Stroming en samenstelling van de sprengen en het grondwater van de Veluwe in 1996; een vergelijking met de toestand van 1986
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Series / Report no.
Open Access
Type
Report
Language
nl
Date
1999-04-01
Research Projects
Organizational Units
Journal Issue
Title
Stroming en samenstelling van de sprengen en het
grondwater van de Veluwe in 1996; een vergelijking met de toestand van
1986
Translated Title
Flow and composition of groundwater and sprengen
of the Veluwe
Published in
Abstract
Monsters water uit sprengen en grondwater van de Veluwe
zijn onderzocht op concentraties van hoofdcomponenten en van
microcomponenten (bepalingen door NITG). Onderzoek is gedaan ter bepaling
van verblijftijden in de bodem van grondwater en van het water in sprengen.
De intrekgebieden van de sprengen en het neerslagoverschot zijn bepaald.
Bij de onderzochte monsters van het grondwater en de sprengen bestaat een
verband tussen concentraties van de hoofdcomponenten en varierende
concentraties in de atmosferische depositie als rekening wordt gehouden met
verblijftijden in de bodem en indampfactoren. Concentraties aan nitraat in
grondwater en sprengen zijn een gevolg van de atmosferische depositie van
stikstof, waarbij ca. 78% door denitrificatie in de bodem verdwijnt. De
concentraties zijn toegenomen van 0.3 tot bijna 5 mg.l-1 en ze kunnen nog
verder toenemen tot 10 mg.l-1 (als N). De zuurgraad is afgenomen van
pH=6.5 tot pH=5.5 in 1996 en die kan nog verder dalen tot pH=4.5 in de
komende eeuw. Verhoogde concentraties in het grondwater en de zuidelijke
sprengen van Be, B, Al, Mn, Fe, Co, Ni, Zn, As, Rb, Y, Cd, Cs en Ba zijn
vermoedelijk het gevolg van een extra belasting aan maaiveld. De
concentraties in het water van de lantaniden (zeldzame aarden) zijn ongeveer
een factor 10 hoger bij de huidige lage pH in vergelijking tot
vroeger
"Sprengen" are water courses dug ages ago to discharge groundwater from the Veluwe hills, where natural vegetation has always prevailed. An investigation in 1996, comprising sampling of sprengen and groundwater in the surroundings, was aimed at studying the relationship between precipitation, groundwater and the water from the sprengen. The concentrations of the major components and of micro-components in the water were considered. Investigations carried out to study residence times of the water in the soil revealed the extent of the drainage basins and produced values for net precipitation. Discharge of the sprengen is relatively constant in time. Concentrations of the major components are related to the aerial deposition, taking into account travel times in the soil and condensation factors. Aerial deposition is the only source for the major components in the eastern sprengen. Nitrate concentrations in the sprengen result from the total deposition of nitrogen compounds, but 77% vanishes through denitrification in the soil. They have increased from 0.3 to roughly 5 and they will further increase to 10 mg.l-1 in the coming century, if the aerial deposition remains the same. Sulphate concentrations result from aerial deposition of sulphur. The groundwater acidity has decreased from pH=6.5 to now pH=5.5 and it will further decrease to pH=4.5 at an unchanged aerial deposition in the coming century. Increased concentrations in groundwater and/or the southern sprengen of B, Al, Mn, Fe, Co, Ni, Zn, As, Rb, Y, Cd, Cs and Ba probably result from an additional load at land surface. The lantanide concentrations increase roughly at low pH values by a factor of 10 (when compared to a former situation) by dissolution in soil. The same results were obtained with aluminium.
"Sprengen" are water courses dug ages ago to discharge groundwater from the Veluwe hills, where natural vegetation has always prevailed. An investigation in 1996, comprising sampling of sprengen and groundwater in the surroundings, was aimed at studying the relationship between precipitation, groundwater and the water from the sprengen. The concentrations of the major components and of micro-components in the water were considered. Investigations carried out to study residence times of the water in the soil revealed the extent of the drainage basins and produced values for net precipitation. Discharge of the sprengen is relatively constant in time. Concentrations of the major components are related to the aerial deposition, taking into account travel times in the soil and condensation factors. Aerial deposition is the only source for the major components in the eastern sprengen. Nitrate concentrations in the sprengen result from the total deposition of nitrogen compounds, but 77% vanishes through denitrification in the soil. They have increased from 0.3 to roughly 5 and they will further increase to 10 mg.l-1 in the coming century, if the aerial deposition remains the same. Sulphate concentrations result from aerial deposition of sulphur. The groundwater acidity has decreased from pH=6.5 to now pH=5.5 and it will further decrease to pH=4.5 at an unchanged aerial deposition in the coming century. Increased concentrations in groundwater and/or the southern sprengen of B, Al, Mn, Fe, Co, Ni, Zn, As, Rb, Y, Cd, Cs and Ba probably result from an additional load at land surface. The lantanide concentrations increase roughly at low pH values by a factor of 10 (when compared to a former situation) by dissolution in soil. The same results were obtained with aluminium.
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