Spatial and temporal changes in water quality in a Spanish river

• Published in: The Science of the total environment Vol. 241; no. 1; pp. 75 - 90
• Main Authors: Perona, E., Bonilla, I., Mateo, P.
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier B.V 29.10.1999; Elsevier Science
• Subjects: Applied sciences; Continental surface waters; Dissolved inorganic nitrogen; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Eutrophication; Exact sciences and technology; Natural water pollution; Phosphorus reactive soluble; Pollution; Pollution, environment geology; Principal components analysis; River; Spain, Alberche R; Water quality; Water treatment and pollution; Europe; Spain; River; Principal components analysis; Phosphorus reactive soluble; Dissolved inorganic nitrogen; Water quality; Eutrophication; Statistical analysis; Nitrogen compounds; Spatial variation; Time variation; Medium effect; Seasonal variation; Content; Surface water; Chemical composition; Stream; Phosphorus compound; Water pollution; Physicochemical properties; Principal component analysis
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/S0048-9697(99)00334-4

Spatial and temporal variation in the water quality of a Spanish river (Alberche River) were examined during 2 consecutive years. Principal component analysis was used to analyse the environmental factors associated with the physico-chemical variability. The first principal component corresponded to the variation of water solute content along the course of the river. In general, the conservative parameters (alkalinity, sulphate, calcium, and chloride) gradually increased in a downstream direction. However, nutrient variables showed marked differences depending on the location and the season. Two sections can be distinguished in the river. The first in an upstream zone with little human occupation, a siliceous substrate produces waters with low ionic composition and few nutrients. However, the second, downstream zone, featured high levels of phosphate and dissolved inorganic nitrogen in summer and to a lesser extent in spring. The variation in nutrient content in this section of the river can be attributed to anthropogenic sources since in these seasons the presence of holiday-makers leads to a high population density in the residential buildings and recreation areas. Thus, in this area, seasonal increases in human activities at some locations cause high levels of nutrients and may therefore be considered to be classed subject to spatio-temporal eutrophication.