Evaluation of Shallow Groundwater Chemical Quality for Raw Water Supply in Bangkalan Regency, Indonesia

Abstract

Groundwater serves as the primary source of domestic water for many rural communities in Indonesia. However, increasing anthropogenic activities and environmental changes may alter groundwater quality, making periodic chemical quality assessment essential to ensure its suitability as a raw water source. Information regarding groundwater quality in Dusun Tambak Agung, Tanah Merah Laok Village, Bangkalan Regency, remains limited. Objective: This study aimed to evaluate the chemical quality of shallow groundwater as a raw water source based on the Regulation of the Indonesian Ministry of Health No. 2 of 2023. Methodology: A quantitative descriptive approach was employed by collecting groundwater samples from seven representative household wells. The samples were analyzed in an accredited laboratory to determine pH, nitrate (NO₃⁻), nitrite (NO₂⁻), hexavalent chromium (Cr⁶⁺), iron (Kristanto et al.), and manganese (Mn). The analytical results were compared with national drinking water quality standards, followed by groundwater suitability classification using the Sturges scoring approach and spatial evaluation through Geographic Information System (GIS). Findings: The laboratory analysis revealed that all groundwater samples complied with the established quality standards for the analyzed chemical parameters. Neutral pH values and relatively low concentrations of nitrate, nitrite, chromium, iron, and manganese indicate that the investigated groundwater is chemically suitable for use as a raw water source. The findings also suggest that groundwater quality in the study area is predominantly influenced by favorable hydrogeological conditions with limited evidence of anthropogenic contamination. Implications: The findings provide scientific evidence for groundwater resource management and support local governments in implementing routine groundwater quality monitoring, groundwater protection measures, and sustainable water resource planning in rural communities. Originality: This study provides updated baseline information on groundwater chemical quality at the village scale by integrating standardized laboratory analysis, groundwater suitability assessment, and GIS-based spatial evaluation. The proposed approach contributes practical knowledge for sustainable groundwater management and environmental decision-making in rural Indonesia.