WQRA HealthStream - Issue 52

INFORMATION AND ANALYSIS FOR WATER AND HEALTH PROFESSIONALS

Issue 52 Public Health Newsletter of the CRC for Water Quality and Treatment December 2008

In this Issue:

WSAA Aquality Update 1

DWI Outbreak Investigation 4

Victorian Regulatory Audit 6

News Items 8

From The Literature 9

Web Bonus Articles

Arsenic

Diabetes

Emerging Pathogens

Helicobacter

Inflammatory Bowel Disease

Naegleria

Norovirus

Radon

Turbidity

Mailing List Details 20

Editor Martha Sinclair

Assistant Editor Pam Lightbody

CRCWQT Internet Address: www.waterquality.crc.org.au A searchable Archive of Health Stream articles, literature summaries and news items is available on the CRC Web page.

WSAA Aquality Update The Water Services Association of Australia is currently reviewing the first 2 years of experience with the Aquality tool, a computer software program which enables water suppliers to assess how well they are implementing the Australian Drinking Water Guidelines Framework for Management of Drinking Water Quality. Aquality was developed in response to industry concerns that a formal system was needed to ensure a consistent assessment of implementation despite the generic nature of the Framework and the diversity of water supply systems and industry structures across Australia. The program was modelled on Aquamark, a highly successful software program developed by WSAA for assessment and benchmarking of asset management in the water industry. A pilot version of the Aquality program was initially trialled by six water utilities of differing sizes operating under different regulatory regimes. After extensive development and piloting of the tool, in November 2006 the software was released for use by WSAA members and associates. This report summarises discussions at a Review and Learnings Workshop which was held recently in Melbourne. Aquality provides a means of assessing implementation of the 12 elements, 32 components and 76 actions specified in the Framework by providing 187 measures against which progress can be practically assessed. The scoring system assesses: the Capability of the organisation to apply the

risk management Framework through tracking Process Development for risk assessment and management programs and Process Documentation,

HEALTH STREAM DECEMBER 2008 PAGE 1

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COOPERATIVE RESEARCH CENTRE FOR WATER QUALITY AND TREATMENT

the Execution of risk management through tracking the Coverage (geographic extent, utility staff and extent of the water cycle) within the organisation and the Frequency with which processes and procedures are actually used in day to day operations.

For high level reporting a percentage score is produced for each of the 12 Framework elements, and users can drill down to see scoring details for each component, action and measure. This enables water suppliers to assess how well they are progressing with Framework implementation and to identify their specific strengths and weaknesses. Scores for each measure are assigned on a graded scale (not simply pass/fail) and certain constraints are built-in so that more important measures receive higher weighting and it is not possible to achieve a high score for a given element if a significant weakness exists in one or more aspects. Changes can be tracked over time, and the system can be used for benchmarking against other water suppliers, although this feature has not yet been implemented. Aquality has been designed to be compatible with a range of quality management and regulatory systems including ISO, HACCP and the Victorian regulatory system, and therefore can be used to support auditing under these systems and help provide regulators with assurance that robust systems are in place to manage water quality risks. Speakers at the Melbourne workshop included representatives of several water providers: South Australian Water - a catchment-to-tap

state-wide utility which manages 76 water supply systems of various sizes across the state including the city of Adelaide.

Water Corporation - another catchment-to-tap state-wide utility which manages multiple water sources for the city of Perth in addition to 221 regional localities in Western Australia.

Gold Coast Water - former catchment-to-tap water supplier for the rapidly growing urban coastal area of Queensland. With the structural changes now being implemented in that state, Gold Coast Water will become part of a larger distribution-only company.

South East Queensland Water - a newly formed organisation with responsibility for managing and treating water for about 50 townships. Bulk water supply and distribution functions will be performed by other organisations.

Coliban Water - a Victorian regional urban water supplier which provides water to 49 towns and is also a bulk water provider.

East Gippsland Water - a Victorian regional urban water supplier for 27 townships.

The whole-of-state water suppliers (SA Water and Water Corporation) had both commenced work on implementation of the ADWG Framework even before the final version of the Framework was officially published in the Australian Drinking Water Guidelines in late 2004. While both companies had well established risk assessment and management plans, they reported that use of Aquality provided new insights and useful outcomes for their organisations. Gold Coast Water also had well established risk management systems but also found advantages from using Aquality. Beneficial aspects reported by these organisations included: highlighting the inter-relationships between

water quality and other sections of business operations such as asset management and staff training. This helps to influence organisational priorities to support water quality improvements.

providing a consistent system to track progress over time despite organisational changes and staff turnover.

promoting a balanced approach to implementation by ensuring that no aspect of the Framework was being neglected.

preventing complacency among middle and senior management.

enabling gap analysis in risk management for contractors.

provision of results in an easy to understand graphical format.

The smaller water supply organisations generally were less advanced in Framework implementation prior to using the Aquality system but they also reported similar benefits. One organisation noted that process had highlighted how contractual arrangements with other entities in the water supply



chain could limit or delay their ability to make the necessary changes in management. Another found that although current operations were considered best practice on a technical level, the Aquality analysis showed risks associated with too much reliance on standby equipment and lack of a long term equipment maintenance plan. Other weaknesses mentioned were controls on the quality of water treatment chemicals and management of risks associated with delivery and storage of chemicals, plus the frequency of equipment calibration processes. A common theme across large and small organisations was the identification of weaknesses in Framework Element 7: Employee Awareness and Training. Shortcomings in training, succession planning, knowledge transfer and adequate coverage for staff absences were noted and in fact have been highlighted by other stakeholders in the water sector for areas other than drinking water production. During discussions it was emphasised that achieving high numerical scores on the initial assessment should not be seen as the object of the exercise - the value of carrying out the Aquality analysis lies in the discussions it stimulates within the organisation and the improved understanding of how to implement the ADWG Framework more effectively. Users reported that comparison of assessments by different groups of staff and external assessors indicated that operational staff tended to assign lower scores, perhaps because they have first-hand knowledge of day to day problems. There appeared to be little evidence of people assigning unrealistically high scores. It was also noted that Aquality is not the only measure of water quality management that should be applied within an organisation. Other tools, performance indicators and corporate targets are also needed, but Aquality is a useful adjunct that can be applied across the industry. Several users of the system noted that a significant staff time commitment (in the order of 100 hours or more) is needed to carry out the initial Aquality assessment, and this can be difficult for smaller organisations. Speakers agreed that it was important to have a “champion” or “gatekeeper” to coordinate and drive the process within the organisation. The importance of adequate documentation to record the

process and support the risk assessment decisions was emphasised. It was agreed that “documentation” should be interpreted broadly to include flow charts, CD-ROMs and links to manufacturer’s equipment manuals as well as conventional written documents. One presenter noted that after being initially sceptical about the need to document all processes he now realised the value of good documentation for preserving knowledge in the event of staff turnover and assisting in the training of new staff. The relationship of Aquality to regulatory audit processes was also discussed and there was general agreement that the primary focus should remain on providing an effective internal assessment and benchmarking tool for the water industry, although Aquality can clearly be used to support regulatory auditing of risk management systems. Lack of familiarity of auditors with the Aquality system was seen as an issue by some Victorian businesses which had recently undergone regulatory audits. One organisation reported that staff who committed considerable effort to completing an Aquality assessment were frustrated to find that the auditor did not refer to it. Aquality is currently available only to WSAA member and associate organisations, so auditors cannot access the software until they have been contracted for an audit by a water supplier. A number of useful suggestions for improvement of the Aquality program were raised by the audience including improvements in reporting systems, tracking the date of edits along with the identity of the staff member, improved screen layouts and expanded space for notes and comments. The need for improved induction materials was raised and introductory workshops for new users were suggested. Establishment of a user support network or discussion list was also suggested. The anonymous benchmarking feature was anticipated to be very useful in allowing water suppliers to compare themselves to other organisations of similar size, and (via WSAA) to seek information and advice from others who score well on elements where they have scored poorly. The issue of providing a single overall implementation score as well as a score for each of the 12 Framework elements was discussed. Several people noted that Boards and Managing Directors



often asked for this but there were variable opinions on whether it was desirable. If an overall score were to be derived it would be important not to allow a high overall figure to disguise a significant weakness in one or more Framework elements. This would be contradictory to the philosophy of the ADWG Framework because all 12 elements are deemed essential for effective risk management. WSAA will now collate the feedback received from the users and undertake changes to Aquality before releasing an improved version of the software next year. The workshop participants also heard three presentations on expansion of the ADWG Framework into other areas of the water cycle. Professor Don Bursill (former CEO of the CRC for Water Quality and Treatment, and current chair of the NHMRC Water Quality Advisory Committee) spoke on the need for risk management to deal with challenges of the new urban water cycle, Dr Melita Stevens (Research Programs Manager, Melbourne Water) outlined the adaptation of the Framework for the Australian Guidelines for Water Recycling (including potable and non-potable reuse of water derived from sewage, managed aquifer recharge and use of stormwater), and Dr David Cunliffe (Department of Health, South Australia) spoke about inclusion of the Framework in legislation. During discussions it was noted that the risk management approach has been more readily accepted in the recycled water area, perhaps because the high risk nature of the source water (sewage) is so clearly obvious. There is a pressing need for effective auditing systems for recycled water and other alternative water schemes due to the larger range of players involved in these schemes compared to conventional drinking water supplies. It is also essential that regulatory agencies have a good understanding of risk management issues so they are able to adequately assess proposed schemes and risk management systems. To address this need WSAA has commenced development of an assessment tool similar to Aquality for assessing implementation of the risk management framework for recycled water. This assessment tool (dubbed Requality) is expected to undergo pilot trials in 2009.

DWI Outbreak Investigation The UK Drinking Water Inspectorate (DWI) has completed its investigation into the Cryptosporidium contamination incident notice in the Northampton area in June this year (1). The incident led to a 10-day boil water notice affecting over 250 000 people and 22 cases of cryptosporidiosis linked to the contamination were identified. Genotyping of oocysts from the water supply and from human cases showed that they belonged to a type previously only reported in rabbits. The DWI investigation confirmed that the outbreak was caused by a rabbit gaining access to a water tank within the Pitsford Water Treatment Works which is operated by Anglian Water. The raw water supply to the Treatment Works is drawn from a surface reservoir which is open to the public for recreational uses. Water is treated by per-ozonation, clarification, filtration, ozonation, granular activated carbon (GAC) adsorption, chlorination and phosphate dosing for control of lead solvency. Contamination of the treated water supply was detected through a continuous monitoring program being carried out as part of the operational monitoring strategy of the company. Oocysts were detected on 24 June when analysis was conducted on a filter cartridge which had been used to sample water from the morning of 19 June to midday on 23 June. Only 6 oocysts were detected from an estimated 11 848 litres of finished water, however no positive samples had previously been found in 874 finished water samples taken since 2000, although oocysts were sometimes detected in raw water. The result was therefore considered sufficiently unusual to trigger immediate analysis of the next filter cartridge. This analysis showed 418 oocysts from a volume of 5064 litres (an average of 0.08 oocysts per litre). Although this concentration did not exceed the former regulatory limit set by the DWI (2), a decision was made to issue a boil water notice. As no oocysts had been detected in the raw water supply, investigations focused on the possibility of contamination within the water treatment works. External inspection of the water treatment process units showed two missing ventilator meshes and damage to one corner of an access hatch on the GAC



backwash tank. These breaches in the physical integrity of the tank could have permitted entry of small animals or insects. Oocysts were detected in two water samples – one from the GAC backwash tank outlet and one from the disinfection contact tank outlet. These tanks were drained and the interiors inspected. A fresh rabbit carcass was found immediately below the inlet pipe of the disinfection contact tank, and it was concluded that the animal had entered the GAC backwash tank, been trapped against the fine wire support for the GAC media during a backwash cycle then carried into the disinfection contact tank located immediately downstream. Given that Cryptosporidium oocysts are highly resistant to chlorine, the disinfectant would have had no effect on the viability of oocysts released from the rabbit. The contaminated water then passed into the distribution system to consumers. The DWI Inspector was very critical of the failure in basic hygiene procedures leading to this incident. Regular routine checks of tank integrity were reportedly part of risk management procedures carried out by Anglian Water, however it was evident that multiple breaches of the GAC backwash tank had not been detected. This tank may have been overlooked in site inspection programs because it was located outside the secure compound which enclosed the main operational works site, although it was within the larger secure gated Treatment Works compound. It also appeared that pest and vermin control measures at the Treatment Works were limited to buildings in the operational compound. The DWI has recommended that a thorough review of all Anglian Water sites be undertaken to ensure that hygiene arrangements are satisfactory, and that the company should also undertake a review of its risk assessment methodology to ensure such hazards are adequately assessed and controlled. Anglian Water was commended for its monitoring strategy and rapid response to the initial positive test result. The second filter sample was analysed at the company’s laboratory within 6 hours of the initial result, and subsequent communication with the local Health Protection Agency was fast and effective. However the company was criticised for not immediately sending the oocysts to the UK Health

Protection Agency Cryptosporidium Reference Unit for genotyping. The DWI concluded that Anglian Water had provided accurate and timely information to consumers, and had fully met its legal requirements for notification and reporting. Indeed the Inspector commended the communication and outreach efforts of Anglian Water and recommended that lessons learnt with regard to communication activities be shared with other organisations. Although the DWI investigation found that Anglian Water had probably supplied water unfit for human consumption for a short period, it had for the most part acted with due diligence before, during and after the incident to, so far as is practicable, identify and mitigate the risk of Cryptosporidium being present in the water supplied from its Pitsford Water Treatment Works. Therefore the DWI Inspector considered there were insufficient grounds for instituting legal proceedings against the company. While no instances of human infection by the rabbit genotype of Cryptosporidium had been published in the literature prior to this outbreak, a case report was subsequently published by the UK Cryptosporidium Reference Unit (3). This paper (which was already in press at the time of the Pitsford incident) described three individuals each infected with an unusual genotype of Cryptosporidium (respectively skunk, horse and rabbit). Comparison of the rabbit and human genotypes by PCR-RFLP analysis of three different genetic loci (SSU rRNA, HSP70 and COWP) failed to separate them under conventional gel running conditions. However by altering the agarose gel concentration and extending the running time, the small size difference in DNA fragments could be detected (C. hominis diagnostic band 449 basepairs versus rabbit genotype 472 basepairs). DNA sequence analysis was able to differentiate the three genotypes but the sequence differences were minor. These results suggest that infections by the rabbit genotype (or some other rare genotypes) could be mistakenly attributed to C. hominis under conventional PCR-RFLP gel running conditions. From the viewpoint of risk assessment for water supplies, it now appears that rabbits may have to be considered as a possible source of human-infectious oocysts. However given that this genotype is likely to



have been misclassified as C. hominis in genotyping studies, risk assessments based in genotyping would still be valid as human infection risks would not have been underestimated. The single human case report (3) recorded prior to (but published after) the Pitsford incident arose from examination of over 16 000 Cryptosporidium-positive human faecal specimens collected in the UK since 2000, although not all of these may have been analysed in a manner that would have permitted discrimination of the rabbit and C. hominis genotypes. This suggests that the rabbit genotype is not a common cause of human disease, however the fact that the oocysts originating from a single rabbit could cause 22 human cases from a water contamination incident indicates at least some strains of the genotype must be highly infectious. Dose-response models derived from studies of Cryptosporidium infection in human volunteer subjects have indicated that for some strains ingestion of a single oocyst may entail a risk of infection in the order of 5% to 10%. As a result of the Anglian Water outbreak, the DWI has commissioned the UK Health Protection Agency Cryptosporidium Reference Unit to undertake a research program to improve understanding of the human health risk posed by the rabbit genotype. This will include: establishing the taxonomic status of the rabbit

genotype of Cryptosporidium determining its prevalence in human

cryptosporidiosis surveying its occurrence in rabbits characterising the diversity, epidemiology and

pathogenicity of the genotype. (1) See the September 2008 Issue of Health Stream for a report on the incident.

(2) A limit of 1 oocyst per 10 litres was specified under DWI regulations introduced in 2000, and water treatment plants deemed to be at risk for Cryptosporidium contamination were required to undertake continuous monitoring of finished water. In late 2007 these regulations were superseded by more comprehensive requirements for risk-based management. The Pitsford Water Treatment Works was not classified as being at risk of Cryptosporidium under the 2000 regulations and was never legally obligated to carry out continuous monitoring of this nature.

(3) Unusual Cryptosporidium Genotypes in Human Cases of Diarrhea. G Robinson, K Elwin, and RM Chalmers (2008) Emerging Infectious Diseases 14(11) 1800-1802.

Victorian Regulatory Audit Victorian drinking water suppliers recently completed the first round of regulatory audits required under the Safe Drinking Water Act 2003. The Act, which came into operation on 1 July 2004, requires water suppliers and water storage managers to prepare, implement and review risk management plans for their supplies of drinking water and regulated water (1). In addition, the Safe Drinking Water Regulations (2005) associated with the Act set down maximum levels for a small number of key water quality parameters, and specify that drinking water must not contain any algal toxin, pathogen, substance or chemical in such amounts that may pose a risk to human health. The Act also empowers the Secretary to the Department of Human Services, or their delegate to require that a water supplier or water storage manager have their risk management plan audited. This regulatory approach is consistent with the Framework for Management of Drinking Water Quality contained within the Australian Drinking Water Guidelines (2004).

Victoria was the first state in Australia to introduce legislation of this nature to ensure the quality and safety of drinking water supplied to the public. On 1 July this year Queensland became the second Australian jurisdiction to introduce legislation covering drinking water supplies with the enactment of the Water Supply (Safety and Reliability) Act 2008. The regulatory changes coincide with major structural reforms for water supply arrangements in Queensland. Drinking water quality in other Australian states is currently controlled by a range of non-legislative mechanisms as well as general provisions under state Public Health Acts, however it is understood that regulatory reforms relating to drinking water supplies are also being considered or developed in a number of these jurisdictions. Implementation of the Victorian legislation required the development of training and accreditation processes for auditors before the audit component could be undertaken. A certification scheme for Drinking Water-Quality Management System Auditors was therefore developed through a collaborative process involving the Department of



Human Services (DHS), the Water Services Association of Australia, the Victorian Water Industry Association and RABQSA International. Certification as an auditor requires the demonstration of knowledge competency, appropriate educational qualifications, relevant work experience, suitable personal attributes, and demonstration of skill competency through conduct of an audit on a drinking water service provider. For the regulatory audits in Victoria, a water business wishing to engage an auditor must apply to the Department of Human Services’ Drinking Water Regulatory Section for approval, providing details of the auditor’s RABQSA certification and declaring any potential conflicts of interest (for example an auditor cannot audit a risk management plan which they have developed or reviewed). The Department provides written confirmation of approval of the auditor, the risk management plan they are approved to audit, the duration of the approval, and any conditions imposed on the approval. Seven auditors were approved in total, for 25 audits. The implementation schedule for the Victorian legislation required water businesses to develop a risk management plan by July 2005, and the first round of audits covered the period January 2006 to December 2007. The audits were preceded by a series of information seminars organised by the Drinking Water Regulatory Section during December 2007. Auditors were required to assess the water quality risk management plan for each water business, and to determine: • whether the plan has been prepared in accordance

with the requirements of the Act and the Regulations,

• whether the plan has been implemented and complied with,

• whether the plan has been reviewed and, where appropriate, revised,

• whether the risk management plan adequately identifies the nature and level of hazards and risks for each of the water supply systems covered in the scope of the audit,

• whether the control measures identified in the risk management plans are in place operationally and are adequate to reliably control water safety risks

The first round of audits of Victorian water businesses were undertaken between May and September 2008, and the results were presented by the Drinking Water Regulatory Section at a series of four industry workshops around Victoria during November and December 2008 (2). A workshop was also held with auditors to inform them of the results and obtain their feedback on the audit process. A total of 25 water businesses were audited, comprising the three metropolitan Melbourne suppliers, 13 regional water suppliers, 3 water storage managers and 6 suppliers for alpine resorts and Parks Victoria. Overall, 15 of the 25 water businesses were found to be compliant with the requirements of the Safe Drinking Water Act 2003. All three metropolitan water businesses were compliant as were 9 of the 13 regional water suppliers. Lower rates of compliance were seen for water storage managers (1 compliant of 3 audited) and alpine resorts and Parks Victoria (2 compliant of 6 audited). Importantly, no critical non-compliances (defined as posing a serious or imminent risk to public health) were identified during the audits. Reasons for non-compliance with audited requirements were variable; sometimes relating to adequacy of the risk management plan, and sometimes to the degree and depth of implementation of the plan. In some instances risk assessment and management processes appeared to have been carried out in a satisfactory manner by water suppliers, but documentation of these activities and the associated decision-making processes was insufficient. Poor integration of risk management plans for water storage managers and corresponding water suppliers was also noted. Feedback from representatives of water businesses at the workshops was generally positive, with some remarking that the audit process is helping to secure resources for water quality improvements and driving culture change towards the proactive approach embodied in the ADWG Framework. Involvement of operators in developing and implementing risk management plans was seen to be a key feature in successful transition to the new approach. Department of Human Services staff noted that water quality in regional Victoria has improved, and



incident response processes have become more rapid and effective since introduction of the regulatory changes. Bottlenecks in the auditor training and approval process were also discussed, with concerns that a significant increase in demand for auditing services will occur as a result of the recent legislation in Queensland. A number of organisations also noted that some auditors were unfamiliar with the water industry and that perhaps more tailored training programs were needed for auditors to provide relevant background on risk management issues relating to water quality. Use of the Aquality tool (see article on p1 of this issue) to familiarise auditors was also suggested to be beneficial. Overall the Drinking Water Regulatory Section reported that it was satisfied with the conduct of the first round of audits and the consistency of audit findings between different auditors. Water businesses which were found to be non-compliant at audit have entered into formal undertakings with the Department of Human Services to carry out corrective actions to rectify the identified problems. In addition, those businesses which were compliant at audit have been requested to specify how they will address opportunities for improvement which were identified by the audit process. The Department of Human Services plans to update its audit guidance notes in response to the feedback generated from the first round of audits, and a second round of audits will be conducted in 2009. In keeping with the public reporting requirements of the Safe Drinking Water Act, water businesses which completed the audit before 1 July 2008 are required to publish the outcome of the audit in their annual water quality report for 2007/08, and a summary of the audit findings will also be presented in the Department of Human Services 2007/08 Annual Report, expected to be tabled in Parliament in March next year. The remaining audit results will be discussed in detail in the 2008/09 Annual Reports of the relevant water suppliers. (1) Under the Act, Regulated water is water that is not intended for drinking but which could reasonably be mistaken as being drinking water. In most instances this means piped water supplied for non-potable purposes through taps that may be accessed by the public.

(2) The workshop presentation is available at: www.health.vic.gov.au/environment/water/drinking.htm

News Items Health Stream to continue in 2009 This is the last issue of Health Stream to be produced under the auspices of the CRC for Water Quality and Treatment. The CRC officially came to an end on 30 June 2008 but provided funding for production of this newsletter until the end of the year. The CRC has been succeeded by Water Quality Research Australia Limited (WQRA), a not-for-profit research organisation which will undertake collaborative research of national application on drinking water quality, recycled water and relevant areas of wastewater management. We are happy to announce that the production of Health Stream will continue under WQRA in 2009. The WQRA website can be found at: www.wqra.com.au CRC Research Reports Although the CRC has ended, production of Research Reports from completed projects is continuing. All reports are available for downloading from the CRC’s website at: www.waterquality.crc.org.au Recently added reports include: 44 Development of Low Cost Online Monitoring

Package to Improve Chloramination Control

45 A Series of Exposure Experiments - Recycled Water and Alternative Water Sources: Part A - Aerosol-sizing and Endotoxin Experiments

46 A Series of Exposure Experiments - Recycled Water and Alternative Water Sources: Part B - Microbial transfer efficiency during machine clothes washing and microbial survival turfgrass experiments

47 Investigation of the survival of Cryptosporidium in environmental waters

53 Study of Water Usage in Urban Areas

59 Artificial mixing for destratification and control of cyanobacterial growth in reservoirs

57 Modelling DOC Removal by Enhanced Coagulation

60 Screening Assays for Water-borne Toxicants

61 Cylindrospermopsin Mechanisms of Toxicity and Genotoxicity

63 Membrane Distillation of Brine Wastes

64 Biological filtration processes for the removal of algal metabolites




From the Literature

Web-bonus articles Summaries of these additional articles are available in the web page version of Health Stream and are included in the searchable archive at: www.waterquality.crc.org.au/pubs

Intra-individual variability in toenail arsenic concentrations in a Michigan population, USA. Slotnick MJ, Meliker JR. and Nriagu JO. (2008) J Exposure Science & Environmental Epidemiology, 18(2); 149-157.

Increased childhood liver cancer mortality and arsenic in drinking water in northern Chile. Liaw J, Marshall G, et al. (2008) Cancer Epidemiology Biomarkers & Prevention, 17(8); 1982-1987.

Water intake and bladder cancer risk in Los Angeles County. Jiang X, Castelao JE, Groshen S et al. (2008) International Journal of Cancer, 123(7); 1649-1656.

Seasonal variation of phytoplankton and cyanobacteria composition and associated microcystins in six Portuguese freshwater reservoirs. Valério E, Faria N, et al.. (2008) Annales de Limnologie, 44(3); 189-196.

Water-related diseases outbreaks reported in Italy. Blasi MF, Carere M, et al.(2008) J Water and Health, 6(3); 423-432.

Investigating public health impacts of deer in a protected drinking water supply watershed. Cinque K, Stevens MA et al. (2008) Water Science and Technology, 58(1); 127-132.

Nitrogen-nitrate exposure from drinking water and colorectal cancer risk for rural women in Wisconsin, USA. McElroy JA, Trentham-Dietz A et al. (2008) J Water and Health, 6(3); 399-409.

The semantics and pragmatics of water notices and the impact on public health. Rundblad G. (2008) J Water and Health, 6(SUPPL. 1); 77-86.

Sodium hypochlorite dosage for household and emergency water treatment. Lantagne DS. (2008) E-journal AWWA, 100(8); 106-119+14.

An integrated method for evaluating community-based safe water programmes and an application in rural Mexico. DeWilde CK, Milman A et al. (2008) Health Policy and Planning, 23(6); 452-464.

Does the reuse of PET bottles during solar water disinfection pose a health risk due to migration of plasticers and other chemicals into the water? Schmid P, Kohler M et al. (2008) Water Research, In Press DOI:10.1016/j.watres.2008.09.025

Risk of learning and behavioral disorders following prenatal and early postnatal exposure to tetrachloroethylene (PCE)-contaminated drinking water. Janulewicz PA, White RF et al. (2008) Neurotoxicology and Teratology, 30(3); 175-185.

Biomonitoring of surface and coastal water for Cryptosporidium, Giardia, and human-virulent microsporidia using molluscan shellfish. Lucy FE, Graczyk TK, Tamang L et al. (2008) Parasitology Research, 103(6); 1369-1375.

Arsenic Low-level arsenic exposure in drinking water and bladder cancer: A review and meta-analysis. Mink, P.J., Alexander, D.D., Barraj, L.M., Kelsh, M.A. and Tsuji, J.S. (2008) Regulatory Toxicology & Pharmacology, DOI:10.1016/j.yrtph.2008.08.010 (In Press) Exposure to high levels of arsenic in drinking water has been found to be associated with excess risk of skin, bladder and lung cancer. Studies conducted at lower arsenic exposures (less than 100-200 micro g/L) have in general not found significantly increased risks of potential arsenic-related cancers. These epidemiological studies of populations with low-level exposure are limited by methodological issues including inadequate statistical power and exposure misclassification. Also a linear dose response association may have been assumed at all levels of exposure without examining the relationship between arsenic in drinking water and cancer at low-level exposures independent of high-level exposure. This review focused on the potential association between low-level exposures to arsenic in drinking water and bladder cancer using a meta-analysis to address study design and sample size issues and to improve the precision of estimates. Medline database was searched to identify studies of exposure to arsenic in drinking water and bladder cancer incidence and/or mortality. Also bibliographies of recently published paper and reviews were examined for relevant articles. Studies were selected that met the inclusion criteria for the meta-analysis modelling. Models were created that evaluated three population groups: (1) all study participants; (2) participants classified as never smokers; and (3) ever smokers (former and current smokers). In addition to the main analyses, several sensitively analyses were conducted based on a variety of study characteristics and exposure metrics. Other sensitivity analyses were conducted by generating sub-group meta-analysis models according to characteristics that may produce heterogeneity. Subgroup models were generated that: (1) included studies reporting data for incident cases only; (2) excluded studies using toenail arsenic

http://www.waterquality.crc.org.au/


concentrations; (3) included studies reporting data for cumulative exposure; and (4) included studies conducted among US populations. There were eight of the identified studies that met the inclusion criteria and were eligible for meta-analysis. Three case-control studies and one cohort study were conducted in US populations. Other studies were conducted in Argentina (case-control), Finland (case-control and case-cohort), and north-eastern Taiwan (cohort study). Meta-analysis of never smokers, highest versus lowest exposure category produced summary relative risk estimates (SRREs) below 1.0. This suggests that even in the presence of some degree of exposure misclassification, on average and within the range of what is considered low-level arsenic exposure, arsenic alone is unlikely to significantly increase the risk of bladder cancer. In the meta-analysis of all exposure categories combined, the SRRE was slightly elevated, however not significantly (1.11; 95% CI: 0.95-1.30: p-values for heterogeneity = 0.21). A positive but non-significant association was seen among ever smokers (all exposure categories: SRRE = 1.24, 95% CI: 0.99-1.56). Results from the subgroup analyses that included all study participants did not vary considerably; all were weak in magnitude (SRREs ranged between 1.05 and 1.29) and none of the associations were statistically significant. Inverse associations were observed consistently in all subgroup analyses among never smokers (SRREs ranged between 0.69 and 0.91), and p-values for heterogeneity ranged between 0.653 and 0.938, indicating little variability between studies. Positive associations for ever smokers were found with SRREs ranging between 1.21 and 2.35 but models were more heterogeneous. Overall the results do not support an independent association of low-level arsenic exposure in drinking water and risk of bladder cancer. The lack of association found was most apparent in the analyses limited to never smokers where associations observed between arsenic exposure and bladder cancer were neither confounded nor modified by tobacco smoking. Studies are needed with more detailed information on smoking history to resolve whether smoking acts as an effect modifier of the association

between low-level arsenic exposure and bladder cancer. The authors note that the risk estimates derived from this study are lower than those predicted by the US National Research Council using linear extrapolation from Taiwanese data in populations exposed to much higher levels of arsenic. Available evidence on the mechanism(s) of action of inorganic arsenic and its metabolites is suggestive of a non-linear dose-response relationship. Diabetes Exposure to environmental factors in drinking water: Risk of islet autoimmunity and type 1 diabetes - the BABYDIAB Study. Winkler, C., Mollenhauer, U., Hummel, S., Bonifacio, E. and Zieglei, A.-C. (2008) Hormone and Metabolic Research, 40(8); 566-571. Type 1 diabetes (T1D) is a chronic disease characterised by autoimmunity against pancreatic islets. Autoantibodies may be present for years before diagnosis, and both early nutrition and environmental factors may play important roles in development of the disease. A number of studies have found an association between drinking water and risk of T1D however it is not possible to determine whether water quality is associated with initiation or progression of islet autoimmunity. The nationwide German BABYDIAB study is a prospective observational study that follows newborn offspring of mothers or fathers with T1D from birth up to 17 years of age. This present study investigated whether exposure to factors contained in the drinking water within the first year of life of BABYDIAB offspring is associated with the development and progression of islet autoimmunity. Recruitment into the BABYDIAB study began in 1989 and ended in 2000. Cord blood was obtained in obstetric departments from eligible families that consented to participate. Venous blood samples were obtained from the child during the follow-up visits. A nested case-control population was selected for this current analysis from the 1650 offspring who were recruited at birth into the BABYDIAB study and who had participated in at least the nine-month follow-up. There were 107 cases that developed islet



autoantibodies by January 2006 and 150 selected controls that were islet autoantibody negative by January 2006. Local offices of the German Legal Water Supply Authorities were contacted and asked to provide information on the quality of drinking water from the year the BABYDIAB offspring was born and for the first year of the participant’s life. Data were collected for 95 cases and 139 controls. There were three reports of analyses of drinking water quality on average per household with most reports containing complete data on the pH of the drinking water and the concentrations of nitrate, nitrite, iron, aluminium and manganese. Autoantibodies to insulin (IAA), glutamic acid decarboxylase (GADA), and IA-2 (IA2A) were measured in blood samples. There was no significant difference found in the pH or quality of drinking water (concentration of nitrate, nitrite, iron, aluminium and manganese) used by families in the first year of life of children who later developed or did not develop islet autoimmunity. After adjustment for potential confounding variables, there was no difference in risk of developing islet autoimmunity for children exposed to high or low drinking water concentrations of the variables examined. There were no differences seen when the variables were categorised as quartiles or as continuous variables or when multiple islet autoantibodies were used as outcome. There was an inverse association between nitrate concentrations and pH levels (r=-0.28, p less than 0.001). There was significant association between tap water pH was and risk of progression to T1D in children with islet autoimmunity (OR 2.5; 95% CI: 1.1, 5.7; Puncorrected =0.03) when other tap water parameters were not corrected for. The cumulative risk of progression to T1D within five years after islet autoantibody seroconversion was 28% (95% CI: 14-42%) in children exposed to water pH below the median (pH 7.62) compared with 12% (95% CI: 1-24%) in children exposed to water pH greater than 7.62 (p less than 0.05). Other water quality parameters were not associated with T1D risk. After correction for the drinking water variables examined, there was no significant association for any variable with progression to diabetes.

This study found no difference in drinking water quality between BABYDIAB children who developed islet autoimmunity and children who stayed islet autoimmune negative. There was a suggestion that water pH may significantly modify progression to T1D. Further prospective studies are required to validate the results found here as the association is marginal and was not maintained after correction for the other drinking water variables examined. Also water quality was assessed in the water supply and not from the tap water for each household. Emerging Pathogens Addressing emerging pathogens: Philadelphia's reflections on Giardia and Cryptosporidium. Burlingame, G.A. (2008) Journal of the New England Water Works Association, 122(2); 117-129. Giardia was once classed as an emerging pathogen for the North American drinking water community. The first waterborne outbreak of giardiasis in the US was reported in Rome, New York in 1978 and giardiasis outbreaks continued throughout the 1980s and 1990s and were mostly attributed to unfiltered and/or unchlorinated drinking water. In the 1990s Giardia was overshadowed by Cryptosporidium as an emerging pathogen. Cryptosporidium was found to be a concern for humans in 1976 and recognised as a potential waterborne pathogen in 1984. The 1993 cryptosporidiosis outbreak in Milwaukee brought increased awareness of the threat from Cryptosporidium and led to millions of dollars spent on research and water treatment plant upgrades. This paper reflects on the challenges presented by the waterborne pathogens Giardia and Cryptosporidium to see what lessons were learned by the Philadelphia Water Department (PWD) through treatment, monitoring, research, communication and public health surveillance. After a waterborne disease outbreak an emerging pathogen may become a concern for drinking water, however it may take years for the monitoring capability to develop to assess exposure to the pathogen through drinking water. Until the time that water surveillance can begin to provide information



about potential exposure it is important to understand and establish the health aspects and the occurrence of the diseases. Following the 1993 Milwaukee outbreak PWD and Philadelphia’s Department of Public Health began regular communication and collaboration concerning cryptosporidiosis. As a result of this, mandatory reporting by clinical laboratories of cryptosporidiosis cases began in Philadelphia as of 1994. During 1995-1999 in Philadelphia, the rate of giardiasis was ten times greater than that of cryptosporidiosis. During August through October peaks in both giardiasis and cryptosporidiosis cases occurred, with the lowest reported cases in April through May. This seasonal occurrence suggests that exposure occurred by other routes than drinking water. Recreational water contact in public and private pools is one likely source of exposure. During the initial years of concern for an emerging pathogen public health information is limited and pathogen occurrence data often not available, however water utilities should review their multiple barriers for optimisation based on existing knowledge. PWD is considered to be highly vulnerable to Giardia and Cryptosporidium as the drinking water comes from watersheds with varied uses. PWD has optimised its treatment process due to concern about Giardia and Cryptosporidium. PWD funded research on Giardia and Cryptosporidium inactivation in Philadelphia’s waters using chlorine, chloramine, and ozone disinfection schemes. This confirmed that PWD’s chlorine disinfection should adequately achieve the necessary goal for Giardia, but the necessary inactivation for Cryptosporidium could not be achieved. PWD voluntarily joined the Partnership for Safe Water program in 1996 which resulted in the lowering of its finished water turbidity to below 0.1 NTU and this was viewed as the means needed to control Cryptosporidium. PWD has a well-developed cross connection control program which has been reducing the risk of contamination from backflow. Also, PWD has a program to approve additions to the systems such as water main installation and applies best industry practices to minimise the contamination risk.

There was a need for an effective communication plan as information became available to be shared with stakeholders internally within the PWD and external to PWD. In 1994 PDoPH released its first quarterly report to physicians that addressed Cryptosporidium. Communication about Giardia and Cryptosporidium has continued and PWD sends out Consumer Confidence Reports every year as required by the Safe Drinking Water Act. PWD has also enhanced communication within the organisation by forming a Water Quality Committee to help key managers stay informed of water quality issues. Under the Water Quality Committee, a communication plan was established. The communication plan is a dynamic document that gives guidance on data evaluation, triggers for response and routes of communication. PWD also maintains biannual meetings with its regulatory agency the Pennsylvania Department of Environmental Protection (PaDEP) to share new data, prepare for new regulations, summarise research and conduct training. During the later half of the 1990s, PWD’s central laboratory established capability and method development for conducting protozoan analyses. PWD participated in research with the Awwa Research Foundation and the EPA. In 1996, PWD developed a new method for raw water collection which appeared to improve recovery of protozoa. Data has been collected on the occurrences of protozoa in PWD’s source waters and peak and average densities since 1994-1995 and data collection has continued. These data established a baseline for Philadelphia which eventually showed a seasonal pattern of occurrence which shows clearly the winter months with the greatest frequencies of pathogen occurrences. It is important to collect data during unusual situations such as during storm events as well as when a treatment operation experiences problems so it is possible to effectively identify the conditions that are of most concern when pathogen breakthrough would most likely occur. Between 1998 and 2000, special storm hydrograph sampling was conducted at two treatment plant intakes to understand the various flow-related impacts on Giardia levels. Recent



advancements in polymerase chain reaction (PCR) or PCR technology have led to identification of genotypes of detected Cryptosporidium in water. Studies are finding that many of the Cryptosporidium oocysts detected in Philadelphia’s watershed are from domestic or wild animals unrelated to human disease as found elsewhere. Philadelphia’s experience has provided valuable lessons for addressing the issues centred around Giardia and Cryptosporidium over the last twenty years, and can be used as a model for future responses to other emerging pathogens. Helicobacter Persistence of Helicobacter pylori in heterotrophic drinking-water biofilms. Giao, M.S., Azevedo, N.F., Wilks, S.A., Vieira, M.J. and Keevil, C.W. (2008) Applied & Environmental Microbiology, 74(19); 5898-904. Helicobacter pylori is a prevalent pathogen especially in developing countries where up to 90% of the population may be infected. Most infected individuals are asymptomatic however it is now well established that H. pylori infection can lead to the development of peptic and duodenal ulcer disease and gastric mucosa-associated lymphoid tissue lymphoma. The route of transmission of H. pylori is still unknown with person-to-person transmission appearing to be the most likely however water, food and animals have also been suggested as possible transmission vectors. Molecular techniques such as PCR have demonstrated the presence of H. pylori in drinking water distribution systems (DWDS), especially in systems with biofilms. However, DNA isolation alone does not indicate whether the bacterium is viable or not. In recent years fluorescence in situ hybridization (FISH) has successfully detected this pathogen in DWDS and other bodies of water and provides some indication of viability due to the maintenance of a high rRNA content. This study aimed to apply both FISH and a selective culture medium to assess the number of H. pylori cells found in an autochthonous complex consortium of drinking water biofilms formed under

different conditions to better understand the dynamics of H. pylori populations in real DWDS. Biofilms were formed using a two-stage chemostat model system and then inoculated with H. pylori NCTC 11637. Water samples were taken on days 1,2,4,8,16 and 31 after seeding and biofilm growth vessels were analysed to determine the total number of cells, the number of heterotrophic plate count (HPC) cells and the number of cultivable H. pylori cells. Cultivable H. pylori cells were quantified by standard plating onto selective H. pylori medium. Also total H. pylori cells were quantified using a specific peptide nucleic acid (PNA) probe in a FISH assay. Three different conditions were studied at 20 degrees C and 15 degrees C. The conditions were: low shear stress and low carbon concentration (LS/LC conditions) which served as the control, high shear stress and low carbon concentration (HS/LC) and low shear stress and high carbon concentration (LS/HC). For all water samples analysed it was not possible to recover cultivable H. pylori. At 20 degrees C, increasing the shear stress did not appear to affect the total number of cells, as on average, 4.31 x 108 cells cm-2 was obtained when a biofilm was formed in the LS/LC vessel and 4.14 x 108 cells cm-2 was obtained for the HS/LC vessel. When the carbon concentration was increased differences became evident with 4.00 x 106 CFU cm-2 versus 4.87 x 105 CFU cm-2 for the LS/LC conditions and 4.55 x 105 CFU cm-2 for the HS/LC conditions (P less than 0.1). Comparison of the results at the two temperatures suggests that when the concentration of carbon was increased, formation of a biofilm was favoured at 20 degrees C (P less than 0.005). It was possible to consistently detect and quantify H. pylori within biofilm structures by use of the H. pylori PNA probe. When the effects of the different conditions tested were compared, the results obtained for the total number of H. pylori cells (at 20 degrees C) showed a trend similar to the trend for results for the total numbers of cells, with the total numbers of H. pylori cells not statistically different (P less than 0.02) for the three conditions tested (on average, 2.25 x 106 cells cm-2 for the LS/LC conditions, 2.12 x 106 cells cm--2 for the HS/LC conditions and 2.15 x 106 cells



cm-2 for the LS/HC conditions). There was no significant difference between the three conditions tested at 15 degrees C either. A comparison of results obtained at the two temperatures showed that differences in numbers were also not statistically significant (P less than 0.05). The physicochemical parameters studied here did not affect the presence of H. pylori in heterotrophic biofilms, which indicates that if a sporadic occurrence of the pathogen passes through a drinking water supply, H. pylori is included in biofilms regardless of the DWDS characteristics. The morphology of H. pylori cells has been intimately connected with viability and infection capacity. Using PNA–FISH, spiral and coccoid cells were observed at both temperatures; however there were a larger proportion of spiral cells at 20 degrees C than at 15 degrees C. Spiral shaped cells are cultivable. It has been shown that coccoid cells are the manifestation of an environmentally robust type of cells that might be considered to be in the viable but non-cultivable state. The PNA probe used here targets sites on the 16S rRNA molecule and it is known that the RNA content of a cell can be indicative of viability, suggesting that the cells detected were still viable. The concentration of all H. pylori cells in the biofilms formed in this study was either higher than or very similar to the concentrations found when pure-culture biofilms were formed. Also, the detection of H. pylori embedded in biofilms suggests that there is a close association with other bacteria present in the biofilms. These two factors along with the persistence of a bright PNA-FISH signal, which indicates high rRNA content, suggest that in this study the heterotrophic bacteria present in the biofilms formed were not a negative influence on H. pylori but instead helped its transformation to the more robust coccoid morphology. The results of this study provide new evidence about the survival of H. pylori in drinking water biofilms and show that even though this pathogen is fastidious and loses cultivability easily and rapidly it can still remain viable in an environmentally robust viable but non-cultivable state for long periods of time. This study shows the capacity of H. pylori to adapt to stress situations by taking advantage of the presence

of other microorganisms. Standard cultivation methods may not be the best approach to assessing the safety of drinking water in regard to H. pylori and while improved recovery methods are not available it is important to use PNA-FISH as a monitoring method. This pathogen is found to persist in biofilms under most conditions present in aquatic environments which suggest that water biofilms might have a role in H. pylori transmission. Comment The prevalence of Helicobacter infection in developed nations is 25 to 40% with the highest rates occurring in lower socio-economic groups. Up to one-third of infected people may eventually develop peptic ulcer disease. Some US studies have suggested drinking untreated well water containing H. pylori is associated with increased rates of gastritis symptoms but to date there appears to be no published epidemiological evidence linking disinfected tap water to H. pylori infection. This organism has been included in the US EPA Candidate Contaminant List 3 for consideration for possible development of drinking water regulations. Inflammatory Bowel Disease The association between water supply and inflammatory bowel disease based on a 1990-1993 cohort study in southeastern Norway. Aamodt, G., Bukholm, G., Jahnsen, J., Moum, B., Vatn, M.H. and IBSEN Study Group (2008) American Journal of Epidemiology, 168(9); 1065-1072. Inflammatory bowel diseases (IBD) refer to a group of chronic diseases including ulcerative colitis and Crohn’s disease. The cause of these diseases is unknown, and a recent theory suggests they are due to abnormal immune responses to normal gut bacteria. IBD may cluster in families with evidence that several genes are involved in predisposition to these conditions. IBD has been shown to be related to socioeconomic factors, hygiene and exposure to microorganisms. Several studies have indicated a variable geographic distribution within countries. There have been some studies that have linked drinking water to IBD however most have focused on the content of different microorganisms. The aim of



this investigation was to study the relationship between important metals and other qualities indirectly related to organic components of the drinking water and incidence rates of IBD. Participants for this study were recruited from a population-based incidence study investigating IBD in four counties in southeastern Norway during 1990-1993. The counties studied were Ostfold, Oslo, Telemark and Aust-Agder, with populations living in a mixture of urban and rural districts. Incidence rates for IBD varied by as much as 10-fold between different municipalities within these four counties with no obvious geographic pattern. Data from the Norwegian waterworks registry of water quality was used in this study. The mean values for purified water from 1994 were used, which was the closest time to when the patient data were collected. There were six drinking water variables included in the analyses: iron, aluminium, pH (acidity), coliform bacteria, colour and turbidity. The waterworks registry contained data from 35 of the 43 waterworks and a model was used to predict the values of the components for the remaining waterworks and their sites. To assess drinking water exposure, values from each waterworks were linked to the address of every person living in that district at the approximate time of diagnosis. Statistically significant correlation coefficients were found between colour and turbidity (r = 0.75, P less than 0.001), coliform bacteria and turbidity (r = 0.50, P less than 0.001) and iron and colour (r = 0.36, P = 0.032). Using univariate models, several of the water parameters were significantly associated with Crohn’s disease, ulcerative colitis, or both. Using multivariate models, only iron and pH were significantly related to the combined category of IBD. Iron and coliform bacteria were significantly related to ulcerative colitis, and only iron was significantly related to Crohn’s disease. All variables except iron showed small effect sizes. When iron increased by 0.1 mg per L, the relative risk was 1.21 (21%) for IBD (95% confidence interval: 9, 34). For ulcerative colitis the corresponding figure was 18% (95% CI: 3, 35), and for Crohn’s disease 22% (95% CI: 0, 48). A small positive association was found between the incidence rate of IBD and pH (2% when

pH increased by 1 unit, 95% CI: 1, 3) and a negative association between coliform bacteria and ulcerative colitis (1% reduction in incidence rate, 95% CI: 0, 2) however for this latter result only four observation for this variable were not zero. Age at onset of disease and gender had no impact on this finding. This study found that the risk of developing inflammatory bowel disease, including ulcerative colitis and Crohn’s disease was associated with iron content in the drinking water. The results found here may be explained by two mechanisms, increased oxidative stress or increased bacterial growth that increases the chances of adverse immune responses in generically predisposed individuals. Iron works as a catalyst and increases oxidative stress and production of reactive oxygen molecules. The excess of reactive oxygen molecules has been shown to be important in the inflammation process initiating or propagating the development of inflammatory bowel disease. Also metabolic oxidative stress increases the likelihood of genomic instability. Iron is also an important factor influencing the growth of bacteria and their expression of virulence. When iron levels are enhanced, the interaction between bacteria and host tissue will also be altered including the ability of the bacteria to express virulence. A higher concentration of mucosal bacteria flora has been reported in patients with inflammatory bowel disease compared with controls. The authors comment that consumption of bottled water in Norway was low at the time of the study and tap water was assumed to be the main source of drinking water. There was no information on iron intake from food among the population studied. Comment This paper provides few details about the water supplies or water treatment methods except that all were from surface water sources. The maximum measured iron level was 0.39 mg/L with a mean of 0.08 and a median of 0.04 mg/L. The Norwegian Drinking Water Act specifies a maximum level of 0.20 mg/L for iron, while the Australian Drinking Water Guideline value is 0.30 mg/L. These levels are set on the basis of avoiding adverse taste or staining problems and are not health-related.



Naegleria Operational management of Naegleria spp. in drinking water supplies in Western Australia. Trolio, R., Bath, A., Gordon, C., Walker, R. and Wyber, A. (2008) Water science & Technology: Water Supply, 8(2); 207-215. The protozoa Naegleria fowleri is a free living thermophilic amoeboflagellate which is found in aquatic and soil habitats. N. fowleri is pathogenic to humans and can cause the waterborne disease primary amoebic meningoencephalitis (PAM). Cases of this rare and sometimes fatal disease have been reported in many countries and are often associated with geothermal water or heated swimming pools, although there have been cases reported where the source was traced back to reticulated water. In Australia, there have been reports of the disease in Western Australia (WA), South Australia, Queensland and New South Wales although not in recent decades. In WA, the primary supplier of drinking water supplies is the Water Corporation, operating 245 distribution schemes. Some of the main issues in the control of N. fowleri in WA are the large water supply distribution systems and the ability of the pathogens to infect and re-infect drinking water supplies. This paper aims to outline some of the conditions in which Naegleria has been detected in WA drinking water supplies and describe the methods used within the supply area to reduce the risk posed by this pathogen. The Water Corporation uses a multiple barrier approach to ensure that for any hazard that could compromise drinking water quality there are at least two barriers to prevent the hazard affecting the customer’s water quality. At locations where Naegleria has been isolated and/or where the water temperature is consistently greater than 25 degrees C for 4 months a year, the source is classified as high risk for Naegleria contamination. The most effective barrier in the control and elimination of Naegleria is to establish continuous free chlorine residuals. A free chlorine residual of a least 0.2 mg/L should be continuously maintained at the end of the distribution system. However detections of Naegleria do occasionally occur in some chlorinated systems.

Following any Naegleria detections, disinfectant residuals must be maintained for a minimum of 18 months, regardless of the disinfectant used. This is required as Naegleria spp. may persist in a dormant state through cyst formation within the biofilm. The monitoring frequency for chlorine residuals should vary depending on the disinfectant method, residual analysers and storage/distribution configuration. Water Safety Plans for each water supply are being developed which assist in monitoring and maintaining the optimum system requirements for supplying safe drinking water. The plans include a process control table that show the key sampling points, disinfectant residual target (with an upper and lower range), and corrective actions to bring the supply back within the target limits. There has been a significant reduction in the number of Naegleria detections across WA with a noticeable decline since 1997/98. In the past two years there have been no Naegleria detections. In addition to disinfection management, there are operational controls used within the distribution system to manage Naegleria. These operational controls often involve regular asset maintenance and cleaning to ensure all parameters through the water supply operate under conditions which minimise the risk of Naegleria. Following any Naegleria detection, incident management procedures developed jointly by the Water Corporation and the Department of Health, WA are triggered. The most important response to a Naegleria incident is to ensure that new water entering the reticulation system is adequately disinfected. The operator is required to complete a number of tasks including checking the status of the chlorinator to establish if the unit failed and how much water was not chlorinated. Also, rapid sampling of monitoring points through the whole supply is required to map the residuals. The best option to reinstate disinfection and maintain residuals is determined from information gathered during the incident response. Once chlorine residuals are back to within the target range for a period of at least 12 hours, re-sampling in the distribution is carried out. Two localities in the Goldfields and Agricultural Region of WA have had Naegleria repeatedly



detected and are therefore considered as high risk. Specific monitoring and risk management procedures have been developed for these supplies. The effective approach developed by Water Corporation is reflected in a steady improvement in Naegleria management resulting in improved regulatory compliance and disinfection residual maintenance practices. There is still a considerable gap however in the understanding of the factors and processes that affect the distribution, presence and control of Naegleria in drinking water supplies. Comment Naegleria infections are generally associated with forcible entry of water into the nasal and sinus passages (through squirting water up the nose or jumping into water) and subsequent spread of the infection to the brain. Norovirus Inactivation of norovirus by chlorine disinfection of water. Shin, G.A. and Sobsey, M.D. (2008) Water research, 42(17); 4562-4568. Norwalk virus (NV) and other human caliciviruses of the norovirus genus are major causes of epidemic gastroenteritis, with water one of the major routes of their transmission. A few previous studies have suggested that noroviruses are relatively resistant to free chlorine disinfection, however studies of this virus are limited by the absence of a simple infectivity test. Inactivation of microorganisms by disinfection is influenced by a variety of factors including the type and physiological condition of microorganisms, type of disinfectants, physical and chemical water quality parameters such as pH, temperature, inorganic and organic constituents and particulates, and hydraulic conditions such as reactor design and mixing conditions. Added to these factors, the preparation of test microorganisms could significantly influence the kinetics of inactivation especially in bench-scale water disinfection experiments. A study of hepatitis A virus (HAV) found that HAV was considerably more resistant to free chlorine when no mechanical dispersion or purification of virus stock was performed before disinfection experiments. A recent poliovirus 1

(PV1) and feline calicivirus (FCV) chlorination study also showed that aggregated PV1 and FCV were tens to hundreds of times more resistant to free chlorine than dispersed viruses. It is possible that NV might respond quite differently to free chlorine disinfection if it is purified and dispersed. The objective of this study was to determine the inactivation of purified and dispersed NV by bench-scale free chlorine disinfection in typical water treatment conditions using RT-PCR for virus assays. NV stocks were purified and dispersed using solvent extraction and membrane filtration and assayed for NV using conventional short template (ST) RT-PCR and more recently developed long template (LT) RT-PCR. (LT) RT-PCR can amplify larger regions of virus genomes (11-14% of the entire viral genomes compared to 2.5-6% in conventional ST/RT-PCR). PV1 and coliphage MS2 were also tested to compare their inactivation to that of NV and to determine the agreement between virus inactivation based on infectivity assays (cell culture for PV1 and layer agar for MS2) and based on RT-PCR assays. Infectivity assays of coliphage MS2 showed rapid inactivation by a 1 mg/L dose of free chlorine and reached the detection limit (approx. 5 log10 reduction) within 20 seconds contact time. The inactivation of PV1 based on infectivity assay was also rapid and reached the detection limit (approx. 4 log10 reduction) within 10 minutes contact time. Inactivation of these viruses when judged by RT-PCR assays was considerably slower and reached only 1.5 and 2 log10

based on ST/RT-PCR and LT/RT-PCR respectively within the same time interval. The inactivation of NV based on both RT-PCR assays was 2 log10 at 3 min, contact time under the same experimental conditions which was somewhat slower than that of coliphage MS2, but much faster than that of PV1. The inactivation of the three viruses by 5 mg/L dose of free chlorine was much faster than that seen with 1 mg/L free chlorine based on both infectively and RT-PCR assays. Inactivation of all the viruses reached detection limits within 10 min based on the infectivity assays and also the RT-PCR assays. Inactivation of coliphage MS2 and PV1 was still faster based on infectivity assays compared to the two RT-PCR assays, however the discrepancy



became less apparent at this higher free chlorine dose than was seen at the 1 mg/L dose. Inactivation of NV based on ST/RT-PCR assays was 3 log10 at 20s, which was similar to that of coliphage MS2, but much faster than that of PV1 under the experimental conditions. The predicted CT (disinfectant concentration times contact time) values for PV1 and coliphage MS2 were calculated using 1 mg/L free chlorine at pH6 and 5 degrees C based on infectivity assays and were 6 times and 14 times, respectively, lower than the ones based on ST/RT-PCR assays. The predicted CT values for NV based on the ST/RT-PCR assay were somewhat higher than those for coliphage MS2 but considerably lower than the ones for PV1 based on the same assay. Both RT-PCR assays in this study underestimated virus inactivation by free chlorine, especially when the rate of virus inactivation was slow. These results indicate that NV is not appreciably more resistant to free chlorine than PV1 and coliphage MS2 under the test conditions. Therefore NV contamination of drinking water can be controlled by adequate free chlorine disinfection practices providing there are proper pre-treatment processes such as conventional filtration, direct filtration, or slow sand filtration to reduce chlorine demand and remove aggregated and particle-associated viruses. The authors estimate that CT values specified under US EPA guidelines would be adequate to give at least 4-logs reduction of most enteric viruses. Radon Radon in drinking water and cancer mortality: An ecological study in Japan. Yoshinaga, S., Ishikawa, T., Tokonami, S., Mizoue, T., Narazaki, Y., Mizuno, S. and Akiba, S. (2008) AIP Conference Proceedings, 1034; 29-432. There is limited information available as to the health effects of radon in drinking water with inconsistent results found from several epidemiological studies. An ecological study was conducted in a small town in Japan where groundwater radon concentrations are high in order to examine radon concentrations in drinking water and cancer mortality.

Nijo-town in Fukuoka prefecture was selected as a high radon concentration area (HRA). Two surrounding municipalities (Maebaru-city and Shima-town) were selected as control areas (CA) where lifestyle is likely to be similar. Preliminary measurements of radon concentrations in water and in air were made for selected houses in HRA to ascertain the level of exposure due to radon. There were 19 volunteers from three geographical sections who were recruited for radon measurements in tap water and/or well water. For 10 of these 19 volunteers, indoor radon concentrations were also measured. Data was obtained on population size and number of cancer deaths from 1972 to 1997 from the national census every five years and from vital statistics for every year, respectively. Standardised mortality ratios (SMRs) were calculated from all cancers and selected sites of cancers for both HRA and CA on the basis of sex-, attained age-, and calendar year-specific national rates. To directly compare cancer mortality between HRA and CA, a Poisson regression model was used. Radon concentrations in water were measured from the tap in 4 houses, from a well in 10 houses and from both in 5 houses. Radon concentrations in tap water and well water ranged from 0.6 to 175 Bq/L and 2.6 to 287 Bq/L, respectively. Indoor radon concentrations were found to range from 3 to 32 Bq/m3. There was no statistically significant correlation found between indoor radon concentrations and water radon concentrations. There were 607 cancer deaths from 1972 to 1997 in the HRA. The predominant sites of cancer in both HRA and CA were the stomach, lung and liver. SMRs in the HRA population were 1.01 (95% CI: 0.93-1.09) for all cancers, 1.10 (95% CI: 0.95-1.28) for stomach cancer, 0.88 (95% CI: 0.70-1.10) for lung cancer and 1.14 (95% CI: 0.87-1.48) for liver cancer. SMRs for stomach and liver cancer in the HRA population were higher for females than males however this was not statistically significant. Poisson regression analysis showed mortality from liver cancer in the HRA was significantly higher than in CA with a relative risk of 1.40 (95% CI: 1.04-1.89). There was no other site-specific cancer that was significantly different between the HRA and CA.



With the exception of liver cancer, mortality from all causes and site-specific cancers were not significantly different between the HRA and CA. The authors note that increased cancer risks would not be expected from the measured levels of radon in water and indoor air in this study. The result of increased risk for liver cancer could be due to either a chance finding, bias associated with lack of information on possible confounders including diet, alcohol, smoking and hepatitis virus infection, or inappropriateness of control selection. Six neighbouring municipalities were selected and no increase in liver cancer risk was found (RR=0.95, 95% CI: 0.73-1.23). Turbidity Drinking water turbidity and emergency department visits for gastrointestinal illness in Atlanta, 1993-2004. Tinker, S.C., Moe, C.L., Klein, M., Flanders, W.D., Uber, J., Amirtharajah, A., Singer, P. and Tolbert, P.E. (2008) Journal of Exposure Science & Environmental Epidemiology, (In Press) 1-10. doi:10.1038/jes.2008.68 In the United States, the drinking water quality is among the best in the world however despite the enormous resources dedicated to keeping the US water supply safe, pathogenic organisms are still transmitted through drinking water. Randomised-controlled trials have yielded conflicting results in regard to the extent to which drinking water contributes to endemic GI illness and estimates of the disease burden range from 4.3 to 16.4 million cases of gastrointestinal illness (GI) annually. The association between turbidity in water and healthcare utilisation for GI illness has been examined and significant positive associations have been reported. In this study, time-series methods were used to examine the association between turbidity measures at eight drinking water treatment plants serving the five-county metropolitan Atlanta area and emergency department visits for GI illness over a 12–year period (1993-2004). Raw water serving the utilities in the Atlanta area is drawn from surface water sources that are subject to contamination from many point and non-point sources.

Water quality data included daily summary measures of hourly turbidity measurements, in nephelometric turbidity units (NTU), taken at the treatment plants. The service area of each treatment plant was determined. Each zip code in the study area was assigned to a treatment plant where possible. Data from two plants was combined because they blended their water before distribution. Another plant was excluded as no zip codes could be assigned exclusively to its service. Information on emergency department visits from all of the hospitals operating within the five-county Atlanta area (23 hospitals) and from five hospitals located outside the study area that contributed a substantial number of visits by five-county residents was obtained. The data provided included medical record number, date of admission, International Classification of Diseases, 9th Revision (ICD-9) diagnosis codes and zip code of residence. The mean daily average filtered water turbidity ranged from 0.03 to 0.17 NTU and the mean maximum daily filtered water turbidity ranged from 0.04 to 0.29 NTU. The mean minimum daily raw water turbidity during the study period ranged from 1.1 to 16.3 NTU and the mean maximum daily raw water turbidity ranged from 1.5 to 55.0 NTU. Raw water turbidity levels peaked in winter although filtered water turbidity varied little by season. There were 240,925 emergency department visits for GI illness over the 12-year period. Counts of GI illness varied by season with large winter peaks, especially among children. These peaks corresponded to peaks for diagnosed rotavirus mainly among children. No association was observed overall between filtered water turbidity and GI illness with a summary rate ratio estimate of 0.98 (95% confidence interval (CI) = 0.96-1.01) for a 0.1 NTU average incremental increase in average filtered water turbidity and 0.99 (95% CI = 0.98-1.01) for maximum filtered water turbidity. The majority of the plant specific rate ratio estimates were consistent the null however the rate ratio estimate for one of the plants was 1.68 (95% CI = 1.26-2.24) using the average filtered water turbidity exposure metric and was 1.26 (95% CI = 1.07-1.47) when maximum filtered water turbidity was considered.




A modest positive association was seen with emergency department visits for GI illness for both minimum and maximum raw water turbidity. The summary rate ratio estimate for a 10 NTU average incremental increase in daily minimum raw water turbidity was 1.06 (95% CI = 1.04-1.08) and when daily maximum raw water turbidity was considered, the summary rate ratio estimate was 1.02 (95% CI = 1.01-1.03). Age-specific models were considered to assess possible effect modification by age. When each age group was considered separately, little association of GI illness with filtered water turbidity measures was seen. However for raw water the majority of the rate ratio estimates for the different age groups were slightly above one. The association of raw water turbidity with GI illness for children in the age 5 years and younger age group was somewhat stronger than for the other age groups. Analyses were also conducted in which the turbidity exposure was defined as a series of 3-day moving averages in an attempt to identify the organisms that might be responsible for drinking water-related GI illness. All rate ratio estimated from models for which filtered water turbidity was used as the exposure metric were consistent with the null, but when raw water turbidity was used the rate ratio estimates were greater than one.

The strongest associations were seen for lag times approximately 6 through 9 days before the date of the emergency visits. Similar results were found when the daily maximum raw water turbidity was considered. This lag period is consistent with all three of the main types of organisms causing waterborne diseases (bacterial pathogens, viruses and protozoa) if the variable time taken for water to travel through the distribution system is also taken into account. The results here suggest little association between filtered water turbidity and rates of emergency department visits for GI illness. A modest association between raw water turbidity and emergency department visits for GI illness was observed, however it is filtered water turbidity that is regulated by EPA and State standards. More refined indicators of water quality and health risk need to be developed such as standardised and reliable particle counters or more sensitive microbial indicators.

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WQRA HealthStream - Issue 52

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