Acute toxicity of potentially toxic elements on ciliated protozoa from Lake Maracaibo (Venezuela)

Abstract

Aim In this article the acute ecotoxicological effects of Cr(III), Cr(VI), Cd(II) and V(V) on ciliated protozoa isolated from Lake Maracaibo were evaluated, by estimating of the LC50 for an exposure time of 1-h and observations every 5 min. Methods Isolations and cultures of ciliated protozoa were made from surface water samples to then carry out toxicity essays under static and controlled conditions, identifying cell immobility (death) as the endpoint. Results The response of the ciliated protozoa made it possible to unequivocally determine the acute toxicity in presence of potentially toxic elements (PTE), with variable mortalities depending on the gender, the element tested and its concentration. The results obtained with Euplotes sp. indicate that protozoan is a sensitive biomonitor indicated for the biomonitoring of PTE contamination in Lake Maracaibo. Conclusions The use of shorter exposure periods offers opportunities to show early toxicity effects on natural populations and to act in a timely manner (early warning systems) in contamination events by PTEs, as well as the development of sensitive and rapid biomonitoring methods for detection of these elements in the environment.

Cytotoxicity and Antioxidant Defences in Euplotes aediculatus Exposed to Single and Binary Mixtures of Heavy Metals and Nanoparticles

“…Euplotes aediculatus is a freshwater ciliate belonging to the class Hypotrichea and the family Euplotidae. Although this and other congeneric species have been extensively studied in various biological aspects, including toxicity assessment [40][41][42][43], to the best of our knowledge, only one recent study has attempted to analyse the toxic effects induced by NPs, specifically Cu and CuO, on E. aediculatus [44]. In this regard, our study further extends this analysis by increasing the number of NPs tested (i.e., ZnO, CuO, TiO 2 , and SiO 2 ) and for the first time, assessing their acute and chronic effects in combination with heavy metals (i.e., Cd, Zn, and Cu) on E. aediculatus.…”