Sodium anisate

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

toxicity to microorganisms, other

Remarks:

Toxicity control of the study Biodegradation in water OECD 301 F

Type of information:

experimental study

Adequacy of study:

key study

Study period:

03 - 31 Aug 2017

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Data based on the inhibition control of a ready biodegradability study. This approach is in accordance with the Guidance on information requirements and chemical safety assessment (Chapter R.7b: Endpoint specific guidance, ECHA 2017).

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Hessisches Ministerium für Umwelt, Klimaschutz, Landwirtschaft und Verbraucherschutz, Wiesbaden, Germany

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: The amounts of test item (102.7 mg/L) and reference item (104.1 mg/L) were directly weighed into the test flasks.

Test organisms (species):

activated sludge, domestic

Details on inoculum:

- Source of inoculum/activated sludge: Aerobic activated sludge from sewage treatment plant Bensheim, Germany
- Storage conditions: aerated
- Storage length: aerated for 2 days
- Preparation of inoculum for exposure: Activated sludge was washed by centrifugation and the supernatant liquid phase was decanted; solid material was resuspended in test water and centrifuged again and repeated three times; based on the the ration of wet sludge to its dry weight calculated aliquots of washed sludge suspension, corresponding to 3.5 g dry material per litre were mixed with test water and aerated for 2 days.
- Pretreatment: An aliquot of sludge suspension was weighed, dried and the ratio of wet sludge to its dry weight was determined.
- Concentration of sludge: 3.5 g dry material per litre

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

14 d

Remarks on exposure duration:

Test item is not inhibitory to aerobic activated sludge microorganisms since degradation was 30% after 14 days (and 46% after 28 d).

Details on test conditions:

TEST CONDITIONS
- Composition of medium: according the OECD guideline 301
- Test temperature: 22 ± 1 °C
- pH: 7.5 to 8.2
- Continuous darkness: yes
- Other: continuous stirring

TEST SYSTEM
- Culturing apparatus and measuring equipment: BSB/BOD-Sensor-System, Aqualytic Dortmund, Germany (Manometric Test System, 500 mL fill volume in flasks)
- Number of culture flasks/concentration: 2
- Details of trap for CO2: potassium hydroxide solution (45%)

SAMPLING
- Sampling method: change of pressure in the test flasks was measured by means of a manometric method

CONTROL AND BLANK SYSTEM
- Inoculum control: 2 replicates
- Abiotic sterile control: 1 replicate (poisoned with HgCl2)
- Toxicity control: 1 replicate
- Other: procedure control - 1 replicate

Reference substance (positive control):

yes

Remarks:

sodium bezoate

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

102.7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Result of toxicity control from ready biodegradability test

Results with reference substance (positive control):

Test item is not inhibitory to aerobic activated sludge microorganisms since degradation was >25% within 14 days (30% after 14 d and 46% after 28 d).

The toxicity control attained 30% degradation after 14 days of incubation (based on ThODNH4 of Sodium anisate: 1.562 mg O2/mg test item and ThODNH4 of sodium benzoate: 1.666 mg O2/mg reference item).

 

“If in  a toxicity test, containing both the test and reference substance, less than 35% degradation (based on total DOC) or less than 25% (based on total ThOD or ThCO2) occurred within 14 days, the test substance can be assumed to be inhibitory.” (OECD guideline 301)

Since more than 25% degradation occurred in the toxicity control, the substance is with high probability not toxic to aquatic microorganisms. The test item concentration in the toxicity control of 102.7 mg test item/L can be used as NOEC value for the toxicity to aquatic microorganisms.

Validity criteria fulfilled:

yes

Conclusions:

NOEC (14d) = 102.7 mg/L (activated sludge, OECD 301 F)

Description of key information

NOEC (14d) = 102.7 mg/L (activated sludge, OECD 301 F)

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

102.7 mg/L

Additional information

Since no studies on the toxicity to aquatic microorganisms are available a ready biodegradability study is used to derive a NOEC for the toxicity to aquatic microorganisms. If a compound degrades well in a ready biodegradability test, or does not inhibit the degradation of a positive control at a certain concentration, this concentration can be used as a NOEC value. This approach is in accordance with the Guidance on information requirements and chemical safety assessment (Chapter R.7b: Endpoint specific guidance, ECHA 2017).

A substance can be assumed to be not inhibitory to aquatic microorganisms, if in the toxicity control of a ready biodegradation test, more than 25% degradation based on ThOD occurred within 14 days (OECD guideline 301F). For the test item Sodium Anisate (CAS 536-45-8) a biodegradation test according to OECD guideline 301F is available. The test includes a toxicity control, which contains 102.7 mg/L of the test item and 104.1 mg/L mg/L of sodium benzoate. The toxicity control attained 30% degradation after 14 days of incubation. Hence, the substance is not toxic to aquatic microorganisms in the toxicity control and the test item concentration of 102.7 mg/L can be used as NOEC.