Salix rubens and Salix triandra Species as Phytoremediators of Soil Contaminated with Petroleum-Derived Hydrocarbons

Cunha, Ana Cristina Borba da; Sabedot, Sydney; Sampaio, Carlos Hoffmann; Ramos, Claudete Gindri; Silva, Alexandre Rodrigues

doi:10.1007/s11270-012-1228-z

Cited by 26 publications

(9 citation statements)

References 20 publications

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“…purpurea -microbe xenobiotic degradation systems that target C4-C16 alkanes, fluoranthene, anthracene, benzo(a)pyrene, biphenyl, and/or PCBs. This interpretation is consistent with the demonstrated rhizoremediation capabilities of willows [ 9 , 33 , 35 ], but it also expands the list of common soil contaminants that may be cleaned up with these trees.…”

Section: Discussionsupporting

confidence: 82%

Salix purpurea Stimulates the Expression of Specific Bacterial Xenobiotic Degradation Genes in a Soil Contaminated with Hydrocarbons

2015

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The objectives of this study were to uncover Salix purpurea-microbe xenobiotic degradation systems that could be harnessed in rhizoremediation, and to identify microorganisms that are likely involved in these partnerships. To do so, we tested S. purpurea‘s ability to stimulate the expression of 10 marker microbial oxygenase genes in a soil contaminated with hydrocarbons. In what appeared to be a detoxification rhizosphere effect, transcripts encoding for alkane 1-monooxygenases, cytochrome P450 monooxygenases, laccase/polyphenol oxidases, and biphenyl 2,3-dioxygenase small subunits were significantly more abundant in the vicinity of the plant's roots than in bulk soil. This gene expression induction is consistent with willows' known rhizoremediation capabilities, and suggests the existence of S. purpurea-microbe systems that target many organic contaminants of interest (i.e. C4-C16 alkanes, fluoranthene, anthracene, benzo(a)pyrene, biphenyl, polychlorinated biphenyls). An enhanced expression of the 4 genes was also observed within the bacterial orders Actinomycetales, Rhodospirillales, Burkholderiales, Alteromonadales, Solirubrobacterales, Caulobacterales, and Rhizobiales, which suggest that members of these taxa are active participants in the exposed partnerships. Although the expression of the other 6 marker genes did not appear to be stimulated by the plant at the community level, signs of additional systems that rest on their expression by members of the orders Solirubrobacterales, Sphingomonadales, Actinomycetales, and Sphingobacteriales were observed. Our study presents the first transcriptomics-based identification of microbes whose xenobiotic degradation activity in soil appears stimulated by a plant. It paints a portrait that contrasts with the current views on these consortia's composition, and opens the door for the development of laboratory test models geared towards the identification of root exudate characteristics that limit the efficiency of current willow-based rhizoremediation applications.

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Section: Discussionsupporting

confidence: 82%

Salix purpurea Stimulates the Expression of Specific Bacterial Xenobiotic Degradation Genes in a Soil Contaminated with Hydrocarbons

2015

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“…Willow is known to exert a positive influence on the remediation of soil and sediments, e.g., Vervaeke et al (2003) noted a 57% reduction of aromatic compounds and mineral oils during 1.5 yr of willow ( Salix viminalis L.) cultivation. A 98.56% reduction of soil hydrocarbons by Salix × rubens (Schrank) and 98.65% by Salix triandra (L.) within 36 mo was reported by da Cunha et al (2012). Similarly, our previous study demonstrated a 49% reduction in the PCB TEQ concentration along a 40‐km stretch of the Pilica River between Points 1 and 2, which was covered by approximately 30 ha of natural willow communities (Skłodowski et al, 2014).…”

Section: Resultssupporting

confidence: 62%

The Role of Hydrology in the Polychlorinated Dibenzo-p -dioxin and Dibenzofuran Distributions in a Lowland River

et al. 2015

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Persistent organic pollutants such as polychlorinated dibenzo--dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are environmental contaminants that have widespread distribution and pose a serious threat to aquatic ecosystems. We conducted a study to quantify the distribution, patterns, and transport of PCDDs and PCDFs along the Pilica River in central Poland under different hydrological conditions to estimate the loads of these compounds and understand their fate in aquatic systems. Water samples were collected at five sampling points along the river that represent a range of hydrological conditions including flooding and stable and low water flows. Reduced river water flow was associated with lower average total and toxic equivalent (TEQ) concentrations of PCDDs plus PCDFs: 33.6 pg L and 4.21 pg TEQ L for flooding; 28.3 pg L and 3.6 pg TEQ L for stable flow; 18.4 pg L and 1.0 pg TEQ L for low-water flow. Similar results were observed for daily loadings of total and TEQ concentrations: the highest values were observed during flooding (331.1-839.4 mg d and 27.8-110.7 mg TEQ d), medium under stable hydrological conditions (55.8-121.0 mg d and 7.7-15.3 mg TEQ d), and the lowest values during low water flow (30.9 and 40.3 mg d and 1.4-2.4 mg TEQ d). The results demonstrate that diffuse sources of pollution play a key role during periods of high water flow (i.e., flooding season), whereas point sources of pollution, including municipal and industrial wastewater treatment plant discharges, mainly determine the PCDD and PCDF concentrations seen during low water periods.

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“…6 However, not only the cost and the weight of the whole equipment are increased, but also the discharge of the oil and grease is unfriendly to the environment. 7 More importantly, lubricants might fail in some extreme conditions, such as high or low temperatures, vacuum environments, etc. 8…”

Section: Introductionmentioning

confidence: 99%

Geometric design, meshing simulation, and stress analysis of pure rolling cylindrical helical gear drives

Chen

Zeng

Fuentes-Aznar

2020

Proceedings of the Institution of Mechanical Engineers, Part C:

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The geometric design, meshing performance, and mechanical behavior of pure rolling helical gear drives are presented. Parametric equations for contact curves on the pinion and gear are determined by coordinate transformation of the active designed pure rolling meshing line for the whole cycle of meshing. Moreover, parametric equations for the tooth surfaces of helical gears with convex-to-convex meshing type are derived according to the motion of generatrices in the transverse section along the calculated contact curves. Then, the basic design parameters are analyzed and formulas for calculation of the geometric size are given. The meshing performance and mechanical behavior, including contact patterns, loaded function of transmission errors, and variation of stresses for two pitch angles of meshing are compared with those of a reference design of micro-geometry modified involute helical gears. Besides, the influence of basic design parameters on tooth contact analysis and stress analysis is studied. The analysis of the results shows that the proposed pure rolling helical gears have the advantage of reducing the relative sliding between tooth surfaces and the possibility of designing pure rolling helical gears with a small number of teeth, though the contact strength of the surfaces is impaired. However, if the appropriate design parameters and Hermite curve parameters for the fillets are properly evaluated as proposed here, the mechanical behavior of the proposed pure rolling helical gear drive, in terms of contact patterns and variation of bending stresses can be superior to that of the micro-geometry modified involute helical gear drives.

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Salix rubens and Salix triandra Species as Phytoremediators of Soil Contaminated with Petroleum-Derived Hydrocarbons

Cited by 26 publications

References 20 publications

Salix purpurea Stimulates the Expression of Specific Bacterial Xenobiotic Degradation Genes in a Soil Contaminated with Hydrocarbons

Salix purpurea Stimulates the Expression of Specific Bacterial Xenobiotic Degradation Genes in a Soil Contaminated with Hydrocarbons

The Role of Hydrology in the Polychlorinated Dibenzo-p -dioxin and Dibenzofuran Distributions in a Lowland River

Geometric design, meshing simulation, and stress analysis of pure rolling cylindrical helical gear drives

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