Nanosilver toxicity thresholds estimative for aquatic and sediment environmental safety

Abstract Silver nanoparticles (AgNPs) have been largely utilized. Despite that, comprehensive studies on their ecotoxicological effects and environmental risk are still required. In the present study, the AgNPs effect was assessed to some organisms including algae, plants, microcrustaceans, cnidaria, nematodes, aquatic insect, earthworm, and fish embryos. The no-observed-effect concentration (NOEC) was calculated for each organism using a log-logistic function. AgNPs remained stable in contact with culture media during the analyzed period and conditions employed, presenting dispersion less than 20%, except for Artemia salina medium. On this occasion, NPs presented dispersion of approximately 25%, although their size remained unchangeable. The Predicted No Effect Concentration (PNEC) of AgNPs in the aquatic compartment was estimated in the concentration range from 0.13 to 0.66 µg L-1. A Risk Quotient (RQ) of 15.1 was derived for the NP tested with the aid of a maximum AgNPs Predicted Environmental Concentration (PEC) estimated value. The RQ value superior to one indicates a risk and the need for its management measures implementation. These data, in addition to the expected increase in AgNPs use, reinforce the importance of the AgNPs safety levels establishment that can contribute to performing their risk assessment studies.