Thursday, 12 April 2018
In Belgium, a beer country, the issue of water is of national significance. Tap water is usually seen, in Western countries, as the cheapest, safest water to drink – around 800 times cheaper than bottled water! However, in early February, the European Commission’s proposal for a revision of the Drinking Water Directive caused an outcry in the Belgian press. Its impact assessment singled out Belgium as one of the worst performers, with 850,000 people or 8% of the population “at potential health risk” from drinking tap water. “Misleading” screamed every water management authority in the country. Who’s telling the truth?
The concept of population potentially at health risk (PPHR) was “specifically developed in the context of the impact assessment study,” explains the Commission. In the absence of statistics linking water quality to health problems, this indicator was used to assess a number of people in each country, “which could potentially suffer health problems through the consumption of lower quality water.”
Acteon, an Irish consultancy that helped draft the impact assessment, led the consortium which developed the PPHR indicator. The latter is based on health data collected by the Stockholm-based European Centre for Disease Prevention and Control. The figures for Belgium come from the national Scientific Institute for Public Health (ISP-WIV), which forwarded them to Stockholm.
The consultants used statistics of sicknesses attributed to Campylobacteriosis, Cryptosporidiosis, E.coli, Giardosis, Shigellasis and Legionella. “These very low and discrete figures could however not be linked to available drinking water quality figures,” the Commission explained. Hence the consultants had to estimate the likelihood that they came from drinking water.
A comparison of statistics for the six diseases with the PPHR indicator showed a statistical correlation. For Belgium, the impact assessment lists 23,681 sick days attributable to the six diseases. “This is significantly more than the EU average of 14,568, thus this corresponds to a higher PPHR for Belgium,” the Commission concluded.
The figures are impressive but the estimates that use them, for example of where diseases come from, are less definitive. “Sometimes, we have ‘shaky’ estimates, whose reliability has to be seen,” warns Milo Fiasconaro, Executive Director for Aqua Publica Europea, the European Association of Public Water Operators. Some of the data behind the estimates is also poor, he adds.
Major methodological mistakes
The PPHR modelling is not only based on the number of sick cases, but also incorporates nationally available data such as water network connection rates and bottled water consumption. For Belgium, the main parameters for water quality that were significantly different to other European countries include: a low percentage of water bodies in good quality status; high pharmaceutical products consumption; high nitrogen losses to surface and ground water; high percentage of water bodies subject to point source pollution and low achievements on environmental objectives for groundwater.
This reflects the high pressures in a densely populated country with intensive industry and agriculture, the Commission explains. With these and other inputs, such as lists of polluting substances, the study estimated how drinking water was affected. In other countries, other parameters were crucial, for example low connection rates or weaker risk-based approaches to water management.
“PPHR is based on major methodological mistakes,” says Cédric Prevedello, scientific adviser at Aquawal, the federation of public water operators of Wallonia, who questions the PPHR modelling. If it is true that Belgians consume a lot of pharmaceuticals, they are mostly found in surface waters. A recent study in Wallonia showed that “the contamination level of drinking water by pharmaceuticals is almost absent,” he says.
Nitrogen is problematic for bottled-fed infants once the nitrate concentration is above 50mg/l, according to the World Health Organisation. The most-used method for reducing nitrate contamination of water is to mix water from different sources together to lower the concentration. In Wallonia, more than 99% of drinking water complies with the 50mg/l standard.
As for water bodies subject to point source pollution, the study does not distinguish between groundwater and surface water. “Moreover, water is never distributed without treatment, usually chlorine, in order to prevent its microbiological deterioration,” Prevedello adds. This impact assessment study “shows a very high level of mistakes regarding both methodology and figures. The consortium of research centres shows evidence of very low knowledge on the functioning of the water sector in general,” he concludes.
The methodology for modelling the PPHR indicator was discussed with the water sector experts who warned against “the lack of scientific soundness” of the theoretical indicator. However, they agreed that for the purpose of the modelling, for which it was developed, it is indeed valuable. In other words, the purpose of the indicator is not to evaluate the real current situation, but to have a tool to assess and compare the impacts of different policy options.
An indicator such as the PPHR does not give “real” information on health risks, an EU official explains. It just helps the Commission to quantify benefits and justify policy choices. In this case, the impact assessment suggested that the Commission’s proposal would reduce the PPHR for Belgium down to 290,000 people or 2% of the population. But as far as the on-the-ground situation is concerned, “there is no real danger for Belgium when it comes to the quality of its drinking water,” the Commission acknowledges.
The leakage issue
Nevertheless, a high rate of leakage from pipes in Belgium (50%, second after Bulgaria and twice as much as the European average) was also identified by the Commission as a health issue. In 2015, the University of Sheffield published a study which is the first to prove beyond a doubt that contaminants can enter pipes through leaks and be transported throughout the network.
The pressure in mains water pipes usually forces water out through leaks, preventing anything else from getting in. But when there is a significant pressure drop in a damaged section of pipe, water surrounding that pipe can be sucked in through the hole. Lead researcher Professor Joby Boxall says: “Previous studies have shown that material around water pipes contains harmful contaminants, including viruses and bacteria from faeces, so anything sucked into the network through a leak is going to include things we don’t want to be drinking.”
For Prevedello, “the leakage rate has nothing to do with the quality of water.” It’s the compliance rate with the EU Drinking Water Directive which matters, and that’s well above 99% in Belgium. In Brussels, controls at the tap by water network operator Viavaqua show that water distributed in the Brussels-Capital Region is “of excellent quality,” according to the Ministry of Environment. Compliance with the EU Drinking Water Directive in 2016 was 99,59%. According to the Flemish Environment Agency, “the quality of the drinking water in Flanders to a very great extent meets the relevant quality requirements.”
In any case, the leakage rate “is not a good indicator of the quality of a network – or investments made in it,” according to Fiasconaro. “Other indicators are better. You need to look at consumption and network size to have a comparable indicator.” Even in Belgium, it’s difficult to compare Flanders, which has 90 distribution zones to supply 6 million inhabitants and Wallonia, which has 600 distribution zones to supply 3.4 million inhabitants,” notes Prevedello. The Flemish water grid is therefore much denser than the Wallonian one, because of differences in demographics and topography – Flanders is much flatter than Wallonia.
Still some issues
So, is all well in Belgium? Well, unusually the Commission study quotes the example of a whole pack of scouts who were once infected by water in Belgium. “This happens all the time,” Prevedello says, pointing out that private distribution, e.g. from camping sites, is still a real problem. “The issue was addressed at the last informal meeting of Member States’ experts with the Commission when they discussed the new Drinking Water Directive. Opinions are diverging,” Fiasconaro acknowledges.
In Wallonia, the latest drinking water report dates back to 2012, when more than a third of private distribution zones (read: camping sites) were non-compliant, especially on microbiological indicators (particularly E.Coli) and chemicals, especially pesticides. The next report on Wallonia will be issued in 2019. In the meantime, “I would check data on compliance before going camping in some places,” Prevedello says, pointing to the lack of treatment, bad state of pipes, and illegal supplies straight from surface and groundwater in remote areas.
Willy Verstraete, Emeritus Professor at Ghent University’s Department of Biochemical and Microbial Technology, assures me that overall, the microbial quality of Belgian drinking water is fine: “There was nothing shocking so far.” However, he raises the problem of pharmaceuticals, which are increasingly present in wastewater and therefore re-consumed through tap water.
“You need a more advanced microbiological approach in relation to these molecules, but we still don’t know how to do it,” he warns. Verstraete advocates for more fundamental research on micropollutants because “some bacteria must be able to digest these molecules”. So far, they are untouched by micro-organisms present in water and accumulate in the environment. “This contributes to the general resistance to antibiotics,” Verstraete warns.
One of the solutions may come from upgrading water treatment, but it’s expensive. “Most European wastewater treatment plants today clean water in three steps. A fourth step would allow the elimination of drugs and micropollutants, for instance by ozonisation,” explains Cedric Hananel, Director of Arctik, the consultancy in charge of communications for the EU research project Powerstep. “The problem is that this fourth step is very expensive,” he explains.
European wastewater treatment plants today eat up the biggest part – a fifth – of municipalities’ electricity bills. Upgrading European wastewater treatment plants to generate energy “makes economic sense,” he says: more efficient plants can reduce the cost of water quality improvements or compensate for the additional energy demand of more advanced future treatments. Moreover, energy-neutral plants produce water of the same or even better quality as conventional plants.
The potential in Europe is huge: “They could be producing up to twelve power plants’ worth of efficient, renewable, flexible energy that contributes to the low-carbon, circular development of the European economy,” Hananel says. It already exists in Copenhagen and could be replicated anywhere in Europe, including Belgium.
By Hughes Belin