Fecal Indicator Bacteria and Pathogen Persistence in by hjt98841


									                     Fecal Indicator Bacteria and
                       Pathogen Persistence in
                Dry Beach Sand and Sediment Biofilms
                                         Jennifer A. Jay
                              Civil and Environmental Engineering
                              University of California, Los Angeles
 This year our goals were to: 1) investigate fecal indicator bacteria (FIB) dynamics in beach sand fol-
 lowing sewage spills; 2) use traditional FIB measurements along with a novel rapid FIB method and
 Bacteroides levels in water and sand to conduct fecal source tracking and identification at three im-
 paired beaches; and 3) continue to collaborate with the Southern California Coastal Water Research
 Project on an epidemiological study of adverse health impacts due to water and sand exposure.

Coastal sediments are increasingly recognized          Solar disinfection with mechanical mixing was
as important reservoirs of E. coli and entero-         pilot-tested as a disinfection procedure after
cocci, referred to as fecal indicator bacteria         a large sewage spill in the Los Angeles area.
(FIB). The abundance of FIB in sediment can            Effects of solar exposure, mechanical mixing,
have two distinct implications for public health.      predation and/or competition, season, and
On one hand, persistence and regrowth of               moisture were tested at bench scale. Desic-
non-pathogenic FIB in sediment weakens the             cation was a dominant factor for E. coli but not
relationship between FIB and the pathogens             enterococci inactivation. Effects of season were
they are meant to proxy. On the other hand,            investigated through a comparison of exper-
sediments may provide a favorable environ-             imental results from winter, spring, and fall.
ment for pathogens, as they do for FIB, and            Moisture was the dominant factor controlling
may be an unexplored route of exposure.                E. coli inactivation kinetics. Initial microbial
Importantly, both FIB and pathogens appear             community and sand temperature were also
to have greater persistence in sediments               important factors. Mechanical mixing, com-
than in water. In general, sediments may be            mon in beach grooming, did not consistently
more conducive to FIB survival relative to the         reduce bacterial levels. Inactivation rates are
water column due to reduced sunlight inacti-           mainly dependent on moisture and high sand
vation, protection from predators, nutrient            temperature. Chlorination was an effective
and organic carbon availability, and the pres-         disinfection treatment.
ence of a surface for the formation of biofilms.       Use of traditional FIB measurements along
Fecal pollution is a major cause of water quality      with a novel rapid FIB method and Bacter-
impairment in coastal areas. However, our              oides levels in water and sand to conduct
understanding of the fate of fecal pollution in        fecal source tracking and identification at
coastal ecosystems, as well as our ability to          three impaired beaches.
identify and mitigate its sources, is greatly          We completed laboratory and field testing of
limited by uncertainties surrounding its be-           our rapid method for E. coli and enterococci
havior in two major reservoirs: wetlands and           based on immunomagnetic separation/ATP
beach sediments.                                       quantification (IMS/ATP).
Investigation of FIB dynamics in beach sand            One approach to addressing coastal water
following sewage spills.                               quality concerns is the use of source tracking
Factors affecting FIB and pathogen survival/           and identification strategies, which have his-
persistence in sand remain largely unstud-             torically been based on FIB as a first tier to
ied. This work elucidates how biological and           direct additional sampling efforts. This tiered
physical factors affect die-off in beach sand          approach is hampered by the temporal vari-
following sewage spills.                               ability of FIB in aquatic environments. The
tiered approach is further limited by the ab-     Continued collaboration with the Southern
sence of an economical rapid detection            California Coastal Water Research Project
method to serve as a middle tier that would       (SCCWRP) on an epidemiological study of
allow investigators to obtain results from        adverse health impacts due to water and
multiple samples in near real time and before     sand exposure.
the contamination source has dissipated.          This past summer, we analyzed FIB in sand
The development of rapid detection assays,        at Doheny and Avalon beaches as part of
allowing enumeration of microbial contami-        the SCCWRP study. We also extracted and
nants as quickly as one hour and enabling a       purified DNA, and are in the midst of analyz-
more diverse suite of organisms to be stud-       ing DNA extracts for human-specific and
ied, has progressed significantly in recent       universal Bacteroides. The study is ongoing
years. While many of these assays are prom-       and results are not yet available.
ising, only IMS/ATP currently incorporates a      Selected Professional Presentations
feasible on-site analysis that can be optimized
to a 30 minute assay of multiple samples.         Mika, K., G. Imamura, C. Change, C.M. Lee,
                                                  J.A. Jay, Dynamics in Sand of Fecal Indica-
Until recently, impediments have obstructed       tor Bacteria (FIB) and Salmonella From Con-
the transition and application of IMS/ATP to      taminated Water, Runoff, and Sewage in an
measurement of water quality in marine sys-       Urbanized Southern California Shoreline.
tems. We have made significant improve-           American Geophysical Union Annual Meet-
ments to the IMS/ATP protocol and its appli-      ing, San Francisco, CA, December, 2007.
cations; this includes devising a more robust
anti-E.coli biosorbent, testing the biosorbent    Lee, C.M., W. Kaiser, J.A. Jay. Immu-
in both freshwater and marine waters, and         nomagnetic separation and ATP quantifica-
examining IMS/ATP as a rapid and poten-           tion (IMS/ATP): Evaluating a method of rap-
tially adaptive tier in microbial source track-   idly detecting pathogen indicators in aquatic
ing and pollution identification.                 environments with respect to identifying hot-
                                                  spots of contamination. Gordon Research
We devised a covalently-linked anti-E.coli        Conference. Environmental Sciences: Water,
bead complex that was used to measure wa-         New Hampshire, June 22-26, 2008.
ter quality in freshwater and marine systems
by IMS/ATP. We collected and analyzed             Collaborative Efforts
samples from freshwater and marine sys-           My lab has continued our very meaningful
tems. R2 values for the correlation between       collaboration with Dr. Sharon Walker (UCR).
traditional measurements and the rapid            We have received a second year of funding
method were 0.87 and 0.94 in freshwater           from UC Marine Council for a project stem-
and marine, respectively. IMS/ ATP was also       ming from our Center for Water Resources
evaluated as a rapid, intermediate tier for a     Grant. This year’s UC Marine Council award
multi-tiered approach in source tracking and      is also in collaboration with Rich Ambrose
identification and was able to rapidly identify   (UCLA) and Trish Holden (UCSB). Our lab is
the presence of high E. coli loading in one of    also pursuing additional source identification
the two channels, which resulted in high lev-     funding in collaboration with Trish Holden, Ali
els at the confluence of the two channels.        Boehm (Stanford) and the Southern California
We are currently applying this rapid method       Coastal Water Research Project (SCCWRP).
along with human-specific and universal            For further information please contact:
Bacteroides measurements by quantitative
PCR in two additional watersheds in Malibu                     Jennifer Jay
and Ventura. We have detected human fecal                   jennyjay@ucla.edu
pollution in the Ventura Marina and are cur-                   310-267-5365
rently continuing source tracking efforts.                www.cee.ucla.edu/jay.htm

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