 - Radionuclide monitoring requirements

Current through all regulations passed and filed through July 1, 2024
Community public water systems shall monitor as described in
				this rule to determine compliance with the maximum contaminant levels (MCLs)
				for radionuclides listed in rule
				3745-81-15
				of the Administrative Code. Analytical procedures which are acceptable for
				monitoring of radionuclide contaminants in drinking water are listed in rule
				3745-81-27
				of the Administrative Code. Community public water systems shall monitor for
				radionuclide contaminants according to a schedule provided by the
				director.
(A) Monitoring requirements
			 for gross alpha particle activity, radium-226, radium-228, and uranium.
(1) 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 in
			 paragraph (D) of this rule.
(2) All
			 existing community public water systems shall sample at every sampling point
			 that is representative of all sources being used under normal operating
			 conditions for that sampling point. The system shall take each sample at the
			 same sampling point unless the director determines that conditions make another
			 sampling location more representative of each source.
(3) All new community public water systems or
			 community public water systems that use a new source of water shall begin
			 initial monitoring within the first quarter after initiating use of the
			 source.
(4) Initial monitoring.
			 Systems shall conduct initial monitoring for gross alpha particle activity,
			 radium-226, radium-228, and uranium as follows:
(a) Systems shall collect four consecutive
			 quarterly samples at all sampling points.
(b) For gross alpha particle activity,
			 uranium, radium-226, and radium-228 monitoring, the director 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.
(5) If the
			 average of the initial monitoring results for a sampling point is above the
			 maximum contaminant level (MCL), the community public water system shall
			 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.
(6) Reduced monitoring. The
			 director may allow community public 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:
(a) 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 paragraph
			 (D) of this rule, the community public system shall collect and analyze for
			 that contaminant using at least one sample at that sampling point every nine
			 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 fifty per cent
			 of the MCL, the community public water system shall 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
				shall 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 fifty per cent of the MCL, the community public water system shall
				collect and analyze for the contaminant(s) using at least one sample at that
				sample point every six years.
(c) For gross alpha particle activity and
			 uranium, if the average of the initial monitoring results for each contaminant
			 is above fifty per cent of the MCL but at or below the MCL, the community
			 public water system shall collect and analyze at least one sample at that
			 sampling point every three years.
For combined radium-226 and radium-228, the analytical results
				shall be combined. If the average of the combined initial monitoring results
				for radium-226 and radium-228 is above fifty per cent of the MCL but at or
				below the MCL, the community public water system shall collect and analyze at
				least one sample at that sampling point every three years.
(d) Community public water systems shall 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 fifty per cent of MCL but at or below the MCL, then the next monitoring
			 period for that sampling point is at least one sample every three
			 years.)
(e) If a community public
			 water system has a monitoring result that exceeds the MCL while on reduced
			 monitoring, the system shall 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.
(7) 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 five 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 fifteen pCi/L. The gross alpha measurement shall have a
			 confidence interval of ninety-five per cent ( 1.96 sigma where sigma is the
			 standard deviation of the net counting rate of the sample) for radium-226 and
			 uranium. When a community public water system uses a gross alpha particle
			 activity measurement in lieu of 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, fifty per cent of the
			 detection limit will be used to determine compliance and the future monitoring
			 frequency.