Acute toxicity of heavy metals towards freshwater ciliated protists
Dipartimento di Scienze Ambientali, Università degli Studi di Parma, Parco Area delle Scienze 11/A, 43100 Parma, Italy. Environmental Pollution
(Impact Factor: 4.14).
06/2006; 141(1):1-7. DOI: 10.1016/j.envpol.2005.08.025
The acute toxicity of five heavy metals to four species of freshwater ciliates (Colpidium colpoda, Dexiotricha granulosa, Euplotes aediculatus, and Halteria grandinella) was examined in laboratory tests. After exposing the ciliates to soluble compound of cadmium, copper, chromium, lead, and nickel at several selected concentrations, the mortality rate was registered and the LC50 values (with 95% confidence intervals) were calculated. Large differences appeared in sensitivities of the four species to the metals. H. grandinella showed the highest sensitivity for cadmium (0.07 mg l(-1), LC50) and lead (0.12 mg l(-1), LC50), whilst E. aediculatus showed the highest sensitivity for nickel (0.03 mg l(-1), LC50). The comparison with data obtained with other species indicate that Halteria grandinella and Euplotes aediculatus are excellent and convenient bioindicator for evaluating the toxicity of waters and wastewaters polluted by heavy metals. The short time (24 h) and simplicity of the test procedure enable this test to be used in laboratory studies.
Available from: José Augusto Pires Bitencourt
- "Euplotes sp. are cosmopolitan ciliates that are often adapted to polluted ecosystems (Lynn, 2008). They can connect bacterial biomass production to high trophic levels (Azam et al., 1983; Pomeroy et al., 2007) and may transport metals by a biomagnification process (Fernandez-Leborans and Novillo, 1996; Madoni and Romeo, 2006; Martín-González et al., 2006). However, there is little information available on the heavy metal resistance of ciliated protozoa (Vieira and Volesky, 2000). "
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ABSTRACT: The main focus of this study was to evaluate the copper sensitivity of Euplotes vannus, Euplotes crassus, and their naturally associated bacteria from Guanabara Bay, a Brazilian polluted bay, during 96 h of laboratory assay. In the control, both microorganisms did not appear to be negatively affected, and . vannus and . crassus produced the highest biomass at 48 h (6.3×102 and ). With 0.001 mg Cu L−1, . vannus and . crassus showed the highest biomass (1.90×10−1 μg C cm−3, 24–72 h, and 8.52×102 μg C cm−3, 24 h), while their bacteria showed highest biomass at 24 h with exposition of 0,1 mg Cu L−1 (1.32 μg C cm−3, . vannus) and with 0.001 mg Cu L−1 (1.90×10−1 μg C cm−3, . crassus). However, . crassus showed more resistance and both following bacteria showed better adaptation to higher copper concentration, possibly due to previous environmental selection. The basis of the microbial loop may be active under copper stress and facilitates the biomagnification process.
- "hether accidental or intentional, the pollution of waters and soils by some chemical products whose origin may be industrial (heavy metals, dyes…) or agricultural rise to worldwide particular interest   . Beyond a certain concentration, heavy metals do turn into highly toxic species . "
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ABSTRACT: A new poly(vinylchloride) (PVC) membrane electrode based on tannin from the bark of Quercus macrolepis (acorn) as the ionophore was prepared and modified onto the surface of a gold electrode. The electrochemical impedance spectroscopy (EIS) technique was used to study the sensitivity of the electrode that was modified with a thin layer of polymeric biomembrane, in order to detect heavy metals ions in solution. The device shows a good sensitivity for Zn2+, Ni2+ ions and a little less for Cd2+. The electrode indicates a good linear response for the three metals over a wide concentration range from 1.0 × 10-9 to 1.0 × 10-4 M, with a detection limit of 1.0 × 10-9 M.
Available from: Grzegorz Lagod
- "The species composition and the abundance of ciliates were determined  . It is known that the protozoa communities in activated sludge can be treated as bioindicators of wastewater purification process and their community composition varies depending on many environmental factors            . Oxygen is one of the most important factors for activated sludge organisms. "
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ABSTRACT: Several experiments were performed in the laboratory condition using an SBR bioreactor modelling the expected conditions, created by malfunction of certain bioreactor elements, thus the different oxygen condition. In the course of the experiments, the concentrations of ammonia nitrogen, nitrates(III), nitrates(V), TOC, and TC were systematically measured. Besides physico-chemical parameters, the structure of activated sludge community was analyzed. In the samples, the number and species composition of protozoa (ciliates) were determined. Each of the three measuring series conducted for various types of process conditions was repeated three times. The activated sludge used for inoculation of the bioreactor was sampled at Hajdow WWTP in Lublin. The results obtained are the average of three repetitions of every experimental series. On this ground, we may conclude that the number of ciliates shows a high correlation with the O2 concentration, pH and TOC.
Zmiany w Strukturze Zbiorowiska Pierwotniaków Osadu Czynnego w Zróżnicowanych Warunkach Tlenowych
W pracy przedstawiono wyniki badań prowadzonych w laboratoryjnym bioreaktorze SBR, symulującym warunki występujące w przypadku awarii urządzeń stanowiących wyposażenie bioreaktora (systemu mieszania i systemu napowietrzania). Analizowano skład chemiczny ścieków, w tym stężenia związków azotu (azot amonowy, azotany(III) i azotany(V)), a także stężenia związków organicznych wyrażanych jako ogólny węgiel organiczny (OWO) i węgiel całkowity. Oprócz wskaźników chemicznych analizowany był również zespół organizmów osadu czynnego. W pobieranych próbkach określano ilość pierwotniaków (orzęski) w wymienionej grupie. Każdą z trzech serii pomiarowych prowadzonych dla różnych warunków procesowych powtarzano trzykrotnie. W eksperymencie wykorzystano osad czynny pobierany z oczyszczalni ścieków Hajdów w Lublinie. Na podstawie uzyskanych wyników badań można stwierdzić, że liczebności analizowanych zbiorowisk orzęsków wykazują związek ze stężeniem tlenu, pH oraz wartością OWO.
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