Preliminary Study on Toxicity of Some Heavy Metals Towards the Ciliated Protozoan Paramecium sp.

Mostafa, Osama M. S.; Mostafa, Amr B.; Abd El-Hady, Nourhan A. A.; Nigm, Ahmed M. H.

doi:10.21608/ejabf.2023.337886

Preliminary Study on Toxicity of Some Heavy Metals Towards the Ciliated Protozoan Paramecium sp.

Document Type : Original Article

Authors

10.21608/ejabf.2023.337886

Abstract

In the present study, the ciliated protozoan Paramecium sp. obtained from the Ismailia Canal, Cairo, Egypt, was cultured in a laboratory and then exposed to heavy metal ions of cadmium, copper, and lead at various concentrations. The purpose of the present work was to assess the sensitivity of Paramecium sp. to heavy metals and to get predictive data for risk and hazard assessments in standards for water quality. The careful microscopic examination and measurements of cultured non-stressed Paramecium sp. revealed that the species could be a part of the P. aurelia complex since its morphological features matched those described by Sonneborn (1975). Further investigation is required to validate the present identification of Paramecium sp. Concerned with heavy metal toxicity against cultured Paramecium sp., copper at concentrations of 10, 30, and 60μg ml⁻¹ appeared highly toxic since the organisms became motionless and died indoors a few minutes post-exposure. No full mortality was seen in Paramecium sp. culture exposed to lead within concentrations up to 150μg ml⁻¹ before 3hr of incubation. All tested lead concentrations (30, 80, and 150μg ml⁻¹) induced full mortality at 6hr post-incubation. The LD50 of this pollutant was 19.11μg ml⁻¹. Furthermore, complete mortality wasn’t noted in Paramecium sp. communities subjected to 10, 25, and 50μg ml⁻¹ of cadmium during the experiment. The LD50 values of this pollutant at 3, 6, and 12 hours of incubation were 13.9, 8.08, and 11.2μg ml⁻¹, respectively. Moreover, an unexpected observation was recorded since the mortality rate decreased as the cadmium concentrations and the exposed time increased. This exploratory work may be useful for ecotoxicological testing and applications, especially in heavy metal-contaminated aquatic ecosystems and systems. Furthermore, the presence of consistent and distinguishable growth in contaminated samples might be employed as a quick qualitative test field.

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