(A) Combined
radium-226 and radium-228: the maximum contaminant level (MCL) for combined
radium-226 and radium-228 is five picocuries per liter (pCi/L). The combined
radium-226 and radium-228 value is determined by the addition of the results of
the analysis for radium-226 and the analysis for radium-228.
(B) Gross alpha particle activity: the MCL
for gross alpha particle activity (including radium-226 but excluding radon and
uranium) is fifteen pCi/L. The gross alpha particle activity value may be
adjusted by subtracting the result of the analysis for uranium. If the result
for uranium is reported as a mass measurement in micrograms per liter (µg/L),
the activity value in pCi/L shall be obtained by multiplying the result with a
conversion factor of 0.67 pCi/µg.
(C) Beta particle and photon radioactivity:
(1) The MCL for beta particle and photon
radioactivity from man-made radionuclides is an annual dose equivalent of four
millirem/year (mrem/yr) to the total body or any internal organ. The annual
dose equivalent is determined by converting the running annual average
concentration for the radionuclide from pCi/L to mrem/yr (running annual
average concentration divided by the dose equivalent for the radionuclide). If
two or more radionuclides are present, the sum of their annual dose equivalent
to the total body or to any organ shall not exceed four mrem/yr.
(2) The annual
dose equivalent for
radionuclides may be determined using the conversion table below. For
radionuclides not listed, the concentration causing four mrem/yr total body or
organ dose equivalents may be obtained from appendix I of the "Implementation
Guidance for Radionuclides" dated March 2002 and designated EPA 816-F-00-002.
[Comment: This rule references the U.S. EPA "Implementation
Guidance for Radionuclides" and "Implementation Guidance for Radionuclides
Appendices A - J," issued March 2002. This document is available from the "U.S.
EPA Office of Ground Water and Drinking Water, Ariel Rios Building, 1200
Pennsylvania Ave., N.W., Washington, D.C. 20460-0003, (202) 564-3750,
www.epa.gov/safewater." A
copy may also be obtained by contacting "Ohio EPA, Lazarus Government Center,
50 West Town Street, Suite 700, Columbus, OH, 43215."]
Dose Equivalents Assumed to Produce a Total Body or Organ Dose
of four mrem/yr
|
Radionuclide
|
Critical Organ
|
pCi/L
|
|
Tritium
|
Total body
|
20,000
|
|
Strontium-89
|
Bone marrow
|
20
|
|
Strontium-90
|
Bone marrow
|
8
|
|
Iodine-131
|
Thyroid
|
3
|
|
Cesium-134
|
Total body
|
80
|
(D) Uranium: the MCL for uranium is thirty
µg/L (activity level of twenty pCi/L). If the result for uranium is reported as
an activity measurement in pCi/L, the mass in µg/L shall be obtained by
multiplying the result with a conversion factor of
1.49
µg/pCi.
(E) The
director may
determine that
require a
public water system
shall
to
apply
best available technology in order to reduce the level of a
contaminant
to below
its
the MCL. The
director hereby identifies the following
technologies, treatment techniques, or other means as the best available
technologies (BATs) for removal of the following radionuclide contaminants from
water.
|
Contaminant
|
BATs
|
|
Combined radium-226 and radium-228
|
1a,
2b, 3c,
4d, 5e, 6,
7f
|
|
Gross alpha particle activity (excluding Radon and
Uranium)
|
2b
|
|
Beta particle and photon radioactivity
|
1a,
2b
|
|
Uranium
|
1a,
2b, 3c,
8a,g, 9h
|
Key to BATs in table:
1 = Ion exchange
2 = Reverse Osmosis
3 = Lime softening
4 = Green sand filtration
5 = Co-precipitation with barium sulfate
6 = Electrodialysis/electrodialysis reversal
7 = Pre-formed hydrous manganese oxide filtration
8 = Activated alumina
9 = Enhanced coagulation/filtration
Limitations footnotes:
a) The regeneration solution contains high
concentrations of the contaminant ions. Disposal options should be carefully
considered before choosing this technology.
b) Reject water disposal options and other
reverse osmosis limitations should be carefully considered before choosing this
technology.
c) This technology
should not be used for public water systems serving a population of five
hundred or less.
d) Removal
efficiencies can vary depending on water quality.
e) This technology may be very limited in
application to small systems. Since the process requires static mixing,
detention basins, and filtration, it is most applicable to the systems with
sufficiently high sulfate levels that already have a suitable filtration
treatment train in place.
f) This
technology is most applicable to small systems that already have filtration in
place.
g) Competing anion
concentrations may affect regeneration frequency. Handling of chemicals
required during regeneration and pH adjustment may be too difficult for small
systems without an adequately trained operator.
h) Assumes modification to a
coagulation/filtration process already in place.
