Microbial impacts of metallic nanoparticles depend upon their bioavailable forms, which may be nanoparticles or dissolved ions, depending on the stability of the particles in the specific aquatic media being investigated. The impacts of water chemistry on nanoparticle stability and bioavailability was evaluated using a Gram-negative bacterium (Pseudomonas putida), a Gram-positive bacterium (Bacillus subtilis), and a freshwater microalga (Chlamydomonas reinhardtii) exposed to varying concentrations (0.001-100 mg/L) of Ag, Cu, Zn, and Cu/Ag nanoparticles in different aquatic media. Particle sizes, zeta potentials, total dissolved metal concentrations, microbial growth rates and cell viability were determined for all combinations of nanoparticle, microorganism, and water chemistry. Data suggest the following: (1) nanoparticle aggregation and dissolution vary with changes in ionic strength, pH, ORP, hardness, and alkalinity; (2) algae were generally more susceptible than bacteria for all NPs tested; (3) Gram-positive bacteria were more sensitive than Gram-negative bacteria.

Impacts of water chemistry on nanoparticle stability and bioavailability for freshwater bacteria and algae

240th National Meeting (2010)

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