Analysis of drip water in an urban karst cave beneath the Hungarian capital (Budapest)

Urban pollution significantly alters the natural hydrochemical processes in karst caves, as demonstrated by a study of drip water in Budapest's Pál-völgyi Cave System. Researchers found that anthropogenic factors—such as de-icing agents and reduced land cover—dominate water quality at shallow, fractured sites (TG), whereas deeper, tectonically stable areas (YC) retain stronger natural periodicity linked to karst processes. Time-series analysis revealed that while pH and redox potential (Eh) showed mature diurnal cycles at both sites, electrical conductivity exhibited far less periodic behavior in polluted zones (21% vs. 56% at YC). These findings highlight the vulnerability of urban caves to human activity, offering critical insights for conservation efforts.

Fehér, K., Kovács, J., Márkus, L., Borbás, E., Tanos, P., & Hatvani, I. G. (2016). Analysis of drip water in an urban karst cave beneath the Hungarian capital (Budapest). Acta Carsologica, 45(3). https://doi.org/10.3986/ac.v45i3.3440