Effect of agricultural practice on groundwater qualityin south-eastern Sicily

Abstract

Agricultural practice in southeastern Sicily is among the most important activities carried out in the island from the economic point of view. For this reason, groundwater has been exploited in the latest 20 years by all the agricultural companies of the area. Such activity persisted with no management of the resource, thus compromising the water quality. The goal of this paper is to highlight the worsening of the groundwater quality due to the intense agricultural practice. The evolutive trend of chemical indicators testify the efficiency of the productive system and their knowledge can lead the producers to choice of the best available technology non entailing excessive costs (BATNEEC). The carbonate aquifers, because of their permeability, are exposed to pollution, especially in agricultural areas where fertilizers and pesticides are intensively used. The confined and unconfined aquifers exploited in the study area have been monitored in 1996, 2006 and 2008 to outline the groundwater quality. Most of the analyzed samples are enriched of elements deriving from the use of fertilizers. Particularly the nitrate, in both aquifers, overcomes 50 mg/l concentration (the legal limit value of drinking water). To classify the groundwater suitability for irrigation purpose, chemical indices like TDS, Percent Sodium (Na%), Sodium Adsorption Ratio (SAR), Permeability Index (PI) and residual sodium carbonate (RSC) were carried out. Results show a worsening of the groundwater quality in the time interval 1996-2008, which makes the water not suitable for farming activity.