Subacute Toxicity Analyses of Green Synthesized Magnetite Nanoparticles on Lemna minor L. (Duckweed) Plant

Abstract

Magnetite nanoparticles (MNPs) are widely used in medicine, environmental technologies and biotechnology and green synthesis of MNPs could be an option to minimize potential environmental pollution by their usage. In this study, subacute toxicity of green synthesized magnetite (Fe3O4) nanoparticle was evaluated on Lemna minor, a main autotroph in lakes. Laurel (Laurus nobilis) leaf extract was used to synthesize the magnetite nanoparticles. Characterization of the nanoparticles were performed by UV/Vis spectrophotometer, Fourier transform infrared spectroscopy (FT-IR), Inductively Coupled Plasma Mass Spectrometry (ICP-MS) Zeta size and potential and Scanning electron microscopy (SEM-EDS) analysis. Nanoparticles were around 108.5 nm, spherical in shape and capped with phyto-content. Subacute toxicity of magnetite nanoparticle was tested according to modified OECD 221 protocol, by treating L. minor plants with different MNPs concentrations (0.1, 1, 10, 100, 1000, 2000 mg L− 1) in petri dishes containing Steinberg medium for 15 days. The MNPs up to 1000 mg L− 1 did not cause any toxic effect on Lemna minor even it promoted growth and development of the plant in the concentrations less than 100 mg L− 1. The number of fronds, colonies and photosynthetic pigment contents significantly decreased by magnetite nanoparticle application of 1000 and 2000 mg L− 1 concentrations. Moreover, in these concentrations the nanoparticle caused oxidative stress indicated by the increased hydrogen peroxide and superoxide anion content and lipid peroxidation level. As a conclusion, this study showed that 1000 mg L− 1 green synthesized MNPs concentration is the starting point of subacute toxicity for L. minor.