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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

One key study according 301B (enhanced test, 60 days with natural river water) indicate that the test iten is not readily biodegradable but primarily degradable. The 3 supporting studies according OECD 301 A and OECD 302 B shows that the substance is not readily and not inherently biodegradable. 

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

Key study (OECD 301 B, enhanced)

The biodegradability of the test item was determined with natural river water inoculum over a test period of 60 days in an Enhanced Modified Sturm Test. The study was conducted from 2012-05-03 to 2012-07-17 according to OECD 301 B and ECHA at DR.U.NOACK-LABORATORIEN. The test item was tested at a concentration of 12 mg/L with 3 replicates, corresponding to a carbon content (TOC) of 4.8 mg C/L in the test vessels. The biodegradation of the test item was followed by titrimetric analysis of the quantity of CO2produced by the respiration of bacteria. The degradation was stopped on day 60 by acidification of the test solutions. The last titration was made on day 61, after residual CO2had been purged from the test solutions over a period of 24 hours. The percentage CO2production was calculated in relation to the theoretical CO2production (ThCO2) of the test item. The biodegradation was calculated for each titration time. Furthermore the primary biodegradation was determined by Lc-MS/MS analysis at test end.

 

To check the activity of the test system, aniline was used as functional control. The percentage degradation of the functional control reached the pass level of 60 % within 11 days and a biodegradation of 75 % after 15 days.

 

The biodegradation of thetest itemis shown graphically in Figure 1 in comparison to the readily degradable functional control. The 10 % pass level (= start of biodegradation) was reached by the mean of replicates after 9 days. Two of the replicates reached 32 % and 31 % degradation after 60 days. The 3rdreplicate reached a final degradation of 23 % after 60 days.

 

To determine the primary degradation the concentrations of M = 223 and M = 251, the main active ingredients of Afilan V5760, were determined via LC-MS/MS in test item replicates at test end. A recovery of 0.4% was obtained for M = 223. Recoveries of 3 % and 4% were obtained for M = 251. These data indicate that the main active ingredients were metabolised during the course of the biodegradability test.

 

The biodegradation results indicate that the test item isnot readily biodegradableaccording to OECD 301 B and ECHA (2008). Nevertheless, the results also indicate a potential for degradation in the environment and the test item isprimarily biodegradable.

 

The test item is classified as not readily biodegradable but primarily degradable in natural environmental media.

Supporting studies

One supporting study according OECD 301A and two supporting studies according OECD 302B showed that the test item is not readily biodegradable and also not inherently biodegradable.