In this chapter is presented part of the results of a project of the Greek Ministry of Rural Development and Foods (MRDF). This project aimed at the investigation of the freshwater quality (surface and groundwater) in River Water Basins EL07 and ELO4 located in Sterea Hellas, central Greece. This includes the identification of pollution sources as well as the proposal of measures for protection and restoration of water quality, according to the provisions of Community Directive 2000/60 and national regulations. The water properties discussed in this chapter are pH, electrical conductivity, and the inorganic nitrogen ions nitrite, nitrate, and ammonium. The entire area was divided into 11 catchments from which, for two consecutive years (2017–2018), water samples were taken at specified intervals from rivers, lakes, canals, and wells. These samples were analyzed in situ and in the laboratory, evaluated as to their suitability for drinking and irrigation, according to European Union and national regulations. The values of the parameters studied ranged widely among rivers, lakes, groundwater, and drainage canals, reflecting the various prevailing conditions in the different water sources and the special characteristics of the sampling positions. The median values of all the properties studied are lying within the normal and acceptable levels. However, in some places, extreme values, unacceptable for any use were recorded. The pH was higher in lake water, followed by rivers, canals, and groundwaters; electrical conductivity was found to be higher in river and canal waters, followed by canals and groundwaters; nitrite was higher in groundwaters followed by canals, rivers, and lake waters, while nitrate was higher in groundwaters followed by all other categories, and ammonium was higher in canals, followed by lakes, rivers, and groundwaters.
The sources of contamination on a case-by-case basis appear to be anthropogenic, such as poor agricultural practices and, in particular, unsound management of inputs (fertilizers and pesticides), the dumping into drainage canals of untreated municipal or/and industrial waste, livestock farming (as it was found in the catchments, Sperceios – C1, Kifisos – C5, and Asopos – C6). And there are natural sources, such as seawater intrusion and the chemical composition of the rocks of the study area (especially in the catchments: Sperceios – C1, Amfissa – C4, Messapios-Lilantas – C8, Nireas-Kireas-Voudoros-Kimasi – C9, Kallas – C10). The most significant suggested measurement of water contamination are the tracing of contamination sources to identify their origin (agricultural, livestock, urban, industrial), the implementation of good agricultural practices (especially in applying appropriate irrigation methods that reduce nutrient leaching into the aquifer), and the estimation of the nutrient needs by soil and plant analysis or by using precision agriculture practices, both of which permit the differentiation of the amount of nitrogen fertilizers needs by taking into account the significant variability of the soil properties. Furthermore, suggestions include the continuous monitoring of surface and groundwater through certain environmental indicators (for example nitrate content), and taking protection measures of water drilling and application of their protection zones following the River Basin Management Plans, which propose detailed measures based on the article 4 of the Water Framework Directive 2000/60.