2-hexyldecanoic acid

Biodegradation in water: screening tests

Description of key information

The ready biodegradability of 2 -Hexyldecanoic acid was determined with a non-adapted activated sludge over a test period of 28 days in the Modified Sturm Test in compliance with GLP. The mean of replicates reached the 10% level (beginning of biodegradation) within 6 days. The mean of the replicates reached the 60% threshold within 14 days. The mean biodegradation on day 28 was 85%. The test item was judged to be readily biodegradable, fulfilling the 10 -day window.

This result is supported by further tests with similar substances and in a computer model calculation.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

The ready biodegradability of 2 -Hexyldecanoic acid was determined with a non-adapted activated sludge over a test period of 28 days in the Modified Sturm Test (OECD guideline no. 301B) in compliance with GLP. The mean of replicates reached the 10% level (beginning of biodegradation) within 6 days. The mean of the replicates reached the 60% threshold within 14 days. The mean biodegradation on day 28 was 85%. The test item was therefore considered to be readily biodegradable, fulfilling the 10 -day window.

The biodegradation in water of 2 -hexyldecanoic acid was calculated using BIOWIN v4.10, a subroutine of of the computer program EPI SuiteTM version 4.11. The computer model calculation predicts 2 -hexyldecanoic acid to be ready biodegradable.

In further supporting studies similar test substances were tested for biodegradation as follows:

2 -butyloctanoic acid was tested according to OECD guideline no. 301B in compliance with GLP. In this study the biodegradation of 2 -Butyl octanoic acid was 69 % after 28 days. Also the percentage biodegradation exceeded 60% within the 10 -day window. The test item was therefore be considered to be readily biodegradable.

Reaction mass of n-undecanoic-acid and 2-methyl-decanoic-acid and 2-ethyl-nonanoic-acid and 2-propyl-octanoic-acid and 2-butyl-heptanoic-acid was tested for ready biodegradation according to OECD 301B. The degradation of the test item was 77.2 % within 28 days after acidification. The biodegradation of the test item reached the criterion for ready biodegradation.

2 -decyltetradecanoic acid was determined with a non-adapted activated sludge over a test period of 35 days in the Modified Sturm Test according to OECD 301 B. In this study four of six replicates reached a mean of 63 % biodegradation after 28 days. Therefore under the test conditions 2-decyltetradecanoic acid was classified as readily biodegradable, but failing the 10-day-window. In an additional supporting study with 2-decyltetradecanoic acid according to OECD 301 F the substance did not meet the 10-day window for ready biodegradable status. It consistently and uniquely fails and exceeds the criterion of less than 20 % ThOD difference between replicates in three tests. However, based on the extent of the biodegradabalility at the end of the 28-day with some replicates % ThOD greater than 60 %, 2-Decyltetradecanoic acid was considered inherently biodegradable.