Contains a hydrochemical amount/compositional data set obtained from several rivers in the Llobregat river basin, in northeastern Spain.
data(Hydrochem)Data matrix with 485 cases and 19 variables.
This hydrochemical data set contains measurements of 14 components, H, Na, K, Ca, Mg, Sr, Ba, \(\mathrm{NH}_4\), Cl, \(\mathrm{HCO}_3\), \(\mathrm{NO}_3\), \(\mathrm{SO}_4\), \(\mathrm{PO}_4\), TOC. From them, hydrogen was derived by inverting the relationship between its stable form in water, \(\mathrm{H}_3\mathrm{O}^+\), and pH. Details can be found in Otero et al. (2005). Each of these parameters is measured approximately once each month during 2 years in 31 stations, placed along the rivers and main tributaries of the Llobregat river, one of the medium rivers in northeastern Spain.
The Llobregat river drains an area of 4948.2 \(km^2\), and it is 156.6 km long, with two main tributaries, Cardener and Anoia. The headwaters of Llobregat and Cardener are in a rather unpolluted area of the Eastern Pyrenees. Mid-waters these rivers flow through a densely populated and industrialized area, where potash mining activity occurs and there are large salt mine tailings stored with no water proofing. There, the main land use is agriculture and stockbreeding. The lower course flows through one of the most densely populated areas of the Mediterranean region (around the city of Barcelona) and the river receives large inputs from industry and urban origin, while intensive agriculture activity is again present in the Llobregat delta. Anoia is quite different. Its headwaters are in an agricultural area, downwaters it flows through an industrialized zone (paper mills, tannery and textile industries), and near the confluence with Llobregat the main land use is agriculture again, mainly vineyards, with a decrease in industry and urban contribution. Given this variety in geological background and human activities, the sample has been splitted in four groups (higher Llobregat course, Cardener, Anoia and lower Llobregat course), which in turn are splitted into main river and tributaries (Otero et al, 2005). Information on these groupings, the sampling locations and sampling time is included in 5 complementary variables.
Otero, N.; R. Tolosana-Delgado, A. Soler, V. Pawlowsky-Glahn and A. Canals (2005). Relative vs. absolute statistical analysis of compositions: A comparative study of surface waters of a Mediterranean river. Water Research, 39(7): 1404-1414. doi: 10.1016/j.watres.2005.01.012
Tolosana-Delgado, R.; Otero, N.; Pawlowsky-Glahn, V.; Soler, A. (2005). Latent Compositional Factors in The Llobregat River Basin (Spain) Hydrogeochemistry. Mathematical Geology 37(7): 681-702.
# NOT RUN {
data(Hydrochem)
biplot(princomp(rplus(Hydrochem)))
biplot(princomp(rcomp(Hydrochem)))
biplot(princomp(aplus(Hydrochem)))
biplot(princomp(acomp(Hydrochem)))
# }
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