Octan-1-ol, ethoxylated

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

toxicity to microorganisms, other

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Data based on the inhibition control of a ready biodegradability study

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: the test item was dissolved directly in mineral medium with the aid of ultrasonication for appr. 20 minutes.

Test organisms (species):

activated sludge, domestic

Details on inoculum:

- Source of inoculum/activated sludge: Sewage treatment micro-organisms from the final effluent stage of the Severn Trent Water Plc sewage treatment plant at Loughborough, Leicestershire, UK (obtianed on 28 Jan 2019). The STP treats predominantly domestic sewage.
- Pretreatment: The sample of effluent was filtered through coarse filter paper (first approximate 200 mL discarded) and maintained on aeration in a temperature controlled room at temperatures of between 20 and 21 °C prior to use.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

14 d

Test temperature:

21 - 22 °C

pH:

7.4 - 7.5

Nominal and measured concentrations:

Toxicity control: 100 mg test item/L and 100 mg aniline/L

Details on test conditions:

TEST SYSTEM
- Culturing apparatus: CES Multi-Channel Aerobic Respirometer
- Number of culture flasks/concentration: 3
- Method used to create aerobic conditions: the pressure reduction caused by the adsorption of carbon dioxide triggers an electrolytic process, generating oxygen and restoring the pressure in the sample flask.
- Details of trap for CO2 and volatile organics if used: ethanolamine solution (50% v/v)
- No. of vessels per concentration (replicates): 2


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: according to OECD guideline 301F
- Particulate matter:
OTHER TEST CONDITIONS
- Adjustment of pH: no
- Light intensity: diffuse light

Reference substance (positive control):

yes

Remarks:

Aniline

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: O2 consumption

Remarks:

Result of toxicity control from ready biodegradability test

Results with reference substance (positive control):

Reference contol (Anilin): 76% degradation after 14 days (ten-day window criterion met)

The toxicity control attained 76% degradation after 14 days of incubation.

 “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 35% 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 100 mg/L can be used as NOEC value for the toxicity to aquatic microorganisms.

Description of key information

The assessment of the toxicity of the target substance to microorganisms is based on the results of the toxicity control of the available biodegradation study. A NOEC(14 d): 100 mg/L (based on toxicity control of OECD 301 F) is used as key value for the CSA of the target substance.  

Additional information

The toxicity of the Ethoxylates (AE) category substances to microorganisms was assessed by read-across based on the grouping of substances (category approach). The available data were used for a general assessment of the toxicity of the Alcohol Ethoxylates (AE) category substances to microorganisms. Based on the available data adverse effects on microbial activity are not expected. The substances of the Alcohol Ethoxylates (AE) category are readily biodegradable. In all studies conducted with a toxicity control, no inhibition of the degradation process by the test substance was observed. The available studies investigating the respiration inhibition of activated sludge organisms and Pseudomonas putida determined no detrimental effects of the tested Alcohol Ethoxylates.