Current through Register Vol. 48, No. 38, September 20, 2024
a) Cryptosporidium. A supplier must analyze
for Cryptosporidium using USEPA 1623 (05), USEPA 1623.1(12), or USEPA 1622
(05), each incorporated by reference in Section
611.102,
or alternative methods approved by the Agency under Section
611.480.
1) The supplier must analyze at least a 10 l
sample or a packed pellet volume of at least 2 ml as generated by the methods
listed in subsection (a). A supplier unable to process a 10 l sample must
analyze as much sample volume as can be filtered by two filters approved by
USEPA for the methods listed in subsection (a), up to a packed pellet volume of
at least 2 ml.
2) Matrix Spike (MS)
Samples
A) MS samples, as required by the
methods in subsection (a), must be spiked and filtered by a laboratory approved
for Cryptosporidium analysis under Section
611.1005.
B) If the volume of the MS sample is greater
than 10 l, the supplier may filter all but 10 l of the MS sample in the field,
and ship the filtered sample and the remaining 10 l of source water to the
laboratory. In this case, the laboratory must spike the remaining 10 l of water
and filter it through the filter used to collect the balance of the sample in
the field.
3) Flow
cytometer-counted spiking suspensions must be used for MS samples and ongoing
precision and recovery samples.
b) E. coli. A supplier must use methods for
enumeration of E. coli in source water approved in
40 CFR
136.3(a), incorporated by
reference in Section 611.102, or alternative methods approved by the Agency
under Section 611.480.
1) The time from
sample collection to initiation of analysis may not exceed 30 hours, unless the
supplier meets the condition of subsection (b)(2).
2) The Agency may, by a SEP, approve on a
case-by-case basis the holding of an E. coli sample for up to 48 hours between
sample collection and initiation of analysis if it determines that analyzing an
E. coli sample within 30 hours is not feasible. E. coli samples held between 30
to 48 hours must be analyzed by the Colilert® Test reagent version of SM
9223 B listed in
40 CFR
136.3(a), incorporated by
reference in Section 611.102.
3) A
supplier must maintain the temperature of its samples between 0°C and
10°C during storage and transit to the laboratory.
4) The supplier may use the membrane
filtration, two-step procedure described in SM 9222 D (97)
(20th ed. only) and SM 9222 G (97)
(20th ed. only), incorporated by reference in
Section 611.102.
c)
Turbidity. A supplier must use methods for turbidity measurement approved in
Section
611.531(a).
BOARD NOTE: Derived from
40 CFR 141.704
and appendix A to subpart C of 40 CFR 141. The Board has not separately listed
the following approved alternative methods from Standard Methods Online that
are the same version as a method that appears in a printed edition of Standard
Methods. Use of the Standard Methods Online copy is acceptable.
Standard Methods Online, Methods 9222 D-97 and 9222 G-97
appear in the 20th and
21st editions as Methods 9222 D and 9222 G, but
USEPA approved the method in the 20th edition only.
In this Section, these appear as SM 9222 D (97) and SM 9222 G (97).
