The difficulty in accurately enumerating C. parvum has made it impractical to suggest or
reasonably enforce regulatory guidelines for this pathogen. Recent investigations have presented
statistical approaches for the calculation of confidence intervals for both C. parvum
concentrations and removals by treatment processes. These approaches account for the various
analytical errors (representative sampling, random analytical error, and non-constant analytical
recovery) associated with C. parvum concentration and enumeration. A Poisson distribution was
utilized to model true sample counts (representative sampling), a binomial distribution to model
the recovered fraction of oocysts (random analytical error), and a Beta distribution to describe
non-constant analytical recovery. This fundamental statistical framework was utilized to: demonstrate the relationship between analytical recovery profiles and
the feasibility of concentration-based regulatory limits for C. parvum concentrations in raw and
treated waters; and, propose sampling objectives to increase the reliability of pathogen
concentration and removal data.
Includes 7 references, tables, figures.