Forest floor leachate fluxes under six different tree species on a metal contaminated site

• Published in: The Science of the total environment Vol. 447; pp. 99 - 107
• Main Authors: Van Nevel, Lotte, Mertens, Jan, De Schrijver, An, Baeten, Lander, De Neve, Stefaan, Tack, Filip M.G., Meers, Erik, Verheyen, Kris
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 01.03.2013; Elsevier
• Subjects: Animals; Applied sciences; Base cations; Belgium; Betula - physiology; Betula pendula; Cadmium; Cadmium - metabolism; Carbon - metabolism; Cations; Decontamination. Miscellaneous; DOC; Exact sciences and technology; Fluxes; Forest floor leachate; Forests; Oak; Oligochaeta - metabolism; Phytostabilization; Pine; Pinus - physiology; Pinus sylvestris; Pinus sylvestris - physiology; Plant Leaves - chemistry; Plant Leaves - metabolism; Pollution; Populus - physiology; Populus tremula; Pseudotsuga - physiology; Pseudotsuga menziesii; Quercus - physiology; Quercus robur; Robinia - physiology; Robinia pseudoacacia; Soil; Soil and sediments pollution; Soil Pollutants - metabolism; Trace metals; Tree species; Trees; Trees - metabolism; Trees - physiology; Zinc; Zinc - metabolism; Belgium; Tree species; Base cations; DOC; Forest floor leachate; Trace metals; Phytostabilization; Quercus robur; Populus tremula; Forest soil; Pinus sylvestris; Pseudotsuga menziesii; Dissolved organic carbon; Decontamination; Dicotyledones; Angiospermae; Gymnospermae; Bioremediation; Betula pendula; Quercus petraea; Betulaceae; Cadmium; Transition metal; Fagaceae; Robinia pseudoacacia; Zinc; Salicaceae; Heavy metal; Phytoremediation; Trace element; Leguminosae; Coniferales; Spermatophyta; Leachate
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2012.12.074

Trees play an important role in the biogeochemical cycling of metals, although the influence of different tree species on the mobilization of metals is not yet clear. This study examined effects of six tree species on fluxes of Cd, Zn, DOC, H+ and base cations in forest floor leachates on a metal polluted site in Belgium. Forest floor leachates were sampled with zero-tension lysimeters in a 12-year-old post-agricultural forest on a sandy soil. The tree species included were silver birch (Betula pendula), oak (Quercus robur and Q. petraea), black locust (Robinia pseudoacacia), aspen (Populus tremula), Scots pine (Pinus sylvestris) and Douglas fir (Pseudotsuga menziesii). We show that total Cd fluxes in forest floor leachate under aspen were slightly higher than those in the other species' leachates, yet the relative differences between the species were considerably smaller when looking at dissolved Cd fluxes. The latter was probably caused by extremely low H+ amounts leaching from aspen's forest floor. No tree species effect was found for Zn leachate fluxes. We expected higher metal leachate fluxes under aspen as its leaf litter was significantly contaminated with Cd and Zn. We propose that the low amounts of Cd and Zn leaching under aspen's forest floor were possibly caused by high activity of soil biota, for example burrowing earthworms. Furthermore, our results reveal that Scots pine and oak were characterized by high H+ and DOC fluxes as well as low base cation fluxes in their forest floor leachates, implying that those species might enhance metal mobilization in the soil profile and thus bear a potential risk for belowground metal dispersion. ► We examined tree species effects on leachate fluxes of Cd, Zn, DOC, H+ and cations. ► Cd fluxes in aspen leachate were slightly higher compared to the other tree species. ► Differences in metal leachate fluxes were much smaller than metal fluxes in leaf litterfall. ► We found significant differences in DOC, H+ and cation leachate fluxes between species. ► Differences in DOC, H+ and cation leachate fluxes might influence metal mobilization.