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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

not readly and inherently biodegradable

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed
Type of water:
freshwater

Additional information

Two tests for the assessment of the biodegradability of the substance in water were performed in order to assess both the readily and inherently biodegradability potential.

The ready biodegradability test was performed according to OECD 301F “manometric respirometry test”. The results show that the substance is not readily biodegradable in 28 d under the following test conditions: 22 ± °C; range of pH between flasks from 7.3 to 7.7; darkness. No toxicity against microorganisms was detected. The validity of the test was fulfilled since it met all the criteria of the followed OECD (Gruntzner, 1994).

The inherently biodegradability test was performed according to OECD 302C “modified MITI-Test (II)”. The results show that the substance is not inherently biodegradable in 28 d under the following test conditions: 24 °C; range of pH between flasks from 7.0 to 8.7.

The validity of the test was fulfilled since it met all the criteria of the followed OECD (Gruntzner, 1994).

During the experiments, the substance did not inhibite microorganisms.

It should be noted that a deviation from the OECD 302C guideline was present, regarding the preparation of sludge samples: microorganisms were collected from just one domestic water treatment plant instead of from at least ten different places as recommended by the guideline. In any case, the results of the test could be considered representative for the substance, because of its very low biodegradability.

In conclusion, the substance has to be considered not readly and inherently biodegradable.