Acute toxicity of heavy metals (copper, lead, zinc), phenol and sodium on Allium cepa L., Lepidium sativum L. and Daphnia magna St.: Comparative investigations and the practical applications

The investigations of the effects of various heavy metal: Cu (as CuSO4), Pb (as Pb(NO3)2) and Zn (as ZnSO4), phenol and Na (as Na2SO4 and NaCl) concentrations on root length of onion bulbs (Allium cepa L.) and garden cress (Lepidium sativum L.), as well as on the survival rate of great water flea (Daphnia magna St.) showed varied sensitivity of the above test organisms. Based on IC50 value (50% inhibitory concentration) for A. cepa L. and L. sativum L. and on LC50 value for D. magna St., the acute toxicity of the tested substances decreased after a 48-hour exposition in the following order: A. cepa L.: Cu > Pb > Zn > phenol > Na2SO4 > NaCl; L. sativum L.: phenol > Cu > Pb > Zn > Na2SO4 > NaCl; D. magna St.: Cu > Zn > phenol > Pb > Na2SO4 > NaCl.