Investigation of the responses of the <i>Eisenia fetida</i> worms when copper and zinc nanoparticles are introduced into the habitat

Abstract

In our study, we chose Eisenia fetida worms as the object of study, which were cultivated on artificial soil, where Zn and Cu NPs were added at doses of 0; 100; 250; 500 and 1000 mg/kg dry soil. The survival rate of worms when exposed to an artificial substrate in the control was 100%. 20% decrease in survival was recorded when Zn NPs were introduced at a dose of 500 mg/kg of dry soil on the 14th day. The survival rate with the introduction of Cu NP was 90-100%, at the same time the lowest survival rate (20%) was noted at a concentration of 500 mg/kg on day 14. In the course of studies, the dose-dependent nature of the accumulation of copper and zinc in Eisenia fetida was established. At a dose of 1000 mg/kg Zn NPs, zinc was excreted from the body of worms at a rate of 3.9 mg/kg/day and decreased with an increase in the dose of introduced Zn NPs. Excretion of copper from the body of worms occurred at a concentration of 500 mg/kg of Cu NP on day 14. At the same time, the rate of elimination from the body of the worm increased with an increase in the concentration of metal in the soil (by 34-53%). The maximum bioaccumulation was recorded with the addition of 100 mg/kg of Cu NP. Thus, on artificial soil, the accumulation of copper and zinc was a dose-dependent parameter. The worm's body is capable of accumulating zinc when NPs are added up to 500 mg / kg, inclusive, with subsequent excretion into the external environment at a concentration of 1000 mg / kg of soil. At a concentration of 500 mg/kg of Cu NPs on artificial soil, the removal of metal from the body of the worm on the 14th day was noted. The maximum bioaccumulation of Cu NPs was recorded upon the addition of 100 mg/kg Cu NP.