Rhizosphere Gradients of Polycyclic Aromatic Hydrocarbon (PAH) Dissipation in Two Industrial Soils and the Impact of Arbuscular Mycorrhiza

Environmental Pollution

et al. 2008

Combined colonization of alfalfa roots by an arbuscular mycorrhizal fungus and addition of non-ionic surfactant to the soil promoted root and shoot uptake and soil dissipation of DDT. AbstractA greenhouse pot experiment was conducted to investigate the colonization of alfalfa roots by the arbuscular mycorrhizal (AM) fungus Glomus etunicatum and application of the non-ionic surfactant Triton X-100 on DDT uptake by alfalfa and depletion in soil. Mycorrhizal colonization led to an increase in the accumulation of DDT in roots but a decrease in shoots. The combination of AM inoculation and Triton X-100 application enhanced DDT uptake by both the roots and shoots. Application of Triton X-100 gave much lower residual concentrations of DDT in the bulk soil than in the rhizosphere soil or in the bulk soil without Triton X-100. AM colonization significantly increased bacterial and fungal counts and dehydrogenase activity in the rhizosphere soil. The combined AM inoculation of plants and soil application of surfactant may have potential as a biotechnological approach for the decontamination of soil polluted with DDT.

Section: Discussionmentioning

confidence: 71%

Section: Introductionmentioning

confidence: 99%

DDT uptake by arbuscular mycorrhizal alfalfa and depletion in soil as influenced by soil application of a non-ionic surfactant

Environmental Pollution

et al. 2008

“…Despite the potential role of AM in the phytoremediation of soils with organic contaminants, very few studies have been carried out on interactions between AM and organic pollutants such as PAHs in soil and variable results have been obtained. Positive effects of AM on the dissipation of PAHs in soils have been observed by Joner et al (Joner and Leyval, 2003;Joner et al, 2001). In contrast, no impact of AM fungi on PAH dissipation was observed by Binet et al (2000) and a depression in PAH dissipation was observed in the presence of ectomycorrhizas (Joner et al, 2006;Genney et al, 2004).…”

Section: Introductionmentioning

confidence: 79%

“…Arbuscular mycorrhiza (AM) is a ubiquitous association between soil fungi and the roots of most herbaceous plant species that permits the host plant to exploit nutrients in the soil beyond the rhizosphere through fungal transport (Joner and Leyval, 2003). Mycorrhizal colonization can result in quantitative and qualitative changes in root exudation and in the soil microbial community, particularly in the rhizosphere.…”

Section: Introductionmentioning

confidence: 99%

Enhanced dissipation of phenanthrene in spiked soil by arbuscular mycorrhizal alfalfa combined with a non-ionic surfactant amendment

Science of The Total Environment

et al. 2008

IntroductionPolycyclic aromatic hydrocarbons (PAHs) are widely distributed hydrophobic organic contaminants (HOCs) and accumulate in soil that has been contaminated with crude oil, creosote, or coal tar. PAHs are also generated and dispersed into the environment by fossil fuel combustion, wood treatment processes, automobile exhausts, and waste incineration (Wilson and Jones, 1993). Because of their widespread distribution and their toxicity and mutagenicity, PAHs are listed as priority pollutants, and remediation of soils contaminated with PAHs is of great importance. Phytoremediation is a promising alternative approach to soil remediation due to its convenience, cost-effectiveness and environmental acceptability. The HOCs in soil usually exhibit low bioavailability to both microorganisms and plants due to their strong affinity to the soil matrix, especially to soil organic matter (Chen et al., 2005), which limits the application of phytoremediation. Solubilization agents such as the surfactant Triton X-100 have been added to soil to enhance the release of HOCs from the sorbed phase and, thereby, to increase their aqueous concentrations and bioavailability (Zhou and Zhu, 2005). Although addition of surfactants has been explored in the cleanup of contaminated soils (Zhu et al., 2003), there are few reports of their application in phytoremediation.Arbuscular mycorrhiza (AM) is a ubiquitous association between soil fungi and the roots of most herbaceous plant

“…The fact that only the metabolites DEA and DIA were detected in the plant roots could contribute to the important role of the plant-derived enzymes in roots in degradation and then the metabolites assimilated into the plant tissue (Boyajian and Carriera, 1997). AM fungi were reported to obligate symbionts with little or no capacity for degradation of organics (Joner and Leyval, 2003b). Therefore, the increasing enzyme activity and microorganism stimulated by colonization was the possible reason for the enhanced metabolism in mycorrhizal colonized roots.…”

Section: Discussionmentioning

confidence: 99%

Effect of arbuscular mycorrhizal fungus (Glomus caledonium) on the accumulation and metabolism of atrazine in maize (Zea mays L.) and atrazine dissipation in soil

Environmental Pollution

Shan

et al. 2007

Arbuscular mycorrhizal fungus increases the accumulation and metabolism of atrazine in maize. AbstractEffects of an arbuscular mycorrhizal (AM) fungus (Glomus caledonium) on accumulation and metabolism of atrazine in maize grown in soil contaminated with different concentrations of atrazine were investigated in a series of pot experiments. Roots of mycorrhizal plants accumulated more atrazine than non-mycorrhizal roots. In contrast, atrazine accumulation in shoot decreased in mycorrhizal compared with nonmycorrhizal plants. No atrazine derivatives were detected in the soil, either with or without mycorrhizal colonization. However, atrazine metabolites, deethylatrazine (DEA) and deisopropylatrazine (DIA), were detected in plant roots and the AM colonization enhanced the metabolism. After plant harvest atrazine concentrations decreased markedly in the soils compared to the initial concentrations. The decreases were the most in rhizosphere soil and then near-rhizosphere soil and the least in bulk soil. Mycorrhizal treatment enhanced atrazine dissipation in the nearrhizosphere and bulk soils irrespective of atrazine application rates.