Comparative Assessment of the toxic effects of potassium dichromate, phenol, and lambda-cyhalothrin on the functional activity of carp (Cyprinus carpio L.) spermatozoa using biotesting

The results of an experimental study on the toxic effects of compounds of different chemical natures on the functional state of fish germ cells, using the biotesting method, are presented. The study examines the effects of potassium dichromate, phenol, and λ-cyhalothrin on the motility of carp (Cyprinus carpio L.) spermatozoa, a sensitive bioindicator of aquatic environmental quality. The work aimed to determine the specific features of the toxic effects of these substances under short-term exposure and to provide a comparative evaluation of their influence on the duration of active sperm motility. The research methodology used freshly obtained carp milt, which was exposed to aqueous solutions of toxicants at specified concentrations. Biotesting was performed by determining the duration of sperm motility after activation in media containing phenol (1, 10, 300 mg/L), potassium dichromate (5, 10, 155 mg/L), and λ-cyhalothrin (37.1 mg/L). Control samples were prepared without the addition of toxic substances. The evaluation was carried out microscopically by recording the time until complete cessation of sperm movement. The obtained results were statistically processed by calculating mean values and assessing the significance of differences. The study established that all tested toxicants under short-term exposure (60 s) cause a decrease in the motility of carp spermatozoa; however, the toxic effect manifests only at concentrations that significantly exceed the maximum permissible levels. It was found that the most pronounced inhibitory effect on the functional activity of spermatozoa is observed with potassium dichromate, which is associated with its ability to disrupt cellular respiration and adenosine triphosphate synthesis rapidly. For phenol and potassium dichromate, no clear “dose–effect” relationship was established within the concentration ranges studied, indicating the initial stage of toxic action development during short-term contact. The effect of λ-cyhalothrin was accompanied not only by a reduction in the duration of motility but also by a disturbance in its character, manifested as chaotic (non-progressive) sperm motility. It is shown that using carp spermatozoa as a test system has limitations due to their short activity, which complicates the assessment of the toxicity of substances with different mechanisms of action. At the same time, this approach may be effective in detecting acute effects of highly concentrated pollutants and could serve as a rapid biotesting method.