Spontaneous skeletal deformities in the Zebra Danio (Brachydanio rerio) bred for fish toxicity tests

Among the disinfection processes of urban waste water, ozonation and UV irradiation are fast gathering interest. To avoid what happened with chlorine it is necessary to have a look at the formation of by-products and the risks of toxicity when such processes are used. We were already working on this type of problem in 1984, although we did not make a point of communicating in extenso the results obtained during a 2-year period of pilot plant and laboratory studies at La Roche sur Yon (Vendée, France). The present paper reminds of the changes in chemical nature of the effluent after an ozonation from 6 to 12 g O3/m3 resulting in an abatement of fecal coliforms and fecal streptococci to the extent of 3 to 4 logarithmic units. No evidence of compounds known for their toxicity was brought to light. The toxicity tests performed on fish (Brachydanio rerio) and crustacean (Artemia nauplii) showed that the secondary effluent upstream or dowstream of the ozonation did not have toxic effects on the used biological material except for the fish when strong ammonia nitrogen concentrations occur. The toxicity tests performed on green algae (Scenedesmus subspicatus) showed that ozonated effluent seemed less conductive to algal growth than non ozonated effluent.

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On the possibility of using biological toxicity tests to monitor the work of wastewater treatment plants

Archives of Biological Sciences ◽

10.2298/abs0803431z ◽

2008 ◽

Vol 60 (3) ◽

pp. 431-436

Author(s):

Jelena Zoric ◽

V. Simic ◽

Ana Petrovic

Keyword(s):

Wastewater Treatment ◽

Acute Toxicity ◽

Wastewater Treatment Plants ◽

Treatment Plant ◽

Test Organism ◽

Toxicity Tests ◽

Brachydanio Rerio ◽

Toxic Pollutants ◽

Biological Toxicity ◽

Before And After

The aim of this study was to ascertain the possibility of using biological toxicity tests to monitor influent and effluent wastewaters of wastewater treatment plants. The information obtained through these tests is used to prevent toxic pollutants from entering wastewater treatment plants and discharge of toxic pollutants into the recipient. Samples of wastewaters from the wastewater treatment plants of Kragujevac and Gornji Milanovac, as well as from the Lepenica and Despotovica Rivers immediately before and after the influx of wastewaters from the plants, were collected between October 2004 and June 2005. Used as the test organism in these tests was the zebrafish Brachydanio rerio Hamilton - Buchanon (Cyprinidae). The acute toxicity test of 96/h duration showed that the tested samples had a slight acutely toxic effect on B. rerio, except for the sample of influent wastewater into the Cvetojevac wastewater treatment plant, which had moderately acute toxicity, indicating that such water should be prevented from entering the system in order to eliminate its detrimental effect on the purification process.

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