Second Canadian Study of Endemic Gastroenteritis Published

Methods
The study was undertaken in the same area of Montreal, Canada as the first study (Payment et al. American Journal of Public Health 81 p703-708, 1991). The study population consisted of families with at least one child between 2 and 12 years of age. All families were served from the same water treatment plant, that received water from a watershed that drains both rural and urban areas. The water is treated by conventional treatment (alum flocculation, settling, filtration on sand anthracite) ozonisation and a final chlorination. The water temperature varied considerably during the study from 1°C in winter to over 20°C in summer.

The families were randomised to one of four groups. Two groups (tap water group and tap valve water group) received normal water through kitchen taps: the only difference between these two groups was that the tap valve group had a valve fitted to their house to prevent stagnation of water in the household plumbing (purged between 100 to 500 mls/minute). The other two groups received finished water from the plant (plant water group and purified water group) that was bottled before it entered the distribution system. The water for the purified water group was also passed through a reverse osmosis filter before it was bottled.

Each family completed a health survey every 2 weeks. The principle outcome measure was highly credible gastroenteritis (HCGI). This was defined as vomiting or liquid diarrhoea alone or soft stools or nausea with abdominal cramps. This was the same as the definition from the earlier study.

Results
Water Quality Finished water samples collected during the study complied with all North American drinking water regulations including the Total Coliform Rule and the Surface Water Treatment Rule. Only 4 (0.6%) of 633 water samples from the distribution system were positive for coliforms. No pathogens were found in the finished water. The raw water quality however was poor with up to 100 Cryptosporidium oocysts per 100 litres, 1,000 Giardia cysts per 100 litres, and 10,000 human enteric viruses per100 litres.

The heterotrophic plate counts (HPC) of the households taps were less than 300 cfu/100ml when cultured at 25°C. After two weeks at room temperature, the bottled water contained a geometric mean titre for HPC of 1,273,700 cfu/100ml. Total coliforms, Pseudomonas aeruginosa and Aeromonas hydrophilia were rarely detected (no value given).

Retention Rates Not all families who enrolled completed the study. The least number of families “dropped out” in the tap water group (21%), but in the plant water group 48% of families did not complete the full 18 months of the study. A relatively high proportion of the plant water group dropped out because of taste and odour problems associated with their bottled water.

Reported Gastrointestinal Illness HCGI occurred at a rate of between 0.5 and 1.0 episodes per person per year. The rate of HCGI as episodes per person per year was 0.58 in the purified water group, 0.60 in the plant water group, 0.66 in the tap water group and 0.70 in the tap valve group. Using the purified water group as the comparison group, the rates of HCGI were 14% and 21% higher for the tap water and tap valve water groups respectively. There was no statistically significant difference between the plant water and purified water groups or between the tap water and tap valve groups.

Other features of the results It is interesting to note some features about the differences in gastrointestinal illness rates found in this study:

• The entire statistical difference in rates of HCGI between the different groups was restricted to the first 9 months of the study. The authors made special mention of the observation that record low temperatures (often -20°C) occurred during this period.
• Despite the study implicating the distribution system, there was no correlation between the time of residence of the water in the distribution system and the rate of HCGI.
• The statistically significant difference in rates of HCGI was restricted to those between 2 to 12 years old. The rates of HCGI were low in adults and therefore the study did not have sufficient statistical power to detect any differences in HCGI rates in this age group.
• The dose response relationship was inconsistent. In fact children who drank more water actually got less HCGI. Children (2-12 years of age) who drank less than 2.7 glasses of water, had 30% MORE episodes of HCGI than those who drank more than 4.5 glasses of water. The absence of a dose response relationship is concerning.

• the rate of HCGI seen in this study was similar to other community based studies.
• the very high bacterial counts in the bottled water were not associated with an increase in HCGI and it was postulated that high bacterial counts may have inactivated pathogens.
• the lack of an association between the residence time of the water in the distribution system and HCGI suggests that bacterial regrowth is not the cause of the excess disease observed in this group. It was noted however that the residence time never exceeded 34 hours.
• because the excess in disease was localised to a specific period, it may represent contamination of the water.

This important study has been carefully undertaken and extensively reported in a long and detailed article. It is necessary however to recognise that the study has some methodological limitations. These limitations are discussed below.

Blinding The most important limitation is that this study, like the first study was not blinded. This means that all the groups were aware of what sort of water they received and this may have influenced the way they reported their symptoms. For example those receiving the bottled water (plant or purified) may have believed they were not supposed to get gastroenteritis and hence may have under reported their symptoms. This may have in part or completely accounted for any difference seen between the bottled water groups and those who received tap water.

Dose response relationship The validity of an observed association between an exposure and illness is often checked by looking for a dose response relationship. To identify this, one looks for an increase in the rate of disease with increasing exposure. In this study one might expect those in the tap water group to suffer more episodes of HCGI if they drank more water. There was however no consistent dose response relationship, and for children between 2 and 12 higher water consumption protected against HCGI.

What does the study mean for Australia? The results of this study have limited relevance to most Australian water supplies. This is because in most Australian cities the raw water quality is better than in the area of the Canadian study. The treatment the water received included ozone which is not used in any major city in Australia. The climatic conditions during the study were not comparable to Australian conditions.

The extremely cold winter temperatures would have led to freezing and thawing of parts of the distribution system, and this may have caused shifting and cracking of pipes and allowed external contamination to occur.

These differences are particularly important considering that the difference in rates of HCGI were localised to two specific time periods suggesting contamination occurring in the distribution system.

Summary This study is the most sophisticated and detailed study ever undertaken on water quality and human health. It implicated the distribution system and in particular external contamination rather than regrowth of microorganisms. However there are a number of methodological limitations that raise concern about the strength of its findings.

Most importantly the groups participating were aware of the type of water they had received (not blinded), and this may have caused significant bias in reporting of illness. The study is of limited relevance to the Australian water supply system because the quality of the raw water, water treatment and climatic conditions are considerably different.

New Research Projects

Fluoridation of drinking water supplies has been progressively introduced in many cities and towns around the world since US studies in the 1940s demonstrated a protective effect against dental caries. In Australia, fluoridation began in the 1960s and currently all capital cities except Brisbane have fluoridated water supplies.

From its inception, water fluoridation has been a contentious issue with strong opposition from those who object on principle to “mass medication”. Public concerns over possible adverse health effects have also been raised from time to time, and in 1990 the National Health and Medical Research Council formed a Working Group to review the issue. The report of the Working Group was published in 1991 and concluded there was no evidence that fluoridation was harmful to humans.

Since that date a large body of literature has been published and new health issues have been raised. This project will review and assess the evidence on public health effects of water fluoridation that has become available since 1990, providing an update on new data since the NHMRC Working Group Report. The review will cover:

• sources of fluoride intake in different age groups
• metabolism of fluoride
• possible adverse effects
• possible protective effects for atherosclerosis
• interactions with other chemicals
• alternative sources of fluoride
• safety margins in different age groups

The health issues to be examined include dental fluorosis, allergic reactions, gastrointestinal complications, bone disease, cancer, pregnancy outcomes, effects on children’s intelligence - all of which have been raised in the literature in the last few years. The review is being funded by the Department of Human Services Victoria and will be completed in late 1998.

The “text book” answer to community concern is that the risk of death from chlorination’s potential to cause cancer is many fold less than the risk of death from gastroenteritis if chlorine was not used. The community may then ask how different are these risks and how do we know how great they are? While it is easy to point to the marked effect of chlorination of drinking water on diarrhoeal disease in developing nations, the situation in developed world is somewhat different and parallels cannot readily be drawn.

In developed nations water sources are generally better protected, sanitation systems are of a higher standard and the likelihood of contamination of source water by prevalent third world pathogens such as cholera is relatively remote. Water treatment (in addition to chlorination) may also be used to remove organic matter (and with it pathogens) to varying degrees.

Mathematical models have been used to estimate the risks, and these generally predict the risk of death from gastroenteritis (without chlorine) to be perhaps 100-fold higher than the risk of death from chlorination (if it does actually cause cancer). However these models are not backed up by epidemiological research and have many uncertainties leading to large error margins.

This project will assess the impact of chlorination on gastroenteritis in the city of Melbourne by examining morbidity and mortality figures for the interval spanning the introduction of chlorination. Melbourne offers a unique opportunity in this respect as the main water supply was chlorinated only in 1978, decades after most major cities in the world. Thus data from high quality medical records with sophisticated coding systems are available. The study will focus specifically on rates of gastroenteritis in children as this population is likely to suffer gastroenteritis predominantly from infectious causes. The study has been funded by the Melbourne Water Corporation and will be completed early in 1998.

WHO Guidelines for Cyanobacterial Toxins in Drinking Water

• Dr T Kuiper Goodman and Dr S Gupta - Health Canada
• Prof W Carmichael - Wright State University
• Prof S Hrudey - University of Alberta
• Prof G Codd - Dundee University
• Prof S-Z Yu - Shanghai Medical School
• Dr J Fitzgerald - SA Health Commission

Further CRCWQT personnel contributing to this monograph are Mr Michael Burch of the Australian Water Quality Centre in Adelaide, and Dr Louis Pilotto from the National Centre for Epidemiology and Population Health in Canberra.

Bathing water guidelines are also being considered, as a separate task, and both Louis Pilotto and Ian Falconer are contributing to this area. The independent WHO International Program on chemical safety are also considering safety guidelines for cyanobacterial toxins. The recommendations arising from the Bad Elster meeting have been circulated to participating countries for comment. The first draft of the monograph text is being edited and will be finalised in November.

Cryptosporidium Handbook

The 150 member Working Group was convened in 1996 by the Centres for Disease Control and included representatives of a wide range of organisations in the fields of public health, environment, the water industry, agriculture, government and lobby groups for immunocompromised people. The publication was seen as a high priority in the light of mandatory Cryptosporidium testing under the Information Collection Rule which came into effect in the US this year. The 7 chapters in the 120 page handbook cover the following topics:

Coordination and Preparation The group advocates the formation of local task forces prior to any detection of Cryptosporidium in water supplies, so that responses and procedures can be developed in advance of an outbreak situation. It is recommended that such groups should contain representatives of organisations with responsibility for drinking water issues, technical experts, a designated public spokesperson, together with those who may be particularly affected by a Cryptosporidium outbreak (eg hospitals and pathology laboratories, nursing homes, food industry/restaurant businesses, local community groups, immunosuppressed persons groups).

The task force should develop an Action/Response plan which defines “trigger events” that will require investigation. This plan should ensure that appropriate notifications and investigations are carried out rapidly, so that the degree of health risk can be assessed and decisions can be made on the need for public warnings and boil water advisories. Criteria to downgrade or terminate health warnings should also be decided.

Epidemiologic Surveillance This chapter outlines a number of possibilities for monitoring that may be useful for identifying outbreak situations, for example - sales of anti-diarrhoeal medications, incidence of diarrhoea in nursing homes, laboratory data for Cryptosporidium detection.

Clinical Laboratory Testing The pros and cons of current methods and testing kits are described, together with conditions for faecal specimen collection, transportation and processing. It is suggested that laboratories should review their reporting formats so that it is clear to clinicians ordering tests whether specific tests for Cryptosporidium have been performed. Many doctors wrongly assume that tests for protozoa are always carried out on gastroenteritis specimens, but most labs require a specific request for such investigations. Laboratories should also develop procedures to monitor the number and type of faecal specimens processed so that unusual increases can be detected and reported to health authorities.

Evaluating Water Test Results Drinking water treatment and testing methods, and environmental sampling techniques are briefly described. Available detection methods are summarised in tabular form together with details of commercial antibody kits for detection and speciation of Cryptosporidium oocysts. The factors to be considered in issuing and rescinding boil water advisories are also outlined.

Outbreak Management The steps involved in investigation of a possible outbreak are detailed:

• determine whether an outbreak of cryptosporidiosis is occurring
• determine whether water is a likely source of infection
• if a waterborne cryptosporidiosis outbreak appears likely, carry out a rapid epidemiological investigation to verify that illness is linked to the water supply and not other possible sources

Educational Information A number of Fact Sheets developed by the CDC are reproduced:

• Preventing Cryptosporidiosis: a Guide for Persons with HIV and AIDS
• Preventing Cryptosporidiosis: a Guide for the Public
• Preventing Cryptosporidiosis: a Guide to Water Filters and Bottled Water

The Appendix of the Handbook includes a glossary of terms, three previously published papers, and a Reference list. This publication is available from the US AWWA Bookstore - email bookstor@awwa.org or Fax +1 303 347 0804.

Tap Water Wins the Taste Test

The panel members were:

• Antony Worrall Thompson, a television chef and restaurant owner
• Annabel Croft, a former professional tennis player and media personality
• Diane Youdale, presenter of a TV fitness program
• Rebecca Hull, master of wine and buyer for Sainsburys department store
• Carol Ash, a scientist with Thames Water

The comments of panel members included:

• “aroma of body odour or chlorine” - Highland Spring bottled water
• “delicious” “fresh with a smooth edge” - Kent tap water
• “refreshing” “fresh sweet lemony aroma” “a sweet sparkle”- Birmingham tap water (from public toilets in the city centre)
• “very bland” “no distinctive taste” - Buxton bottled water

Meanwhile, several water utilities in the US are developing plans to market bottled municipal water. It was reported in the New York Times on August 6th that Kansas City, Miami Beach North and Houston are exploring the possibility of entering the lucrative bottled water market. While there has been some scepticism about the chances of public acceptance, some officials see this as promising means of supplementing revenue while avoiding price rises to tap water consumers.

FDA regulations on the labelling of bottled waters were tightened last year, but US advertisers still enjoy considerable leeway in the description of their product. For example “Yosemite” brand bottled water does not originate from the famous national park, but instead comes from a well in the district of Fullerton in the midst of the Los Angeles freeway network. Similarly, terms such as “mountain fresh” and “glacier pure” need not indicate an alpine source.

Consumption of bottled water in the US has increased 10 fold in the last 20 years, and the annual market is estimated at US $4 billion. More than 35% of bottled water originates from municipal supplies, usually with an additional filtration step. While water industry spokesmen acknowledge some degree of irony may be seen in their involvement with selling bottled water, the revenue potential is large and the popularity of bottled water is likely to remain high.

Fluoridation Debate Resurfaces

Many studies have concluded that the average level of tooth decay in children is reduced by fluoridated drinking water. The effect of fluoride in water seems to be smaller now than it was in the 1960s probably because of fluoride in toothpaste, fluoride treatments and mouthwashes. Fluoridation is seen as being of particular benefit to socially disadvantaged groups who have the highest rates of tooth decay and have less access to dental services. Fluoridation is also considered to be a cost-effective means of reducing tooth decay when compared to alternatives like government funded school dental programs.

One of the acknowledged problems of excessive fluoride intake is dental fluorosis, caused by a build-up of fluoride giving teeth a mottled appearance. Ceasing fluoridation of drinking water is one option to reduce fluorosis, it is however estimated that over half the fluoride intake of two year olds comes from toothpaste. Using fluoride reduced toothpaste for young children, making up infant formula without fluoridated water and avoiding inappropriate use of fluoride supplements are all alternative ways of reducing fluoride intake in young children. Foods including tea, fish and root vegetables can contribute substantial amounts of fluoride to the diet - tea in particular may contain up to 4 mg per cup.

Opponents of fluoridation believe that the benefits in terms of prevention of tooth decay are overestimated or non-existent, and are not adequate to justify the possible long term risks of exposure. They contend that fluoride treatment of children’s teeth could be achieved by other means, without requiring lifetime exposure of the entire population. It is now recognised that most of the effect of fluoride occurs on the surface of teeth so ingestion of fluoride is not required.

In recent years a variety of health risks including bone cancer, skeletal fluorosis (a build-up of fluoride in the bones) and hip fracture have been linked to fluoride exposure, but the evidence for these effects is generally regarded as inconclusive at present. Indeed, the interpretation of results is so contentious that the data from one New Zealand study have been claimed by both pro- and anti-fluoridation camps as supporting their viewpoint.

Choice Magazine came to the conclusion that fluoridation of drinking water was the “most effective, cost-effective and socially equitable means of achieving community-wide exposure to the effects of fluoride in preventing tooth decay” but also that ongoing assessment of possible side effects by health authorities was needed.

The Sunday Age article Every drop you drink concentrated mainly on the more recent research findings linking fluoride to adverse health effects. Writer Bob Woffinden asks whether it is reasonable to assume that the effects of fluoride are limited to the teeth, when it is known that only 50% of ingested fluoride is excreted while the remainder rapidly becomes associated with teeth and bones. In addition to possible risks of hip fracture, skeletal fluorosis and osteosarcoma mentioned in the Choice article, this article mentions reports of effects on the immune system, adverse pregnancy outcomes and reduction in children’s IQ.

The historical data on which fluoridation was initially based is also called into question - the initial trials in the US were intended to run in a few towns for up to 15 years, but the move towards mass fluoridation began after only 18 months of favourable data. Thus the intended long term controlled comparisons of similar populations differing only in fluoridation status were never completed.

Examples are cited where some former advocates of fluoridation have now changed camps - notably Dr John Colquhoun, former chief dental officer of Auckland, NZ and Dr Richard Foulkes, special consultant to the Health Minister of British Columbia, Canada. In both cases the change was motivated by a re-examination of statistics on dental health which showed no apparent benefit from fluoridation.

The overall tone of the Sunday Age article is somewhat alarmist with a plethora of adverse effects being attributed to fluoridation. While one would not expect a comprehensive review of the scientific literature in such an article, the failure to acknowledge negative findings is noticeable. For example, on the issue of osteosarcoma (bone cancer) a preliminary study showing increased risk is described, but several subsequent more detailed studies which found no increase in risk are not mentioned.

These articles illustrate the controversy that surrounds this issue and periodically comes to prominence in the public arena. Clearly there is a need for continuing research into the effects of fluoridation in order to provide governments with up to date data on risks and benefits, and reliable balanced information for concerned members of the public.

Conference Report

The conference program covered topics such as Ethics in Research, Air Pollution (asthma and respiratory disease), Occupational Epidemiology, and Heavy Metals with specific sessions on Arsenic, Reproductive Hazards and Water Quality to name but a few.

There were quite a few presentations outlining the use of Geographical Information Systems (GIS) to map disease or even to provide evidence for environmental causes or contributions to disease. Few of the presentations were able to effectively demonstrate such associations, although there are benefits to using GIS in some circumstances. Other presentations on genetic biomarkers were interesting, but whether they can be linked to diseases associated with environmental causes remains to be seen.

This report focuses on sessions relating to chemical contamination, treatment of water supply and waterborne disease and associated health effects.

Arsenic Two sessions during the conference were held on Arsenic and its health effects. My presentations were both in the second afternoon session on Arsenic (abstracts below).

Background: This study aims to determine the degree of human absorption in residents living in areas with high arsenic concentrations in different environmental media by measuring inorganic arsenic concentrations in urine.

Methods: 200 residents have been recruited from rural areas in Victoria classified into four environmental exposure strata: HS/HW (high soil arsenic (greater than 100mg/kg) / high water arsenic (greater than 0.01mg/L), HS/LW (high soil / low water), HW/LS (high water /low soil) and a control population. Inorganic arsenic analyses have been performed on spot urine samples and corrected for creatinine.

Results: Preliminary data for 149 residents showed the geometric mean inorganic arsenic concentrations (mg/g creatinine) for each of the strata were: HS/HW 1.22; HS/LW 2.21; HW/LS 6.22 and Control 1.12. The HW/LS and HS/LW strata had urinary arsenic means that were significantly higher than the control population (p<0.001). The HS/HW strata did not show a statistically significant difference compared with the control group. This may be explained by some exposure misclassification of residents and further investigation is required. Stratification by age and sex made no difference to the significance of the result.

Conclusion: These preliminary data show that increased absorption of inorganic arsenic is occurring in residents living in areas with high concentrations of arsenic in water and soil and suggest that ingestion of contaminated water is a greater determinant of absorption than being exposed to contaminated soil. More specific exposure indices based on household soil, dust and water will be determined in the next phase of this study.

AN ECOLOGICAL STUDY OF CANCER INCIDENCE AND HIGH ENVIRONMENTAL ARSENIC CONCENTRATIONS IN RURAL POPULATIONS
Hinwood A.L.*, Jolley D.J.**, Sim M.R.*, Bastone E.B.* *Department of Epidemiology and Preventive Medicine, Monash University; **Department of Public Health and Community Medicine, University of Melbourne: Victoria, Australia.

Background: A number of ecologic studies have found dose-response relationships between drinking water contaminated with arsenic and increased rates of some internal cancers. To investigate such associations in areas with high arsenic concentrations in rural Victoria, geographical areas with median surface soil inorganic arsenic concentrations of >100mg/kg and/or drinking water arsenic concentrations >0.01mg/L were chosen.

Methods: Standardised cancer incidence rates (SIRs) were generated for twenty-two areas delineated by postcode in rural Victoria between 1982 and 1991 using Victorian Cancer Registry data and overall Victorian cancer rates as a baseline. SIRs were also generated for the combined areas and groupings according to environmental exposure type; HS/HW (high soil/high water), HS/LW (high soil/low water) and HW/LS (high water/low soil). A dose- response curve was generated for both individual and all cancers for the combined areas and drinking water concentrations but was not possible for soil concentrations.

Results: SIRs for all cancers for combined areas were; males 1.06 (1.03-1.10), females 1.07 (1.03-1.11), persons 1.06 (1.03-1.09). SIRS for the grouped areas were: HS/HW 1.11 (1.07-1.15); HS/LW 0.98 (0.94-1.02); HW/LS 1.11 (1.05-1.15). The study had low power to detect excesses of specific cancers in each of the twenty two areas. No significant dose-response relationship between drinking water and specific cancers was observed.

Conclusion: This study indicates that residents living in areas with elevated arsenic concentrations in soil and drinking water may be at an increased risk of developing cancer, however the data do not support a dose-response relationship between bladder, kidney and liver cancer and arsenic concentrations in drinking water.

Dr Smith provided risk estimates for high concentrations of arsenic and back extrapolated to lower concentrations indicating that at concentrations less than 50ug/L in drinking water would present risks of the order of 1 cancer per thousand. This was considered unacceptable. He indicated arsenic was one of the most potent carcinogens and one of the most important environmental contaminants, and more work to further define its health effects was necessary.

A paper by Dr Hung-Yi Chiou on the health effects on the Taiwanese population affected by arsenic also indicated the need for evaluating vascular disease at lower concentrations of arsenic.

Papers presented by other speakers elaborated on the scale of the problem worldwide and one presentation outlined impairment of neuropsychological function in children with chronic absorption of arsenic as determined by hair arsenic concentrations. This presentation from Thailand presented some convincing data on such effects which have not previously been reported.

There was much interest expressed in the work being done in Australia and in particular the completion of speciation testing of urine and results of long term absorption of arsenic. Interest was also expressed in whether we would do some further work on cancer and non-cancer effects of arsenic on drinking water at lower concentrations of arsenic, if absorption is confirmed in the populations currently under investigation.

Waterborne Disease Dr D Juranek from the Centres for Disease Control, presented a keynote address on waterborne cryptosporidiosis in the USA. He presented information on the following:

• Seroprevalence of antibodies to C.parvum is estimated to be 1/3 of the population.
• It isn’t known how long the antibody lasts but may be 3-5 years and residents are probably infected every 3-5 years.
• The number of outbreaks in the last few years has increased.
• In these outbreaks, chlorine, coliform and turbidity levels were all in the acceptable range. C. parvum is very stable and water disinfection is not adequate to kill at currently accepted concentrations of chlorine and ozone.
• Current sand filtration units with 70µm pore size are also problematic as C. parvum is only 5µm in diameter.

• Which species of Cryptosporidium are present in water supply?
• What is the viability of the oocysts and what are the differences in strains and their respective virulence?
• What is a sufficient dose to cause infection in humans?
• What the infectious dose is for patients with AIDS?

Water Treatment and Health Effects Dr Morris from the USA presented data from a range of sources on the health effects of water chlorination, in particular bladder cancer.

He presented data from a meta analysis with a highly significant increased risk of bladder cancer associated with water chlorination by-products. Several case-control studies were also reported which showed increasing relative risks with increasing chlorine or trihalomethanes in drinking water. One recent study presented showed no such increase in risk.

Two new unpublished studies presented by Dr Morris indicated Relative Risks of bladder cancer with chlorination of 1.4 and 1.3. The picture for rectal cancer is much less clear. Dr K Cantor found an increased risk for colon cancer. The variation in results found between different studies may be due to differences in chlorination by-products and concentrations in different water supplies. In the USA 24 chlorination by-products are under consideration for regulatory review.

Emerging pathogens: Giardia, Cryptosporidium, Microsporidium. There is increasing chlorine resistance and decreasing size of pathogens. The response is to utilise more and stronger oxidants, finer filters and better protection of water supplies.

Dr Morris provided information on emerging information on birth defects associated with chlorination in studies being conducted in New Jersey, Massachusetts and Iowa in the USA.

He summarised by saying there was consistent evidence for an association with bladder cancer, and inconsistent data for an association with colorectal cancer. There was some evidence for possible association with other cancer sites and emerging toxicological and epidemiological evidence of birth defects and growth retardation.

News Items

The honour was awarded for Andrea’s work on the United Nations Environment Programme on reduction of Ozone Depleting Substances. In 1989 while working with the Victorian EPA, Andrea developed Victoria’s strategy on ozone protection, which was largely used as a basis for Australia’s National Ozone Phase Out Program. She chaired the UNEP Technical Options Committee on Aerosols, Sterilants, Miscellaneous uses and CTC, and served as a member of the Technology and Economic Options Committee from 1990 to 1995.

The USEPA used the occasion of the 10th anniversary of the landmark “Montreal Protocol” to recognize extraordinary achievements in environmental protection in its Best-of-the-Best Stratospheric Ozone Protection Awards. Andrea was one of 40 individuals who were honoured from a field of 300 previous winners of Annual awards under the USEPA program. The awards were presented to those whose accomplishments were deemed to have resulted in significant environmental improvements through leadership, motivation and technical innovation.

Andrea accepted her award in Montreal on 14th September, then returned to Melbourne to continue her work on the EnvAs Study - Environmental arsenic exposure and human absorption.

Sydney to cover Potts Hill reservoirs
Sydney Water has announced a plan to cover the Potts Hill reservoir system to enhance protection of the city’s water supply. In a media release dated 17th July, Managing Director Paul Broad said the plan was in line with overseas trends to completely enclose treated water supplies.

The open reservoirs have been criticised for presenting an opportunity for recontamination of water after it leaves the Prospect Filtration plant. The temporary closure of the No.2 reservoir was reported in the July 19th issue of the Sydney Morning Herald after low levels of Cryptosporidium -like organisms were recorded.

Record rains fail to break UK drought
Record June rainfall in England and Wales has brought little benefit to water supplies depleted by the two year drought. Although it was the wettest June since 1879 with rainfall in most areas almost double the average, the water failed to reach the underground aquifiers that serve 30% of the population. On a lighter note the record rains brought a bonanza for umbrella manufacturers - sales rose by 234% from last year!

While the rains decreased consumer demand for water, several companies in southern England continue to enforce bans on hosepipe and sprinkler use in an attempt to conserve supplies. Water companies are hoping for a wet winter to replenish the aquifiers, many of which are at the lowest levels ever recorded.

In the event that the drought continues next winter, strategies to provide water may include importation of Scottish water. It was reported in the Electronic Telegraph on 14th August that the West of Scotland Water Authority is carrying out a feasibility study on the use of ships to transport water to England. The tankers would each carry 100,000 tonnes of water at 4 to 5 day intervals.

Some English water companies have confirmed they have had talks with the Scottish authority on this possibility, but presently consider it likely to be more expensive than alternatives such as desalination of sea water.

Water - the Panacea?
A recently launched book Your Body’s Many Cries for Water advocates drinking water to combat many common diseases. The author, Iranian born Dr Batmanghelidj bases this theory on his experiences during 2 ½ years in prison following the Iranian revolution. With virtually no medicines he provided medical aid for 3,000 prisoners, and claims that increasing water intake alleviated many illnesses.

Dr Batmanghelidj proposes that conditions including angina, headaches, stomach ulcers, diabetes and asthma are actually caused by dehydration and subsequent abnormalities in normal cellular functions. His theories have not been accepted by conventional medicine, but most health professionals would agree that few people drink adequate amounts of plain water as opposed to other beverages.

Water profits criticised
The profit margins of UK water companies have been criticised following a survey by the WaterWatch pressure group. The group surveyed the ten largest water and sewerage companies in the UK and concluded that the equivalent of 20% to 30% of customers water bills went to shareholder dividends. The WaterWatch survey estimated the highest dividend payments amounted to 42% of average customer bills for the North West Water company.

The water companies have rejected the results of the survey but have also been criticised by the Department of the Environment for failing to provide adequate details of dividend payments and profits from different components of their businesses. Public anger at the apparent high profit margins has been fuelled by proposed water price increases ranging from 13% to 22%.

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