Umoren, et al (2024) The Influence of BiocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More on Heavy Metals Phytoaccumulation by Okra and Fluted Pumpkin Plants in Soil Contaminated With Petroleum Hydrocarbons. Environmental Quality Management. https://doi.org/10.1002/tqem.22286

Soil contamination by petroleum hydrocarbons poses significant environmental hazards, adversely affecting soil health, plant growth, and human well-being. A recent study conducted by researchers from Nigeria aimed to assess the impact of biochar on the phytoaccumulation of heavy metals by okra and fluted pumpkin plants in petroleum hydrocarbon-polluted soil. This research was performed at an automobile workshop site using a randomized complete block design, with biochar treatments derived from maize stalks (MSB) and nipa palm (NPB).

Biochar, produced from the pyrolysisPyrolysis is a thermochemical process that converts waste biomass into bio-char, bio-oil, and pyro-gas. It offers significant advantages in waste valorization, turning low-value materials into economically valuable resources. Its versatility allows for tailored products based on operational conditions, presenting itself as a cost-effective and efficient More of organic biomassBiomass is a complex biological organic or non-organic solid product derived from living or recently living organism and available naturally. Various types of wastes such as animal manure, waste paper, sludge and many industrial wastes are also treated as biomass because like natural biomass these More, has been recognized for its potential to enhance soil quality and facilitate the breakdown of petroleum contaminants. The study found that biochar application significantly decreased the total petroleum hydrocarbon content (PHCt) and heavy metal concentrations in the soil. Notably, NPB-treated plots recorded the lowest levels of PHCt, lead (Pb), and nickel (Ni), while MSB-treated plots had the lowest levels of cadmium (Cd) and chromium (Cr). This reduction in contaminants can be attributed to biochar’s ability to enhance soil structure and promote microbial activity, which aids in the degradation of pollutants.

Phytoaccumulation, the process by which plants absorb contaminants from the soil, was evaluated using bioaccumulation factor (BAF). Fluted pumpkin exhibited higher BAF values for Cd, Cr, Pb, and Ni compared to okra, indicating its potential as an effective phytoremediator. Despite the biochar treatment, the levels of heavy metals accumulated in the plant tissues exceeded the maximum allowable levels set by the FAO/WHO, except for Ni. This finding suggests that while biochar can reduce soil contamination, the harvested plants may still pose health risks if consumed.

Ecological risk assessment using hazard quotient (HQ) revealed that Cr and Pb posed high ecological risks to the local ecosystem, even after biochar application. The HQ values for Cd and Ni, however, were below the threshold, indicating a lower risk of adverse effects. These results underscore the persistent threat of certain heavy metals in contaminated soils, despite remediation efforts.

The study highlights the potential of biochar to mitigate soil pollution and improve soil health, making it a valuable tool for environmental management. However, the continued presence of heavy metals in plant tissues calls for caution in the consumption of crops grown in contaminated areas. Further research is needed to explore the long-term effects of biochar on soil and plant health, as well as its impact on microbial communities responsible for contaminant degradation.

In conclusion, while biochar shows promise in reducing soil contamination and enhancing the phytoaccumulation of heavy metals by plants, its application must be carefully managed to ensure food safety. The findings emphasize the importance of effective prevention measures, stringent regulations, and the development of cleaner energy alternatives to mitigate the risks associated with petroleum hydrocarbon pollution.