International Rainwater Cistern Systems Conference
Khon Kaen, Thailand
- January, 1987
Section F: Water Quality
The Microbiological Quality of Cistern Waters in the
Tantalus Area of Honolulu, Hawaii
Roger S. Fujioka
Water Resources Research Centre and School of Public Heath
University of Hawaii
Robert D. Chin
School of Public Heath
University of Hawaii
The drinking water quality of cistern waters in the Tantalus
area of Honolulu, Hawaii was evaluated by analyzing 18 cistern systems for
concentrations of bacteria, conductivity/ turbidity and total solids. The
results indicate that concentrations of total salts, and total solids in these
cistern waters were well within the current U.S. drinking water standards.
Moreover, only 2 of 36 cistern water samples exceeded the maximum turbidity
level of 5.0 NTU established for individual sources. However, high
concentrations of one of the three fecal indicator bacteria (total coli-form,
fecal coliform, fecal streptococci) were often recovered from these waters
indicating that most of the cistern waters would not be able to meet U.S.
microbiological drinking water standards. Fecal streptococci was recovered much
more frequently and at higher concentrations than coliforms indicating that the
source of fecal contamination was birds rather than humans. These cistern
waters were also determined to contain very high concentrations of total
bacteria, almost always exceeding 500/ml, the minimum level at which
interference with the recovery of total coliform bacteria have been reported.
Since assays for fecal coliform and fecal streptococci are not interfered by
the presence of high concentrations of total bacteria, we recommend that these
alternative indicator bacteria be analyzed for to determine the extent of fecal
contamination of cistern water supplies.
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