Giardia and Cryptosporidium in raw and finished water

Abstract

The D/DBP Rule and the ESWTR must be orchestrated carefully to ensure protection of public health. The American Water System has conducted extensive monitoring of its operations since 1988. Analysis of 347 surface water samples collected between 1988 and 1993 showed that the prevalence rate of Giardia and Cryptosporidium was 53.9 percent and 60.2 percent, respectively. But because the parasite assay does not indicate viability or virulence, these results do not necessarily indicate that these water systems were at risk from waterborne pathogens. To supplement coagulation and filtration, the average system will have to apply sufficient disinfection to reduce viable Giardia levels by 3.1 log10. An analysis of existing disinfection practices shows that most systems are already applying disinfectant at a level sufficient to reduce Giardia levels. However, the proposed Disinfectants/Disinfection By‐products (D/DBP) Rule may hamper the ability of water utilities to apply sufficient disinfection under current operating conditions. Careful integration of the D/DBP and the Enhanced Surface Water Treatment rule is encouraged.

Climate variability and change in the United States: potential impacts on water- and foodborne diseases caused by microbiologic agents.

“…That same study showed that 39% of filtered drinking water samples from these treatment plants contained C. parvum (27%) or G. lamblia (17%), although 78% of the plants met the turbidity requirements of the then-applicable Surface Water Treatment Rule (30). A subsequent study in 1995 still found 13% of finished treated water to be contaminated with Cryptosporidium oocysts (31). Correlations between increased rainfall and increased Cryptosporidium oocyst and Giardia cyst concentrations in river water have been reported (32).…”

Occurrence of Cryptosporidium oocysts and Giardia cysts in raw water from the Atibaia river, Campinas, Brazil

“…Presently, there is a worldwide recommendation that systems serving populations between 10,000 and 100,000 people be required to monitor for presence of Giardia and Cryptosporidium in drinking water samples 10 .…”

Scientific Opinion on the minimum hygiene criteria to be applied to clean seawater and on the public health risks and hygiene criteria for bottled seawater intended for domestic use

“…Cryptosporidium has been detected in marine mammals (Hughes-Hanks et al, 2005;Rengifo-Herrera et al, 2010) although their infectiousness to humans is poorly understood, however C.hominis has been detected in a dougon in Australia (Morgan et al, 2000). Outbreaks associated with contaminated drinking water have been reported world-wide (Fayer et al, 2004;LeChevallier and Moser, 1995).…”

“…Giardia has been detected in marine mammals (Hughes-Hanks et al, 2005) although their infectious to humans in poorly understood. Outbreaks associated with contaminated drinking water have been reported world-wide (LeChevallier and Moser, 1995).…”