Nitrate concentration and transport simulation of a rural basin aquifer under the strict compliance to the E.U. Nitrates Directive (91/676/EEC)

One of the major global threats of groundwater resources of rural basins is the nitrate contamination from the excessive use of nitrogenous fertilizers at cultivated areas (Almasri and Kaluarachchi 2007). This phenomenon has been created by the consecutive need of agricultural product maximization due to population growth (Rutting et al. 2018). Problems regarding the safeguarding public health are raised when nitrate contaminated groundwater is used for potable needs. For this reason, the World Health Organization recommended a health-based guideline value for nitrate of 50 mg/L for drinking-water. European Union, through the Nitrates Directive (91/676/EEC), set "threshold" values on nitrate fertilization of crops (kg/ha) to prevent nitrate contamination of groundwater. Furthermore, a stricter "threshold" value has been set for continuous existence of nitrate concentration in groundwater, that of 25 mg/L by Nitrates Directive. The study estimates the spatially distributed nitrate concentrations of Lake Karla aquifer of Eastern Thessaly with the use of simulation models through two scenarios regarding nitrate fertilization of crops: i) the current status; and ii) the strict compliance with the Nitrates Directive. For that reason, a modelling system has been applied, which has been proposed by Sidiropoulos et al. (2018). The study highlights the importance of the full compliance with Nitrates Directive requirements by the farmers of rural basins, where the groundwater resources are used for potable needs; otherwise the public health is threatened.