How can plants manage polycyclic aromatic hydrocarbons? May these effects represent a useful tool for an effective soil remediation? A review

Bioaccumulation of HMW PAHs in the roots of wild blackberry from the Bor region (Serbia): Phytoremediation and biomonitoring aspects

“…However, it was shown in many studies that plants may evolve some very specific mechanisms for PAH degradation in terms of their transformation into less toxic metabolites. Plants can perform these actions inside their cells using mechanisms very similar to mammals (the "green liver" concept), or by excreting compounds that may change PAH molecules (Alagić et al, 2015a;Abhilash et al, 2009;Gao et al, 2013;Gąsecka et al, 2015;Reichenauer and Germida, 2008). Excretion of various compounds helps plants to accomplish not only a detoxification but also an immobilization of pollutants in soil forming their reactive radicals.…”

“…The formed radicals can be precipitated, polymerized, or covalently bound to the humic acids. At the same time, the excretion of exudates can adjust geochemical environment in the area of rhizosphere in a way that provides optimal conditions for bacterial and fungal growth, so that plants may further cooperate with their associated microbes which may result in a significant PAH degradation in the soil near plant roots (Alagić et al, 2015a;Gan et al, 2009;Gąsecka et al, 2015;Haritash and Kaushik, 2009;Reichenauer and Germida, 2008). It should be pointed here that actions performed by soil microorganisms usually degrade PAHs more effectively than any plant, because microbial decomposition of PAHs can lead to their total mineralization (Haritash and Kaushik, 2009), whereas plant management refers only to limited transformations of PAHs molecules (mostly LMW PAHs), or to PAH accumulation in the tissues (Alagić et al, 2015a).…”

“…The contribution of anthropogenic activities to their presence in the environment increased in rates that correspond to the industrial and technological civilization development (Banach-Szott et al, 2015;Wilcke, 2000). Incomplete combustion of fossil fuels (gas, oil, coal, wood) and other organic materials (waste materials, tobacco, grilled meat), that may result from the industry, traffic, residential heating and many other anthropogenic sources is recognized as the main cause of PAHs releasing into the atmosphere and other environmental compartments (Alagić et al, 2015a;Maliszewska-Kordybach and Smreczak, 2003;Tao et al, 2006). The main sink for PAHs accumulation is surface soil (Banach-Szott et al, 2015;Bandowe et al, 2010;Cvetkovic et al, 2016;Maliszewska-Kordybach, 2005).…”

“…For the sake of protecting human health, 16 PAH compounds have been included in the list of pollutants of highest priority by the United States Environmental Protection Agency (USEPA): naphthalene (Nap), acenaphthylene (Acy), acenaphthene (Ace), fluorene (Flr), phenanthrene (Phe), anthracene (Ant), fluoranthene (Flt), pyrene (Pyr), benzo[a]anthracene (BaA), chrysene (CHR), benzo [b]fluoranthene (BbF), benzo[k]fluoranthene (BkF), benzo[a]pyrene (BaP), dibenz [a,h]anthracene (DhA), benzo [g,h,i]perylene (BgP), and indeno[1,2,3-cd]pyrene (IcP). Except BgP, all HMW PAHs (BbF, BkF, BaP, DhA and IcP) are treated by US EPA as probable carcinogenic (Alagić et al, 2015a;Simon and Sobieraj, 2006;Wang et al, 2012).…”

“…Based on the complexity of molecular structure and molecular weights, PAHs are divided into: low-, medium-, and high-molecular weight PAHs (LMW, MMW and HMW PAHs) (Alagić et al, 2015a;Boström et al, 2002;Gan et al, 2009;Simon and Sobieraj, 2006). The compounds with the most complex structure, containing five or more benzene rings in their molecules, i.e.…”