Rhizosphere Influence and Seasonal Impact on Phytostabilisation of Metals—A Field Study

Abstract

Field experiments were conducted to assess the influence of plant growth and amendment addition on phytostabilisation of copper (Cu), lead (Pb), manganese (Mn) and zinc (Zn) along highway soil in southwest British Columbia, Canada. The plant species tested were Lolium perenne L (perennial rye grass), Festuca rubra L. (creeping red fescue) and Poa pratensis L. (Kentucky blue grass) and the amendments, lime and phosphate. The treatment efficiencies were assessed during different seasons as a completely randomized factorial experiment in split plot design. The research tasks involved: (1) quantifying the seasonal extent of metal accumulation in soil and assessing the seasonal impact on metal speciation for different soil amendments and plant species; (2) determining seasonal accumulation differences between sampling periods in plant parts; and (3) assessing the influence of root-soil interactions on metal dynamics. The amendments decreased the exchangeable fraction and plant uptake of all four metals. The lowest mobile fractions (exchangeable and carbonate bound) were found in soils growing Festuca for Cu, Lolium for Mn and a Lolium/Poa/ Festuca combination for Pb and Zn. Metal accumulation and metal dynamics in the rhizosphere soil are compared with those of the bulk soil. The final outcome was the development of a remediation strategy for all four metals involving suitable plants and amendments and incorporating seasonal and rhizosphere influences.

Heavy Metals Behavior in Soil/Plant System after Sewage Sludge Application

“…Presented research showed both positive and negative significant correlations for the BCF and TF with the tested soil characteristics depending on the location and year of the study, which may indicate a complex and ambiguous influence of the application of sludge to urban soils. The obtained results were different depending on the year of the experiment, which confirmed the observations of Padmavathiamma and Li [46], indicating that the uptake of metals by plants shows seasonal changes.…”

“…In our study, the pH of the soil on which the experiment was carried was alkaline; therefore, adding organic matter in the form of sludge could cause immobilization of HMs in the root system. Additionally, plants from the Poaceae and Fabaceae families (species, e.g., Lollium perenne, Festuca rubra, Poa pratensis, and Agrostis capillaris) have the ability to bound HMs in the root system [45,46]. In the current study, the experiments were set up with the use of lawn grass mixtures containing Lollium perenne, Festuca rubra, and Poa pratensis, which were characterized by a suitable potential for HMs phytostabilization.…”

Tanacetum vulgare as a Bioindicator of Trace-Metal Contamination: A Study of a Naturally Colonized Open-Pit Lignite Mine

“…However, although having BFs > 1, Co, Cr, Ni, and Pb were accumulated by T. vulgare in concentrations greater than typical for terrestrial plants from clean areas (Kabata-Pendias 2001). Padmavathiamma and Li (2012) had much lower TFs: Cu = 0.41–0.43, Mn = 0.78–0.92, Pb = 0.19–0.25, and Zn 0.69 = 0.78 for L. perenne , Festuca rubra , and Poa pratensis growing along highways in Canada. Significantly greater accumulation of Cr and Fe occurred in roots than in leaves, suggesting limited mobility and translocation of these metals once absorbed by T. vulgare .…”

Phytoremediation: A Promising Approach for Revegetation of Heavy Metal-Polluted Land

“…Root exudates acidify the rhizosphere by lowering soil pH, which promotes the desorption of heavy metals from insoluble complexes to form free ion, thus increasing the concentration of heavy metals in the soil (Thangavel and Subbhuraam, 2004). Plants can also secrete metal-mobilizing compounds in the rhizosphere, such as phytosiderophores, carboxylates, and organic acids, which affect physicochemical properties of the soil and facilitate heavy metal chelation, thereby increasing solubility, mobility, and bioavailability of heavy metals in the soil (Lone et al, 2008;Gerhardt et al, 2009;Robinson et al, 2009;Padmavathiamma and Li, 2012).…”