BIOINDICATION STATE OF THE AQUATIC ENVIRONMENT IN A COMPREHENSIVE ASSESSMENT OF THE LOW-FLOWING RESERVOIRS TOXICITY

Abstract

The experimental method of bioindication state of the aquatic environment includes a) toxicity assessment by the common duckweed test object; b) reaction of the ichthyofauna (fish test) by the reaction of fish to the aquatic environment toxicity; c) composition of benthic invertebrates: larvae of plecoptera, mayflies, caddisflies, their number (Mayer index) and the Goodnight-Whitley index (by the specific weight of oligochaetes to the total number of benthic organisms). The reaction indices of hydrobionts during laboratory modelling, as well as under field conditions, were developed. The state of the aquatic environment of the Ustia river was tested based on the observations of common duckweed populations, the Mayer index, and ecological indexing of the state of the Ustia river in three blocks: salt composition, tropho-saprobiological characteristics, and toxicity. Accordingly, it is possible to carry out field studies of the state of the aquatic environment based on the reaction of the common duckweed and benthic organisms' population. In contrast to laboratory methods of water quality research (hydrochemical, hydrobiological), which provide operational information on stream systems at the moment of water sampling, water quality bioindication provides reliable information on the impact of the state of the environment on the test object in the system of "water environment biome". The biotest gives an operational summation of the effects of impurities in the aquatic environment and therefore can be included in a complex of ichthyological studies when taking water samples and obtaining a reliable assessment of the general ecological situation. Thus, the list of ichthyo ecological studies in the summer period should include physical parameters (colour, transparency, smell, temperature, gas regime, foaming, suspensions, salt composition (main ions, mineralization, dry residue), organic and biogenic impurities (C, N, P), toxic impurities (heavy metals), biotesting of invertebrate benthic organisms (Mayer, Goodnight – Whitley, Woodіwiss index) and dynamics of phytoplankton and its composition by saprobity.