Slaughterhouses generate large volumes of wastewater that is rich in organic matter, nutrients, heavy metals, and microbial contaminants. In Rabat, as in many other cities, managing slaughterhouse wastewater is a significant environmental challenge. Direct discharge of untreated wastewater can contaminate soil, surface water, and groundwater, thereby threatening environmental quality and public health. This study evaluated soil quality by examining the accumulation and bioaccumulation of heavy metals, including chromium (Cr), lead (Pb), copper (Cu), zinc (Zn), cadmium (Cd), and iron (Fe), and their transfer from soil to bean plants (Vicia faba). Metal concentrations were determined in agricultural soils and different plant organs (roots, stems, and leaves) exposed to irrigation with untreated wastewater. The results showed that heavy metals mainly accumulated in the soil and roots, with lower concentrations detected in stems and leaves. Elevated concentrations of Pb and Zn were observed in the roots, indicating limited translocation of these metals to the plant's aerial parts. Additionally, soils irrigated with untreated wastewater exhibited higher metal concentrations, contributing to increased metal uptake by V. faba. These findings demonstrate that using untreated slaughterhouse wastewater for irrigation promotes the accumulation of heavy metals in soil and their transfer to crops. This highlights the importance of implementing effective wastewater treatment and regular monitoring programmes to prevent the contamination of agricultural products by heavy metals and to protect environmental and food safety.
