The aim of this study is to determine the toxicity of solutions obtained after the advanced oxidation processes of chlorfenvinphos using ozone (O3), ultraviolet light-assisted ozonation (O3/UV) and photocatalysis (TiO2/UV) as well as persulfates activated by visible light (PS/Vis). Basic technological parameters for improving the environmental safety of treated aqueous solutions polluted with chlorfenvinphos were determined. The model solution prepared based on deionised water and a chlorfenvinphos standard was subjected to various methods of advanced oxidation (O3; O3/UV; TiO2/UV; PS/Vis). The advanced oxidation processes were conducted for up to 45 minutes, and the post-process solution toxicity was subsequently analysed using the embryophyte Lepidium sativum (garden cress) and the bacteria Aliivibrio fischeri (MICROTOX® biotest). It was revealed that the PS/Vis process was the most effective for CFVP removal [(C/C0[CFVP]), mineralisation (%TOC) and biological safety (bioluminescence inhibition, germination index). The toxicity assessment by Aliivibrio fischeri and Lepidium sativum demonstrated that the reaction mixture subjected to the effects of PS/Vis was within the scale of nontoxicity. The experimental testing showed that optimal process conditions result in the highest efficiency of CFVP degradation and improved biological safety. It was found that the PS/Vis process can be a valuable alternative to O3, O3/UV and TiO2/UV.