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Ecotoxicological information

Toxicity to microorganisms

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Reference
Endpoint:
toxicity to microorganisms, other
Remarks:
Study was a toxicity control conducted as part of a CO2 evolution test in accordance with OECD Guideline 301B.
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
10 September 2012 to 22 November 2012
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
The analogue approach is used for the hazard assessment of toxicological endpoints for the registration of the target substance pentaerythritol ricinoleate (CAS 78-22-8) based on generation of different breakdown/metabolic products, resulting not only in similar physical and biological systems (Scenario 2 of the Read-Across Assessment Framework (RAAF, ECHA, 2015), but also consequently in similar physico-chemical, environmental fate and ecotoxicological properties. The source compound for read-across is fatty acids, C16-18 and C18 unsatd., esters with pentaerythritol (CAS 85116-93-4). It is proposed that the different alcohols resulting from ester hydrolysis of the source compound and the target substance will not result in significant variation in biological effects. Neither target nor source compounds are classified for hazardous effects based on aquatic toxicity. The use of reliable experimental data, all evaluated as reliable according to Klimisch scores of 1 or 2, to estimate the environmental fate and ecotoxicity of the registered substance is adequate for the purposes of fulfilling the data requirements of registration and classifying potential hazards. Similar grouping into categories has been accepted by other regulatory agencies (U.S. EPA, 2010; U.S. FDA for food notifications). Thus, this read-across approach is adequate for the purposes of risk assessment and classification and labeling.


Reason / purpose for cross-reference:
read-across source
Qualifier:
according to guideline
Guideline:
other:
Version / remarks:
According to OECD 301B and EU C.4-C Toxicity test performed as part of a ready biodegradability CO2 evolution test performed according to OECD 301B and EU C.4-C
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Analytical monitoring:
yes
Vehicle:
no
Test organisms (species):
activated sludge of a predominantly domestic sewage
Details on inoculum:
Activated sludge from a biologic sewage treatment plant treating mostly domestic sewage was used. The sludge was taken from the activation basin of the ESN (Stadtentsorgung Neustadt) sewage treatment plant, Im Altenschemel, NW-Lachen-Speyerdorf on 19 October 2012. The sludge was filtrated, washed with tap water twice, then washed with and re-suspended in test medium. It was then aerated for > 12 hours.
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
28 d
Nominal and measured concentrations:
A toxicity control, containing the test item at a nominal concentration of 26.7 mg/L and aniline at a nominal concentration of 25.3 mg/L corresponding to a combined total of 40.4 mg carbon/L was prepared to assess any toxic effect of the test item on the sewage sludge micro-organisms used in the test.
Reference substance (positive control):
yes
Remarks:
Aniline.
Key result
Duration:
14 d
Dose descriptor:
NOEC
Effect conc.:
26.7 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: inhibition of CO2 evolution.
Details on results:
At a test substance concentration of 26.7 mg/L and a reference substance concentration of 25.3 mg aniline /L, the toxicity control attained 61% degradation after 14 days, thereby confirming that the test substance did not exhibit an inhibitory effect on the sewage treatment micro-organisms used in the test. The test substance and reference substance attained ≥ 25% degradation by Day 14 for the test substance to be considered as non-inhibitory).
Validity criteria fulfilled:
yes
Remarks:
IC content <1% (protocol ≤ 5%); CO2 emitted by controls 14.0 mg/L (protocol <70 mg/L; difference replicates 14.5% (protocol ≤20 %); degradation positive control >60% at 11 d (protocol ≤14 d), degradation toxicity d 14, 61% (protocol > 25%).
Conclusions:
The test substance is considered as not toxic towards the inoculum at a concentration of 26.7 mg/L. Degradation in the toxicity flask was 61% after 14 days. The guideline indicates that the test item can be considered as toxic towards the inoculum if degradation in the toxicity flask is below 25% after 14 days. Therefore, the NOEC = 26.7 mg/L.

Description of key information

The key study was a toxicity control as part of a CO2 evolution test conducted on an analogue substance in accordance with OECD Guideline 301B. The test substance was shown to be non-inhibitory toward the inoculum at a concentration of 26.7 mg/L. Degradation in the toxicity flask was 61% after 14 days. Therefore, the NOEC was reported as = 26.7 mg/L.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:
26.7 mg/L

Additional information