Municipal solid wastes as a resource for environmental recovery: impact of water treatment residuals and compost on the microbial and biochemical features of As and trace metal-polluted soils
Articolo
Data di Pubblicazione:
2019
Citazione:
Municipal solid wastes as a resource for environmental recovery: impact of water treatment residuals and compost on the microbial and biochemical features of As and trace metal-polluted soils / Garau, G., Porceddu, A., Sanna, M., Silvetti, M., Castaldi, P.. - In: ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY. - ISSN 0147-6513. - 174:(2019), pp. 445-454. [10.1016/j.ecoenv.2019.03.007]
Abstract:
In this study we evaluated the microbiological and biochemical impact of iron-based water treatment residuals
(Fe-WTRs) and municipal solid waste compost (MSWC), alone and combined, on three different soils co-contaminated with arsenic (As) and trace-metals (TM), i.e. Pb, Cu and Zn. Overall, all the amendments considered
significantly increased the abundance of culturable heterotrophic bacteria, with MSWC showing the greatest
impact across all soils (up to a 24% increase). In most of treated soils this was accompanied by a significant
reduction of both the (culturable) fungal/bacterial ratio, and the proportion of culturable As(V)- and As(III)-
resistant bacteria with respect to total bacterial population. The catabolic potential and versatility of the resident
microbial communities (assessed by community level physiological profile) was highly soil-dependent and
substantial increases of both parameters were observed in the amended soils with the higher total As concentration (from approx. 749 to 22,600 mg kg−1
). Moreover, both carbon source utilisation profile and 16S
rRNA soil metagenome sequencing indicated a significant impact of MSWC and Fe-WTRs on the structure and
diversity of soil microbial communities, with Proteobacteria, Actinobacteria and Firmicutes being the most affected
taxa. The assessment of selected soil enzyme activities (dehydrogenase, urease and β-glucosidase) indicated an
increase of metabolic functioning especially in soils treated with MSWC (e.g. dehydrogenase activity increased
up to 19.5-fold in the most contaminated soil treated with MSWC). Finally, the microbial and biochemical
features of treated (and untreated) contaminated soils (i.e. total bacterial counts, catabolic potential and versatility and soil enzyme activities) were highly correlated with the concentrations of labile As and TM in these
latter soils and supported a clear role of the tested amendments (especially MSWC) as As- and TM-immobilising
agents.
(Fe-WTRs) and municipal solid waste compost (MSWC), alone and combined, on three different soils co-contaminated with arsenic (As) and trace-metals (TM), i.e. Pb, Cu and Zn. Overall, all the amendments considered
significantly increased the abundance of culturable heterotrophic bacteria, with MSWC showing the greatest
impact across all soils (up to a 24% increase). In most of treated soils this was accompanied by a significant
reduction of both the (culturable) fungal/bacterial ratio, and the proportion of culturable As(V)- and As(III)-
resistant bacteria with respect to total bacterial population. The catabolic potential and versatility of the resident
microbial communities (assessed by community level physiological profile) was highly soil-dependent and
substantial increases of both parameters were observed in the amended soils with the higher total As concentration (from approx. 749 to 22,600 mg kg−1
). Moreover, both carbon source utilisation profile and 16S
rRNA soil metagenome sequencing indicated a significant impact of MSWC and Fe-WTRs on the structure and
diversity of soil microbial communities, with Proteobacteria, Actinobacteria and Firmicutes being the most affected
taxa. The assessment of selected soil enzyme activities (dehydrogenase, urease and β-glucosidase) indicated an
increase of metabolic functioning especially in soils treated with MSWC (e.g. dehydrogenase activity increased
up to 19.5-fold in the most contaminated soil treated with MSWC). Finally, the microbial and biochemical
features of treated (and untreated) contaminated soils (i.e. total bacterial counts, catabolic potential and versatility and soil enzyme activities) were highly correlated with the concentrations of labile As and TM in these
latter soils and supported a clear role of the tested amendments (especially MSWC) as As- and TM-immobilising
agents.
Tipologia CRIS:
1.1 Articolo in rivista
Keywords:
Arsenic, Trace metals, Culturable microbial community, Soil enzyme activity, Community level physiological profile, 16S rRNA metagenome
Elenco autori:
Garau, Giovanni; Porceddu, Andrea; Sanna, Monica; Silvetti, Margherita; Castaldi, Paola
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