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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

A ‘ready’ biodegradability (modified Sturm test) was conducted with di C8-C10, branched, C9 rich, alkylnaphthalene sulphonic acid (DNNSA). The relative biodegradation values calculated from the measurements performed during the 29-day test period revealed 14 and 17% biodegradation (Wil, 2012).
In addition an inherent biodegradation study was conducted with DNNSA according to a modified protocol based on OECD guideline No. 310 (Wil 2013). The major modifications on the procedure were the re adaptation of sludge during a 13-day period, before the start of the test and prolongation of the test period up to 56 days. The relative biodegradation values calculated from the measurements performed during the test period revealed no significant biodegradation of DNNSA (0%). In conclusion, di C8-C10, branched, C9 rich, alkylnaphthalene sulphonic acid (DNNSA) is designated as not inherently biodegradable.
Based on the structural similarities between ZnDNNSA and its acid, it is concluded that ZnDNNSA is not readily biodegradable.
 

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

DNNSA is a structural analogue of Zinc ( di C8-C10, branched, C9 rich, alkylnaphthalene sulphonate). Under the conditions of the OECD 301B test, di C8-C10, branched, C9 rich, alkylnaphthalene sulphonic acid (DNNSA) was not readily biodegradable. Degradation of DNNSA was 14-17% after 28 days.In a test for inherent biodegradation, no degradation of DNNSA was observed over the 56-day study period. These results are indicative of very slow biodegradation of ZnDNNSA.