Nkurunziza, HermèsSous la direction de : Dr Nkurunziza Rémy Marie2026-02-112026-02-112026-01https://repository.ub.edu.bi/handle/123456789/2219Mémoire présenté et soutenu publiquement en vue de l’obtention du Diplôme de Master en Sciences, Spécialité : Enseignement de la ChimiePond aquaculture in Burundi is expanding through government initiatives and national and international projects aimed at enhancing food security and rural development. To support the planning of sustainable management strategies for fish ponds in the Imbo Plain, a water quality study was conducted on two ponds located at RUKARAMU (site 1) and MINEAGRIE (site 2). Samples were collected in July 2025 at a depth of 30–40 cm and analyzed at the laboratory of the ISABU. Thirteen physico-chemical parameters were investigated: temperature, pH, electrical conductivity, TDS, DO, nutrients (nitrates, phosphates), major ions (Ca²⁺, Mg²⁺, Na⁺, K⁺, Cl⁻, SO₄²⁻, F⁻), alkalinity, Kjeldahl nitrogen, minor elements (Fe, Mn), total hardness, and heavy metals (Pb, Cd) and transparency. The results indicate that most parameters comply with recommended standards for tropical aquaculture. Nitrate concentrations are within acceptable limits (0.1–1 mg/l), whereas phosphate levels are slightly elevated (0.05–0.07 mg/l), suggesting a potential risk of eutrophication. Dissolved oxygen is largely sufficient at site 1 (7.56–9.23 mg/l), exceeding the minimum recommended threshold of 5 mg/l, while site 2 shows poor values (2.03–2.18 mg O₂/l), with a mean difference of 6.58 mg O₂/l between the two sites, indicating significant stress associated with a high organic load. Electrical conductivity is markedly higher at site 2 than at site 1, with a mean difference of 556.33 μS/cm, although remaining within the recommended range (100–2000 μS/cm). TDS (285–312 mg/l) and total hardness (252–291 mg/l as CaCO₃) exceed recommended values for tropical fish ponds (80–200 mg/l and 50–150 mg/l, respectively). Iron (3.0–3.2 mg/l) and manganese (0.2–0.4 mg/l) are elevated at site 1, whereas they remain within acceptable limits at site 2 (Fe 0.20–0.25 mg/l; Mn 0 mg/l). Cluster analysis (dendrogram) reveals homogeneous water quality at site 1 and heterogeneous conditions at site 2, as confirmed by Stiff and Schoeller diagrams, indicating stable mineralization at site 1 and critical nitrate and sulfate concentrations at site 2. The results show that both ponds have aquaculture potential, but with distinct constraints. Site 1 is weakly mineralized and characterized by elevated iron and manganese concentrations, requiring close monitoring and corrective management measures. In contrast, Site 2 has harder, better-buffered, and chemically more stable water, making it overall more suitable for sustainable aquaculture, despite low dissolved oxygen levels that can be corrected through appropriate management practices.fr