The waters of the Pindus ranges are as clear as they look. Water quality in Epirus, excepting its coastal areas, is exceptionally good.
The quality of lake and river water in Greece varies widely. Typically, bodies of water that have been subject to human activity, chiefly in the form of industry and agriculture, but also in the form of urban waste, have poor quality water. By contrast, surface waters in the Pindus region and throughout Epirus, apart from its coast, are considered to be the cleanest in Europe.
The basic cause of pollution of surface water “is not the lack of legislation so much as the lack of monitoring compliance with it,” George Zalidis, director of the Applied Soil Science laboratory at Aristotle University in Thessaloniki, said. Moreover, local government, which is responsible for inspections, is vulnerable to pressure from local communities.
Hence there are cases such as that of Lake Koroneia, where once again scores of dead birds were found in the past few days. That lake receives unprocessed urban effluent from the Municipality of Langada, around 10,000 inhabitants, because the waste processing plant installed 10 years ago is not in operation.
Applying the European Union directive on water quality (2000/60), Aristotle University studied five physical and chemical parameters to measure water quality in rivers and lakes, using data collected by the Agriculture Ministry.
The first parameter they examined was the electrical conductivity of the water, which depends on the degree of salinity. As Zalidis explained, salinity comes from sea water entering bodies of fresh water (in estuaries, for example), but also from human activity. In Koroneia, large amounts of salt used by dyeing firms enter the lake. A more serious problem affects water in eastern and central Macedonia, due to pollutants from both Greece and neighboring countries.
The second parameter examined was the increase in the water’s pH, which is a common phenomenon in Koroneia. The rise in pH stems from substances that enter the lake as a result of industrial activity. “Fish and other organisms cannot tolerate these sudden changes and they die,” said Zalidis. The same applies to the third parameter, the concentration of dissolved oxygen. When the oxygen in water falls below a certain level, life cannot survive in the water and mass deaths ensue.
The levels of nitrates and phosphorus in the water rise as a result of farming and the use of fertilizers, as well as due to industrial outflow which overloads lakes and rivers with organic substances. In terms of geography, the highest levels of nitrates appear in rivers such as the Nestos, Evros and Axios that also cross other states.
High concentrations also occur in areas with intensive farming, such as the plain of Thessaly with the Pineios river, the Serres plain (Strymonas) and Appollonia (Axios). High levels of phosphorus appear in the Evros and Axios rivers, and the lakes of Petres, Heimaitidia, Zazari, Koronia and Ioannina.