Evaluatie van de grondwaterkwaliteit in de provincie Zuid-Holland
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Series / Report no.
Open Access
Type
Report
Language
nl
Date
1998-01-31
Research Projects
Organizational Units
Journal Issue
Title
Evaluatie van de grondwaterkwaliteit in de provincie
Zuid-Holland
Translated Title
Evaluation of the groundwater quality of the
province of Zuid-Holland, the Netherlands
Published in
Abstract
De Provincie Zuid-Holland heeft sinds 1989 een meetnet
grondwaterkwaliteit, met als doel de kwaliteit van het grondwater en de
veranderingen hierin te meten. Doelen van deze evaluatie waren: een beeld
te schetsen van de grondwaterkwaliteit in de provincie Zuid-Holland, en
onderzoeken of er in dit beeld trendmatige wijzigingen zijn opgetreden sinds
de inrichting van het meetnet. In de provincie Zuid-Holland vindt veel
overschrijding van de streefwaarde voor chloride, kalium, ammonium en
fosfaat plaats. De concentraties voor deze stoffen zijn van nature hoog in
de provincie, net als in andere laagveengebieden en door de zee beinvloede
gebieden in Nederland. Nitraatconcentraties en concentraties van zware
metalen zijn in de hele provincie laag. De grondwaterkwaliteit in de
provincie Zuid-Holland bleek in de periode 1989 - 1996 nauwelijks te zijn
veranderd. Zowel per meetpunt als per homogeen deelgebied was het aantal
trends gering. Er zijn geen aanwijzingen gevonden voor trends in het
grondwater als gevolg van recente antropogene
beinvloeding.
Groundwater has been sampled yearly since 1989 in the province of Zuid-Holland in the Netherlands at approximately 85 locations at depths of 10 en 25 m below soil surface. The current study had the objective of: (1) describing and explaining groundwater quality in Zuid-Holland, with Dutch target values as a reference and (2) calculating trends in the groundwater quality over the 1989-1996 period. Information on hydrology, land use and soil type was used to classify the data into so-called homogenic sub-areas (hsa). The study yielded mean concentrations and 95% confidence intervals per hsa, along with estimates of areal percentages target value exceedance per hsa. These estimates are presented in maps. Trends were calculated for each individual location and per hsa. Concentrations of chloride, potassium, phosphate and ammonia exceeded target values due to marine influence and soil type. Concentrations of nitrate and heavy metals in groundwater were found to be low. No trends were detected for any of the hsa. The groundwater quality in Zuid-Holland was concluded to be mainly governed by natural processes. Anthropogenic influence is (still) relatively small.
Groundwater has been sampled yearly since 1989 in the province of Zuid-Holland in the Netherlands at approximately 85 locations at depths of 10 en 25 m below soil surface. The current study had the objective of: (1) describing and explaining groundwater quality in Zuid-Holland, with Dutch target values as a reference and (2) calculating trends in the groundwater quality over the 1989-1996 period. Information on hydrology, land use and soil type was used to classify the data into so-called homogenic sub-areas (hsa). The study yielded mean concentrations and 95% confidence intervals per hsa, along with estimates of areal percentages target value exceedance per hsa. These estimates are presented in maps. Trends were calculated for each individual location and per hsa. Concentrations of chloride, potassium, phosphate and ammonia exceeded target values due to marine influence and soil type. Concentrations of nitrate and heavy metals in groundwater were found to be low. No trends were detected for any of the hsa. The groundwater quality in Zuid-Holland was concluded to be mainly governed by natural processes. Anthropogenic influence is (still) relatively small.
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Publisher
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Provincie Zuid-Holland