Naphthalene, phenanthrene and surfactant biodegradation.

Area of Science:

• Environmental Science
• Microbiology
• Bioremediation

Background:

• Surfactants are widely used in soil and groundwater remediation.
• Polycyclic aromatic hydrocarbons (PAHs) like naphthalene and phenanthrene are common environmental pollutants.
• Understanding surfactant-PAH interactions is crucial for effective bioremediation strategies.

Purpose of the Study:

• To evaluate the impact of four different surfactants on naphthalene and phenanthrene biodegradation.
• To assess the biodegradation of surfactants in the presence of naphthalene and phenanthrene.
• To determine the optimal surfactant for bioremediation of naphthalene and phenanthrene contaminated sites.

Main Methods:

• Microcosm experiments were conducted to assess biodegradation rates.
• Four surfactants were tested: sodium dodecyl sulfate (SDS), sodium dodecyl benzene sulfonate (SDBS), POE (20) sorbitan monooleate (T-maz-80), and octylphenol poly(ethyleneoxy) ethanol (CA-620).
• Biodegradation of PAHs and surfactants was monitored over time.

Main Results:

• Naphthalene biodegradation was unaffected by SDS but inhibited by SDBS, T-maz-80, and CA-620.
• Phenanthrene biodegradation was reduced by SDS and inhibited by SDBS, T-maz-80, and CA-620.
• SDS biodegradation was inhibited by naphthalene, while SDBS and T-maz-80 showed reduced depletion rates.
• CA-620 showed low degradation in the presence of naphthalene.
• SDS and T-maz-80 showed reduced biodegradation rates in the presence of phenanthrene.

Conclusions:

• Sodium dodecyl sulfate (SDS) is the most suitable surfactant for phenanthrene-contaminated sites.
• SDS is also a good choice for naphthalene-contaminated sites, as it does not adversely affect naphthalene biodegradation and is preferentially utilized by microorganisms.
• T-maz-80 is another viable option for naphthalene-contaminated sites.