Acidification of Surface Water

Indices of sulphates and alkalinity are used for the observation of acidification. The reduction in sulphur deposition leads to an improvement in water chemistry and partly also to a recovery of the invertebrate fauna. The changes in sulphate concentration cause changes in concentrations of other constituents in the water as well. Alkalinity is a measure of water quality. In general, high values are good and low values are acid sensitive or acidified waters. Increase in alkalinity indicates improved water quality and recovery from acidification. In 1997 sulphate concentrations in the selected sampling sites of rivers responded to category I according to STN 75 7221, only the measurement location Morava - Devínska Nová Ves responded to category II.

Trend analyses of alkalinity and sulphate indicators of main rivers in the Slovak Republic are presented as indicator 1 and indicator 2.

Indicator 1 Trend in analyses of the alkalinity indicators (the measurement localities are at the mouth or downstream frontiers of main rivers in the SR)
 

Indicator 2 Trend in analyses of the sulphate indicators (the measurement localities are at the mouth or downstream frontiers of main rivers in the SR)
 
 

1996 pH values in selected rivers of SR (yearly average)
 

Rivers	Acidity (in pH)
Dunaj	8.1
Malý Dunaj	7.9
Váh	8.0
Nitra	7.8
Hron	7.6
Hornád	8.0
Laborec	7.8
Ondava	8.0
Bodva	7.9
Bodrog	7.8
Slaná	7.8
Morava	8.0
Poprad1	8.2
Dunajec1	8.2
Latorica1	7.8
Uh1	7.8

Note: ¹ - data from 1995   Source: ŠÚ SR