2 research outputs found
Heavy metal contamination and health risk assessment in Critical Zone of Luan River Catchment in the North China Plain
These graphs quantitatively describe importance of thirteen parameters for manganese, iron and lead content in maize for P1 and P2 profiles using the Gini index of random forest method
Sulfidation of Silver Nanoparticles Decreases <i>Escherichia coli</i> Growth Inhibition
Sulfidation of metallic nanoparticles such as silver
nanoparticles
(AgNPs) released to the environment may be an important detoxification
mechanism. Two types of AgNPsî—¸an engineered polydisperse and
aggregated AgNP powder, and a laboratory-synthesized, relatively monodisperse
AgNP aqueous dispersionî—¸were studied. The particles were sulfidized
to varying degrees and characterized to determine the effect of initial
AgNP polydispersity and aggregation state on AgNP sulfidation, and
then exposed to <i>Escherichia coli</i> to determine if
the degree of sulfidation of pristine AgNPs affects growth inhibition
of bacteria. The extent of sulfidation was found to depend on the
HS<sup>–</sup>/Ag ratio. However, for the same reaction times,
the more monodisperse particles were fully transformed to Ag<sub>2</sub>S, and the polydisperse, aggregated particles were not fully sulfidized,
thus preserving the toxic potential of Ag<sup>0</sup> in the aggregates.
A higher Ag<sub>2</sub>S:Ag<sup>0</sup> ratio in the sulfidized nanoparticles
resulted in less growth inhibition of <i>E. coli</i> over
6 h of exposure. These results suggest that the initial properties
of AgNPs can affect sulfidation products, which in turn affect microbial
growth inhibition, and that these properties should be considered
in assessing the environmental impact of AgNPs