The effects of CuO and ZnO nanoparticles on survival, reproduction, absorption, overweight and accumulation in Eisenia foetida earthworm tissues in two substrates

This study was designed to investigate the effects of CuO and ZnO NPs on absorption, accumulation, survival and reproduction of Eisenia foetida earthworm. For this reason, a 4×2×2 factorial experiment and completely randomized was designed with three replications. The factors were included: contents of NPs at four levels (0, 0.4, 0.8 and 1.2 gr/kg weight of substrate), types of NPs at two levels (CuO and ZnO) and types of substrates at two levels (cow manure and spent mushroom compost (SMC)). After preparation of substrates, adult worms were added to each pot which containing of 6 kg of each type of substrates. The aqua solution of NPs was added to cultures. Then, NPs effects on overweight, mortality, accumulation and reproduction were measured at the end of two periods of seven and fourteen days after exposure to NPs. The results showed that there is no mortality in both periods and the absorption and accumulation in tissues of earthworm enhanced with increasing NPs concentrations. Increasing in cow manure was more than SMC and the absorption and accumulation of nano ZnO were more than CuO. The numbers of earthworm egg capsules decreased in both seventh and fourteenth days with increasing NPs concentrations and ZnO NPs were more effective in reducing reproduction than CuO in the seventh day after substrates treatment. In addition, overweight decreased in both seventh and fourteenth days with increasing NPs concentrations. Nano CuO was more effective in reducing overweight than nano ZnO and this decrease in worm tissues in SMC was more than cow manure substrate, in the fourteenth day after treatment.