Sequestration Specificity of Single or Co-existing Benzene, 1,3,5-Trimethylbenzene, and Naphthalene in Soil

Abstract

The sequestration (aging) of petroleum hydrocarbons in soil can have a significant effect on the remediation of contaminated sites, but organic chemicals and how they co-exist can result in different sequestration abilities. In this study, sorption, methanol extraction, and sequestration of single and co-existing benzene, 1,3,5-trimethylbenzene, and naphthalene in soil were investigated to evaluate their sequestration ability in soil and the influence of co-existing organic chemicals. A higher linear adsorption coefficient based on the linear sorption equation (k e) was observed for naphthalene (11.5-25.0) compared with benzene (3.8-3.9) and 1,3,5-trimethylbenzene (2.8-5.6), followed by a lower linear methanol extraction coefficient based on the methanol extraction equation (k m = 0.3) and a higher linear sequestration coefficient based on the linear sequestration equation (k s = 0.7). The coexistence of benzene, 1,3,5-trimethylbenzene, and naphthalene increased the sorption ability of 1,3,5-trimethylbenzene (k e increased from 2.8 in the single system to 5.6 in the mixed system) and naphthalene (k e increased from 11.5 in the single system to 25.0 in the mixed system) due to their larger molecular size and higher molecular polarity; however, this was not observed for benzene (k e ranged from 3.8 to 3.9 in the single and mixed systems). In summary, the coexistence of benzene, 1,3,5trimethylbenzene, and naphthalene does not affect methanol extraction and sequestration ability.

Inoculation of Triticum Aestivum L. (Poaceae) with Plant-Growth-Promoting Fungi Alleviates Plant Oxidative Stress and Enhances Phenanthrene Dissipation in Soil

“…According to Conejo-Saucedo et al [3], PAHs can be present in the environment in carboncontaining organic materials such as charcoal; can be released by incomplete combustion of fossil fuels, forest fires, or volcanic eruptions; and can be synthetized during degradation of organic matter. In the soil, these compounds are mainly present after atmospheric deposition or wastewater irrigation, affecting microbial communities and plant diversity [4,5]. Soil microorganisms and plants have contributed to PAH dissipation, but also have caused a bioaccumulation of PAHs in plant tissues, leading to food chain contamination [6][7][8].…”