Accurate Determination of Polycyclic Aromatic Hydrocarbons in Soil Remedied with Sodium Persulfate

Polycyclic aromatic hydrocarbons (PAHs) are a series of carcinogenic, mutagenic and teratogenic hydrocarbons with high octanol-water partition coefficients, which are easily adsorbed by soil particles and affect the environment and human health. Sodium persulfate (Na₂S₂O₈) oxidation method to remediate PAHs in organic contaminated soil is a more commonly used method in recent years both domestically and internationally. However, at the present stage, the urgent problem to be solved in measuring the content of PAHs in the remediation soil and evaluating the effect of soil remediation is that if sodium persulfate remains in the soil, the oxidation reaction of PAHs may be further accelerated due to the high extraction temperature in the sample pretreatment process.

To develop an accurate method to determine PAHs in soil after remediation.

The effects of no reductant and pre-added reductant-Soxhlet extraction on the recoveries of 16 polycyclic aromatic hydrocarbons and 6 substitutes in soil after remediation were investigated using gas chromatography-mass spectrometry (GC-MS).

The results showed that the method of pre-added reductant (Vitamin C) was better than no reductant. The PAHs recoveries of pre-added reductant and no reductant were 76.2%-110.0% and 6.0%-72.4%, respectively.

The comparative analysis showed that adding reducing agent before sample extraction could effectively eliminate the influence of residual sodium persulfate and improve the accuracy of PAHs determination results in soil after remediation. This study provides a new method for the accurate determination of PAHs in soil after remediation.