Remediation of Heavy Metal–Contaminated Forest Soil Using Recycled Organic Matter and Native Woody Plants

Abstract

The main aim of this study was to determine how the application of a mulch cover (a mixture of household biocompost and woodchips) onto heavy metal-polluted forest soil affects (i) long-term survival and growth of planted dwarf shrubs and tree seedlings and (ii) natural revegetation. Native woody plants (Pinus sylvestris, Betula pubescens, Empetrum nigrum, and Arctostaphylos uva-ursi) were planted in mulch pockets on mulch-covered and uncovered plots in summer 1996 in a highly polluted Scots pine stand in southwest Finland. Spreading a mulch layer on the soil surface was essential for the recolonization of natural vegetation and increased dwarf shrub survival, partly through protection against drought. Despite initial mortality, transplant establishment was relatively successful during the following 10 yr. Tree species had higher survival rates, but the dwarf shrubs covered a larger area of the soil surface during the experiment. Especially E. nigrum and P. sylvestris proved to be suitable for revegetating heavy metal-polluted and degraded forests. Natural recolonization of pioneer species (e.g., Epilobium angustifolium, Taraxacum coll., and grasses) and tree seedlings (P. sylvestris, Betula sp., and Salix sp.) was strongly enhanced on the mulched plots, whereas there was no natural vegetation on the untreated plots. These results indicate that a heavy metal-polluted site can be ecologically remediated without having to remove the soil. Household compost and woodchips are low-cost mulching materials that are suitable for restoring heavy metal-polluted soil.

Effects of Calamagrostis epigejos, Chamaenerion palustre and Tussilago farfara on nutrient availability and microbial activity in the surface layer of spoil heaps after hard coal mining

“…and Betula sp. have been proved to reduce adverse environmental impacts and increase the esthetical quality of industrial wasteland (Hüttl and Weber, 2001;Helmisaari et al, 2007;Pietrzykowski et al, 2015).…”

Heavy Metals in Contaminated Soils: A Review of Sources, Chemistry, Risks and Best Available Strategies for Remediation

“…This process uses organic materials such as bitumen, polyethylene, paraffins, waxes, and other polyolefins as thermoplastic or thermosetting resins. For polymer encapsulation, the organic materials are heated and mixed with the contaminated matrix at elevated temperatures (120 • to 200 • C). The organic materials polymerize and agglomerate the waste, and the waste matrix is encapsulated [84].…”

“…Phytoremediation, also called green remediation, botanoremediation, agroremediation, or vegetative remediation, can be defined as an in situ remediation strategy that uses vegetation and associated microbiota, soil amendments, and agronomic techniques to remove, contain, or render environmental contaminants harmless [119,120]. The idea of using metal-accumulating plants to remove heavy metals and other compounds was first introduced in 1983, but the concept has actually been implemented for the past 300 years on wastewater discharges [121,122].…”

Agronomic and environmental effects of land application of residues in short-rotation tree plantations: A literature review

“…Composting during two years was more effective than during one year [92]. It was also shown that a mixture of domestic compost and wood chips caused a natural recolonization in polluted environments with heavy metals, including willow seedlings [93].…”