ABSTRACT

ABSTRACT. Intensive agricultural activities on the Maresme region have been carried out for decades. The initial composition of groundwater-calcium bicarbonate type-has been shifted to calcium sulphate type. Sometimes even nitrate is the dominant anion. Excesive fertilizer amounts, jointly with local soil characteristics and hydrogeological features produce a high mineralization of resources by the recirculation of groundwater. The great thickness of the unsatured zone explains the low concentration levels of pesticides found in preliminary surveys in groundwater. General features are commented in this introductory paper.