WEF Discussion Forums
Laboratory Management and Technical Issues
12th Edition of Standard Methods Needed!
I am trying to see what the hold time for Fecal Coliform samples was prior to the creation of EPA. If anyone has a 12th edition of Std Methods could you check in Section 400 and tell me what the suggested hold time for bacteriological samples is. I think it is in Section 405. Thanks, Keith
Standard Methods 12th ed. 1965 section VII Bacteriological Examination - Samples 2. Preservation and Storage. "The bacteriological exam should be initiated immediately after collection. However this is seldom practical and more realistic arrangements must be established. It is reccommended that the technical procedures be started preferably within 1 hour after collection; the time elapsing between collection and examination should in no case exceed 30 hours. During the period between collection and examination, the temperature of the sample should be maintained as close as possible to that at time of collection."
Aha. The 13th Edition (1971) suggests no longer than six (6) hours of holding time. EPA's decision to require a 6 hour hold time for fecal coliform testing dates from the early 70's and, according to someone who worked for Region 9 and Region 10 during this period, was somewhat arbitrary. No matter, we are stuck with it now. I am still trying to find any documentation of a holding time study on which it could have been based.
Anyone else have some information that could shed some light on the subject?
This Forum is still not user-friendly, it's slow, and still gives me that error message when accessing the reply option. Guess WEF did not hear the cries. Anyway, so much for my ranting--probably wasn't missed. Keith, looking at my EPA manual EPA-600/8-78-017 "Microbiological Methods for Monitoring the Environment: Water and Wastes, section 6 Preservation and Transit of Sample, and specifically sections 6.2 Holding Time Limitations it goes on to state "Although samples should be examined as soon as possible after collection, they should not be held longer than six hours between collection and initiation of analyses (14). This limit is applied to fresh waters, seawaters and shellfish-bed waters. The exception is water supply samples mailed from water treatment systems. Current regulations permit these samples to be held up to 30 hours"
subsection 6.2.1 "Despite establishment of a six hour limit, sewage samples, organically-rich wastes, and marine waters are particularly susceptible to rapid increases or die-away and hence should be held for the shortest time possible to minimize change"
The quoted reference in section 6.1 (14) comes from
Public Health Laboratory Service Water Subcommittee, 1953. The Effect of storage on the coliform and Bacterium coli counts of water samples. Storage for six hours at room temperature and refrigerator temperatures. J. Hyg. 51:559.
Hope this helps.
C ya later!