Hydrogeochemical and Microbiological Characterization of Potable Water Resources and Associated Health Risks : A Multi-Elemental Study of the Ikongo District, Madagascar

ABSTRACT This study provides a comprehensive socio-sanitary and hydrogeochemical assessment of potable water resources in the Ikongo district, specifically within the communes of Kalafotsy, Antodinga, and Ifanirea. Utilizing Total Reflection X-ray Fluorescence (TXRF) spectrometry and standardized bacteriological analyses, the research evaluates the potability of both traditional sources and modern boreholes. Findings reveal a precarious sanitary situation characterized by systemic geogenic acidity (pH 5.4–6.45) and localized nitrate peaks reaching 60 mg/L, exceeding WHO (2022) guidelines. Furthermore, critical fecal coliform contamination (>30 CFU 100 mL) was detected in unprotected sources and specific health center boreholes, identifying them as primary vectors for the high diarrheal prevalence (reaching 40%) recorded in local DHIS2 registries. The research confirms that structural barriers in deep boreholes are often compromised by technical failures, such as casing corrosion and poor sealing. To mitigate these risks, a prioritized action plan is proposed, focusing on artisanal neutralization (limestone filtration), the establishment of 30-meter protection perimeters, and the institutionalization of a Local Water Observatory. This study underscores the urgent need for integrated water resource management to harmonize technical infrastructure with communal hygiene behaviors, ensuring long-term epidemiological resilience in rural Madagascar. Keywords: Hydrogeochemistry, TXRF Spectrometry, Waterborne Diseases, Ikongo District, Potability.