This ICR is
approved. OMB understands that, due to budgetary concerns, EPA has
scaled back its plans for this information collection and no longer
intends to collect and analyze samples for cryptosporidium using
method 1622. Instead the survey will be limited to collecting and
analyzing biweekly samples for turbidity, pH, temperature, total
coliforms, and e coli/fecal coloforms (at system expense) and
monthly samples for TOC, alkalinity, UV254, bromide, and amonia (at
Agency expense). Thus, the concerns raised by one commenter
concerning the accuracy and reliability of method 1622 are moot. An
open question remains, however, as to the adequacy of the data to
satisfy the survey objective of determining if the detailed data on
microbial contamination at large systems currently being collected
through the Information Collection Rule (ICR) is also applicable to
small systems. The sample size of 40 systems was originally
designed to distinguish, with 90% confidence, a difference in the
mean 90th percentile concentraion of cryptosporidium between small
and large systems of one-half log (approximately a factor of three)
or greater. Because the survey will no longer measure protozoan
concentrations directly, but will rely on indicator variables such
as turbididy and bacterial contamination to assess the
applicability of the large system ICR data to small systems, it is
not clear that the sample size will be adequate to reliably
distinguish differences of even this relatively large magnitude.
While no quantitative analysis has been conducted on the
variability and appropriate sample sizes to draw conclusions for
the parameters that remain in the survey, the supporting
documentation does note that in general, the variability of these
parameters is lower than for microorganism counts, and thus higher
confidence levels for conclusions regarding these other parameters
would be expected. However, this reasoning does not account for the
imperfect correlation between the indicator variables and the
protozoan variables of interest that will no longer be measured
directly, and so it is not clear with what level of confidence the
Agency will be able to draw conclusions about the applicability of
the ICR data on protozoan concentrations to small systems. Before
the Agency uses the results of this survey to draw any such
conclusions, it should carefully analyze the uncertainties involved
(which are difficult to determine in advance because the
variability in the results is not yet known) and present any
resulting analyses in a way that clearly identifies and quantifies
these uncertainties and the confidence levels associated with any
conclusions that may be drawn.
Inventory as of this Action
Requested
Previously Approved
01/31/2001
01/31/2001
960
0
0
1,320
0
0
55,000
0
0
Participation in the Small System
Supplemental Survey is voluntary. Forty small systems will
participate in the survey and will sample twice a month during a
12-month monitoring period. EPA will use this information to
support drinking water regulation development.
On behalf of this Federal agency, I certify that
the collection of information encompassed by this request complies
with 5 CFR 1320.9 and the related provisions of 5 CFR
1320.8(b)(3).
The following is a summary of the topics, regarding
the proposed collection of information, that the certification
covers:
(i) Why the information is being collected;
(ii) Use of information;
(iii) Burden estimate;
(iv) Nature of response (voluntary, required for a
benefit, or mandatory);
(v) Nature and extent of confidentiality; and
(vi) Need to display currently valid OMB control
number;
If you are unable to certify compliance with any of
these provisions, identify the item by leaving the box unchecked
and explain the reason in the Supporting Statement.
Small System Survey