Characteristics of Acute Toxicity Dynamics of Selected Toxicants on Aquatic Crustaceans

Abstract

Determining the value of a half-effective or half-life concentration or dose of toxicant is the main purpose of acute toxicity studies, and this is also the most commonly used value in the toxicity characteristics of substances. By conducting tests that meet the criteria and requirements for the determination of acute toxicity, due to the use of appropriate mathematical tools and concentrations resulting in complete lethal effects in the studied groups, considerably more important values can be achieved, which give a possibility for the analysis of the entire process’s dynamics, as well as determining the threshold values of the effect time and toxicant concentration. This was the purpose of our research, in which the research species were Daphnia magna and Cypris pubera. The effect of the conducted research allowed to determine and compare the two toxicants: ammonium and copper(II) ions by it’s: concentration limit values (Cth), internal toxicity of the receptor-ligand complex (α), apparent, constant disintegration of this complex (Kapp) and different time values of the effect (Tt, Tin, MLT), which, along with concentration, is equally important determinant of the development of a toxic effect.

An Empirical Study on Environmental Efficiency Measurements and Influencing Factors

“…The higher the proportion of cargo and mail turnover, the higher the operational efficiency of the airline, which in turn helps improve environmental efficiency [18][19][20]. Market share embodies the scale of airline production, which has some effect on improving an airline's environmental efficiency [21][22][23][24][25]. It is necessary, therefore, to control the impact of the proportion of cargo and mail turnover and market share on airline environmental efficiency.…”