Lauric acid, monoester with propane-1,2-diol

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: No analysis was carried out to determine the homogeneity, concentration or stability of the test item formulation. This exception is considered not to affect the purpose or integrity of the study, although is contrary to GLP Guidelines

Justification for type of information:

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
A read-across approach has been suggested based on the metabolism of the common structure of propylene glycol fatty acid esters. Read-across is implemented from already existing data from testing on Dapro FX511, on metabolism products (fatty acid and propylene glycol) and on propylene glycol monolaurate.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)

Source chemical:

Dapro FX 511
EC Number: 285-503-5
CAS Number: 85114-00-7

Target chemical:

RM1004755:
Einecs No. 248-315-4
CAS No. 27194-74-7

See read-across justification report in section 13

3. ANALOGUE APPROACH JUSTIFICATION
A matrix of data has been created using the Dapro FX511 REACH dossier, read-across document for aquatic tox from Dapro FX510 (source) to Dapro FX511 (target), a HPV test plan for the glycol esters of the aliphatic esters chemicals (including Propylene glycol, monostearate (CAS 1323-39-3)) and a Petition to include propylene glycol monolaurate into 7 CFR 205 (constituent of RM1004755).
See read-across justification report in section 13

4. DATA MATRIX
Data matrix is given in read-across justification report in section 13

- Name of test material (as cited in study report): SER-AD FX 511
- Physical state: liquid (colourless, slightly viscous)
- Analytical purity: no data; the purity of the test material was the responsibility of the sponsor
- Storage condition of test material: room temperature

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

Identification: RL 610/11
Description: clear colorless liquid
Batch: 1023M18305
Purity: 100%
Expiry / retest date: not supplied
Storage conditions: room temperature in the dark

Analytical monitoring:

no

Vehicle:

yes

Remarks:

water

Test organisms (species):

activated sludge of a predominantly domestic sewage

Test type:

static

Water media type:

not specified

Limit test:

yes

Total exposure duration:

3 h

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

560 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

180 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Range-Finding Test

The dissolved oxygen concentrations after 30 minutes contact time in several of the vessels were lower

than 60% of the dissolved oxygen saturation level of 8.9 mg O2/L. This deviation was considered to

have had no adverse effect on the study given that all oxygen consumption values were measured/

calculated over the linear portion of the traces. No statistically significant toxic effects were shown at

the test concentrations of 10 and 100 mg/L, however statistically significant toxic effects were shown

at the test concentration of 1000 mg/L. Based on these results and after discussion with the Sponsor,

it was considered necessary to perform a definitive test in order to obtain both a NOEC and an EC50

value for the test item. Based on this information test concentrations of 100, 180, 320, 560 and 1000

mg/L were selected for the definitive test.

Validity criteria fulfilled:

yes

Conclusions:

The effect of the test item on the respiration of activated sewage sludge gave a 3-Hour EC50 value of 560 mg/L. The No Observed Effect Concentration (NOEC) after 3 hours exposure was 180 mg/L.

Description of key information

The effect of the test item on the respiration of activated sewage sludge gave a 3-Hour EC50 value of 590 mg/L. The No Observed Effect Concentration (NOEC) after 3 hours exposure was 180 mg/L.

Key value for chemical safety assessment

EC50 for microorganisms:

560 mg/L

EC10 or NOEC for microorganisms:

180 mg/L