Identification of groundwater conditions in the recharge zone of regionally extended aquifer system with use of water chemistry and isotopes (Lwowek region, Poland)

Abstract

Study region: The studied recharge zone of regionally extended Quaternary aquifers - Lwówek region (Wielkpolska, Poland) is located in a region where Quaternary aquifers are the principal source of drinking water. A visible water quality deterioration trend was observed, manifested mainly by increase of nitrate concentration. Study focus: The main objective of the presented study is to examine groundwater flow patterns and vertical difference of groundwater chemistry using a multicomponent chemical tracers approach and groundwater isotopic compositions (stable isotopes, tritium and radiocarbon). New hydrological insights for the region: This study documented the influence of water extraction on groundwater contamination. The contamination plume that moves to the deepest parts of the aquifer in the region, where water extraction is performed, was documented. As a consequence, in deep parts of the aquifer, nitrates appear, and the groundwater chemistry is very similar to that observed in the shallow part. Meanwhile, in regions where natural gradients exist (without water extraction) the contamination in the shallow part is also evident, but recently infiltrating water does not reach the deeper parts of the aquifer. A stagnation point exists in the deep part of the aquifer, with completely different groundwater chemistry in the deep and shallow parts of the aquifer. This work shown how groundwater chemistry can help to investigate groundwater flow systems.

Keywords

• Groundwater flow pattern
• Groundwater chemistry
• Regional aquifer system
• Groundwater contamination by nitrate
• Stagnation point