Abstract

Abattoir wastewater in Nigeria is widely characterized as a high-strength effluent. However, abattoir effluents are usually discharged into surrounding land and receiving water bodies, without treatment thereby increasing the potential for environmental degradation. This study characterized the physicochemical properties and selected heavy metals in wastewater from the Swale and Tombia abattoirs in Yenagoa, Bayelsa State, to establish baseline evidence for pollution control and wastewater management. Nine samples were collected from discharge, upstream/reference, and downstream/impact locations and analysed for pH, electrical conductivity (EC), total dissolved solids (TDS), turbidity, salinity, dissolved oxygen (DO), and Fe, Zn, Pb, Cd, and Cu using standard analytical procedures and atomic absorption spectrophotometry. Significant differences between the abattoirs occurred for pH, TDS, salinity, DO, Fe, and Zn (p < 0.05), whereas EC, turbidity, Pb, Cd, and Cu showed no significant differences. Swale recorded higher pH (7.83 ± 0.10), EC (4222.00 ± 2.00 µS/cm), and Fe (19.45 ± 0.48 mg/L), while Tombia had higher TDS (2364.67 ± 66.58 mg/L), salinity (2.59 ± 0.03 ppt), and Zn (0.57 ± 0.04 mg/L). Dissolved oxygen remained low at both sites (1.14–1.22 mg/L), while Pb (0.11–0.14 mg/L) and Cd (0.04 mg/L) were detected. These findings establish a site-specific pollution baseline and demonstrate the need for systematic abattoir wastewater treatment and monitoring. Environmental regulators and abattoir operators should prioritize effluent treatment, routine surveillance, and pollution-prevention measures to protect receiving waters and public health.