May 15, 2019 by Dean Leverett

Last May, I highlighted some work that I had been involved in to compare the ecotoxicity of ionic and nano forms of silver using standardised toxicity tests.

I am pleased to announce that the follow-up paper detailing the results of the comparative testing in water has been published.

Mertens, Oorts, Leverett and Arijs. 2019. Effects of silver nitrate are a conservative estimate for the effects of silver nanoparticles on algae growth and Daphnia magna reproduction. Environmental Toxicology and Chemistry. DOI: 10.1002/etc.4463

This paper reports on the aquatic toxicity to algae growth and Daphnia magna reproduction, and the aquatic fate and behaviour of silver nitrate (AgNO₃₎ versus nanosilver (nanoAg). Total silver, ‘conventionally’ dissolved silver (0.45 µm) and ‘truly’ dissolved silver (3 kDa) were measured in all exposures and results were determined based on these measured concentrations of silver. Algae were the most sensitive test species to AgNO3 when expressed as conventionally dissolved Ag, and using measured silver concentrations, AgNO3 was experimentally shown to be more toxic than nanoAg for all silver fractions. The observations were explained by a different dissolution behaviour of AgNO₃ vs nanoAg. This work provided experimental confirmation that AgNO₃ can be used as a conservative estimate for the aquatic effects of nanoAg at comparable Ag concentrations.