Risk Assessment for Safe Drinking Water Supplies - Global Drinking Water Management and Conservation - page 143

Third, our review above indicates that QMRA is in principle excellent but the
computational burden of fitting PDFs to samples of water with pathogens is

enormous. Even when that is done, it is necessary to determine the acceptable level
of DALYs (DALYs/per person per year) that are politically tolerable and accept-
able. This review argues that it is always (or almost always) cost-effective to add a
newer UV disinfection module, rather than take all the mathematical and statistical
steps in the numerical estimation of a QMRA model, because the new UV modules
will de

nitely enhance safety by inactivating all pathogens. QMRA has its uses,
such as determining beach safety for swimming, but for drinking water, faith in
(cheap) equipment is a superior risk averse policy.
Fourth, the case studies indicate that the most successful risk minimization
procedure is the mini HACCP protocol used in Iceland, and the similar planning
tool utilized in Australia. Indeed, what can be simpler than treating drinking water
simply as a food, as Iceland has done for a number of years? Both Iceland and
Australia take risk very seriously and focus on the critical control points, where the
required action can be taken. Australia has demonstrated that even remote indig-
enous communities can do this and thereby enhance their water safety.
The importance of risk assessment of drinking water is likely to become even
more important, as the global impact of climate change will affect the quantity and
quality of fresh water (Dore and Simcisko 2013 ). The new IPCC Fifth Assessment
(AR5) (Intergovernmental Panel on Climate Change Working Group I 2013 )
con rms that patterns of precipitation are likely to continue to change; dry areas are

likely to become even drier and wet areas are likely to get wetter (Dore 2005 ); and
the frequency and intensity of hydrometeorological disasters is expected to
increase. This will be seen in more extreme weather events, which will affect water
turbidity and change the distributions of pathogens with increased variance. Earlier
and faster spring snow melt will mean earlier runoff of water, causing more oods

and also more forceful transport of natural organic matter in watercourses. Water
treatment will no longer be but these weather events will force

increased vigilance in water treatment and management and a greater reliance on
risk assessment methods. We propose that all drinking water utilities aspire for
certi

“ business as usual, ”

cation under ISO 22000, which integrates HACCP with quality management.
Due to climate change, pathogens will continue to be a challenge. But once an
acceptable threshold of pathogen-free water is secured, attention can then focus on
the emerging chemical contaminants, such as pharmaceuticals and personal care
products which consumers all over the world discharge into their wastewater that in
turn end up in the source waters for drinking. This is the next frontier in drinking
water treatment; this can be done, if there is political will, or if consumers demand
this from their elected politicians. But for all countries, the first order of business is

likely to be first monitoring and then effective elimination or inactivation of

pathogens in drinking water.