Assessment of Pseudomonas aeruginosa Presence in Metal-Rust-Associated Soil from Scrap Dump Sites in Damba, Gusau, Zamfara State

Abstract

Metal corrosion, commonly referred to as rusting, poses significant public health risks by contaminating soil and drinking water systems, particularly along metallic pipelines. Previous studies have identified Pseudomonas aeruginosa as a major contributor to metal deterioration. This study aimed to detect and characterize P. aeruginosa in soil samples collected from a scrap metal dump site in Damba, Gusau, Nigeria. A comprehensive analysis was conducted to evaluate microbial diversity, heavy metal concentrations, and physicochemical parameters such as soil pH and temperature. Bacterial colony enumeration was performed using MacConkey agar, followed by Gram staining, biochemical testing, and molecular characterization for the identification of Pseudomonas species. Heavy metal concentrations were determined using Atomic Absorption Spectrophotometry (AAS). The colony-forming units ranged from 8.3 × 10⁷ to 1.78 × 10⁴ CFU/g. A total of 25 Pseudomonas spp. were identified biochemically, of which 5 isolates were further confirmed as P. aeruginosa through molecular techniques. Zinc, cadmium, copper, lead, and chromium were detected in all soil samples, with zinc showing the highest concentration (0.34 ± 0.04 mg/kg) and cadmium the lowest (0.01 ± 0.001 mg/kg). The results indicate that P. aeruginosa plays a significant role in metal corrosion processes. Although heavy metal levels were within acceptable limits of United State Environmental Protection Agency (USEPA), continuous monitoring and implementation of bioremediation strategies using metal-resistant bacteria are recommended to mitigate environmental and public health risks associated with scrap metal dump sites.