Nitrate contamination of groundwater was assessed in the crowded area of Ambohidrapeto, Antananarivo city-Madagascar using hydrochemistry and multivariate analysis. Seventeen dug well waters and three spring waters were collected and measured in the field for physical parameters and in the laboratory for major ions. The results showed that all water samples have nitrate concentration above the standard value of 50 mg/L-NO₃ set by the World Health Organization, with a minimum value of 79.3 mg/L-NO₃ and a maximum value of 394.5 mg/L-NO₃. Anthropogenic activities, from the surrounding pit latrines are the main sources of the groundwater nitrate contamination and are dominant over natural processes, which contribute to a lower degree to the groundwater mineralization. Ionic ratios indicated the occurrence of mineral dissolution and silicate weathering as the natural sources of magnesium and sodium, respectively. Furthermore, the correlation between calcium and sodium as well as the Piper diagram revealed the occurrence of ion exchange, resulting in sodium being the dominant cation over calcium. Forty percent (40%) of the water samples have the hydrochemical facies Na–Mg–Cl, followed by Na–Mg–Ca–Cl facies for 25% and Na–Mg–Cl–HCO₃ facies for 20%. By applying principal component analysis, the influence of anthropogenic activities is confirmed. The first principal component extracted, which explained 52.88% of the total variance showed strong positive loadings on TDS, NO₃⁻, Cl⁻, Mg²⁺, Na⁺, K⁺ and Ca²⁺, indicating that these ions contribute as anthropogenic sources, although Mg²⁺, Na⁺, K⁺ and Ca²⁺ contribute to a lesser extent than NO₃⁻, and Cl⁻.

中文翻译：

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应用水化学和多变量分析法分析安布希德拉佩托-塔那那利佛-马达加斯加的地下水中硝酸盐的污染

使用水化学和多变量分析方法，在塔那那利佛市-马达加斯加的安布希德拉佩托拥挤地区评估了地下水的硝酸盐污染。收集了十七个挖井水和三个泉水，并在现场测量了物理参数，并在实验室中测量了主要离子。结果表明，所有水样品中的硝酸盐浓度均高于世界卫生组织设定的标准值50 mg / L-NO ₃，最小值为79.3 mg / L-NO ₃，最大值为394.5 mg / L -NO ₃。来自周围坑厕的人为活动是地下水硝酸盐污染的主要来源，并且在自然过程中占主导地位，自然过程对地下水矿化的影响较小。离子比表明矿物溶解和硅酸盐风化分别是镁和钠的天然来源。此外，钙和钠之间的相关性以及Piper图揭示了离子交换的发生，导致钠是钙的主要阳离子。40％（40％）的水样品的水化学相为Na–Mg–Cl，其次为Na–Mg–Ca–Cl相，其中25％和Na–Mg–Cl–HCO ₃相占20％。通过应用主成分分析，可以确定人为活动的影响。提取的第一主成分，这解释了总方差的52.88％，表现出强阳性负载上TDS，NO ₃ ^- ，氯^- ，镁²⁺，钠⁺，K ⁺和Ca ²⁺，这表明这些离子作为人为来源贡献虽然镁²⁺，钠⁺，K ⁺和Ca ²⁺有助于比NO程度较轻₃ ^-和Cl ^- 。