Waterborne Disease Outbreaks and the Multi-barrier Approach to Protecting Drinking Water - Global Drinking Water Management and Conservation - page 28

nonpoint sources (for example wild animals or birds dying in water bodies at
unknown locations, or contaminating the water with their feces), a good overview
of the wildlife is necessary, and risks of contamination must be estimated. It would
also help if there were water quality monitoring stations, so that when a quality
problem arises, the authorities can try to identify the location of the contamination
and remove it. If the contamination shows up in groundwater, it may be next to
impossible to trace the source of the contamination. But if the frequency has been
calculated, then risk assessment methods can be used and

areas can be
mapped to warn local residents of the dangers of contamination of unknown origin.
In the US, a set of best management practices for animal farming are mandatory
for large farms. For nonpoint source pollution, the US uses the method of Eco-
logical Risk Assessment, on which more details are considered in Chap. 6 . The
principles of watershed protection outlined above should be re

“ high risk ”

ected in legislation,

wherever these principles are taken seriously. In other words, water-

shed protection is impossible and all watershed protection practices should be
embodied in legislation.

“ voluntary ”

2.6 Conclusion

The key lessons are: (a) a water system cannot rely exclusively on chlorine; (b) water
systems must institute careful monitoring of conventional water treatment technol-
ogy, particularly of

flocculation and of chlorination; (c) water systems must be
vigilant over the possibility of animal or human fecal material seeping into the water
supply at all stages; (d) there is a need to institutionalize a regular protocol of
sampling of water quality and the reliability of such sampling, and (e) a determined
policy of continual modernization of all components of the complete water treatment
train, by investing in newer and safer treatment technologies (see Chaps. 3 and 4 ).
As a first step in preventing waterborne disease outbreaks, institute a multi-

barrier approach, of which the first component is the establishment of a sound

watershed management plan that prevents contamination of water courses. The
second step in the multi-barrier approach is a clear understanding of drinking water
treatment technologies, which is the subject of Chaps. 3 and 4 .

References

Aramini J, Stephen C, Dubey J, Engelstoft C, Schwantje H, Ribble C (1999) Potential
contamination of drinking water with Toxoplasma gondii oocysts. Epidemiol Infect 122
(02):305 315

Betancourt W, Rose J (2004) Drinking water treatment processes for removal of Cryptosporidium
and Giardia. Vet Parasitol 126(1):219 - 234
Bridgman S, Robertson R, Syed Q, Speed N, Andrews N, Hunter P (1995) Outbreak of
cryptosporidiosis associated with a disinfected groundwater supply. Epidemiol Infect 115
(03):555 - 566

-