Toxicity test of the active bacteria formula (ABF) treated soil-sludge mixture and untreated crude oil sludge on sweet bell pepper plant (<em>Capsicum Annuum</em>)

The study aimed to evaluate the environmental safety and potential risks of using sweet bell pepper (Capsicum Annuum) for phytoremediation of PAHs and crude oil waste sludge. Sweet bell pepper, an edible perennial tropical crop, was selected due to its rapid structural changes, making it an effective bioindicator for toxicity tests. The plant's growth characteristics, such as shoot length, leaf area, and biomass production, were key indicators of contaminant toxicity. These changes were attributed to the toxic effects of environmental contaminants like PAH accumulation. Greenhouse studies were conducted to assess the plant's response to treated soil-oil sludge mixtures (SSM) formulated with an active bacterial formula (ABF) compared to untreated crude oil waste sludge on the amended plants. Over 90 days, plant growth responses were monitored to determine the feasibility of environmentally safe disposal. The treated SSM mixtures showed potential for safer application than untreated crude oil waste sludge alone, with chlorosis of leaves, necrosis fruits, and scorched and withering observed. The sweet bell pepper plant demonstrated its phytoextraction ability, with roots serving as the primary site for PAH accumulation. Descriptive statistics revealed high variability in initial PAH concentrations, with significant reductions post-treatment. The study provided a comprehensive understanding of PAH concentrations and their distribution across different plant compartments. The results indicated successful uptake mechanisms, with roots acting as the primary accumulation site and minimal translocation to stems and leaves. Key findings included the significant decrease in PAH concentrations over time, validating the effectiveness of the phytoremediation process. The study emphasized the importance of combining phytoremediation with complementary strategies such as composting, bioaugmentation, and soil amendments to enhance PAH removal efficiency. The practical implications highlighted the need for careful monitoring to prevent contaminant bioaccumulation and ensure food safety. The study provided compelling evidence that phytoremediation, particularly rhizoremediation facilitated by ABFs, is a viable approach for reducing PAH contamination in crude oil waste sludge. Future research should focus on optimizing bacterial formulations, assessing microbial dynamics in the rhizosphere, and evaluating the long-term effects of treated soils on agricultural productivity.