ABSTRACT
The purpose of the study was establishing in what degre the presence of surface-active substances affects the influence of herbicides present in surface waters on aquatic organisms. The study was carried out under laboratory conditions using as herbicides promethrin (triazine group) and dichlorophenoxy-acetate sodium (2,4 D), and detergents - sodium alkylsuphonate ABS and non-ionic detergent Rokafenol N8P7. The efTect of these substances was studied on the test organisms from own cultures - Daphnia magna Straus, larvae of insects Chironomus plumosus L, and young fish Lebistes reticulatus. The study showed that promethrin was the herbicide with stronger action on the studied organisms than 2,4 D. The presence of single detergents and their mixtures increased promethrin effects by 10-13% on the testes invertebrates even in concentrations permitted in surface waters. The toxic effect of the herbicide 2,4 D was potentiated by detergents in much higher concentrations, exceeding the permitted values. Contamination of surface waters with detergents may endanger the trophic chain of aquatic biocenoses.