Bioremediation of Hydroca10.56201/ijaes.vol.11.no9.2025.pg67.78rbon-Polluted Mangrove Soil Using Charred Cow Bone

Abstract

This study evaluated the potential of charred cow bone as a soil amendment for bioremediation of hydrocarbon-polluted mangrove soils. The 48-week experiment was conducted using a wooden microcosm (1.43 m 2 ), subdivided into 12 cells (0.25 m), with each containing 20 kg of contaminated soil. Four treatment options were arranged in a completely randomized design. Treatments included unpolluted unamended soil (UPS), polluted unamended soil (PSS), and two amended treatments: CCB (2 kg CCB) and CCBh (6 kg CCB). Soil samples were collected at Week 0 (baseline) and 12-week intervals to evaluate physicochemical properties and polycyclic aromatic hydrocarbons (PAH). Total heterotrophic bacteria (THB) and hydrocarbon-utilizing bacteria (HUB) were enumerated and characterized using morphological and biochemical analyses. Significant increases (p<0.05) in HUB populations were observed in amended soils at Week 36, particularly in treatments CCBh (9.38×107 CFU/g) when compared to PSS (5.83×106 CFU/g) and UPS (1.90×104 CFU/g), indicating enhanced microbial activity. Dominant isolates were Bacillus cereus. The highest PAH reduction (80.43 %) was observed in CCBh while the lowest (22.37 %) occurred in PSS. The degradation efficiency trend was as follows: CCBh > CCB > PSS. Amendments also improved soil quality by enhancing pH while reducing the concentrations of total organic carbon and conductivity. This study demonstrates that charred cow bone is an effective biostimulant for enhancing microbial proliferation and activity; hence, restoring hydrocarbon-impacted mangrove soil.