APPLICATION OF FACTOR-ANALYSIS TO THE STUDY OF CONTAMINATION IN THE AQUIFER SYSTEM OF AYAMONTE-HUELVA (SPAIN)

The growth of cultivation (strawberries and citrus fruits) in the coas tal region of the Huelva province of Spain in the last 10 years has me ant an increase in the demand of water from the Ayamonte-Huelva aquife r system, It has also meant the introduction of an excess of nitrogen via fertilizers from farming. The system now has two problems: salt-wa ter intrusion in the southern sector (Gonzalez and Romero, 1991; Gonza lez, 1992); and a general increase in the nitrate content in the satur ated zone, This second problem has led to average concentrations of ni trates in the aquifer above potable limits (50 ppm), reaching local va lues near to 400 ppm of NO3- (Gonzalez and Romero, 1991; Grande et al. , 1993). This paper delineates the sphere of influence of the two fact ors being considered (salt-water intrusion and agricultural contaminat ion) on the different variables studied, The proximity between both fa ctors is justified for each of the contaminating processes.