Journal of Nanomedicine & Nanotechnology

Abstract

Fate and Immunotoxic Effects of Silver Nanoparticles on Rainbow Trout in Natural Waters

Bruneau A, Turcotte P, Pilote M, Gagné F and Gagnon C

This study investigates the fate and the effects of silver nanoparticles (AgNPs) in rainbow trout (Oncorhynchus mykiss). Juveniles were exposed to 50 μg/L of AgNPs 20 nm and 1 μg/L of dissolved silver Ag⁺ (as AgNO₃) in three types of water differing in conductivity, pH and organic matter: green water (Saint-Lawrence River), brown water (Ottawa River), and UV-treated and dechlorinated tap water. After a 96 h exposure, chemical analyses were performed on both water samples and fish tissues (liver and gills) and a suite of immune and hepatic biomarkers were also performed on fish.Results demonstrated that brown water with high organic carbon values (7 mg/L), promoted the formation of small AgNP aggregates that were bioaccumulated in fish gills and liver. In fish exposed to AgNPs, immunostimulation and hepatic oxidative stress were observed in pronephros and liver respectively. Dissolved Ag⁺ in brown water was associated to small colloids, promoted silver bioavailability and induced leucocytes immunostimulation. The higher alkalinity and conductivity of green water promoted morphological AgNPs transformations. Although, AgNPs neither induced immune nor hepatic damages, AgNO₃ induced leucocyte stimulation and a hepatic pro-inflammatory response. Ag from AgNPs and AgNO₃ was bioaccumulated in gills, and liver without hepatic injury (oxidative stress). AgNO₃ induced immunosuppression and oxidative stress in pronephros. This study shows that water parameters influence the fate, bioavailability and the toxicity AgNPs and dissolved Ag⁺ in fish. Brown water showed more harmful effects with AgNPs than tap and green waters.