Statistical Indicators of Groundwater Geochemical Characteristics in a Quaternary Aquifer from the Mala Mlaka Well Field Catchment Area (Zagreb, Croatia)

• Main Authors: Zoran Nakić, Siniša Horvat, Andrea Bačani
• Format: Article
• Language: English
• Published: Croatian Geological Survey 2005-06-01
• Series: Geologia Croatica
• Subjects: Groundwater geochemistry; Groundwater protection; Statistical analyses; Mala Mlaka well field; Zagreb; Croatia
• Online Access: http://www.geologia-croatica.hr/ojs/index.php/GC/article/view/200
• ISSN: 1330-030X; 1333-4875

<div>High concentrations of sodium, potassium, nitrates and sulphates in</div><div>the groundwater in the Mala Mlaka well field catchment area confirm</div><div>the impact of agricultural activities on water chemistry. Analysis</div><div>of time trends has shown that a decrease in inorganic components</div><div>(nitrates and sulphates), which are sensitive to changes in oxidation/</div><div>reduction conditions in an aquifer, are caused by infiltration of oxygen-</div><div>rich water rich in organic matter into the aquifers. Oxygen content</div><div>reduction due to oxidation of the organic matter causes oxygen</div><div>deprivation in the groundwater and consequently a reduction in nitrate</div><div>and sulphate levels. An increase in chloride levels in the groundwater</div><div>during 1994&ndash;2000 is a consequence of human activities in the catchment</div><div>area. Multivariate statistical analyses, i.e. factor analysis, cluster</div><div>analysis and multidimensional scaling (MDS) analysis have shown</div><div>that the registered pollution sources in the catchment area, particularly</div><div>illegal dump sites, cause degradation of the groundwater quality in</div><div>some sites. This impact is detected over a distance of several hundred</div><div>metres downstream from the registered pollution sources.</div>