International Conference on Rain Water Cistern Systems
"Rainwater Catchment for Future Generations"
Keelung, Taiwan, R.O.C. - August 1991
2: Catchment Water Quality Regulation
Rainwater Quality: Pathogens
And Heavy Metals
Khon Kaen University, Thailand
The quality of rainwater samples collected from collecting system (roof and
gutter), storage containers (both outdoor and indoor) were evaluated both bacteriologically,
using indicator organisms and pathogen isolation, and chemically by analysing
heavy metal concentrations. The source of bacteriological contamination was investigated
employing the ratio of fecal coliform to fecal streptococci (FC:FS). Information
on saitary practices was also investigated.
Approximately 60-91 %, 34-78 %, 43-78 %, and 10-33 % of samples collected from
collecting system and storage containers did not meet the drinking water quality
standard expressed in terms of total bacterial count, total coliform, fecal colliform,
and E.Coli, respectively. About 79-84 % of samples collected from roof and gutter
had FC:FS ratios of less than 1, indicating the source of contamination was animal.
While about 39 % and 47 % of samples collected from in-house containers had FC:FS
ratios of less than 1 and greater than 4 respectively, which indicated the contaminating
sources were both animal and human.°The contamination induced by human was
mainly caused by unsanitary practices on water handling and usage of the villagers.
Pathogenic contamination was found approximately 1.1 % of samples collected,from
such sampling points. The pathogens identified were Salmonella gr.E. and gr.C,
V. parahaemolyticus, and Aromonas. The heavy metals analysed in this study included
Cd, Cr, Pb Cu, Fe, Mn and Zn. Most of the heavy metal concentrations taken from
various sampling points compared favorably with WHO drinking water standards with
two exceptions, Mn and Zn. However, Mn and Zn are considered to affect the asdthetic
quality of drinking water only and were therefore not significant to health.
The findings from this study indicate that any health risk evolving from the
consumption of stored rainwater would be due to bacteriological contamination
rather than heavy metal contamination.
PDF of full document (17pp, 360kb)
|Note: The IRCSA proceedings
section is still new and under active management, If you find any problems,
ommissions or corrections please contact
the administrator so we can put things right.