Risk Assessment for Safe Drinking Water Supplies - Global Drinking Water Management and Conservation - page 123

priced out of the pockets of consumers. On the other hand, the WHO emphasizes
health and safety.

6.3.4 Quantitative Microbial Risk Assessment

What follows is a brief overview of the QMRA model. The entire process of
QMRA is displayed as a flow diagram in Fig. 6.3 .

Step 1: To begin with, it is necessary to find the concentration of a particular

pathogen as the number of microorganisms per liter of source water. This must be
done by taking a large number of samples, which are required in order to be able to

fit a probability density function (PDF). For each pathogen, there is a baseline

Fig. 6.3 General framework for calculating microbial risk from drinking water (Petterson et al.
2006 )