where 𝑀𝑜𝑏 𝑡 2 and 𝑀𝑜𝑏 𝑡 1 are the numbers of the mobile test organisms at the start (𝑡 1 ) and at the end (𝑡 2 ) of the experiment, respectively. Next, the dependence between effect and the concentration of the tested compounds was plotted, and on this basis, an EC50 range was determined.