Reliability of solid phase microextraction in estimating bioavailability of pyrene in soil

Area of Science:

• Environmental Chemistry
• Soil Science
• Bioremediation

Background:

• Polycyclic aromatic hydrocarbons (PAHs) like pyrene are persistent organic pollutants found in soils.
• Understanding pyrene bioavailability is crucial for assessing soil contamination and bioremediation strategies.
• Soil properties significantly influence the fate and transport of contaminants.

Purpose of the Study:

• To estimate the bioavailability of pyrene in soils with varying textures, organic matter content, and aging periods.
• To evaluate the effectiveness of Solid Phase Microextraction (SPME) coupled with gas chromatography for assessing pyrene biodegradation.
• To compare SPME results with traditional biodegradation tests for predicting bioremediation efficacy.

Main Methods:

• Solid Phase Microextraction (SPME) coupled with gas chromatography was used to measure pyrene.
• Soil samples with different textures (sandy loam, silty loam) and organic matter content (1.3% to 7.6%) were analyzed.
• Biodegradation rates and sequestration in aged soil samples were assessed using sonication extraction.

Main Results:

• Biodegradation rates varied with soil texture, increasing from 0.10 to 0.15 µg g⁻¹ hr⁻¹.
• Increased soil organic matter (SOM) content (from 1.3% to 7.6%) decreased pyrene biodegradation by 27%.
• SPME measurements slightly overestimated pyrene degradation (R²=0.74) compared to biodegradation tests, and sequestration was observed in aged soils.

Conclusions:

• Soil organic matter content significantly impacts pyrene distribution and biodegradation.
• Sequestration of pyrene occurs in aged soil samples, affecting its bioavailability.
• SPME is not a suitable replacement for conventional biodegradation tests in predicting bioremediation effectiveness.