A methodology for the assessment of risk of Cryptosporidium contamination of groundwater

Abstract

Water companies are now required by the Drinking Water Inspectorate to install continuous monitoring for Cryptosporidium at all sources (surface water and groundwater) where there is deemed to be a significant risk of Cryptosporidium oocysts being present in the final water. This has substantial cost implications, not only for the one-off installation of monitoring equipment, but also for the daily collection and analysis of samples. This paper describes a methodology that has been used by Southern Water to screen all their groundwater sources, in order to identify those which are at significant risk of Cryptosporidium contamination, and which therefore need continuous monitoring. The methodology is a semi-quantitative scoring technique, developed by the authors, which produces a ranked list of sources and enables action to be prioritized. The methodology is designed to operate with a level of information and data easily available to a water company, overcoming the problems of significant data requirements associated with probabilistic methodologies.

Risk Analysis Strategies in the Water Utility Sector: An Inventory of Applications for Better and More Credible Decision Making

“…Cryptosporidium contamination risk, as described by Boak and Packman. 15 The methodology consists of ranking source waters across ten risk categories (e.g. land use) using pre-determined scoring hierarchies (e.g.…”

“…Evaluating degradation risk Lindley and Buchberger, 83 Besner et al 13 Risk ranking Prioritisation of monitoring strategies Dabrowski et al, 30 Verro et al, 164 Boak and Packman, 15 Feijtel et al 44…”