Molecular Methods for the Detection of Waterborne Pathogens - Waterborne Pathogens: Detection Methods and Applications - page 263

The World Health Organization has set their limit at 1.0 µg L −1 . The route
of exposure is likely inhalation. There is no standardized correlation data on
Microcystis levels in the water and their corresponding levels in air.
Methods currently available for detection of microcystin include whole
cell bioassay in mice that detect levels of 25-150 µg kg −1 ; MALDI-TOF,
which is able to detect microcystin at levels of 1 µg L −1 ; and LC-MS and
GC-MS, which are able to detect levels of 0.02 µg L −1 and 0.0043 µg L −1
respectively. All these methods are expensive and time consuming and not
suited for routine water monitoring. Many newer techniques have been
based on biosensor technology using a wide range of analytes, includ-
ing enzyme-based biosensors, optical biosensors, electrochemical biosen-
sors, immunosensors, and nucleic acid sensors (see Ref. 106 for review).
Recently, Al-Tebrineh et al. 161 described a PCR assay for the detection of
hepatotoxigenic Cyanobacteria that was quantitative.
Currently, no standardized protocol has been approved for routine detec-
tion of cyanobacterial toxins in drinking or recreational waters, although
cyanotoxins, microcystin, anatoxin-a, and cylindrospermopsin have been put
on the Contaminate Candidate List III by the United States Environmental
Protection Agency (USEPA) based on occurrence and prevalence research.
8.4. FECAL SOURCE TRACKING
To adequately assess human health risks and for drinking water
monitoring, it is necessary to know not only the pathogens present but
also the sources of the pathogen contamination. This information can assist
in developing guidelines and management policies to protect watersheds
and reduce waterborne transport of enteropathogens worldwide. 209 To
date, microbial source tracking (MST) using indicator organisms has been
the standard. Besides monitoring for total and fecal coliforms ( E. coli ) ,
Clostridium and fecal Enterococci have been used to determine the source
of the fecal contamination. The ratios of E. coli to Enterococci have been
used to predict human or animal source with mixed success because some
human pathogens such as Giardia and Cryptosporidium are often associated
with animal contamination. Therefore, although the presence of FIBs may
be able to shade some light on the source of the fecal contamination, it
cannot accurately predict the pathogen or the risk associated with the
levels of the pathogen. Information about the route of infection and the
risk assessment for human death would benefit from some of the more