An integral assessment of the state of aquatic environments using biotests is understood as the study of the complex effect of a number of factors such as chemical, physical and biological - on the functions of living organisms. Traditional methods of chemical and physical analysis of the state of various environments (water, air, soil) are based on comparing the results obtained with environmental standards, such as MPC (maximum permissible concentration) or MAL (maximum allowable level). The advantage of biotesting in comparison with other methods for assessing the state of environments is the speed of obtaining the results and their clarity, the absence of expensive reagents and equipment. Organisms used for biotesting are called biotests or bioindicators. When choosing bioindicators the sensitivity of the organism to exposure factors is taken into account as well as the ease of cultivation. Living organisms from different taxonomic groups can act as bioindicators. Such a bioindicator recognized by the International Program for Chemical Safety (IPCS) is the higher plant Allium sulfur L. The Allium test was used to assess aquatic environment treated with zoo compost resulting from the cultivation of the Black Soldier fly larva (Hermetia illucens). The length of the roots of the tested plant was chosen as the primary response to the effect of a complex of factors. The effect of exposure is considered to be established if there is an increase or decrease in the growth of the roots of the tested plants in comparison with the control. The results obtained can be used to develop recommendations for the use of zoo compost.