Environmental impacts of industrial abattoir waste discharge on the quality of water in Douala and Yaounde, Cameroon

Industrial abattoirs discharge wastewater rich in organic and inorganic pollutants, posing serious threats to water quality and public health if not properly managed. This study assessed the spatiotemporal impact of wastewater from two major abattoirs; Bonandale in Douala and Etudi in Yaounde on nearby water bodies during both rainy and dry seasons. Water samples were collected before (PBA), within (PWA), and after (PAA) the abattoirs and analyzed for key parameters including pH, temperature, electrical conductivity (EC), salinity, nitrates, phosphates, and total coliforms. Statistical analyses (ANOVA and t-tests) were used to evaluate variations, and results were compared against WHO standards. Findings revealed that water at PWA consistently exhibited the highest levels of pollution. Coliform counts exceeded WHO’s 0 CFU/100mL limit, reaching 7,560 CFU/100mL in Douala and 6,188 CFU/100mL in Yaounde during the dry season. EC levels also surpassed the WHO limit (500 µS/cm), peaking at 1,062 µS/cm and 639 µS/cm respectively. Elevated nitrate and phosphate concentrations indicated high organic loads, especially during the dry season. Even downstream at PAA, pollution levels remained high. The study concludes that abattoir effluents significantly degrade water quality and recommends urgent wastewater treatment interventions and stronger regulatory enforcement to protect public health and aquatic ecosystems.