Effects of waste dumping on water quality, soil and plant diversity around Cyuve dump site in Musanze city, Rwanda

Abstract

The rapid urban population growth and increasing demand for resources have led to a global surge in waste generation, a trend also evident in Musanze City. At the Cyuve dumpsite, waste accumulation poses potential threats to soil quality, surface water, and plant biodiversity. This study aimed to evaluate the effects of the Cyuve waste dumpsite on the surrounding ecosystem, particularly focusing on soil and water quality and plant diversity. A quantitative research design was employed, with soil samples collected from three distances downstream (0–40 m, 40–80 m, and 80–120 m) and at three depths (0–5 cm, 5–15 cm, and 15–30 cm), whereas the control site was located at 100 meters upstream the dumpsite. Surface water samples were taken from three stream locations nearby to the dumpsite. Samples were analyzed during both wet and dry seasons, and statistical analysis was performed using RStudio version 4.3.1. Results from ANOA and LSD test (p ≤ 0.05), showed that soil closer to the dumpsite (0–40 m) had higher mean values for pH, organic matter (OM), electrical conductivity (EC), total dissolved solids (TDS), and cation exchange capacity (CEC), which decreased with distance. The study revealed that heavy metal concentrations, including lead, chromium, and cadmium, were highest in the soil samples collected closest to the Cyuve dumpsite. Lead levels ranged from 0.19 to 0.88 mg/kg during the wet season, with slightly elevated concentrations of 0.37 to 1.49 mg/kg in the dry season. Similarly, chromium levels varied between 2.62 and 5.44 mg/kg in the wet season, increasing to 3.38 to 6.13 mg/kg in the dry season. Cadmium concentrations followed the same pattern, ranging from 0.353 to 0.54 mg/kg in the wet season and rising slightly to 0.193 to 0.79 mg/kg during the dry season. Surface water analysis revealed increased bacterial contamination (Total Viable Count, Total Coliforms, Escherichia coli), and heavy metal concentrations downstream and middle stream, exceeding safe limits set by the Rwanda Standards Board and WHO. Despite these findings, plant diversity remained high across all distances, indicating a heterogeneous plant community. The study concluded that the Cyuve dumpsite is negatively influencing soil and water quality, posing potential health risks. The study highlights the urgent need for Musanze City to promote public awareness and education on waste reduction, recycling, and reusing materials. Community engagement is essential for fostering responsible waste management. Additionally, proper waste management solutions, such as engineered landfill sites, are crucial to prevent environmental degradation and protect natural resources.