Integrated Spatial Mapping and Arsenic Remediation for Improved Groundwater Quality in Larkana

Groundwater quality in Larkana, Pakistan, was comprehensively assessed using a systematic grid-based approach (n = 112), standardized American Society for Testing and Materials (ASTM)/American Public Health Association (APHA) methods, and advanced GIS techniques. Key physicochemical parameters were measured, with pH values ranging from 6.8 to 8.0 (mean 7.5), turbidity spanning 0.14 to 13.03 NTU (mean 1.4 NTU), electrical conductivity (EC) from 270 to 3593 μS/cm, and total dissolved solids (TDS) between 136 and 1780 mg/L. Arsenic concentrations varied from nondetectable to 48 ppb, with 96% of samples meeting the WHO guideline of ≤10 ppb (0.01 mg/L). A composite water quality index (WQI) indicated that most sites were "good" or "excellent," although localized deviations were noted. A novel, low-cost treatment prototypebased on the Kanchan Arsenic Filterdemonstrated arsenic removal efficiencies of 90-96%, along with reductions in turbidity by 95-99% and significant microbial decreases. GIS analyses using Inverse Distance-Weighted interpolation and Getis-Ord Gi* statistics revealed distinct arsenic hotspots, particularly in eastern Larkana, and significant negative correlations between arsenic and both EC and TDS. These integrated findings present an innovative framework for targeted remediation and sustainable water resource management in arsenic-impacted regions.