Biochar accelerates PAHs biodegradation in petroleum-polluted soil by biostimulation strategy

Area of Science:

• Environmental Science
• Soil Science
• Microbiology

Background:

• Petroleum-polluted soils pose environmental risks due to persistent polycyclic aromatic hydrocarbons (PAHs).
• Biochar, a carbon-rich material derived from biomass pyrolysis, is explored for its potential in soil remediation.
• Understanding the interaction between biochar properties, microbial communities, and PAH degradation is crucial for effective soil management.

Purpose of the Study:

• To evaluate the effectiveness of sawdust and wheat straw biochars, prepared at different temperatures, in removing PAHs from contaminated soil.
• To investigate the influence of biochar amendment on soil microbial diversity and the abundance of PAH-degrading bacteria.
• To determine the impact of biochar preparation temperature and feedstock on PAH removal efficiency.

Main Methods:

• Incubation of petroleum-polluted soil with biochars (300°C and 500°C) for 84 days.
• Analysis of polycyclic aromatic hydrocarbons (PAHs) content using gas chromatography-mass spectrometry (GC-MS).
• Assessment of bacterial community structure and diversity using PCR-DGGE and sequencing analysis.

Main Results:

• Biochar application alone significantly reduced PAHs content in the soil.
• Biochar prepared at 500°C demonstrated higher PAH removal efficiency compared to biochar prepared at 300°C.
• Biochar amendment promoted the abundance of specific PAH-degrading bacteria, enhancing biodegradation.
• High-molecular weight PAHs were more resistant to microbial degradation than low-molecular weight PAHs.

Conclusions:

• Biochar amendment is a promising strategy for accelerating the biodegradation of PAHs in contaminated soils.
• Biochar properties, particularly preparation temperature, significantly influence its effectiveness in PAH removal.
• Biochar enhances soil microbial communities, creating a favorable environment for PAH degradation.