Outdated drinking water network poses threat in the future
THESSALONIKI – A string of serious impending threats to public safety, among which is the presence of asbestos-lined water pipes, was brought to light by a recent study on the quality of drinking water in all the prefectures of Central Macedonia, carried out by the Greek Association of Chemical Engineers. The results of the study, which covered 25 municipal water and sewerage companies in the prefectures of Thessaloniki, Halkidiki, Kilkis, Pella, Imathia, Pieria and Serres, were recently presented at a one-day conference held in Thessaloniki. Traces of heavy metals found in several water samples, the presence of nitrates near bore holes (which are attributed to extensive livestock farming and the unregulated fertilization of nearby agricultural fields), non-satisfactory water chlorination because of aged pipes, threats to microbiologic environments, the insufficient protection of water sources and the conveyance of drinking water from sources to reservoirs are some of the major problems threatening the quality of drinking water today. The most pressing problem, however, is that old-fashioned asbestos-lined pipes have not been replaced with more modern technology and it is estimated that there are 44,000 kilometers of these dated systems running through Greece and carrying drinking water. It is not known whether this water has traces of asbestos or whether it carries corrosive effects. Experts also say that the drop in rain and snowfall this winter, compounded by what is expected to be a dry summer, will further worsen the quality of drinking water, especially in coastal areas that also have to deal with the salification of the water table. The working group of the Greek Association of Chemical Engineers comprised Anthoula Karanasiou, Nikos Karnavos, Constantinos Plakas and Giorgos Siokos. The study has succeeded in putting the municipal authorities on alert, mobilizing them to take frequent water samples in their respective jurisdictions. For example, the majority of the municipal waterworks companies are dealing with the presence of nitrates in drinking water, either by drawing water into the system from cleaner sources or by shouldering the cost of -0.50 per cubic meter to install modern water-processing methods (these are already in place in five municipalities in Central Macedonia). However, municipal water services are failing to keep a close watch on toxic materials such as chlorinated compounds and pesticides, which can contaminate groundwater. Chemical engineer Nikos Karnavos notes that «the quality of available water sources in Central Macedonia does not pose a risk to public health, as 85 percent of intake comes from natural springs and groundwater sources that are unaffected by contaminants.» «This will, however, change over the next few years. Many sectors (such as livestock farming or various leisure activities) will be forced to draw their water from the surface, making it imperative to organize and put into action a mechanism to maintain and protect all investments and to monitor the quality of the water,» he adds. Greatest demand from areas with least reserves How is it that Greece, considered one of the richest countries in the Mediterranean in terms of its water supply, is facing the threat of aridity? Why are the lakes and rivers of this country, which has no heavy industry, contaminated with pollutants? Major fluctuations in rainfall levels, in combination with the fact that the greatest demand for water comes from areas with the least amount of reserves, such as the Cycladic Islands, drastically reduces the levels of available water sources in specific areas. The overdevelopment of Greece, growing populations, agriculture and industry are concentrated in the east of the country (Kavala, Alexandroupolis, Thessaloniki, Athens and Patras), while on the islands of the Aegean, the water table hardly has time to refill – even when it rains – and to form rivers and streams, before the summer months and rising demand come around again. Furthermore, most parts of the country use groundwater sources rather than surface water, because it is easier to bore a well into the ground and tap a source than it is to build reservoirs and dams to collect and preserve the surface water. «We overuse groundwater sources, while initiatives concerning surface water are very limited,» explains Dimitris Koutsoyiannis, an associate professor at the National Technical University of Athens. The country’s lakes and rivers are often the dumping sites for unprocessed wastewater and industrial waste with high concentrations of organic nutrients leak into the water, causing eutrophism (the overgrowth of algae and therefore a reduction in oxygen levels in the water). The lakes that are most at risk from contamination in Greece are Vegoritida, Vistonida, Volvi, Yliki, Koroneia, Marathon, Mitrikou and Petres. However, according to research conducted by Thessaloniki University Professor Giorgos Zalidis, half the lakes in Greece are showing a serious decline in water quality, while 38 percent are showing a rapid reduction in the volume of water. Agricultural runoff is also a major contributor to the contamination of both surface and groundwater, leaching nitrates that come from the overuse of toxic pesticides or waste from livestock farms. But, since agriculture does not use irrigation water, the problem has not been given due attention.
