Bioremediation perspective of historically contaminated sediment with polycyclic aromatic hydrocarbons

The purpose of the current study is to compare the influence of different aerobic conditions (biostimulation (BS), bioaugmentation (BA), and a combination of biostimulation and bioaugmentation (BB)) on polycyclic aromatic hydrocarbons (PAH) degradation and compare the degraded amount with single step XAD-4 extraction as a new tool for bioavailability assessment for chronically contaminated sediment samples obtained from territory of Autonomous Province Vojvodina of Serbia (S1, S2, and S3). A great number of papers dealing with biodegradation of PAHs in spiked sediment or soil have been published, but to the authors’ knowledge, a limited number of papers studied aged, historically polluted sediment and a sum of chosen U.S. Environmental Protection Agency (USEPA) PAHs. A significant reduction (up to 67%) in PAH concentration was observed, while the percentage of reduction varied depending on the sediment sample and treatment used. BS treatment successfully stimulated growth of indigenous bacteria. Further, PAH-degrading strain Sphingomonas paucimobilis F8 inoculated in BA and BB treatment survived for up to 7 weeks after it was suppressed by unfavorable conditions or native microbes. Degraded amounts generally showed good correlation with results obtained from XAD-4 extraction. Results obtained in the current study represent a good start for standardizing a XAD-4 extraction technique as a simplified, easier, and lower cost method for bioavailability assessment.