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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

Based on available data of three read-across source substances, the test item is considered to be readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

No experimental data on ready biodegradation is available for the test item. However, experimental data for three source substances is available and a read-across approach is applied. Please refer to read-across justification document attached in IUCLID Section 13. Furthermore, only key studies are taken into account here. For further supporting information please refer to respective REACH registration dossier of each source substance.

LAS TEA (CAS 121617 -08 -1)

The biodegradability of the substance was studied in a DOC-DIE AWAY test. The test substance (8.55 mg DOC/L) was added to flasks containing activated sludge. The DOC concentration was then measured over the next 28 days. Sodium benzoate was used as a reference substance. The reference substance was 101% degraded in 28 days. Therefore the test is valid. The test substance was 94% degraded in 28 days. For both the reference and test substance >70% degradation within the 10-day window as achieved. The test substance is readily biodegradable.

 

The biodegradability of the substance was studied in a OECD 301 B (CO2 -evolution) test. The test substance (20 mg organic carbon/L, equivalent to 35 mg/L Benzenesulfonic acid, C10-13-alkyl derivs., compds. with triethanolamine (CAS no. 68411-31-4)) was added to flasks containing activated sludge. The CO2 production was then measured as inorganic carbon captured in gas wash flasks filled with 0.2 M NaOH over the next 28 days. Sodium benzoate was used as a reference substance and as toxic control both the test substance and the reference substance were combined. The reference substance reached the pass levels for ready biodegradability within 7 days. The degradation in the toxicity control was 88.1% within 14 days and 99.5% within 28 days (after acidification), so there was no inhibition of the inoculum by the test substance. The test is valid. The test substance was 101% degraded in 28 days (after acidification). On day 7 the mean degradation extent was already higher than 60%. For both the reference and test substance >60% degradation within the 10-day window was achieved. The test substance is readily biodegradable.

 

LAS NA (CAS 68411 -30 -3)

This study examined the biodegradability of the test substance. 34.3 mg/L of test substance was added to flasks containing activated sludge. The amount of CO2 evolved was then measured over the next 29 days. Sodium benzoate was used as a reference substance. The reference substance was 89% degraded in 29 days. Therefore the test is valid. The test substance was 85% degraded in 29 days. The test substance is readily biodegradable.

 

DEA (CAS 111 -42 -2)

The potential for biodegradation of DEA has been comprehensively investigated in a number of standardized and non-standardized tests. In a manometric respirometry test (OECD 301 F) following GLP, DEA is readily biodegradable since the substance was degraded by 93 % after 28 days related to BOD. The inoculum was activated sludge from a laboratory wastewater treatment plant treating domestic sewage (BASF AG, 1992).