Sydney 1998—lessons from a drinking water crisis

Cox, Peter; Fisher, Ian; Kastl, George; Jegatheesan, Veeriah; Warnecke, M.; Angles, Mark; Bustamante, Heri; Chiffings, Tony; Hawkins, Peter

doi:10.1002/j.1551-8833.2003.tb10369.x

Cited by 16 publications

(6 citation statements)

References 13 publications

(21 reference statements)

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“…At the time there were many potential sources of Cryptosporidium and Giardia in Sydney's catchments including sewage treatment plants, septic tanks and cattle grazing in the outer catchments. Floodwater-borne Cryptosporidium and Giardia short-circuited the main storage dam and entered the treatment plant in pulses that also produced rapid fluctuations in water chemistry (Cox et al 2003). Before the incident, the dam was expected to provide an average detention time of three years (Cox et al 2003).…”

Section: Sydney 1998 -Drinking Water Incidentmentioning

confidence: 99%

Water safety plans: planning for adverse events and communicating with consumers

Byleveld

Deere²,

Davison³

2008

Journal of Water and Health

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A wide range of microbial and chemical characteristics in drinking water have the potential to affect human health. However, it is not possible or practical to test drinking water for all potentially harmful characteristics. If drinking water is contaminated, people may already be exposed by the time test results are available. The 'boil water alert' issued in Sydney, Australia in 1998 following the detection of Cryptosporidium and Giardia in the finished water supply, highlighted the uncertainties associated with the public health response to test results.The Sydney experience supports the international consensus that a preventive risk-management approach to the supply of drinking water (manifesting as water safety plans (WSPs)) is the most reliable way to protect public health. A key component of a comprehensive WSP is that water suppliers and health authorities must have plans to respond in the case of water contamination and/or outbreaks. These plans must include clear guidance on when to issue warnings to consumers, and how these warnings are to be communicated. The pressure on health authorities to develop clear and systematic boil-water guidance will increase as utilities all over the world develop their WSPs.

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Section: Sydney 1998 -Drinking Water Incidentmentioning

confidence: 99%

Water safety plans: planning for adverse events and communicating with consumers

Byleveld

Deere²,

Davison³

2008

Journal of Water and Health

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“…A third subset may have partially degraded rRNA producing questionable FISH reactions with hard‐to‐interpret, intermediate fluorescence intensities. The subjectivity in interpreting the FISH reaction of this latter subset is undesirable for critical laboratory assay interpretation (Cox et al. 2003).…”

Section: Introductionmentioning

confidence: 99%

Determination of Cryptosporidium parvum oocyst viability by fluorescence in situ hybridization using a ribosomal RNA-directed probe

et al. 2004

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Aims: Fluorescence in situ hybridization (FISH) has been proposed for species-specific detection, and viability determination of Cryptosporidium parvum oocysts. FISH-based viability determination depends on rRNA decay after loss of viability. We examined the effects of RNase(s) and RNase inhibitors on FISH of C. parvum. Methods and Results: FISH was performed using a 5¢-Texas red-labelled DNA oligonucleotide probe at 1 pmol ll )1 (G. Vesey, N. Ashbolt, E.J. Fricker, D. Deere, K.L. Williams, D.A. Veal and M. Dorsch (1998) Journal of Applied Microbiology 85, 429). Intact and heat-permeabilized oocysts were treated with 1-100 lg ml )1 RNase. FISH of intact oocysts appeared unaffected by exogenous RNase if this was neutralized before permeabilization. FISH fluorescence of heat-killed oocysts stored in phosphate-buffered saline at room temperature decayed by 1/2 after 55 h, but remained detectable after 6 days. Addition of vanadyl ribonucleoside complex (VRC) extended rRNA half-life of heat-permeabilized oocysts to 155 h. Conclusions: Extended rRNA half-life may result in viability overestimation using FISH. RNase pretreatment before FISH is recommended to destroy residual rRNA in recently killed oocysts. Incorporation of 1-10 mmol l )1 VRC before FISH permeabilization steps should neutralize RNase activity. Significance and Impact of the Study: Elimination of FISH fluorescence of nonviable C. parvum is desirable. Use of RNase and VRC is suggested to reduce numbers of false-positive 'viable' oocysts.

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“…Flatbed membrane (293 mm in diameter) filtration (Millipore Corp., Bedford, Mass.) is a laboratory-based concentration method with routine local usage since 1993 (Cox et al 2003). FiltaMax TM foam filter capsules (IDEXX, Laboratories Inc., Westbrook, Maine) use multiple layers of compressed open-cell foam discs to trap target organisms, allow field concentration of samples and subsequent laboratory elution, and are USEPA method 1623 and UK Drinking Water Inspectorate (DWI) approved.…”

Section: Introductionmentioning

confidence: 99%

Comparison of methods for the concentration ofCryptosporidiumoocysts andGiardiacysts from raw waters

Ferguson¹,

Kaucner²,

Krogh³

et al. 2004

Can. J. Microbiol.

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This study compared the recovery of Cryptosporidium oocysts and Giardia cysts ((oo)cysts) from raw waters using 4 different concentration-elution methods: flatbed membranes, FiltaMax foam, Envirochek HV capsules, and Hemoflow ultrafilters. The recovery efficiency of the combined immunomagnetic separation and staining steps was also determined. Analysis of variance of arcsine-transformed data demonstrated that recovery of Cryptosporidium oocysts by 2 of the methods was statistically equivalent (flatbed filtration 26.7% and Hemoflow 28.3%), with FiltaMax and Envirochek HV recoveries significantly lower (18.9% and 18.4%). Recovery of Giardia cysts was significantly higher using flatbed membrane filtration (42.2%) compared with the other 3 methods (Envirochek HV 29.3%, FiltaMax 29.0%, and Hemoflow 20.9%). All methods were generally acceptable and are suitable for laboratory use; 2 of the methods are also suitable for field use (FiltaMax and Envirochek HV). In conclusion, with recoveries generally being statistically equivalent or similar, practical considerations become important in determining which filters to use for particular circumstances. The results indicate that while low-turbidity or "finished" waters can be processed with consistently high recovery efficiencies, recoveries from raw water samples differ significantly with variations in raw water quality. The use of an internal control with each raw water sample is therefore highly recommended.

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Sydney 1998—lessons from a drinking water crisis

Cited by 16 publications

References 13 publications

Water safety plans: planning for adverse events and communicating with consumers

Water safety plans: planning for adverse events and communicating with consumers

Determination of Cryptosporidium parvum oocyst viability by fluorescence in situ hybridization using a ribosomal RNA-directed probe

Comparison of methods for the concentration ofCryptosporidiumoocysts andGiardiacysts from raw waters

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