Hi Folks, the names and/or contact info of
companies that design and install overhead wiring at swimming areas is beseeched.
In Hamilton, Ontario, Canada we’re seriously considering installing overhead wiring at
some E.coli plagued beaches to improve water quality. Local research by
Dr. Tom Edge and some minor bird control and beach maintenance interventions
have produced sufficient local data to pretty much signal a green light that
bird control should reduce E. coli concentrations
Any suggested companies/contacts will be greatly
appreciated!
Thanks and Sincerely,
Eric Mathews, Manager
City of Hamilton
Public Health Services
Health Protection Branch
905-546-2424 xt 2186
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-----Original Message-----
From: owner-beachnet@great-lakes.net
[mailto:owner-beachnet@great-lakes.net] On
Behalf Of Meredith Nevers
Sent: December 17,
2007 5:53 PM
To: beachnet@great-lakes.net
Subject: BEACHNET==> new
article on small-period variations (1-10 min) of enterococci in diverse
environments
Enterococci Concentrations in Diverse Coastal
Environments Exhibit
Extreme Variability
Environ. Sci. Technol., 41 (24), 8227–8232
10.1021/es071807v
Alexandria B. Boehm
Fecal indicator bacteria (FIB) concentrations in a
single grab sample
of water are used to notify the public about the
safety of swimming in
coastal waters. If concentrations are over a
single-sample standard,
waters are closed or placed under an advisory.
Previous work has shown
that notification errors occur often because FIB
vary more quickly
than monitoring results can be obtained (typically
24 h). Rapid
detection technologies (such as quantitative
polymerase chain
reaction) that allow FIB quantification in hours
have been suggested
as a solution to notification errors. In the
present study, I explore
variability of enterococci (ENT) over time scales
less than a day that
might affect interpretation of FIB concentrations
from a single grab
sample, even if obtained rapidly. Five new data
sets of ENT collected
at 10 and 1 min periodicities for 24 and 1 h,
respectively, are
presented. Data sets are collected in diverse
marine environments from
a turbulent surf zone to a quiescent bay. ENT vary
with solar and
tidal cycles, as has been observed in previous studies.
Over short
time scales, ENT are extremely variable in each
environment even the
quiescent bay. Changes in ENT concentrations
between consecutive
samples (1 or 10 min apart) greater than the
single-sample standard
(104 most probable number per 100 mL) are not
unusual. Variability,
defined as the change in concentration between
consecutive samples, is
not distinct between environments. ENT change by
60% on average
between consecutive samples, and by as much as
700%. Spectral analyses
reveal no spectral peaks, but power-law decline of
spectral density
with frequency. Power-law exponents are close to 1
suggesting ENT time
series share properties with 1/f noise and are
fractal in nature.
Since fractal time series have no characteristic
time scale associated
with them, it is not obvious how the fractal
nature of ENT can be
exploited for adaptive sampling or management.
Policy makers, as well
as scientists designing field campaigns for
microbial source tracking
and epidemiology studies, are cautioned that a
single sample of water
reveals little about the true water quality at a
beach. Multiple
samples must be taken to gain a snapshot into the
patchy structure of
microbial water quality and associated human
health risk.
--
Alexandria Boehm, PhD
Clare Boothe Luce Assistant Professor
Department of Civil and Environmental Engineering
Environmental Engineering & Science
Terman Engineering Center M7
Stanford University
Stanford, CA 94305-4020
tel: 650 724-9128
fax: 650 725-3164
website: http://www.stanford.edu/~aboehm
--
Alexandria Boehm, PhD
Clare Boothe Luce Assistant Professor
Department of Civil and Environmental Engineering
Environmental Engineering & Science
Terman Engineering Center M7
Stanford University
Stanford, CA 94305-4020
tel: 650 724-9128
fax: 650 725-3164
website: http://www.stanford.edu/~aboehm
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Meredith B. Nevers
Aquatic Biologist
U.S. Geological Survey
Lake Michigan
Ecological Research Station
1100 N. Mineral Springs Rd.
Porter, IN 46304
phone (219) 926-8336 ext. 425 fax (219) 929-5792
mnevers@usgs.gov
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