Long-term effects of environmentally relevant concentrations of silver nanoparticles on microbial biomass, enzyme activity, and functional genes involved in the nitrogen cycle of loamy soil

Grün, Anna-Lena; Straskraba, Susanne; Schulz, Stefanie; Schloter, Michael; Emmerling, Christoph

doi:10.1016/j.jes.2018.04.013

Cited by 102 publications

(65 citation statements)

References 61 publications

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“…Further to the soil type and the AgNP functionalization, several studies documented a significant impact of the exposure time on the toxicity of AgNP in soils [16,[32][33][34]. By a statistically significant regression and correlation analysis between silver toxicity and exposure time we recently confirmed loamy soils as a sink for silver nanoparticles and their concomitant silver ions due to ageing processes of the silver species and their slow return to the biological soil system [17].…”

Section: Introductionmentioning

confidence: 72%

“…Each replicate was analysed on the effect expressions of the target variables leucine aminopeptidase activity, microbial biomass as well as of functional and taxonomic genes. Furthermore, results of our previous studies [16,17] of the effect assessment of AgPure, with an average size of 20 nm and polyacrylate stabilization, were used to calculate the impact of the five agent species AgPure, Ag10-COOH, Ag10-NH 2 , AgNO 3 , and KNO 3 at concentrations of 0.01; 0.1; and 1.0 mg Ag/kg soil after exposure of 1, 14, 28, and 90 days in the silty loam soil on the same target variables.…”

Section: Experimental Designmentioning

confidence: 84%

“…To quantify the abundance of taxon-specific 16S rRNA gene copy numbers, qPCR assays for Acidobacteria [42,43], Actinobacteria [43,44], alpha-Proteobacteria [45], Bacteroidetes [43,46], and beta-Proteobacteria [47,48] were performed. Detailed descriptions of the used assays are given by Grün and Emmerling [17] and Grün et al [16].…”

Section: Quantitative Detection Of Functional and Taxonomic Genesmentioning

confidence: 99%

“…Today, information about the impact of AgNP on the soil microbiome are still rare, although microbial communities are important and sensitive targets for determining the environmental hazards of AgNP [15]. Recently, we registered significant negative effects on soil microbial biomass (− 38.0%), bacterial ammonia oxidizers (− 17.0%), and the beta-Proteobacteria population (− 14.2%) after 1-year exposure to 0.01 mg AgNP/kg in a loamy soil, while Acidobacteria (44.0%), Actinobacteria (21.1%) and Bacteroidetes (14.6%) were significantly stimulated [16,17]. Therefore, a detrimental disturbance on soil ecosystem functions, such as nitrification, organic carbon transformation and chitin degradation could be assumed.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, we used AgNO 3 as control to determine the effect of Ag + ions on the AgNP results. Based on our preceding observation that the nitrate content of 36.5% in the AgNO 3 compound might also have effects on the microbial community [16], we used NO 3 as a further control. This experiment was restricted to the loamy soil.…”

Section: Introductionmentioning

confidence: 99%

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Impact of silver nanoparticles (AgNP) on soil microbial community depending on functionalization, concentration, exposure time, and soil texture

et al. 2019

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Background: Increasing exposure to engineered inorganic nanoparticles takes actually place in both terrestric and aquatic ecosystems worldwide. Although we already know harmful effects of AgNP on the soil bacterial community, information about the impact of the factors functionalization, concentration, exposure time, and soil texture on the AgNP effect expression are still rare. Hence, in this study, three soils of different grain size were exposed for up to 90 days to bare and functionalized AgNP in concentrations ranging from 0.01 to 1.00 mg/kg soil dry weight. Effects on soil microbial community were quantified by various biological parameters, including 16S rRNA gene, photometric, and fluorescence analyses.Results: Multivariate data analysis revealed significant effects of AgNP exposure for all factors and factor combinations investigated. Analysis of individual factors (silver species, concentration, exposure time, soil texture) in the unifactorial ANOVA explained the largest part of the variance compared to the error variance. In depth analysis of factor combinations revealed even better explanation of variance. For the biological parameters assessed in this study, the matching of soil texture and silver species, and the matching of soil texture and exposure time were the two most relevant factor combinations. The factor AgNP concentration contributed to a lower extent to the effect expression compared to silver species, exposure time and physico-chemical composition of soil. Conclusions:The factors functionalization, concentration, exposure time, and soil texture significantly impacted the effect expression of AgNP on the soil microbial community. Especially long-term exposure scenarios are strongly needed for the reliable environmental impact assessment of AgNP exposure in various soil types. which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

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