The uncontrolled antimicrobial agents use leads to the spread of antibiotic-resistant pathogenic strains. The ingress of antibacterial drugs into surface water through sewage from livestock premises, people's houses, hospitals and during medical and agronomic activities exacerbates this problem. Antimicrobials in surface waters have several ways of developing the process: lethal interaction of antibiotics with hydrobionts, elimination of sensitive taxa and alteration of trophic chains; neutralization of antimicrobials (self-destruction of the molecule, hydrolysis, sorption, abiotic and biotic transformation); non-lethal interaction of antibiotics and hydrobionts with the acquisition of antibiotic resistance signs). There are following indicators proposed to predict the antimicrobial agents impact on the aquatic ecosystem: accumulation factor; the amount of substance per unit mass of plant or animal in one cubic meter of water (mg or mcg per 1m3); the maximum amount of a substance that can be contained in an ecosystem without disturbing its basic trophic properties. The basic principles of a dynamic chamber model construction for studying the effect of antibiotics on the ecosystem are based on the following basic statements: 1) the trophic chain is divided into the chambers in which substance is instantaneously mixed in all parts of the chamber in the same way in any direction; 2) the transfer of the substance from one chamber to another occurs according to the laws of first order kinetics, which is described by the system of differential equations. In this case, transition coefficients of a substance between the chambers are constant. It is advisable to use a dynamic chamber model to analyze the migration pathways of substances in a freshwater non-flowing reservoir. For instance, its simplified version consists of the 3 chambers, namely: water – sediments (silt) – biota. It is advisable to use a stationary chamber model for analysing the pathways of antibiotics which enter into the sea with the river flows. Key words: Antibiotics; Migration; Surface water; Chamber model. References Alonso-Díaz, A., Floriach-Clark, J., Fuentes, J., Capellades, M., Coll, N. S., & Laromaine, A. (2019). Enhancing Localized Pesticide Action through Plant Foliage by Silver-Cellulose Hybrid Patches. ACS Biomaterials Science & Engineering, 5(2), 413–419. https://doi.org/10.1021/acsbiomaterials.8b01171 Bogdanova, L.L., Frolov, I.B. (2016). Investigation of natamycin diffusion in the process of production and storage of semi-solid cheeses. Pyshchevaia promÑshlennost: nauka Ñ tekhnolohyy, 3, 63–67 (in Russian). Danchuk, V., Trach, V., Midyk, S., DanchukÐ., Ushkalov, V., & Kepple, O. (2019). Тhe fatty acids content in the liver of japanese quails after the chemical treatment of hatching eggs. Food Science and Technology, 13(2), 58–64 https://doi.org/10.15673/fst.v13i2.1406 Dhillon, G., Kaur, S., Pulicharla, R., Brar, S., Cledón, M., Verma, M., & Surampalli, R. (2015). Triclosan: current status, occurrence, environmental risks and bioaccumulation potential. International journal of environmental research and public health, 12(5), 5657–5684. https://doi.org/10.3390/ijerph120505657 Fang, H., Han, L., Zhang, H., Long, Z., Cai, L., & Yu, Y. (2018). Dissemination of antibiotic resistance genes and human pathogenic bacteria from a pig feedlot to the surrounding stream and agricultural soils. Journal of hazardous materials, 357, 53–62. https://doi.org/10.1016/j.jhazmat.2018.05.066 Feng, M., Wang, Z., Dionysiou, D.D., & Sharma, V. K. (2018). Metal-mediated oxidation of fluoroquinolone antibiotics in water: a review on kinetics, transformation products, and toxicity assessment. Journal of hazardous materials, 344, 1136–1154. https://doi.org/10.1016/j.jhazmat.2017.08.067 Gelbrand, H., Miller-Petrie, M., Pant, S., Gandra, S., Levinson, J., Barter, D., White, A., Laxminarayan, R., Ganguly, N.K., Kariuki, S., Ndegwa, L., Wesangula, E., Sigaúque, B., Sevene, E., Basnynat, B., Pokharel, P., Mani Dixit, S., Giri, S., Duse, A., Perovic, O., Faure,K., Aboud, S., Mdegela, R., Msami, K., Byarugaba, D. K., Kusemererwa, D.A., Lakony, J., Van Kinh, N., Wertheim, H., Do Thuy Nga (2015). The state of the world's antibiotics. Wound Healing Southern Africa, 8(2), 30–34. Grenni, P., Ancona, V., & Caracciolo, A.B. (2018). Ecological effects of antibiotics on natural ecosystems: a review. Microchemical Journal, 136, 25–39. https://doi.org/10.1016/j.microc.2017.02.006 Hobson, K.A., Norris, D.R., Kardynal, K.J., & Yohannes, E. (2019). Animal migration: A context for using new techniques and approaches. In Tracking animal migration with stable isotopes. Academic Press. Ðsaenko, V.M., Voitsitskiy, V.M., Babenyuk, Yu.D., Khyzhnyak, S.V., Il’yn, V.M., Oliynik, S.A. (2005). Ecological biochemistry. Kyiv, Knyzhkove vydavnyctvo NAU (in Ukrainian). Khyzhnyak, S., Voitsitskiy, V., Danchuk, V., Midyk, S., Laposha, O., Ushkalov, V. (2018). Ways of migration of persistent pesticides by trophic chains of terrestrial and aquatic ecosystems. Bioresources and nature management, 10 (1–2), 36–43 (in Ukrainian). http://dx.doi.org/10.31548/bio2018.01.005 Kutlakhmedov, Ju.A., Matveev Y.V., Ghroza V.A. (2018). Reliability of biological systems. Kyiv, Fytosocyocentr (in Ukrainian). Kutlakhmedov, Ju.O., Voitsitskiy, V.M., Khyzhnyak, S.V. (2011). Radiobiology. Kyiv, VPC Kyiv University (in Ukrainian). Lee, H.J., Jeong, S.E., Lee, S., Kim, S., Han, H., & Jeon, C.O. (2018). Effects of cosmetics on the skin microbiome of facial cheeks with different hydration levels. MicrobiologyOpen, 7(2), 1–14. http://DOI.org/10.1002/mbo3.557 Li, H., Shen, H., Fang, J., Zhang, J., & Ding, X. (2018). Rapid determination of 66 antibiotics in cosmetics using ultra high performance liquid chromatography-linear ion trap/Orbitrap...