Оцінка токсикорезистентності ставковика озерного (Mollusca: Gastropoda) до впливу йонів мангану (II) у водному середовищі

Abstract

<p>Under the conditions of growing environmental pollution heavy metal ions took one of the first places among other pollutants. Nowadays annual anthropic entry of a great number of heavy metals into hydrosphere several times exceeded the entry from natural sources. The topicality of the research influence of the above pollutants on hydrobionts with the aim of introducing the research results to the ecological monitoring system is beyond doubt. <em>Lymnaea stagnalis</em> (Linné, 1758) a secondary-water lung pondmollusc, can be a suitable object for toxicological investigations. The fundamental ecotoxicological indices of <em>L</em><em>.</em><em> stagnalis</em> effected by various concentrations of Mn<sup>2+ </sup>water environment and the ranges of acute – and chronically lethal, trausferred and subthreshold toxicant concentrations as well as the decrease of toxicity of ions covered have been determined. The fundamental ecotoxicological indices of <em>L</em><em>.</em><em> stagnalis</em> effected by various concentrations of Mn<sup>2+</sup> water environment and the ranges of acute – and chronically lethaled, trausferred and subthreshold toxicant concentrations as well as the decrease of toxicity of manganese ions (ІІ) covered have been determined. The effect of Mn<sup>2+</sup> on dimensional and weight characteristics and the survival of adult and young mollusks has been studied. Reversibility of poisoning <em>L</em><em>.</em><em> stagnalis</em> by different Mn<sup>2+</sup> has been studied. Restoration of the broken functions is of a reversible nature. The linear indices varying considerably with toxicity have been distinguished. At first the aquatic balance in the bodies of mollusks is becoming positive along with the increase in the heavy metal concentrations in the environment, while under the toxicant concentration increase the balance gradually tends to be positive. The paper covers the effects of manganese ions on the pond snail behavioral reactions. The paper investigates the effects of Mn<sup>2+</sup> (acute lethal concentration – 100‒195 mg/dm<sup>3</sup>; chronically lethal – 35‒95 mg/dm<sup>3</sup>; trausferred – 0,3‒20 mg/dm<sup>3</sup>; subthreshold concentration – 1 mg/dm<sup>3</sup>) on the peculiarities of <em>L</em><em>.</em><em> stagnalis</em> reproduction and development. There have been determinate sensitive ethological responses of <em>L</em><em>. </em><em>stagnalis</em> at their reproductive period in the polluted environment. The studies have been made into structural stability of mollusk syncapsule, the peculiarities of their texture and formation physiology as well as an incidence of evolution disturbances at different intoxication levels by manganese ions (ІІ). The research makes it possible to ecologically estimate the nature of the substance influence and the response of the affected organism.</p>