Making Every Sip Count: Monitoring Water Supplies
A plentiful supply of clean water is seen by many as a basic right. But even in the developed world, water contains a threat that makes monitoring increasingly important. By Dr Gareth Evans.
The developed world has long been accustomed to a plentiful supply of clean water at the turn of a tap. The idea of contaminated water arriving through the pipes – particularly if that contamination was intentional – strikes a particularly disturbing chord in developed society's collective psyches. But in the post-9 / 11 world, that particular spectre is something that haunts the water industry with a number of mammoth challenges.
The sector's most critical components were designed at a time when the most likely threat to be met was a youthful prank, not a deliberate attack such as that carried out in the name of terrorism.
Given its importance to public health, environmental safety and the smooth functioning of the economy, the propaganda value of a successful strike against the water supply infrastructure makes such an attempt a statistical probability to many people. Nevertheless, how effective it might be remains open to debate.
To date, history suggests that high casualty numbers are difficult to achieve by contaminating water supply because various aspects of the water system have differing intrinsic vulnerabilities.
As consultant biochemist Dr Clare Miles points out, raw water sources like reservoirs are easily accessible and as such would likely make good targets, but this is not necessarily the case.
"If you were going to use chemical or biological agents, the inherent dilution effect would mean that the quantities of chemicals, bacteria or viruses needed would have to be vast," says Miles. "It's hardly a realistic proposition for a terrorist; it’s just not going to work."
The Crystal Springs Reservoir in California, US, supplies water to San Francisco. It has been calculated that to deliberately contaminate the reservoir with sufficient hydrogen cyanide to affect anyone drinking the water, more than 400,000 tonnes of the poison would be required. The logistics alone would make such a task absurd.
The risk at the water treatment and distribution level, however, is considerably more plausible. The FBI's discovery in 2004 of related architectural and engineering software on an al-Qaeda member's computer served to highlight this point.
The bottom line is that the potential for contamination is inversely proportional to the level of dilution, which means that the possibility of success increases the closer the attack is made to the target consumers. Against such underlying fears, it has become clear that the traditional approaches to water monitoring, which provide results in hours and days, are increasingly inappropriate for these new demands.
Case study: Israel
Israel is one of the world leaders in water security where expertise is born of the practical need for a dry nation that is surrounded by less than sympathetic neighbours and mired in ongoing conflict.
"The Israeli position is that it's a concrete threat," says Ori Yogev, chairman of the water technology company Whitewater. "We can combat conventional threats, but there is more of a threat from non-conventional terror, and water is a major factor in this."
Israel's state water company Mekorot is well equipped to monitor its water and tests are carried out on a near-continuous basis. The main National Water Carrier, the key pipeline that carries more than half of the nation's potable supply, is fitted with monitoring devices throughout its length to give instant detection of contamination, and trigger rapid shutdown, if required, in response.
Such high contamination awareness dovetails into the country's overall approach, which is centred on 'five pillars of water security': prevention, protection, detection, crisis management and recovery, and the resulting synergy provides a robust and comprehensive solution.
So far, it has stood the test of time. If the terrorist threat to the water supply does materialise in the way that many fear, it seems likely that more nations will follow the same path.
Monitoring microbes and lasers
To meet any terrorist threat, immediacy is everything and the race is on to provide earlier warnings. Spectroscopy, in its various guises, is an area that is emerging bly, particularly in respect of laser and fluorescent detection technologies, which are beginning to revolutionise the recognition of low concentrations of biological suspensions in water.
These have always proven difficult to monitor under conventional systems, but the rise of spectroscopic analysis has started to re-write the book on continuous online monitoring, now providing an automated response within seconds.
Systems such as JMAR's biosentry not only use patented multi-angle laser light-scattering technology to detect the presence of waterborne microbes, but also identify them by referencing their unique bio-optical signatures.
Offering continuous flow monitoring and real-time event notification, the system is fully SCADA and MIS-compatible, the package providing one of the fastest available monitoring regimes.
It is also remarkably sensitive; in a series of tests of online sensors and instruments conducted by the US Environmental Protection Agency in April 2010 to detect low density pathogen suspensions, the system functioned reliably down to concentrations as low as 600cfu per millilitre.
The need for reliable contaminant identification has introduced a number of biotechnology solutions. Many of these solutions go beyond anti-terrorist applications.
The UK's aptly named CSI Seaside is the first initiative of its kind to bring extended, state-of-the-art forensic DNA techniques to the issue of water contamination. Although on this occasion the latest microbial source tracking (MST) methods were being employed in the quest to counter faecal contamination, the operational efficacy of the project has established the robustness of the general approach in a real-world environment.
"MST has some way to go before it's going to be ready for any of the sort of pathogens a terrorist is likely to use," Miles explains. "But it's really shown what can be done outside the lab. There could be some real game-changers coming out of biotech over the next few years."
One area where some of this promise might lie is in newly emerging techniques that extend the use of microbial assays to the question of contaminant toxicity, once it has been introduced in the environment.
Traditional methods of eco-toxicology typically involve either straightforward extrapolation from chemical analysis – which gives little clue as to likely biological impact – or draw on a single species / single character test, such as the bio-luminescence of Vibrio fischeri bacteria. Although this yields fast results, many in the field have long felt that these are too narrow in their scope.
That may all be about to change if the outcome of a recent project, supported by Sweden's Karolinska Institute, the Scottish Enterprise and the UK's EUREKA scheme, goes according to plan.
Expanding the concept to embrace 11 genetically diverse microbial species (comprising ten bacteria and one yeast), the Microbial Assay for toxic Risk Assessment (MARA) kit offers more potential for monitoring applications. By establishing the microbial toxic concentration (MTC) of the contaminant for each of the 11 in turn and then an average MTC based on the combined results, the sample can be readily characterised by its toxic fingerprint.
While this has obvious benefits for routine monitoring it also has considerable potential for investigative applications to diagnose the nature of unidentified pollutants. When comes to risk management, practical experience has taught that detection is the best point of focus.