New US Arsenic Rule

The USEPA has proposed lowering the Maximum Contaminant Level for arsenic in drinking water from 50 ppb to 5 ppb (ppb=micrograms/litre). The proposal follows EPA consideration of a 1999 report from the National Research Council reviewing epidemiological studies on the health effects of arsenic and data on possible carcinogenic mechanisms⁽¹⁾. The report concluded that the current US regulatory level of 50 ppb did not provide sufficient protection of public health. However, it did not specify a concentration which provided a safe level for long term exposure. The EPA has opened the proposed MCL for comment, prior to making a final decision on the matter and promulgating the new regulatory limit.

The current 50 ppb level was set on the basis of estimated risks of skin cancer, however some recent data suggests that long term consumption of water at this level may be associated with increased risks of internal cancers such as lung and bladder cancer. There are a number of uncertainties in the assumptions used in this risk assessment, however the lifetime risk for bladder cancer may perhaps be as high as 1 in 1,000 for people consuming water at 50ppb. The EPA target value is 1 in 10,000 or less.

The risk estimate of 1 in 1,000 for bladder cancer at the current MCL of 50 ppb is based on linear extrapolation of observations from human exposure to levels of several hundred ppb. The National Research Council report noted that for all modes of arsenic carcinogenicity proposed to date, a non-linear or threshold dose-response relationship would be expected. Therefore in adopting a linear dose-response relationship, the EPA made a policy decision to use a more conservative assumption which produces higher risk estimates for low level exposures than a non-linear model.

The new MCL will apply to all community water systems and non-community non-transient (NTNC) water systems (those which serve 25 of the same people for 6 or more months of the year). NTNC systems (such as schools, nursing homes, service stations) have not previously been subject to arsenic regulations. As few surface water supplies have significant arsenic contamination problems, the change will impact mainly on systems drawing their supplies from groundwater. Large systems will have 3 years to implement the new MCL after it is finalised, while small systems (serving less than 10,000 people) will have 5 years to achieve compliance.

After evaluating current analytical methods the EPA determined that the practical quantitation limit for measurement of arsenic in water supplies was 3 ppm. This was also found to be the lowest level achievable in finished drinking water drawn from arsenic contaminated sources and treated using currently available technologies. An analysis was then carried out to determine the likely impact of adopting a new arsenic MCL for drinking water at levels of 3, 5, 10 or 20 ppb.

The analysis considered the following aspects:

• available data on the occurrence of arsenic in ground and surface water sources in the US
• the number of people supplied by water sources in each category
• co-occurrence of other water contaminants that may affect treatment options and costs
• the sensitivity, reliability and cost of arsenic analytical methods
• monitoring and reporting requirements
• best available treatment technologies
• costs for water systems of different sizes, and costs per household served
• predicted health benefits including medical costs avoided, monetary value of statistical lives saved and nonfatal risks avoided
• risk management decisions
• effect on state regulation programs
• health risk reduction and cost analysis
• administrative requirements

The estimated annual health benefits in terms of fatal and non-fatal bladder cancer cases⁽²⁾ avoided and the equivalent monetary value (based on the Value of a Statistical Life method ⁽³⁾) for community water systems were as follows:

For NTNC systems, the degree of exposure and the number of people at risk are much lower, therefore the estimated health benefits are smaller:

These estimates do not consider possible health benefits from reduction in the risks of other cancers or reduction in non-cancer adverse health effects. There is some evidence that exposure to arsenic may also increase lung cancer risks, although this is less well documented than the effects on bladder cancer. Rates of other internal cancers (eg liver, kidney, prostate) may also be increased. If the potential benefits from reduction in lung cancer risks are also included, the monetary value of health benefits may be about 4-fold higher than these estimates. Reductions in non-cancer risks would also increase the value of health benefits, although by a lesser degree than reductions in cancer risks.

In order to meet a lower MCL, a number of water supply systems will need to implement new water treatment facilities or improve the operation of existing facilities. There will also be additional costs for monitoring arsenic levels, and administration by state authorities. Estimates of annualised national compliance costs at discount rates of 3% or 7% were as follows:

The Benefit /Cost analysis demonstrates that for all scenarios under consideration, the economic costs of lowering the MCL for arsenic are greater than the economic value of the potential health benefits. At a 7% discount rate the Benefit /Cost ratio for an MCL of 3 ppb ranges from 0.06 to 0.14 (ie between 6 cents and 14 cents of health benefit for each dollar spent on compliance). For an assumed MCL of 5 ppb the Benefit /Cost ratio range is 0.07 to 0.20, for an MCL of 10 ppb the Benefit /Cost ratio range is 0.09 to 0.27, and for an MCL of 20 ppb the Benefit /Cost ratio range is 0.11 to 0.42. These ratios are based only on consideration of bladder cancer risks. If other types of cancer and non-cancer benefits are considered, the potential health benefits would be about 4-fold higher.

After considering the potential costs and benefits of different MCLs, the EPA chose 5 ppb as the MCL for the proposed new rule. Due to the adoption of the linear low level risk extrapolation model (ie assuming there is no threshold and therefore any level of arsenic entails some degree of cancer risk), the Maximum Contaminant Level Goal (a non-enforceable level) is zero. In setting the proposed MCL at 5 ppb rather than 3 ppb (the lowest feasible level achievable by water treatment) the EPA has exercised its discretionary power to select an MCL which it deems "maximises health risk reduction at a level where costs and benefits are balanced".

The EPA estimates that about 6,600 community water systems serving a total of about 22.5 million people would be affected by the proposed MCL of 5 ppb. The majority of these are small systems each serving less than 10,000 people. The new regulations would impact most heavily in Southwestern states, with some areas of the West, Midwest and New England also affected. According to EPA estimates, the additional costs for individual households will range from an average of $28 per year for large systems to $85 per year for small systems.

The American Water Works Association Research Foundation commissioned an independent assessment of the compliance costs which found that the actual costs of implementation of a lower MCL are likely to be higher than the EPA estimates. This review found that water treatment costs were likely to be higher and that the EPA had not adequately considered a number of factors which may have a substantial impact on costs:

• The MCL will mainly affect groundwater systems, many of which have no current water treatment or minimal treatment in place. As a consequence many utilities may need to acquire land to accommodate larger treatment plant facilities, and may lack sufficient numbers of staff who are experienced in plant operation. Such utilities may also lack facilities and experience for chemical storage and handling.
• The EPA analysis has assumed that waste from arsenic removal will not be regarded as hazardous material, and may be disposed readily to sewers or streams. If this is not the case, additional facilities will be needed to treat arsenic-containing waste before disposal. Waste disposal considerations may also impact on the choice of water treatment technologies by some utilities.
• The degree of water loss from some treatment technologies may preclude their use by some utilities and force other more expensive methods to be adopted.
• The impact of multiple entry points to distribution systems has not been adequately addressed. Many groundwater systems draw water from multiple wells, and separate treatment facilities will be needed at each source which exceeds the MCL. This could increase costs for these systems by as much as 150% to 250% over a single entry point system of equivalent size.

Overall, the AWWA estimates of compliance costs for the 5 ppb MCL are up to 4-fold higher than the EPA figures. Some estimates have put the capital cost as high as $14 billion, with annual costs of $1.4 billion.

The NRC report noted there is considerable controversy over the interpretation of scientific evidence on the health effects of chronic low level arsenic exposure. Epidemiological data come mainly from populations with exposures in the range of several hundred ppb in drinking water, who also had substantial arsenic exposure from food and may have suffered from nutritional deficiencies. In the light of these uncertainties, some members of the NRC panel have stated the view that a standard below 10 ppb (the current World Health Organisation guideline value) is not scientifically supportable on present evidence.

The Arsenic Rule is due to be finalised and issued by 1 January 2001, despite the fact that the public release of the proposed MCL on 22 June was almost 6 months late. Environmental advocacy group the Natural Resources Defense Council has applied to the US Court for the District of Columbia to order the EPA to comply with the January release date, however this has been opposed by the AWWA on the grounds that Congress intended to allow one full year between the proposal and the final rule. The AWWA argues that full discussion and review is essential due the complex and costly nature of the proposal. According to some estimates, the new Arsenic Rule may be the most expensive drinking water regulation ever introduced in the US, with compliance costs higher than the combined costs of all regulations introduced before 1995.

UK Cryptosporidium Monitoring

The UK Drinking Water Inspectorate has released the results of the first few months of Cryptosporidium monitoring under legislation introduced in June 1999⁽¹⁾. The legislation requires continuous daily sampling from treatment works with significant risk of having Cryptosporidium oocysts in drinking water. Each sample comprises a minimum of 1,000 litres of water sampled through a compressed foam filter at a rate of about 40 litres per hour over 23 hours. Detection of oocysts exceeding an average concentration of 1 per 10 litres of water constitutes a criminal offence under the regulations. The regulations do not distinguish between intact and empty oocysts, nor take account of any measure of viability /infectivity.

Assessment of nearly 1,500 sites in England and Wales resulted in the classification of 335 sites as being at significant risk, and thus subject to the regulations. Water companies have indicated that about 80 of these sites will be either temporarily or permanently abandoned due to the disproportionate costs of bringing them into compliance with the requirements. Installation of monitoring apparatus at the highest risk sites commenced in late 1999, and monitoring at the first 68 sites began in April this year. By the end of August, 190 sites had commenced monitoring.

The first results of the monitoring program were announced in June. Of 6,190 samples processed, 627 (10%) were positive for Cryptosporidium oocysts. A single sample was found to exceed the regulatory level, with an average concentration of 1.4 oocysts per 10 litres detected. The DWI noted that this result coincided with an increase in water turbidity, although there is no information on whether such turbidity increases were also seen in the absence of oocysts.

Cost figures have not been released, however according to a Discussion Paper released by the DWI prior to implementation of the regulations, costs were estimated at £8 million per year based on the assumption that 121 plants would require monitoring. With the revised figure of 335 sites requiring monitoring, and assuming that 80 of these will be abandoned, the annual cost of the monitoring program for the remaining 255 sites is likely to be in the order of £17 million. It is expected that major upgrades (installation of membrane filtration capable of removing particles down to 1 micron in size) will be undertaken at about 100 of the 255 sites, thus exempting them from the monitoring requirements.

Breaches of the regulations constitute a criminal offence punishable by a maximum fine of £5,000 in Magistrates’ Courts, or unlimited fine in Crown Courts. The regulations have yet to be legally tested but it is believed that all cases would initially go to Magistrates’ Courts, and the individual Magistrate would have the discretion to refer the matter to the Crown Court taking into account the views of the Prosecution and Defence counsels and the complexity of the case.

The Drinking Water Inspectorate considers the regulations to be "probably one of the most significant advances in public health protection made in water supply in the last decade".

Comment By any conventional measure of public health programs, the cost of implementing these regulations is disproportionate to the potential benefits. It has been estimated that about 32,500 cases of cryptosporidiosis occur each year in England and Wales (2). If it assumed that 50% of these may be waterborne (absolute worst case) and all such cases are prevented by the regulations (extremely optimistic), then each case prevented would cost more than £1,000. In contrast, each year of life gained as a result of breast screening mammography costs £3,000, and for renal dialysis or coronary-bypass surgery the costs are £25,000 and £5,000 respectively. These are three life-saving interventions, whereas cryptosporidiosis is an illness of about 5 days duration and life-threatening only in a small minority of the population with profound immunodeficiency or serious pre-existing illness.

Walkerton E. coli Outbreak

The Walkerton outbreak was declared over on 13 July, eight weeks after the town's water supply was found to be contaminated by E. coli O157:H7 bacteria⁽¹⁾. Fears of a further outbreak were raised in mid-August by newspaper reports that several new E. coli O157:H7 infections had been diagnosed in young children. However health officials moved quickly to reassure the public that these newly diagnosed infections were cases dating from the original outbreak who had suffered intermittent symptoms and had only recently been brought to medical attention.

As of 17 August, laboratory tests on faecal specimens had confirmed 198 cases of E. coli O157:H7 infection, including 26 people who developed haemolyic uremic syndrome (HUS), a serious complication associated with kidney damage. A further 119 people were diagnosed with Campylobacter infection. Tests for other microorganisms are continuing. At least 68 people were admitted to hospital, about 1,000 attended hospital emergency departments, and 1460 people who suffered gastroenteritis symptoms were interviewed by the local Public Health Unit during the investigation.

The finding of infections from more than one microorganism is not unexpected, as faecal contamination from either human or animal sources is likely to contain a mixture of pathogens. The number of laboratory confirmed cases is relatively low compared to the number of people who became ill (estimated at around 2,000), since even in this highly publicised outbreak only people with severe symptoms submitted faecal specimens for analysis.

A total of 21 deaths in Walkerton and nearby areas during the outbreak period were investigated by Ontario's Chief Coroner. The Coroner concluded that four deaths were directly attributable to the water contamination and that E. coli infection played a contributory role in two additional deaths. Fourteen deaths were found to be unrelated to the outbreak and one had insufficient information available to make a determination.

Investigations into the source of the water contamination continue to focus on faecal contamination from livestock. Several local cattle herds have been found to carry the E. coli O157:H7 strain, including a herd of 95 beef cattle on a farm only half a kilometre from one of the three wells in use at the time of the outbreak. This well (No.5) is only 15 metres deep, and is considered the most vulnerable to contamination. It is also located in closer proximity to livestock than the other two wells (No.6 and 7). However the chlorinators on wells No.5 and 6 are believed to have been operating satisfactorily prior to the outbreak, while that on well No.7 was unreliable.

Well No. 5 was closed when the outbreak was detected in May, and Well No.7 was reportedly shut down on 1 September following detection of high coliform counts. It has been reported that all three wells maybe subject to intermittent contamination from surface waters, and there has been speculation that contamination may even have reached the underground aquifier.

The Ontario provincial government announced a no-fault compensation package for people affected by the outbreak in early June, and by mid-August emergency payouts for expenses totalling about $400,000 had been made. The compensation package also includes payment for illness or death of family members with the amount to be determined by a mediator. No claims of this nature had been lodged by 17 August although over 550 enquiries had been made. People accepting a compensation payment under the government scheme are required to give up their right to sue the province for damages.

A civil class-action suit claiming $300 million in damages has been lodged by lawyers representing a number Walkerton residents and businesses. The suit names five defendants - the Municipality of Brockton, the Walkerton Public Utilities Commission and its Manager, the Bruce-Grey-Owen Sound Health Unit, and the Ontario government. A decision on whether the suit meets legal criteria for class action and is thus eligible to proceed to trial is expected from the Ontario Superior Court by November.

Walkerton schools are expected to reopen in September, with the costs for sending local children to schools outside the area over the last few months estimated at over $300,000. Schools have installed new storage tanks, piping and taps at a cost of $600,000. Provision is being made for supplies of bottled drinking water for students and staff, and primary (elementary) schools will even use imported water for flushing toilets.

The boil water notice issued on 21 May for Walkerton still remained in force at the time of going to press (12 September). Contractors have completed an extensive decontamination program including hyperchlorination and flushing of pipes in all individual homes, schools and businesses, as well as treating and flushing mains. Showerheads and aerators have been replaced, and fire hydrants and water valves cleaned. The Ministry of the Environment has ordered the replacement of 3.5 kilometres of old cast iron water mains after it was decided that build up of iron oxide scale prevented effective cleaning of the system.

The Walkerton Inquiry The Ontario Government established a Commission of Inquiry to investigate the Walkerton outbreak on June 12. The Inquiry is headed by Justice Dennis O'Connor, a senior judge from the Ontario Court of Appeals ⁽²⁾ . The Commission has a mandate to inquire into:

• the circumstances which caused hundreds of people to become ill and as many as 11 people to die at a time when E. coli bacteria were found in the Walkerton water supply;
• the cause of these events, including the effect, if any, of government policies, procedures and practices, and;
• any other relevant matters the Commission considers necessary to ensure the safety of Ontario's drinking water.

The Commission has been specifically excluded from expressing any conclusion or recommendation about the civil or criminal responsibility of any person or organisation in the tragedy. It must also avoid conflict with any criminal investigations and proceedings which may arise in relation to the outbreak. The Opposition political party has welcomed the broad mandate of the Inquiry but expressed concern over the lack of an overall time limit or any requirement to deliver interim reports on urgent matters within a specified time frame.

The Inquiry will be conducted in two parts which will run concurrently. Part I will focus on the events in Walkerton, while Part II will focus on matters relevant to ensure the safety of drinking water in the province. As a prelude to the Inquiry, Justice O'Connor visited Walkerton for a series of public consultations and private meetings with residents over several days during August. These informal meetings were closed to the media and do not constitute legal evidence.

The formal Inquiry will commence in October but will be preceeded by the hearing of applications for "standing" from more than 80 groups and 200 individuals. Applications for funding assistance from parties who would otherwise be unable to participate will be held at the same time. Under Canadian law only those granted legal "standing" are permitted to take part in the proceedings of Public Inquiries and to make submissions. In this instance, standing will be granted to those directly and substantially affected by the events in Walkerton in May and June of this year, and to those who represent clearly ascertainable interests and perspectives that are deemed essential to the mandate of the Inquiry. The Commissioner has the power to determine in which section(s) of the Inquiry each party may participate.

The Inquiry will be assisted by a Research Advisory Panel which is charged with providing the best available scientific and practical advice for the Inquiry's recommendations. The seven members of the panel will assist the Inquiry to identify a series of key topics on which expert review papers will be commissioned. The draft papers will be open to public comment and further discussions with relevant experts, and will provide the basis for policy advice to the Inquiry.

The outbreak and its aftermath continue to attract prominent media coverage in Canada, and associated issues of drinking water safety and regulation are also in the public eye. Shortly after the outbreak, the Ontario Ministry of the Environment ordered inspections of the provinces's 630 drinking water treatment plants, starting with those with a history of problems. Of the first 240 plants inspected, 152 were found to have deficiencies in at least one area including sampling frequency, chlorination, filtration, operator certification and backup systems. In 72 cases the problems were sufficiently serious to warrant immediate orders for remedial action.

The provincial government recently announced new regulations which will set minimum requirements for sampling and testing water supplies by accredited laboratories, immediate reporting of adverse test results to the Ministry of the Environment, posting of public notices regarding water contamination, and production of quarterly reports available to the public. It is also expected that about 30 towns with unfiltered supplies will be required to build filtration plants. Provincial funding of $240 million will be provided over the next two years to assist municipalities to upgrade plants, with matching funding expected from the Canadian Federal government. However the regulations do not cover some small supplies, and critics have charged that they do nothing to provide better protection of water supplies from contamination.

The Walkerton tragedy has also heightened public concern over E. coli infections, with a number of food-borne and animal related outbreaks in Canada and the United States receiving increased publicity. Several large recalls of ground beef have occurred in the past few months following the detection of E. coli contamination in some batches. Canadian scientists are currently testing a vaccine in cattle that may eliminate the O157:H7 strain of E. coli, and thus reduce the contamination risk. Preliminary studies in mice are said to have been encouraging, but the vaccine's effect in cattle and it commercial viability have yet to be established.

(1) See Health Stream Issue 18 for a report on the Walkerton outbreak.
(2) The web page of the Inquiry can be found at:
www.walkertoninquiry.com

OECD Expert Working Group

The OECD has formed an Expert Working Group to examine Approaches for Establishing Links between Drinking Water and Infectious Disease. Forty-two experts from 13 countries attended the first meeting of the group in Basingstoke UK from 9-11 July. The meeting was hosted by the Drinking Water Inspectorate, the body responsible for monitoring the compliance of water companies in England and Wales with the British Water Quality Regulations.

The meeting was organised into five sessions:

• Surveillance of Waterborne Disease
• Outbreak Investigation
• Use of Water Quality, Treatment and Distribution Data to Assess Human Health Risk
• Epidemiological Approaches to Assessing Endemic Waterborne Disease Burden
• International Policy Considerations

The experts discussed a range of new approaches to enhance current methods for surveillance and outbreak investigation, in particular the development of realtime measurements and/or predictive models. Better utilisation of existing water quality data by the public health community was also seen as a priority. The group agreed that the issue of endemic waterborne disease requires further careful investigation to determine the magnitude of its impact on community health in both the developed and developing world.

Following the workshop, the OECD will produce a policy guidance document which is intended to reach a wide variety of audiences, including scientists, health economists, government /industry representatives and the wider general public. The document will set out international guidance on best practice on epidemiological and microbiological approaches to establishing links between infectious disease and drinking water.

News Items

"Crystals" can kill Cryptosporidium

Australian scientists have reportedly discovered a "naturally occurring crystalline material" that severely disrupts the surface structure of Cryptosporidium oocysts. The discovery came during studies of the surface chemistry of oocysts and their behaviour during a range of different water treatment processes. The researchers at the Australian National University found that the strongly negatively charged surface of the oocyst was composed of a series of plate-like segments. While testing a number of materials to see which would most effectively adsorb oocysts, they found a substance which adhered so strongly that it cracked open the oocysts. Binding of the substance to the oocysts is apparently irreversible, and may be sufficient to kill them or make them susceptible to chlorine levels which are ineffective against intact oocysts. Preliminary results were reported in August at the International Association of Colloid and Interface Scientists conference in the UK, but little detail is available on the discovery as a patent application is pending.

Wallis Lakes Appeal Case

The NSW state government and one of Australia's largest oyster growing companies have lost an appeal to the Australian Federal Court over the 1997 Wallis Lakes Hepatitis outbreak. One person died and more than 440 became ill with Hepatitis A after eating oysters from waters contaminated with human waste. In 1999, the Court found the NSW State Government, Great Lakes Council and Graham Barclay Oysters Pty Ltd were equally culpable, and awarded $30,000 to one of the victims in a test case.

In a recent appeal against this judgement, the Court upheld the ruling against the state government and the oyster grower, but ruled that the Great Lakes Council could not be held responsible as it was not "fair, just or reasonable" to impose a duty of care on the Council in this situation. The compensation figure awarded to the plaintiff was reduced to $27,000. More than 280 additional claims from other victims of the outbreak are pending in two other court actions.

Leaks threaten reservoir plan

The UK Environment Agency has warned Thames Water that it may block a new reservoir planned by the company. Thames Water wants to build the new 2 mile x 1.5 mile reservoir to cater for anticipated demand from more than a million new homes expected to be built in the southeast of England in the next 16 years. The Environment Agency has criticised the water company for failing to put enough effort into reducing leaks from its supply system, and said a better performance must be achieved before it would consider a new reservoir. The agency has no direct authority to stop the development of the reservoir, but can refuse to issue the necessary extraction licenses which govern the abstraction and return of water to the river.

Sydney pollution lasts 7 months

Researchers modelling the movement of tides in Sydney Harbour have estimated that the half-life of pollution in the 500 billion litre water body is 225 days or longer. Although no significant barrier to tidal flow exists at the 3 km wide harbour mouth, the geography of the drowned river valley creates numerous eddies and obstructions which retard mixing of the water, particularly in the upper reaches of the harbour.

Disinfection "Pen" For Water Treatment

Researchers at the University of North Carolina have developed a compact water disinfection unit resembling a large writing pen. The "MIOX Disinfection Pen" was designed for use by military personnel and disaster relief workers in situations where safe water supplies are unavailable. The device, which weighs 4 ounces (about 113g) and is 7 inches (180mm) long, contains battery powered electrodes and salt tablets.

When drinking water is required, the user adds a small volume of water to the pen to dissolve the salt tablets, then switches on the battery power. The electrical current inside the device generates oxidising chemicals from the salt within 30 seconds, and the entire solution is then mixed into a quart bottle of water to be treated (about 1 litre). In laboratory tests, a treatment time of 10 minutes produced at least 99.99% reduction in the numbers of common pathogenic viruses and bacteria. A smaller, less costly version of the pen is being developed for the outdoor recreation market.

UK Fluoride Regulation

The British Department of Health has signalled it will soon change legislation to give local council legal powers to compel water companies to fluoridate water supplies. The decision was made following a new report by the University of York which reviewed evidence on the benefits and adverse effects of fluoride on health.

USEPA To Change DBP Monitoring

The USEPA plans to change the way disinfection byproducts in water distribution systems are measured in order to provide tighter controls over levels of major DBP classes. Present regulations require quarterly measurement at 4 points which represent average DBP levels for the system. Considerable discretion is allowed on the timing of samples, so that two subsequent "quarterly" measurements can be almost 6 months apart.

The revised regulations are likely to require one sample at a representative average point, one at a point with high levels of haloacetic acids (HAAs), and two at points with high levels of trihalomethane (THMs). Requirements for the timing of samples will also be more restrictive. While the current limits of 80 microgram/litre for total THMs and 60 microgram/litre for HAAs will be retained under the new "Locational Running Annual Average" scheme, it is expected that the changes to sample location will effectively reduce allowable levels of THMs by 16% and HAAs by 25%. The changes will be incorporated into the Stage 2 Disinfectants/ Disinfection By-products Rule which is due to be proposed in early 2001.

Cryptosporidium Outbreaks

Northern Ireland UK A boil water notice has been issued to more than 60,000 people in townships and suburbs on the southern outskirts of Belfast due to a suspected waterborne cryptosporidiosis outbreak. About 70 laboratory confirmed cases have been diagnosed. Investigations centre on a possible fracture in the 110 year old Lagmore conduit. The conduit is in the process of being replaced, and the Water Service is working to bypass the affected section with new piping, however this may take up to 2 weeks.

Ohio USA About 500 people are believed to have become ill with cryptosporidiosis and 115 cases have been laboratory confirmed over a 4 county area. Swimming pools were initially suspected as the source of infection, but investigations into other possible sources including drinking water are continuing.

Florida USA Hundreds of children may have been affected in a cryptosporidiosis outbreak believed to be associated with a fountain and children's play pool in Sarasota Island Park. Only 5 cases were laboratory confirmed, and the water was not tested for oocysts, however faecal indicators were found. Water in the 4,000 gallon reservoir of the fountain is now being changed daily instead of weekly, and chlorination levels have been increased.

China claims oldest W.C.

Archeological excavations in central China have revealed what may be the oldest water closet ever discovered. The lavatory was discovered in a royal tomb of the Western Han dynasty (206BC to AD24), and according to Chinese government sources is of sophisticated design. However, one of the archeologists who made the discovery has reportedly said he believes the drainage system may have been designed to prevent flooding of the tomb by rain, rather than to flush away waste.

Electrolysed water improves food safety

A system for producing electrolysed water for killing microorganisms while washing fruit and vegetables is being trialed by a US fast-food chain. The system was developed as part of a 3 year ongoing research study funded by the US Food and Drug administration. It consists of a tank holding saline water, through which an electric current is passed, producing a stream of acidic water. The treated water has reportedly been shown to be effective in killing a range of food poisoning bacteria including E. coli O157:H7, Salmonella and Listeria, but does not affect the taste or appearance of the food.

USEPA Avoids Block On Pollution Law

The US EPA is under criticism for issuing new laws on water pollution only hours before President Clinton was due to sign a bill that would block them. The laws (known as the Total Maximum Daily Load Rule) govern a range of pollutants entering water bodies, and will require the development of local programs to assess and manage both point and non-point sources in individual watersheds.

Many state authorities have complained they do not have the resources to implement such laws, and the agricultural community has disputed the EPA’s authority to regulate non-point sources. Members of Congress opposed to the measures had attached an amendment blocking the new laws to an unrelated military construction bill. However the EPA published the new laws in the Federal Register only a few hours before the bill was due to be signed.

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