Organic amendments impact the availability of heavy metal(loid)s in mine-impacted soil and their phytoremediation by Penisitum americanum and Sorghum bicolor

Abstract

The amendment of contaminated soil with organic materials is considered to be an environmentally friendly technique to immobilize heavy metal(loid)s and minimize their subsequent bioaccumulation in plants. This study focuses on the effects of different amendment techniques, such as the use of activated carbons (granulated or powder) and farmyard manure at various application rates (2 and 5 %). These techniques were applied on heavy metal(loid)s such as Ni, Cr, Cd, Pb, Mn, Cu, Zn, Fe, Co, and Al that were present in mine-impacted soil and caused bioaccumulation in cultivated plants. The results showed that, compared with the control, almost all the techniques significantly (P ≤ 0.01) reduced the bioavailability of heavy metal(loid)s in the amended soil. The bioaccumulation of heavy metal(loid)s in Penisitum americanum and Sorghum bicolor was significantly (P ≤ 0.01) reduced with all techniques, while Zn and Cd concentrations increased with the use of farmyard manure. Also compared with the control, plant growth was significantly decreased with the use of activated carbons, particularly with powder activated carbons, while farmyard manure (at 5 %) significantly (P ≤ 0.01) increased plant growth. Among the amendment techniques, powdered activated carbons (at 5 %) were best at reducing the bioavailability of heavy metal(loid)s in soil and plant accumulation. However, it negatively affected the growth of selected plant species.

The evaluation of growth and phytoextraction potential of Miscanthus x giganteus and Sida hermaphrodita on soil contaminated simultaneously with Cd, Cu, Ni, Pb, and Zn

“…However, the role of organic matter is not clear, as results show that application of organic matter as a support in phytoremediation stimulates coniferous trees to collect greater amounts of Cd but smaller amounts of Pb (Placek et al 2016). Minor accumulation could be attributed to that with a significant presence of organic matter, heavy metals are to a greater extent adsorbed by the soil complex, immobilized and less accessible for a plant (Pikuła and Stepien 2007;Chłopecka and Adriano 1997;Nawab et al 2016). The results of Nawab et al (2016) suggest that the type of organic matter has a significant influence on the behavior of HMs in the soil and efficiency of phytoremediation.…”

The influence of humic substance on Cd accumulation of phytostabilizer Athyrium wardii (Hook.) grown in Cd-contaminated soils

“…A dosage (20-80 %) of compost application significantly (P < 0.05) reduced Cd concentrations in Brassica chinensis L. grown in sandy soil (Rosen and Chen 2014). The bioaccumulation of Cd in Penisitum americanum and Sorghum bicolor was also reported to show similar phenomena with the use of activated carbons (Nawab et al 2015). Among these researches, the decrease of Cd uptake by plants referred to higher pH and the decrease of Cd bioavailability in the amended soils.…”

“…Similar results were obtained from the study of different farmyard manures (pig slurry, cow manure, sheep manure, etc.) (Safari et al 2011;Clemente et al 2012;Nawab et al 2015). Application of organic amendments to soils could enhance the physicochemical and biological Fig.…”

“…are known to improve soil fertility and certain physical-chemical properties by adding essential nutrients and enhance the microbial community of soil (Ahmad et al 2015;Nawab et al 2015). Compost produced from different green waste sources (plant leftovers, pine bark, etc.)…”

“…DOM derived from different sources can mobilize metal contaminants (Beesley et al 2010;Tang et al 2016). For the immobilization, metals are less available for plant uptake and human ingestion through food chain, due to adsorption on solid surfaces, complexation with humic substances and precipitation reactions (Nawab et al 2015). Many studies have stated that organic amendments lead to a decrease in the assimilable metal content, such as Cd, Pb, Zn, As, and Cr in soils (Bolan et al 2014;Forján et al 2016).…”