Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/29702
Title: Mitigating the Toxic Effects of Cadmium and Total Petroleum Hydrocarbons Contaminated Soil through Plant-Bacterial Interactions and Organic Amendments
Authors: Areej Arif
Keywords: Environmental Sciences
Issue Date: 2023
Publisher: Quaid I Azam University Islamabad
Abstract: This dissertation describes a unique integrated phytoremediation technique called "phase crop rotation" that addresses the issue of the co-contamination of cadmium (Cd) and total petroleum hydrocarbons (TPH) in contaminated soils. This technique, which consists of two crucial phases, provides a comprehensive solution to the co-contamination problem. The first phase focuses on the simultaneous phytoextraction of cadmium and TPH degradation using two hyperaccumulator grass species, i.e., Lolium multiflorum and Coronopus didymus, compost, and plant growth-promoting rhizobacteria (PGPR). Following that, in the second phase, the residual contamination is targeted via the phytostabilization process, which is facilitated by the use of TPH degrading bacteria and biochar. The study's primary goal is to investigate the effect of compost and Bacillus safencis on the concurrent uptake of Cd and decomposition of TPH. Furthermore, the effects of compost and bacterial inoculation on plant growth and soil physicochemical parameters are thoroughly investigated. The following phase focuses on determining the impact of Bacillus cereus and biochar amendment on cadmium accumulation, TPH breakdown, and maize plant growth. According to the research findings, the treatment containing spiking soil, 10% compost, Lolium multiflorum, and Bacillus safencis displayed the maximum efficacy in removing cadmium (Cd) in the first phase (T6), obtaining a 60% removal rate. In contrast, the highest phytostabilization of Cd was reported in the second phase (T5), which used recycled soil from phase 1, 2% biochar, Zea mays, and Bacillus cereus amendment. Furthermore, with a clearance rate of 94%, this treatment demonstrated remarkable TPH degradation. In terms of plant growth, the treatments T6 in phase 1 and T5 in phase 2 performed very well, with maximum root and shoot weights of 5.5g and 1.5g for T6 and 15g and 28g for T5, respectively. Elevated quantities of chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids were also found in these treatments, indicating strong plant health and photosynthetic activity. Biochemical stress indicators revealed significantly lower levels of catalase (CAT), ascorbate peroxidase (APX), glutathione peroxidase (GPX), malondialdehyde (MDA), and hydrogen peroxidase (H2O2) in these treatments, indicating reduced oxidative stress and improved plant resilience. These findings highlight the efficacy of the "phase crop rotation" strategy in addressing co-contamination while encouraging plant development and health. Key words: Phytoremediation, Phase crop rotation, Co-contamination, Phytoextraction, Phytostabilization
URI: http://hdl.handle.net/123456789/29702
Appears in Collections:M.Phil

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