Willows Used for Phytoremediation Increased Organic Contaminant Concentrations in Soil Surface
The <i>Salix</i> genus includes shrub species that are widely used in phytoremediation and various other phytotechnologies due to their advantageous characteristics, such as a high evapotranspiration (ET) rate, in particular when cultivated in short rotation intensive culture (SRIC). Obs...
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MDPI AG
2021-03-01
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| Series: | Applied Sciences |
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| Online Access: | https://www.mdpi.com/2076-3417/11/7/2979 |
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| author | Maxime Fortin Faubert Dominic Desjardins Mohamed Hijri Michel Labrecque |
| author_facet | Maxime Fortin Faubert Dominic Desjardins Mohamed Hijri Michel Labrecque |
| author_sort | Maxime Fortin Faubert |
| collection | DOAJ |
| description | The <i>Salix</i> genus includes shrub species that are widely used in phytoremediation and various other phytotechnologies due to their advantageous characteristics, such as a high evapotranspiration (ET) rate, in particular when cultivated in short rotation intensive culture (SRIC). Observations made in past field studies suggest that ET and its impact on soil hydrology can also lead to increases in soil pollutant concentrations near shrubs. To investigate this, sections of a mature willow plantation (seven years old) were cut to eliminate transpiration (Cut treatment). Soil concentrations of polychlorinated biphenyls (PCBs), aliphatic compounds C10–C50, polycyclic aromatic hydrocarbons (PAHs) and five trace elements (Cd, Cr, Cu, Ni and Zn) were compared between the Cut and the uncut plots (<i>Salix miyabeana</i> ‘SX61’). Over 24 months, the results clearly show that removal of the willow shrubs limited the contaminants’ increase in the soil surface, as observed for C10–C50 and of 10 PAHs under the Salix treatment. This finding strongly reinforces a hypothesis that SRIC of willows may facilitate the migration of contaminants towards their roots, thus increasing their concentration in the surrounding soil. Such a “pumping effect” in a high-density willow crop is a prominent characteristic specific to field studies that can lead to counterintuitive results. Although apparent increases of contaminant concentrations contradict the purification benefits usually pursued in phytoremediation, the possibility of active phytoextraction and rhizodegradation is not excluded. Moreover, increases of pollutant concentrations under shrubs following migration suggest that decreases would consequently occur at the source points. Some reflections on interpreting field work results are provided. |
| first_indexed | 2024-03-10T12:51:52Z |
| format | Article |
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| issn | 2076-3417 |
| language | English |
| last_indexed | 2024-03-10T12:51:52Z |
| publishDate | 2021-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Applied Sciences |
| spelling | doaj.art-03cbd72c423d44209f35c357be6817c02023-11-21T12:10:10ZengMDPI AGApplied Sciences2076-34172021-03-01117297910.3390/app11072979Willows Used for Phytoremediation Increased Organic Contaminant Concentrations in Soil SurfaceMaxime Fortin Faubert0Dominic Desjardins1Mohamed Hijri2Michel Labrecque3Institut de Recherche en biologie végétale, Université de Montréal and Jardin Botanique de Montréal, 4101 Sherbrooke East, Montréal, QC H1X 2B2, CanadaPhyto Action, 2170 Rue de Paris, Montréal, QC H3K 1V1, CanadaInstitut de Recherche en biologie végétale, Université de Montréal and Jardin Botanique de Montréal, 4101 Sherbrooke East, Montréal, QC H1X 2B2, CanadaInstitut de Recherche en biologie végétale, Université de Montréal and Jardin Botanique de Montréal, 4101 Sherbrooke East, Montréal, QC H1X 2B2, CanadaThe <i>Salix</i> genus includes shrub species that are widely used in phytoremediation and various other phytotechnologies due to their advantageous characteristics, such as a high evapotranspiration (ET) rate, in particular when cultivated in short rotation intensive culture (SRIC). Observations made in past field studies suggest that ET and its impact on soil hydrology can also lead to increases in soil pollutant concentrations near shrubs. To investigate this, sections of a mature willow plantation (seven years old) were cut to eliminate transpiration (Cut treatment). Soil concentrations of polychlorinated biphenyls (PCBs), aliphatic compounds C10–C50, polycyclic aromatic hydrocarbons (PAHs) and five trace elements (Cd, Cr, Cu, Ni and Zn) were compared between the Cut and the uncut plots (<i>Salix miyabeana</i> ‘SX61’). Over 24 months, the results clearly show that removal of the willow shrubs limited the contaminants’ increase in the soil surface, as observed for C10–C50 and of 10 PAHs under the Salix treatment. This finding strongly reinforces a hypothesis that SRIC of willows may facilitate the migration of contaminants towards their roots, thus increasing their concentration in the surrounding soil. Such a “pumping effect” in a high-density willow crop is a prominent characteristic specific to field studies that can lead to counterintuitive results. Although apparent increases of contaminant concentrations contradict the purification benefits usually pursued in phytoremediation, the possibility of active phytoextraction and rhizodegradation is not excluded. Moreover, increases of pollutant concentrations under shrubs following migration suggest that decreases would consequently occur at the source points. Some reflections on interpreting field work results are provided.https://www.mdpi.com/2076-3417/11/7/2979phytoremediationpolycyclic aromatic hydrocarbons (PAHs)polychlorinated biphenyls (PCBs)trace elements (TEs)petroleum hydrocarbons (PHCs)<i>Salix</i> |
| spellingShingle | Maxime Fortin Faubert Dominic Desjardins Mohamed Hijri Michel Labrecque Willows Used for Phytoremediation Increased Organic Contaminant Concentrations in Soil Surface Applied Sciences phytoremediation polycyclic aromatic hydrocarbons (PAHs) polychlorinated biphenyls (PCBs) trace elements (TEs) petroleum hydrocarbons (PHCs) <i>Salix</i> |
| title | Willows Used for Phytoremediation Increased Organic Contaminant Concentrations in Soil Surface |
| title_full | Willows Used for Phytoremediation Increased Organic Contaminant Concentrations in Soil Surface |
| title_fullStr | Willows Used for Phytoremediation Increased Organic Contaminant Concentrations in Soil Surface |
| title_full_unstemmed | Willows Used for Phytoremediation Increased Organic Contaminant Concentrations in Soil Surface |
| title_short | Willows Used for Phytoremediation Increased Organic Contaminant Concentrations in Soil Surface |
| title_sort | willows used for phytoremediation increased organic contaminant concentrations in soil surface |
| topic | phytoremediation polycyclic aromatic hydrocarbons (PAHs) polychlorinated biphenyls (PCBs) trace elements (TEs) petroleum hydrocarbons (PHCs) <i>Salix</i> |
| url | https://www.mdpi.com/2076-3417/11/7/2979 |
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