Different biological strategies for the bioremediation of naturally polluted soils

Naeim, Amin Hossein; Baharlouei, Jila; Ataabadi, Mitra

Different biological strategies for the bioremediation of naturally polluted soils

2021

Naeim, Amin Hossein | Baharlouei, Jila | Ataabadi, Mitra

Finding an appropriate method with the highest rate of polycyclic aromatic hydrocarbon (PAH) removal from naturally polluted soils is an important research issue. A pot factorial experiment (using contaminated soil samples from the Isfahan Refinery, Iran) was conducted in a 90-day period to compare the following bioremediation strategies: (1) natural attenuation (NA): the inherent ability of soil for bioremediation; (2) bioaugmentation (BA): inoculating soil with PAH degrading microbes Marinobacter hydrocarbonoclasticus; (3) biostimulation (BS): using N, P and K nutrients for the stimulation of bioremediating soil bacteria to achieve the C:N:P ratio of 100:10:1, and(4) bioaugmentation + biostimulation (BS + BA). Treatments NA (22.8%) and BA + BS (63.9%) resulted in the least and the highest rate of PAH removal from the soil. The 2-4 ring compounds had a significantly (P ≤ 0.05) higher rate of degradation than the 5-6 ring compounds. The highest rates were resulted by fluorene (76.41%) and acenaphthylene (72.28%) using the BA + BS treatment. However, the lowest degradation rates were resulted by indeno (1,2,3-cd) pyrene (10.05%), benzo [b] fluoranthene (10.17%), benzo (g, h, i) perylene (12.53%), and benzo [k] fluoranthene (13.67%), using NA treatment. The BA + BS treatments are the most effective method for the bioremediation of PAH polluted soils.

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