Long-residence groundwater plays an important role in removing nitrate from karst aquifers

Nicolas Valiente Parra, who is a postdoctoral fellow at CBA, have published a study in Applied Geochemistry about pollution attenuation in evaporitic karst aquifers.

Image may contain: Soil, Vegetation, Plant community, Community, Tree.

The study was performed within the Chaotic Subbetic Complexes (Andalusia, Spain). This vast area is characterized by its hydrogeological heterogeneity, with long-residence groundwater flows, normally affected by evaporite karstification. On the surface, this region is impacted by intensive agriculture. Valiente and his collaborators analyzed stable isotopes (δ2H, δ13C, δ15N, δ18O and δ34S) and water chemistry in wetlands, wells and springs to understand the biogeochemical processes leading to pollutant attenuation (e.g. nitrate) within the complexes.

Their results show that nitrate, which was mainly derived from agricultural inputs, was removed by denitrification in transitional zones and discharge areas of the karst aquifers. For that, long-residence groundwater played an important role by transporting oxidable organic carbon, produced in recharge areas, to deeper zones of the aquifer.

These results highlight the potential of long-residence groundwater in removing pollutants. This knowledge must be taken into account in order to plan agricultural activities and protection strategies.

The paper can be read here

Nicolas Valiente Parra, first author of the paper

Published Mar. 31, 2022 10:47 AM - Last modified Mar. 31, 2022 10:47 AM