BEACHNET==> New Article by Haack et al.

[Richard L Whitman <rwhitman@usgs.gov>]

HNICAL REPORTS


While not specifically on beach water, this
article shows the potential for using chemicals to trace ambient waste
water and thus has important recreational water quality monitoring and
microbial source tracking implications. 

Journal of Environmental Quality. 2009. 38:248-258

Comparing Wastewater Chemicals, Indicator
Bacteria Concentrations, and Bacterial
Pathogen Genes as Fecal Pollution Indicators
Sheridan K. Haack,* Joseph W. Duris, Lisa
R. Fogarty, Dana W. Kolpin, Michael J. Focazio, Edward T. Furlong,
and Michael T. Meyer U.S. Geological
Survey

The objective of this study was to compare
fecal indicator
bacteria (FIB) (fecal coliforms, Escherichia
coli [EC], and
enterococci [ENT]) concentrations with a
wide array of typical
organic wastewater chemicals and selected
bacterial genes as
indicators of fecal pollution in water samples
collected at or
near 18 surface water drinking water intakes.
Genes tested
included esp (indicating human-pathogenic
ENT) and nine
genes associated with various animal sources
of shiga-toxin–
producing EC (STEC). Fecal pollution was
indicated by
genes and/or chemicals for 14 of the 18 tested
samples, with
little relation to FIB standards. Of 13 samples
with <50 EC
100 mL−1, human pharmaceuticals
or chemical indicators of
wastewater treatment plant effl uent occurred
in six, veterinary
antibiotics were detected in three, and stx1
or stx2 genes
(indicating varying animal sources of STEC)
were detected
in eight. Only the EC eaeA gene was
positively correlated
with FIB concentrations. Human-source fecal
pollution was
indicated by the esp gene and the
human pharmaceutical
carbamazepine in one of the nine samples
that met all FIB
recreational water quality standards. Escherichia
coli rfbO157 and
stx2c genes, which are typically associated
with cattle sources
and are of potential human health signifi
cance, were detected
in one sample in the absence of tested chemicals.
Chemical and
gene-based indicators of fecal contamination
may be present
even when FIB standards are met, and some
may, unlike FIB,
indicate potential sources. Application of
multiple water quality
indicators with variable environmental persistence
and fate may
yield greater confi dence in fecal pollution
assessment and may
inform remediation decisions