Reaction mass of 2,2'-(Ethylenedioxy)diethanol and 3,6,9-Trioxaundecane-1,11-diol

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Qualifier:

according to guideline

Guideline:

ISO 8192 (Water quality - Test for inhibition of oxygen consumption by activated sludge for carbonaceous and ammonium oxidation)

GLP compliance:

no

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

activated sludge, domestic

Details on inoculum:

- Inoculum concentration of dry substance 1 g/l
- Name and location of sewage treatment plant where inoculum was collected:Lambsheim, Germany; stp treating predominantly municipal wastewater

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

30 min

Nominal and measured concentrations:

nominal: 15, 150, 750, 1995 mg/L

Key result

Duration:

30 min

Dose descriptor:

other: EC20

Effect conc.:

> 1 995 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Test concentration	Promotion of respiration
[mg/L]	[%]
blank	-
15	-
150	-
750	17
1995	17

Reference 2

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study (non-GLP); Results published in peer-reviewed journal

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

yes

Remarks:

Syntehtic sewage: 10-fold level of K2HPO4 (28.0 g/L); adjustment of pH to 7.0 with H3PO4

GLP compliance:

no

Analytical monitoring:

not required

Vehicle:

no

Test organisms (species):

activated sludge, domestic

Details on inoculum:

- Laboratory culture: yes (sampling was done one day prior to each test series)
- Method of cultivation: 9-L laboratory scale, semi-continuous activated sludge cylinder, 21 °C
- Preparation of inoculum for exposure: washing, aeration
- Pretreatment: supplemented daily with 50 mL synthetic sewage stock solution
- Initial biomass concentration: 4 g/L suspended solids

Test type:

static

Water media type:

freshwater

Total exposure duration:

3 h

Test temperature:

20 ± 2 °C

pH:

7.5 ± 0.5

Details on test conditions:

TEST SYSTEM
- Test vessel: 1-L bottle
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: 500 mL
- Aeration: 0.5-1.0 L/h
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 2
- Biomass loading rate: 1.6 g/L


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: dionized water

OTHER TEST CONDITIONS
- Adjustment of pH: yes

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : respiration rate

TEST CONCENTRATIONS
- Spacing factor for test concentrations: no data

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: graphic analysis

Validity criteria fulfilled:

yes

Description of key information

The inhibition of the degradation activity of activated sludge is not anticipated when introduced in appropriate low concentrations.

Additional information

2,2'-(ethylenedioxy)diethanol 3,6,9-trioxaundecane-1,11-diol (EC 907-131-0) is a multi-constituent substance. The main constituents of EC 907-131-0 are triethylene glycol (TGE, CAS 112-27-6, 10-80% w/w) and tetraethylene glycol (Tetra-EG, CAS 112-60-7, 10-80% w/w). Since no data on the toxicity to aquatic organisms of the reaction mass of 2,2'-(ethylenedioxy)diethanol 3,6,9-trioxaundecane-1,11-diol are available, the assessment is based on the available data for the main components triethylene glycol (CAS 112-27-6) and tetraethylene glycol (112-60-7).

Since no data on the toxicity for aquatic algae are available for main constituents the read-across approach was performed. This read-across approach consists of the available experimental data for the structurally similar substance diethylene glycol (CAS 111-46-6).

The effect of DEG on the respiration activity of activated sludge for a wastewater treatment plant treating predominantly domestic sewage was investigated in two guideline studies. In a study following ISO 8192, which is equivalent to OECD 209, a 30 -min EC20 > 1995 mg/L was determined (BASF AG, 1982).

This result is also supported with the test conducted according to OECD Guidance 209 by Klecka et al. (1985). The 3 -h EC50 was determined to be > 1000 mg/L (nominal).

Based on the available read-across data for the structurally similar substance, it can be concluded that the inhibition of the degradation activity is not anticipated when the substance is introduced in appropriately low concentrations.