Acute toxicity of lead, chromium, and other heavy metals to ciliates from activated sludge plants

Journal Article · Thu Sep 01 00:00:00 EDT 1994 · Bulletin of Environmental Contamination and Toxicology; (United States)

DOI:https://doi.org/10.1007/BF00197235· OSTI ID:6870589

Madoni, P; Gorbi, G ^[1]; Davoli, D ^[2]

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1. Univ. of Parma (Italy)
2. AGAC, Reggio Emilia (Italy)

Numerous papers deal with the occurrence of heavy metals in the various components of freshwater ecosystems and sewage treatment systems. However, few papers refer to the presence and effect of heavy metals in populations of aquatic cilated protozoa. In particular, the lethal concentrations (LC50) of heavy metals in ciliate populations that colonize the activated sludge or the biofilm of waste treatment plants. Ciliated protozoa are very numerous in all types of aerobic biological-treatment systems. They play an important role in the purification process removing, through predation, the major part of dispersed bacteria that cause high turbidity in the final effluent. Changes in the community structure and types of ciliate species may affect the food web of these artifical ecosystems, and may also influence the biological performance of plants. Heavy metals can limit growth of protozoa in aquatic environments. The toxicity of heavy metals in biological treatment depends mainly upon two factors, namely, metal species and concentration. Although the resistance of biological systems to metal toxicity may be enhanced greatly by proper acclimatization, a too-high metal concentration may cause serious upsets in the system. It is important to determine the concentrations of heavy metals causing lethal effects on ciliates. Madoni recently studied the acute toxicity of cadmium, copper, mercury, and zinc on six species of ciliated protozoa from activated sludge plants. The present paper describes the toxic effects of lead and chromium (VI) on 6 cilate species. The acute toxicity of Cd, Cr, Cu, Hg, Pb, and Zn on two other ciliates (Drepanomonas revoluta and Spirostomum teres) is also reported. 18 refs., 4 tabs.

• OSTI ID: 6870589
• Journal Information: Bulletin of Environmental Contamination and Toxicology; (United States), Vol. 53:3; ISSN 0007-4861
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
CILIATA
GROWTH
METALS
BIOLOGICAL EFFECTS
ECOLOGICAL CONCENTRATION
SEWAGE SLUDGE
BIODEGRADATION
ACTIVATED SLUDGE PROCESS
CHROMIUM
LEAD
POLLUTANTS
ANIMALS
BIOLOGICAL MATERIALS
BIOLOGICAL WASTES
CHEMICAL REACTIONS
DECOMPOSITION
ELEMENTS
INVERTEBRATES
MANAGEMENT
MATERIALS
MICROORGANISMS
PROCESSING
PROTOZOA
SEWAGE
SLUDGES
TRANSITION ELEMENTS
WASTE MANAGEMENT
WASTE PROCESSING
WASTES
560300* - Chemicals Metabolism & Toxicology