The paper presents the experimental study of the effect of scrap tire rubber leachates on the production characteristics of two ecological groups of water plants, the phytoplankton Monochrysis lutheri, Phaeodactylum tricornutum, and Exuviaella pusilla and the macrophytes Ulva rigida, Polysiphonia sanguinea, P. denudata, and Ulothrix sp. Data are presented on the dynamics of leachate (zinc, copper, oil products, paraformaldehyde, and acetone) diffusion into the environment from tire rubber preexposed to seawater for various periods of time. The data on leachate effects on the phytoplankton and macrophytes in the Black Sea are discussed. Leachates from fresh (not preexposed to seawater) rubber were found to have the largest impact on the production parameters of water plants. Leachates from rubber preexposed to water for various periods of time produced a significant effect on the production parameters at the initial stages of rubber exposure to water. Taking this into account, the authors argue that scrap tire utilization in artificial fouling substrate construction in heightened trophicity waters should be cautiously controlled to prevent the waters from secondary contamination.