Abstracts for 6 new published articles for water quality

["Shannon Briggs" <BRIGGSSL@michigan.gov>]

Colin Stine , O.; Amy Carnahan; Ruby Singh; Jan Powell; Jon  Furuno ,
P.; Alicia Dorsey; Ellen Silbergeld; Henry  Williams , N., and Glenn
Morris , J. Characterization of Microbial Communities from Coastal
Waters using Microarrays. Environmental Monitoring and Assessment. 2003;
81 (1-3):327-336.
  
Abstract: Molecular methods, including DNA probes, were used to
identify and enumerate pathogenic  Vibrio species in the Chesapeake Bay;
our data indicated that  Vibrio vulnificus exhibits seasonal
fluctuations in number. Our work included a characterization of total
microbial communities from the Bay; development of microarrays that
identify and quantify the diversity of those communities; and
observation of temporal changes in those communities. To identify
members of the microbial community, we amplified the 16S rDNA gene from
community DNA isolated from a biofilm sample collected from the
Chesapeake Bay in February, 2000. The resultant 75 sequences were 95% or
more similar to 7 species including two recently described  Shewanella
species,  baltica and  frigidimarina, that have not been previously
isolated from the Chesapeake. When the genera of bacteria from biofilm
after culturing are compared to those detected by subcloning amplified
16S fragments from community DNA, the cultured sample exhibited a strong
bias. In oysters collected in February, the most common bacteria were
previously unknown. Based on our 16S findings, we are developing
microarrays to detect these and other microbial species in these
estuarine communities. The microarrays will detect each species using
four distinct loci, with the multiple loci serving as an internal
control. The accuracy of the microarray will be measured using sentinel
species such as  Aeromonas species,  Escherichia coli, and  Vibrio
vulnificus. Using microarrays, it should be possible to determine the
annual fluctuations of bacterial species (culturable and non-culturable,
pathogenic and non-pathogenic). The data may be applied to understanding
patterns of environmental change; assessing the "health" of the Bay; and
evaluating the risk of human illness associated with exposure to and
ingestion of water and shellfish.



Greg  Olyphant , A.; Judith Thomas; Richard  Whitman , L., and Denver
Harper. Characterization and Statistical Modeling of Bacterial (
Escherichia Coli) Outflows from Watersheds that Discharge into Southern
Lake Michigan. Environmental Monitoring and Assessment. 2003; 81
(1-3):289-300.
  
Abstract: Two watersheds in northwestern Indiana were selected for
detailed monitoring of bacterially contaminated discharges ( Escherichia
coli) into Lake Michigan. A large watershed that drains an urbanized
area with treatment plants that release raw sewage during storms
discharges into Lake Michigan at the outlet of Burns Ditch. A small
watershed drains part of the Great Marsh, a wetland complex that has
been disrupted by ditching and limited residential development, at the
outlet of Derby Ditch. Monitoring at the outlet of Burns Ditch in 1999
and 2000 indicated that E. coli concentrations vary over two orders of
magnitude during storms. During one storm, sewage overflows caused
concentrations to increase to more than 10,000 cfu/100 mL for several
hours. Monitoring at Derby Ditch from 1997 to 2000 also indicated that 
E. coli concentrations increase during storms with the highest
concentrations generally occurring during rising streamflow. Multiple
regression analysis indicated that 60% of the variability in measured
outflows of  E. coli from Derby Ditch (n = 88) could be accounted for by
a model that utilizes continuously measured rainfall, stream discharge,
soil temperature and depth to water table in the Great Marsh. A similar
analysis indicated that 90% of the variability in measured  E. coli
concentrations at the outlet of Burns Ditch (n = 43) during storms could
be accounted for by a combination of continuously measured water-quality
variables including nitrate and ammonium. These models, which utilize
data that can be collected on a real-time basis, could form part of an 
Early Warning System for predicting beach closures.



Heath Kelsey , R.; Geoffrey  Scott , I.; Dwayne  Porter , E.; Brian
Thompson, and Laura Webster. Using Multiple Antibiotic Resistance and
Land use Characteristics to Determine Sources of Fecal Coliform
Bacterial Pollutiion. Environmental Monitoring and Assessment. 2003; 81
(1-3):337-348.
  
Abstract: Multiple Antibiotic Resistance (MAR) analysis and regression
modeling techniques were used to identify surface water areas impacted
by fecal pollution from human sources, and to determine the effects of
land use on fecal pollution in Murrells Inlet, a small, urbanized,
high-salinity estuary located between Myrtle Beach and Georgetown, South
Carolina. MAR analysis was performed to identify areas in the estuary
that are impacted by human-source fecal pollution. Additionally,
regression analysis was performed to determine if an association exists
between land use and fecal coliform densities over the ten-year period
from 1989 to 1998. Land-use variables were derived using Geographic
Information System (GIS) techniques and were used in the regression
analysis. MAR analyses were conducted by comparing the frequency and
patterns of antibiotic resistance found in  Escherichia coli isolates
derived from surface water samples and from sewage sources in the
Murrells Inlet sewage collection system. The MAR results suggest that
the majority of the fecal pollution detected in the Murrells Inlet
estuary may be from  non-human sources, including fecal coliforms
isolated from areas in close proximity to high densities of active
septic tanks. A MAR Index, which measures the frequency of antibiotic
resistance, was calculated for each of twenty-three water samples and
nine sewage samples. The antibiotic resistance pattern comparisons were
performed using cluster analysis. Although the MAR indices indicated
that several surface water sites had potential human-source
contamination, the cluster analysis suggests that only one sampling site
had MAR patterns that were similar to those found in the sewage samples.
This site was in close proximity to several large pleasure boats as well
as a sewage collection system lift station, but was not near areas with
active septic tanks. The results of the regression analysis also suggest
that sewage sources and rainfall runoff from urbanized areas may
contribute to fecal pollution in the estuary.


Katharine  Field , G.; Anne  Bernhard , E., and Timothy  Brodeur , J.
Molecular Approaches to Microbiological Monitoring: Fecal Source
Detection. Environmental Monitoring and Assessment. 2003 ; 81
(1-3):313-326.
  
Abstract: Molecular methods are useful both to monitor natural
communities of bacteria, and to track specific bacterial markers in
complex environments. Length-heterogeneity polymerase chain reaction
(LH-PCR) and terminal restriction fragment length polymorphism (T-RFLP)
of 16S rDNAs discriminate among 16S rRNA genes based on length
polymorphisms of their PCR products. With these methods, we developed an
alternative indicator that distinguishes the source of fecal pollution
in water. We amplify 16S rRNA gene fragments from the fecal anaerobic
genus  Bacteroides with specific primers. Because  Bacteroides normally
resides in gut habitats, its presence in water indicates fecal
pollution. Molecular detection circumvents the complexities of growing
anaerobic bacteria. We identified  Bacteroides LH-PCR and T-RFLP
ribosomal DNA markers unique to either ruminant or human feces. The same
unique fecal markers were recovered from polluted natural waters. We
cloned and sequenced the unique markers; marker sequences were used to
design specific PCR primers that reliably distinguish human from
ruminant sources of fecal contamination. Primers for more species are
under development. This approach is more sensitive than fecal coliform
assays, is comparable in complexity to standard food safety and public
health diagnostic tests, and lends itself to automation and
high-throughput. Thus molecular genetic markers for fecal anaerobic
bacteria hold promise for monitoring bacterial pollution and water
quality.



Kinzelman, J. ; Ng, C.; Jackson, E.; Gradus, S., and Bagley, R.
Enterococci as Indicators of Lake Michigan Recreational Water Quality:
Comparison of Two Methodologies and Their Impacts on Public Health
Regulatory Events. Applied and Environmental Microbiology. 2003;
69(1):92-96 .
  
Abstract: The frequency of poor-water-quality advisories issued in
Milwaukee and Racine, Wisconsin, in the absence of identifiable sources
of contamination brought into question the reliability of the present
indicator organism, Escherichia coli. Enteroccoci have been suggested as
an alternative to E. coli for freshwater monitoring due to their direct
correlation to swimmer-associated gastroenteritis. The purpose of this
research was threefold: (i) to explore enterococci as an alternative to
E. coli for monitoring freshwater Lake Michigan beaches, (ii) to
evaluate the impact of the two indicators on regulatory decisions, and
(iii) to compare membrane filtration m-enterococcus agar with
indoxyl-beta-D-glucoside to a chemical substrate technique (Enterolert)
for the recovery of enterococci. Recreational water samples from
Milwaukee (n = 305) and Racine (n = 153) were analyzed for the
enumeration of E. coli and enterococci using IDEXX Colilert-18 and
Enterolert. Correlation between the indicators was low (R(2) = 0.60 and
0.69). Based on U.S. Environmental Protection Agency bacterial indicator
threshold levels of risk for full body immersion, using enterococci
would have resulted in 56 additional unsafe-recreational-water-quality
advisories compared to the total from using E. coli and the
substrate-based methods. A comparison of the two enterococcal methods (n
= 124) yielded similar results (R(2) = 0.62). This was further
confounded by the frequent inability to verify enterococci from those
wells producing fluorescence by the defined substrate test using
conventional microbiological methods. These results suggest that further
research is necessary regarding the use of defined substrate technology
interchangeably with the U.S. Environmental Protection Agency-approved
membrane filtration test for the detection of enterococci from fresh
surface water.



Rachel  Noble , T.; Stephen  Weisberg , B.; Molly  Leecaster , K.;
Charles  McGee , D.; Kerry Ritter; Kathy  Walker , O., and Patricia 
Vainik , M. Comparison of Beach Bacterial Water Quality Indicator
Measurement Methods. Environmental Monitoring and Assessment. 2003; 81
(1-3):301-312.
  
Abstract: Three methods (membrane filtration, multiple tube
fermentation, and chromogenic substrate technology kits manufactured by
IDEXX Laboratories, Inc.) are routinely used to measure indicator
bacteria for beach water quality. To assess comparability of these
methods, quantify within-laboratory variability for each method, and
place that variability into context of variability among laboratories
using the same method, 22 southern California laboratories participated
in a series of intercalibration exercises. Each laboratory processed
three to five replicates from thirteen samples, with total coliforms,
fecal coliforms or enterococci measured depending on the sample. Results
were generally comparable among methods, though membrane filtration
appeared to underestimate the other two methods for fecal coliforms,
possibly due to clumping. Variability was greatest for the multiple tube
fermentation method. For all three methods, within laboratory
variability was greater than among laboratories variability.


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