Agro-industrial wastes as effective amendments for ecotoxicity reduction and soil health improvement in aided phytostabilization

Abstract

Aided phytostabilization is a technology that uses metal tolerant plants and organic and/or inorganic amendments to reduce soil metal bioavailability, while improving soil health. Our objective was to determine the effects of the application of amendments [sheep manure (SHEEP), poultry litter (POULTRY), cow slurry (COW), and paper mill sludge mixed with poultry litter (PAPER)], together with the growth of a metallicolous Festuca rubra L. population, on (i) chemical and microbial indicators of soil health and (ii) soil ecotoxicity, during the aided phytostabilization of a Zn/Pb contaminated mine soil. Amendment application led to an increase in soil pH, organic matter content, and inorganic salts, resulting in a decrease in Pb and Zn CaCl2-extractable concentrations in soil, which, in turn, contributed to lower ecotoxicity and a stimulation of plant growth and soil microbial communities. The factor most affecting the metal extractability was probably soil pH. POULTRY was the best amendment in terms of increasing plant growth, chlorophylls content, and soil microbial biomass and activity, but resulted in higher levels of phytoavailable Pb and Zn. SHEEP and PAPER were more effective at reducing metal CaCl2-extractability and, consequently, led to lower values of metal accumulation in plant tissues, thereby reducing the risk of metals entering into the food chain. When combined with the application of organic amendments, the metallicolous F. rubra population studied here appears an excellent candidate for aided phytostabilization. Our results indicate that the application of organic amendments is essential for the short-term recovery of highly contaminated metalliferous soils during aided phytostabilization.

Gentle remediation options for soil with mixed chromium (VI) and lindane pollution: biostimulation, bioaugmentation, phytoremediation and vermiremediation

“…Microbial communities are excellent indicators of soil health, and parameters such as microbial activity, biomass and functional diversity have been used as bioindicators in studies of polluted soil ( Epelde et al., 2014 , 2010 ; Galende et al., 2014b ). In particular, Cr(VI) has been reported to be toxic for soil microbial communities ( Pradhan et al., 2019 ).…”

“…Metal phytoremediation includes phytostabilization (reduction of pollutant mobility and bioavailability) ( Epelde et al., 2009 ; Galende et al., 2014a , 2014b ) and phytoextraction (metal accumulation in plant shoots) ( Barrutia et al., 2010 ; Epelde et al., 2010 ). Phytoremediation may also be suitable for the rhizoremediation of organic pollutants ( Liu et al., 2017 ; Montpetit and Lachapelle, 2017 ), and organic compounds that roots exude to the rhizosphere create a nutrient-rich environment that stimulates microbial communities, enhancing the degradation of organic pollutants ( Kuiper et al., 2004 ).…”

“…Applications of GROs commonly include modification of polluted-soil conditions and/or application of amendments that enhance the biological activity of soil organisms, a process known as biostimulation. Organic amendments are a good choice for this purpose and have been widely used ( Kästner and Miltner, 2016 ), as they add nutrients and carbon sources to the soil, promoting plant growth and microbial activity ( Galende et al., 2014b ) as well as the soil fauna ( Dubey et al., 2019 ). They can also impact the oxidation status of metals and their bioavailability ( Park et al., 2011 ).…”

Effects of the application of an organic amendment and nanoscale zero-valent iron particles on soil Cr(VI) remediation

“…1D) values, as compared to day 0. The stabilization of environmental conditions during the incubation period, as well as the consumption of labile compounds, can lead to a reduction of microbial functional diversity (Galende et al 2014c). Similarly to BR and SIR, in our study, the presence of the organic amendment (M and H soils) greatly increased SCA (Fig.…”

Evaluation of the phytotoxicity of landfill leachate treated with a Rotating Biological Reactor

“…When physicochemical parameters are not reliable, i.e., to assure that residues are environmentally safe for agricultural use (JURADO et al, 2014), it is recommended to use phytotoxicity tests as supplementary methods (ZUCCONI et al, 1981;TIQUIA et al, 1998;OZORES-HAMPTON et al, 2013;DELGADO et al, 2010;GALENDE et al, 2014). There are several advantages of using plants, such as Lactuca sativa, in phytotoxicity tests;.…”