title: Quantifying the Sensitivity of Soil Microbial Communities to Silver Sulfide Nanoparticles Using Metagenome Sequencing.
abstract: Soils are a sink for sulfidised-silver nanoparticles (Ag2S-NPs), yet there are limited ecotoxicity data for their effects on microbial communities. Conventional toxicity tests typically target a single test species or function, which does not reflect the broader community response. Using a combination of quantitative PCR, 16S rRNA amplicon sequencing and species sensitivity distribution (SSD) methods, we have developed a new approach to calculate silver-based NP toxicity thresholds (HCx, hazardous concentrations) that are protective of specific members (operational taxonomic units, OTUs) of the soil microbial community. At the HC20 (80% of species protected), soil OTUs were significantly less sensitive to Ag2S-NPs compared to AgNPs and Ag+ (5.9, 1.4 and 1.4 mg Ag kg-1, respectively). However at more conservative HC values, there were no significant differences. These trends in OTU responses matched with those seen in a specific microbial function (rate of nitrification) and amoA-bacteria gene abundance. This study provides a novel molecular-based framework for quantifying the effect of a toxicant on whole soil microbial communities while still determining sensitive genera/species. Methods and results described here provide a benchmark for microbial community ecotoxicological studies and we recommend that future revisions of Soil Quality Guidelines for AgNPs and other such toxicants consider this approach.
authors: School of Agriculture Food and Wine, The University of Adelaide, Adelaide, Australia.
authors: Casey L
authors: CL
authors: Doolette
authors: CSIRO Agriculture, Functional Microbial Ecology, Adelaide, Australia.
authors: Vadakattu V S R
authors: VV
authors: Gupta
authors: Advanced Water Management Centre (AWMC), The University of Queensland, St. Lucia, Australia.
authors: Yang
authors: Y
authors: Lu
authors: School of Natural and Built Environments, University of South Australia, Adelaide, Australia.
authors: Justin L
authors: JL
authors: Payne
authors: Advanced Water Management Centre (AWMC), The University of Queensland, St. Lucia, Australia.
authors: Damien J
authors: DJ
authors: Batstone
authors: CSIRO Land and Water, Environmental Contaminant Mitigation and Technologies Research Program, Adelaide, Australia.
authors: Jason K
authors: JK
authors: Kirby
authors: School of Agriculture Food and Wine, The University of Adelaide, Adelaide, Australia.|CSIRO Land and Water, Environmental Contaminant Mitigation and Technologies Research Program, Adelaide, Australia.
authors: Divina A
authors: DA
authors: Navarro
authors: School of Agriculture Food and Wine, The University of Adelaide, Adelaide, Australia.|CSIRO Land and Water, Environmental Contaminant Mitigation and Technologies Research Program, Adelaide, Australia.
authors: Mike J
authors: MJ
authors: McLaughlin
mesh_terms: D001419:Bacteria / Q000187:drug effects* / Q000235:genetics; D004269:DNA, Bacterial / Q000032:analysis; D054892:Metagenome; D053768:Metal Nanoparticles; D058465:Nitrification / Q000187:drug effects; D012336:RNA, Ribosomal, 16S / Q000032:analysis; D017422:Sequence Analysis, DNA / Q000379:methods*; D018030:Silver Compounds / Q000494:pharmacology*; D012988:Soil Microbiology
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D018030:Silver Compounds; C013251:silver sulfide