“In Situ” Amendments and Revegetation Reduce Trace Element Leaching in a Contaminated Soil

Abstract

Various amendments and/or a plant cover (Agrostis stolonifera L.) were assessed for their potential to reduce trace element leaching in a contaminated soil under semi-arid conditions. The experiment was carried out in field containers and lasted 30 months. Five treatments with amendments (leonardite (LEO), litter (LIT), municipal waste compost (MWC), biosolid compost (BC) and sugar beet lime (SL)) and a plant cover and two controls (control without amendment but with plant (CTRP) and control without amendment and without plant (CTR)) were established. Drainage volumes were measured after each precipitation event and aliquots were analysed for pH, electrical conductivity (EC) and trace element concentrations (As, Cd, Cu, Pb and Zn). Soil pH and trace element extractability (0.01 M CaCl 2 ) at three different depths (0-10, 10-20 and 20-30 cm) were measured at the end of the experiment. Incorporation of amendments reduced leaching of Cd, Cu and Zn between 40-70% in comparison to untreated soil. The most effective amendments were SL, BC and MWC. At the end of the experiment, extractable concentrations of Cd, Cu and Zn were generally lower in all amended soils and CTRP compared to CTR. Soil pH decreased and extractability of metals increased in all treatments in relation to depth. Results showed that use of these amendments combined with healthy and sustainable plant cover might be a reliable option for "in situ" stabilization of trace elements in moderately contaminated soils.

A greenhouse trial to investigate the ameliorative properties of biosolids and plants on physicochemical conditions of iron ore tailings: Implications for an iron ore mine site remediation

“…After 4 weeks of initiation of the trial, seedlings were thinned to 10 plants per pot (Seleiman et al, 2012;Jiemin and Wong, 2008). Plants were watered twice weekly (Rate et al, 2004;Waterhouse et al, 2014) and were randomly placed in the greenhouse (Perez-de-Mora et al, 2007;Verdugo et al, 2011;Meeinkuirt et al, 2012), relocated once a week. After twelve weeks, plants were cautiously removed from each pot, and soil was placed in open vessels for air drying, subsequent to which they were crushed and passed through a 2 mm sieve.…”

Improving sustainability in the remediation of contaminated soils by the use of compost and energy valorization by Paulownia fortunei

“…Organic materials are among the most commonly used amendments for remediating trace element-contaminated soils, given that the addition of organic matter (OM) can decrease trace element concentration in the soil solution, reducing their availability to plants and the risk of leaching (Pérez de Mora et al, 2007). This practice could partially solve a dual environmental problem, which is the need to find locations for the disposal of this type of waste and the need to improve soil quality in degraded soils, usually poor in organic matter and in semi-arid areas (Bastida et al, 2007).…”

Metal immobilization in hazardous contaminated minesoils after marble slurry waste application. A field assessment at the Tharsis mining district (Spain)

“…Assisted natural remediation (ANR) might offer a cost-effective alternative option to conventional methods as a cleanup tool for metal-polluted soils, as reported in several recent studies [8][9][10][11][12]. The ANR approach is based on the use of certain amendments and/or plants to reactivate key biogeochemical processes (sorption, precipitation, complexation and redox reactions) that occur naturally in soils, thus immobilizing the metals in situ.…”