Ciliate populations and metals in an activated-sludge plant

Abraham, Jijo; Butler, R. D.; Sigee, David C.

doi:10.1016/s0043-1354(96)00334-x

Cited by 42 publications

(30 citation statements)

References 22 publications

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“…In experiments using the free-swimming ciliate Tetrahymena pyriformis, copper above 200 mg l -1 inhibit growth significantly (Nicolau et al 1999). In a study in which ciliate species were monitored in relation to metal concentration over a two-year period (Abraham et al 1997), it was found that the major ciliate species present were able to tolerate high concentrations of contaminant metals, including Fe (>2 mg l -1 ), Zn (>0.5 mg l ). This suggests that acclimatization can reduce the toxicity of heavy metals upon ciliates.…”

Section: Effect Of Toxicants On Protozoa In Sewage Treatment Processesmentioning

confidence: 99%

Protozoa in wastewater treatment processes: A minireview

Madoni

2011

Italian Journal of Zoology

178

114

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Biological wastewater treatment is a process of increasing importance in a world with an ever-increasing human population. Wastewater treatment facilities are designed to maintain the high density and activity levels of those microorganisms that carry out the various purification processes. Protozoa are one of the most common components in these man-made ecosystems and play an important role in wastewater purification processes. Protozoa are responsible for improving the quality of the effluent, maintaining the density of dispersed bacterial populations by predation. Studies of the relationships between protozoa and physicochemical and operational parameters have revealed that the species structure of these communities is an indicator of plant efficiency. The Sludge Biotic Index (SBI), an index based on the structure and abundance of the microfauna inhabiting the activated sludge and mixed liquor, has been devised to monitor activated-sludge plant performance. Heavy metals and other pollutants are toxic to most microorganisms at certain concentrations. These toxicants are common pollutants of sewage, particularly where there is industrial waste input. The protozoa community is a complex assemblage of interacting organisms, often including species that are sensitive, resistant or intermediate in their tolerance to pollutants. Many studies conducted on contaminated activated sludge and mixed liquor have revealed changes in the dynamics of the protozoa community. Tests on the acute toxicity of pollutants on ciliates have revealed that these microorganisms are useful bioindicators for evaluating the toxicity of waters polluted by different concentrations of metals.

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Section: Effect Of Toxicants On Protozoa In Sewage Treatment Processesmentioning

confidence: 99%

Protozoa in wastewater treatment processes: A minireview

Madoni

2011

Italian Journal of Zoology

178

114

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“…For example, throughout 1991-1992, 29 ciliate species have been isolated from an activated-sludge plant in Manchester, U.K., and showed resistance to 60 ppb of copper (Abraham et al, 1997). In bioassays performed with heavy metals, the population of Colpoda steinii, a soil ciliated, was reduced by 50% in the presence of 0.10, 0.22, 0.25, and 0.85 mg L -1 of Ni, Cd, Cu and Zn respectively (Forge et al, 1993).…”

Section: Heavy Metal Exposure Analysismentioning

confidence: 99%

Influence of copper on Euplotes sp. and associated bacterial population

Silva

Bitencourt

Silva

et al. 2014

lajar

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ABSTRACT. The influence of copper on the ciliate Euplotes sp. and associated bacteria isolated from sediment samples of Guanabara Bay were investigated in bioassays. This region is highly affected by heavy metals such as copper, from solid waste constantly dumped in the bay and other sources such as industrial effluents, antifouling paints, atmospheric deposition and urban drainage, and even today there are few data on the metal toxicity to the ecosystem of the Bay of Guanabara. Bioassays were conducted to estimate the LC 50 -24 h of copper, in order to determine the concentration of metal bearing 50% of the population mortality. The results indicated that the concentrations of 0.05 and 0.009 mg L -1 presented no toxicity to Euplotes sp. The associated bacteria are tolerant to copper concentrations used in bioassays, and suggest that they could be used as a potential agent in the bioremediation of areas affected by copper. Keywords: Euplotes sp., bacteria, copper, heavy metals, Guanabara Bay, southeast Brazil.Influencia del cobre sobre Euplotes sp. y la población de bacterias asociada RESUMEN. La influencia del cobre sobre el ciliado Euplotes sp. y las bacterias asociadas aisladas de muestras de sedimentos de la bahía de Guanabara fueron investigados en bioensayos. Esta región está altamente afectada por metales pesados, como el cobre, a partir de residuos sólidos constantemente vertidos en la bahía y de otras fuentes, como los efluentes industriales, pinturas antiincrustantes, deposición atmosférica y drenaje urbano, y hasta hoy hay pocos datos sobre la toxicidad del metal para el ecosistema de la bahía de Guanabara. Se efectuaron bioensayos para estimar la CL 50 -24 h de cobre para determinar la concentración de metales que lleva al 50% de la mortalidad de la población. Los resultados indicaron que las concentraciones de 0,05 y 0,009 mg L -1 , no representan toxicidad para Euplotes sp. Las bacterias asociadas son tolerantes a las concentraciones de cobre utilizadas en los bioensayos, lo que sugiere que podrían ser utilizadas como un agente potencial en la biorremediación de las zonas afectadas por el cobre. Palabras clave: Euplotes sp., bacterias, cobre, metales pesados, bahía de Guanabara, sureste de Brasil.

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“…11,13,14,19,[22][23][24] The study of P. bursaria and its interaction with chromium may be useful for bioremediation of chromium-contaminated environments. The aim of the study was to determine the ability of P. bursaria to accumulate chromium.…”

Section: P Bursariamentioning

confidence: 99%

Toxicity and Bioaccumulation of Hexavalent Chromium in Green Paramecium, Paramecium bursaria

Mortuza

Takahashi

Ueki

et al. 2005

JOURNAL OF HEALTH SCIENCE

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The effects of hexavalent chromium on the cell growth of green paramecium, Paramecium bursaria (P. bursaria), were investigated in this study. Two strains (MB-1 and F 1 generation) of P. bursaria were incubated in lettuce media supplemented with different concentrations of potassium dichromate under light (L) L (24 hr light), L dark (LD) (12 hr light : 12 hr dark) and DD (24 hr dark) conditions, and the IC 50 values were obtained. The IC 50 7-day value showed that the toxicity of potassium dichromate was light-sensitive in both strains of P. bursaria. The results of the toxic effect of chromium on the cell shape of P. bursaria showed that the body ratio of P. bursaria increased, even if the cells were incubated for 24 hr with 0.5 µM potassium dichromate solution, indicating that the cell shape of P. bursaria is very sensitive to potassium dichromate. The average amount of chromium accumulated in green paramecium ranged from 1.72 to 15.5 pg Cr/cell in a time-and concentration-dependent manner. This finding indicates the possibility of the use of P. bursaria as a biomonitor and bioaccumulator for chromium contaminants in aquatic environments. The experiment with electrical stimuli into the culture of P. bursaria indicated that cells accumulated at the negative electrode, suggesting that P. bursaria carried a positive charge. Thus, because the positive charge does not cause any significant absorption of chromium into the cells, P. bursaria may develop a variety of mechanisms for chromium accumulation in the cell. Further research studies are required to elucidate the mechanism of chromium uptake in P. bursaria.

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Ciliate populations and metals in an activated-sludge plant

Cited by 42 publications

References 22 publications

Protozoa in wastewater treatment processes: A minireview

Protozoa in wastewater treatment processes: A minireview

Influence of copper on Euplotes sp. and associated bacterial population

Toxicity and Bioaccumulation of Hexavalent Chromium in Green Paramecium, Paramecium bursaria

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