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