Nitrate concentrations in drinking water and the relation to different crop types production in the province of Valencia (Spain)

Abstract

The aim of the present study was to investigate the evolution of nitrates contamination of public drinking water in the province of Valencia, where is concentrated most fertilizer consumption of Spain, between 1968 and 1991, and its relation to the different types of crops found in this municipalities. Correlation analysis and factorial analysis was made of the between nitrate concentrations in public drinking water in the years 1968, 1981 and 1991, in all the municipalities of the province of Valencia, the percentage of different crop types studied and the nitrogen fertilizer employed per hectare annually. Positive correlations were noted between nitrate levels and the cultivation of citrus fruits, vegetables and cereals, and the use of nitrogen fertilizers. Negative correlations were derived with the rest of dry‐land crops. The greatest correlations were obtained between fertilizer utilization and citrus crops (R2 = 0.82). Factorial analysis reveals, the relationship between the presence of nitrates in underground water layers, the surface dedicated to citrus fruit production, and the presence of nitrates in soils and the minimum influence of cereals with respect to the presence of nitrates both in water and in soil.