Trace elements, pH and organic matter evolution in contaminated soils under assisted natural remediation: A 4-year field study

Abstract

1A four year study was undertaken on the effect of three amendments (biosolid compost 2 (BC), sugar beet lime (SL), and combination of leonardite plus sugar beet lime (LESL)) 3 on reclamation of a moderately trace element contaminated soil under field conditions. 4Results showed that organic C increased in BC and LESL treatments. BC and SL 5 treatments increased soil pH and reduced CaCl 2 -extractable metal concentrations more 6 efficiently. At the end of the experiment, CaCl 2 -extractable metal concentrations 7 decreased and were similar in all treatments pointing out the importance of the natural 8 remediation processes in contaminated soils. Addition of amendments showed no clear 9 reduction in EDTA-extractable trace element concentrations, even, BC and LESL 10 subplots showed some little increase of these elements with time. Amendments did not 11 cause any change in total trace element concentration in soil. Addition of amendments 12 could be a successful and reliable long term technique for stabilization of trace elements 13 in contaminated soils at a field scale with minimum maintenance. 14 15

Traditional agricultural practices enable sustainable remediation of highly polluted soils in Southern Spain for cultivation of food crops

“…The water-soluble fraction and the fraction assessed by CaCl 2 extraction are considered to simulate the proportion of the total soil metal pool that may be available for uptake by plants and play a key role in many transfer pathways (Gupta et al, 1996;Houba et al, 1996). The EDTAextractable fraction is composed of those ions present in the soil solution, as well as those that are loosely bound to sites in the solid phase of the soil and potentially able to move into the plant root system (Madejón et al, 2009). In some cases, EDTA-extractable metal concentrations have been reported to be closely correlated with metal concentrations in plants (e.g.…”

of zinc fractions in relation to properties of some soils of Bangladesh

“…The bio-available fraction is most crucial for assessing the environmental quality and possible health risk (2) . Therefore, understanding of the distribution of Zn fractions in soils will help to characterize the behaviour of Zn in soils and possibly its availability for plant uptake.…”

Do amended, polluted soils require re-treatment for sustainable risk reduction? — Evidence from field experiments

“…The SL-induced changes in pH were sustained over the course of the field trial. In this acid soil, the first two applications of SL raised soil pH close to neutrality (Madejón et al, 2009) and these values have remained constant for at least five years without any further amendment addition. Organic amendments also made soils more alkaline, although less efficiently (Fig.…”

“…In a previous study, Madejón et al (2009) investigated the effects of two consecutive additions of amendments to the same semi-arid soil, moderately contaminated with As, Cd, Cu, Pb and Zn, over a 4-year period. Here we present a longer term investigation of the same soil comparing the effects of two vs four amendment additions to the same soil over a 6-year period.…”