Reaction mass of 2,6-Bis[(dimethylamino)methyl]-4-(1-{3-[(dimethylamino)methyl]-4-hydroxyphenyl}-1-methylethyl)phenol and 4-(1-{3,5-Bis[(dimethylamino)methyl]-4-hydroxyphenyl}-1-methylethyl)-2,6-bis[(dimethylamino)methyl]phenol

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Deviations:

yes

Remarks:

see 'Principles of method if other than guideline'

Qualifier:

according to guideline

Guideline:

EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

Principles of method if other than guideline:

The pH value of one measured replicate 8.7 lay slightly over the recommended range of pH 6-8.5 for replicates were no degradation occurred. Maybe some of the adsorbing sodium hydroxide solution dropped into the test flask resulting in a higher pH value. This probably happened at the end of the test by removing the OxiTop lid.
By technical reasons, the pH value was determined after 30 days instead at the end of the BOD determination after 28 days. This has no influence on the results as the validity criteria were met.

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

- Type: mixed population of aquatic microorganisms (activated sludge)
- Origin: aeration tank of a wastewater plant treating predominantly domestic sewage (Wupper area water authority, WWTP Odenthal)
- Date of collection : 2016-02-29
- Concentration of inoculum: 30 mg/L suspended solids

Pre-treatment of the inoculum
− inoculum was stored for one day at room temperature under continuous stirring with aeration
− sludge was washed twice by adding mineral medium and centrifuging for 10 min at 2000 rpm and 20 °C and decanting off the supernatant
− an aliquot of the wet sludge was dried in order to determine the wet weight / dry weight ratio of the sludge and to prepare a stock suspension (activated sludge) of 3 g dw/L

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

Exposure conditions
- Test volume: 250 mL
- Test apparatus: OxiTopControl System (WTW)
- Sampling: continuously
- Mixing: 1 magnetic stirrer per test vessel
- Incubation time: 28 days
- Incubation temperature: 22 ± 1 °C
- pH: 7.2 - 8.7
- Continuous darkness
- flask preparations: toxicity control: one replicate, test item: three replicates, blank: three replicates, reference: two replicates

Pre-treatment of the test item
- 25 mg of the test item were weighed out and added to the test flasks, filled with 200 mL of mineral medium
- volume was made up to 250 mL with mineral medium containing the inoculum to give a test concentration of 100 mg test item/L

Pre-treatment of the reference compound
- 25 mg of the reference compound were weighed out and added to the test flasks, filled with 200 mL of mineral medium
- volume was made up to 250 mL with mineral medium containing the inoculum to give a test concentration of 100 mg reference compound /L

Pre-treatment of the toxicity control
- 25 mg of the test item and 25 mg of the reference compound were weighed out and added to the test flasks, filled with 200 mL of mineral medium
- volume was made up to 250 mL with mineral medium containing the inoculum to give a test concentration of 100 mg test item and reference compound/L

Reference substance:

benzoic acid, sodium salt

Remarks:

Acros Organics, purity: 99.9 %, batch-no. A0357641

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

28 d

Details on results:

COD of test item: 2.087 mg O2/mg
ThOD of reference item: 1.665 mg O2/mg

The degradation rate of the test item was set in relation to its experimentally determined COD. As the COD implicitly covers the oxygen demand for the nitrification process, there was no need to take additional correction measures into account.

Results with reference substance:

The reference substance was degraded to 81% after 14 d.

In the toxicity control a degradation of 32% was recorded after 14 d. Since the degradation is > 25% after 14 d the test item is not considered to be toxic to the inoculum.

Validity criteria fulfilled:

yes

Remarks:

biodegradation of reference compound ≥ 60 % in 14 d; biodegradation of toxicity control > 25 % in 14 d; differences of biodegradation in replicates of test item <= 20 %; oxygen uptake of inoculum blank ≤ 60 mg/L; pH independent

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

HPP 12879-1 showed 0 % degradation after 28 days. Therefore, HPP 12879-1 is considered to be “Not Readily Biodegradable“.

Executive summary:

A study was performed to assess the ready biodegradability of HPP 12879-1 in accordance with the Council Regulation (EC) No 440/2008, Method C.4-D “Manometric Respirometry Test“(2008). This test method is in all essential parts identical with OECD Guideline 301 F (adopted July 1992).

A suspension of 100 mg/L HPP 12879-1 in a mineral mediu, equalling to 50-100 mg ThOD or COD/Litre as the nominal sole source of organic carbon, was inoculated and incubated for 28 d under aerobic conditions in the dark at a constant temperature (22 ± 1 °C). During this period, degradation was followed by continuous automated BOD determinations.

The endogenous activity of the inoculum was checked running parallel blanks with inoculum but without test item. A reference compound (sodium benzoate) was run in parallel to check the operation of the procedures. A toxicity control (test item and reference compound mixed, one replicate) was run in parallel, to ensure that the chosen concentration of the test item was not inhibitory to microorganisms. Because of the nature of biodegradation and of the mixed bacterial populations used as inoculum, determinations of test item and inoculum blank were carried out in triplicate and of reference compound in duplicate. At the end of incubation, the pH was measured in the flasks.

The degradation rate of the test item was set in relation to its experimentally determined COD. As the COD implicitly covers the oxygen demand for the nitrification process, there was no need to take additional correction measures into account.

HPP 12879-1 showed 0 % degradation after 28 days. Therefore, HPP 12879-1 is considered to be “Not Readily Biodegradable“.

The reference compound sodium benzoate showed 81 % degradation after 14 days.

Description of key information

For HPP 12879 -1 ready biodegradability and inherent biodegradability were studied. In both tests no biodegradation was observed. Thus, HPP 12879 -1 is considered as not readily biodegradable and as not inherently biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

Ready biodegradation

Within 28 days no biodegradation (0 %) was observed for HPP 12879-1. Therefore, HPP 12879 -1 is considered as "Not Readily Biodegradable".

The reference compound sodium benzoate showed 81 % degradation after 14 days.

Inherent biodegradation

Within 28 days a degradation rate of 0 % was determined for HPP 12879-1. Thus, HPP 12879-1 is considered to be "Not Inherently Biodegradable".

The reference compound sodium benzoate showed 86 % degradation after 14 days.