Reaction product of Benzenesulfonic acid, 4-C10-13-sec-alkyl derivs. and Benzenesulfonic acid, 4-methyl- and sodium hydroxide

Biodegradation in water: screening tests

Description of key information

The reaction product and the two substances that comprise the reaction product (i.e., the sodium salt of linear alkylbenzenesulfonate and sodiumtoluene sulphonate) are readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

The 3 key studies are;

The Reaction Product - a 1993 EU DOC Die Away Test comparable to OECD 301A test. The test substance reached 94% DOC removal after 28 days and reached >70% biodegradation in 10 days after reaching 10% degradation.

The main constituent (and read across substance), Sodium 4-undecylbenzenesulfonate (CAS No 68411-30-3) - a 2002 OECD 301B Modified Sturm Test - based on CO2 evolution. The test substance reached 85% CO2 evolution in 29 days and reached the 60% "ready biodegradability" threshold in 9 to 12 days.

The 2nd constituent (and read across substance), Sodium toluene sulphonate (CAS No 12068-03-0) - a 2004 OECD 301B Modified Sturm Test - based on CO2 evolution study. The test substance reached 100-115% CO2 evolution in 28 days and reached the 60% "ready biodegradability" threshold in 4 days.

There are also 6 additional fully documented, guideline biodegradation tests for hydrotrope substances closely related to sodium toluene sulphonate:

Sodium cumene sulphonate (CAS No 28348-53-0) -

There are two OECD guideline biodegradation studies; a 1992 301B Modified Sturm Test - based on CO2 evolution and a 1995 OECD 301D - Closed Bottle test - based on O2 consumption. The test substance reached 60% biodegradation in 6 days as measured by CO2 evolution and 100% CO2 evolution in 28 days in the Modified Sturm Test thus achieving the ready biodegradability criteria. The test substance reached 50% CO2 consumption in 28 days in the supporting Closed Bottle test and was reported as inherently biodegradable but it did not meet the readily biodegradable criteria in this test. There are 5 additional guideline biodegradation tests for closely related substances discussed below. Three of the four Modified Sturm tests concluded "readily biodegradable". The remaining Modified Sturm test reached 82-87% CO2 in 28 days but did not achieve 60% CO2 until day 16. A Closed Bottle test concluded the test substance was inherently biodegradable.

Sodium xylene sulphonate (CAS No 1300-72-7) - a 1993 OECD Guideline study - 301B Modified Sturm Test - based on CO2 evolution. The study was conducted according to GLP requirements and is fully documented. The test substance achieved the 60% biodegradation threshold by Day 6 and reached 93.2% of theoretical CO2 in 28 days. Therefore, the test substance is shown to be readily biodegradable under aerobic conditions. There are two additional supporting studies available for sodium xylene sulphonate. A second OECD guideline 301B test that also demonstrated ready biodegradability, and a OECD 301D - Closed Bottle test - based on O2 consumption that confirmed inherent biodegradability but in which the 60% threshold was not achieved in 6 days.

Calcium xylene sulphonate (CAS No 28088-63-3) - a 1994 OECD 301B Modified Sturm Test - based on CO2 evolution study. The test substance reached 82-87% CO2 evolution in 28 days but took 16 days to reach the 60% "ready biodegradability" threshold.