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Hi
everyone. In cooperation with the CREST stakeholder group, for several years
now we have been conducting studies of bacteria sources along the Los Angeles
River. Just last December, we finalized a final report for the Los Angeles
River Bacteria Source Identification Study, which collected a very large MST
dataset for urban runoff (Bacteroidales and adenovirus, analyzed by
UC-Davis). http://www.crestmdl.org/reports/index.html During
our dry weather studies, along one of the LA River segments, we see consistent,
large increases in E. coli concentrations but not Enterococcus.
Thus it appears that either (1) the sources of E. coli to the this
segment are relatively less enriched with Enterococcus or (2) the sinks
(e.g., decay) of Enterococcus are much stronger. For
possibility #1, I’m wondering if you have ideas for sources that are
highly enriched with E. coli but not Enterococcus. For
instance, several studies of bird feces have found concentrations of Enterococcus
to be significantly lower than E. coli. Sewage, on the other hand,
exhibits very high concentrations of both E. coli and Enterococcus.
·
What
about regrowth/resuscitation in the water column or sediments? Any
documentation of differing potential growth/reactivation rates among ENT vs.
EC? ·
How
could false positives play a role in our findings? We’re using IDEXX
methods. ·
Other
ideas? Thanks
for your help, Dustin ______________________ Dustin Bambic, PH Senior
Hydrologist AMEC
Earth & Environmental Office
615.333.0630 ext. 123 Mobile
615.618.2380 Fax
______________________
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