The toxicity of engineered nanoparticles on seed plants chronically exposed to low-level environmental radiation

Abstract

Nothing is known about how plant populations chronically exposed to radiation adapt to a new anthropogenic stressor as engineered nanoparticles (ENP). A set of ecotoxicity tests was conducted with five types of ENP to investigate seed response of Leonurus quinquelobatus populations growing naturally under low-dose irradiation and background conditions. Five day toxicity tests detect the combined stimulation positive effects of irradiation stress with two types of ENP on seed germination. All of these effects are smoothed in 21 day old seedlings or reveal the significant adverse effects in three of the ENP. The commonly increased mutation load at the radiation pollution area synergistically increases fourfold to eightfold after TiO2 nanoparticle suspension exposure at 0.5–10 mM. These findings highlight the response on the combined nanoparticle and ionizing radiation influence on plant systems in the wild indicating that the environmental risk assessment of 4 of 5 ENP needs to be carried out.