Toxicity Risks Associated with the Use of Untreated Pig Slurry as Organic Amendment by Farmers in the Commune of Kozah 1 (Togo)

The increasing use of untreated pig slurry as an organic amendment in Kozah 1 (Togo) raises environmental and public health concerns. A preliminary survey revealed that 80% of farmers apply raw slurry directly to crops, while 20% discharge it into the environment, from where it is often collected by market gardeners. This study assesses the fertilizing potential and toxicity risks associated with such practices. Samples were collected from ten randomly selected pig farms in Lama canton, a zone dominated by small-scale artisanal pig farming. In each pit, stratified sampling targeted the surface, middle, and bottom layers using a sterile bucket mounted on a 1.5-meter pole. Each layer (500 mL) was homogenized into a composite sample per site. Samples were kept at 4°C until physico-chemical and microbiological analyses. The slurry showed a high organic matter content (730 ± 1.1 g/kgDM) and macronutrients (N = 21 ± 0.2, P<sub>2</sub>O<sub>5</sub> = 25 ± 0.2, K<sub>2</sub>O = 38 ± 0.4 g/kgDM), but a low C/N ratio (5.2), indicating instability. Pathogens (E. coli, Salmonella) and elevated nitrate and phosphate levels were also detected, suggesting health and water pollution risks. The findings underscore the need for pretreatment methods such as co-composting to reduce pathogenic loads and stabilize nutrients for safer agricultural use.