Application of the Water Quality Index (WQI) model for groundwater quality estimation on urban mixed area
Year: 2026
Type: article
Abstract: In recent decades, groundwater has been affected by the growth of urban areas, which causes serious environmental problems such as its enrichment with nitrates and many elements and deteriorates its quality. In the present study, an attempt was made to assess the groundwater quality of a mixed urbanized area by using the Water Quality Index (WQI), by weighted arithmetic mean index method. The monitoring was conducted in the period of 2022, on the watershed of the village of Lozen (near the city of Sofia). Mixed urban areas, where intensive vegetable crops were grown are included in the scheme of the study. The physico-chemical indicators such as (pH, electrical conductivity - EC, total dissolved solids - TDS, total hardness - TH) were studied on the underground waters and their cation-anion composition was determined. It was found that groundwaters were characterized by alkaline reaction and higher content of chemical elements some of which exceed the Maximum Permissible Concentration Level (MPCL) for drinking water. The groundwater was observed to have a calcium-hydrocarbonate-sulfate composition. According to the results of the WQI model, the groundwater quality status could be classified into following categories: excellent and good quality (33% of the investigated wells), poor (42% of the domestic wells), while the remaining samples very poor quality and unsuitable. It was established that the water sources with degraded quality are located mainly in a mixed urban area, where the accumulated amounts of residual nitrogen in the soil will continue to play the role of a point source of nitrates in groundwater due to soil and hydrological characteristics and intensive vegetable grown. The dynamics of the processes causing enrichment of groundwater with various elements and their redistribution in space require periodic monitoring of their chemical composition with a view to updating the information on their condition.
DOI: 10.61308/y67gft27
Authors: Tsetska Simeonova, Lyuba Nenova
Subfield: Water Science and Technology
Field: Environmental Science
Domain: Physical Sciences
Open Access status: hybrid
OpenAlex ID: W7204581618