2,4,6-tri-sec-butylphenol

Toxicity to soil macroorganisms except arthropods

Administrative data

Endpoint:

toxicity to soil macroorganisms except arthropods: short-term

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2009

Report date:

2009

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 207 (Earthworm, Acute Toxicity Tests)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2,4,6-tri-sec-butylphenol

EC Number:

227-572-6

EC Name:

2,4,6-tri-sec-butylphenol

Cas Number:

5892-47-7

Molecular formula:

C18H30O

IUPAC Name:

2,4,6-tris(butan-2-yl)phenol

Test material form:

liquid

Sampling and analysis

Details on sampling:

The test item was weighed out for each test item concentration and mixed thoroughly with quartz sand (10 g per replicate). The treated quartz sand was given to the artificial soil.
Demineralised water was added to adjust the humidity of the artificial soil to a moisture of 54% of the maximum water holding capacity.
Subsequently, the test medium was mixed for at least three minutes and about 555 g soil dry weight were filled into each test vessel.

Test substrate

Vehicle:

no

Test organisms

Test organisms (species):

Eisenia fetida

Animal group:

annelids

Details on test organisms:

Eisenia fetida Savigny 1826 (Annelida, Lumbricidae)
Organisms of the species Eisenia fetida are bred at the test facility. They are kept in covered plastic vessels (volume 60 L) containing potting compost.
The earthworms are fed with dried litter of stinging nettle and porridge oats. The amount of the food is portioned due to the feeding rate and the density of worms in the vessels.
40 test organisms with an individual weight between 0.30 - 0.60 g, divided into four replicates, were tested per test item concentration and control.

Study design

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

no

Total exposure duration:

14 d

Test conditions

Test temperature:

18 - 22°C

pH:

5.32-5.76 at test start

Moisture:

32.0-33.8 % of dw at test start

Details on test conditions:

Four replicates were used per control and concentration of the test item.
10 adult earthworms (with citellum) with an individual live weight of 0.30 to 0.60 g were used per replicate. They were conditioned in artificial soil three days before the start of the toxicity test.

Nominal and measured concentrations:

nominal test item concentrations of 31.25 - 62.5 - 125 - 250 - 500 - 1000 mg/kg soil dry weight (factor 2)
CONTROL: Artificial soil with the addition of quartz sand and moistened with demineralised water without test item was used as control medium. (15 - 30 - 60 mg/kg soil dry weight)

Reference substance (positive control):

yes

Remarks:

2-Chloroacetamide

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

14 d

Dose descriptor:

LOEC

Effect conc.:

500 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Effect concentrations 2

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

250 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Effect concentrations 3

Duration:

14 d

Dose descriptor:

LC50

Effect conc.:

304 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: 278-335 mg/kg soil dw

Effect concentrations 4

Duration:

14 d

Dose descriptor:

LOEC

Effect conc.:

125 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Effect concentrations 5

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

62.5 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth

Effect concentrations 6

Duration:

14 d

Dose descriptor:

LOEC

Effect conc.:

62.5 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

behaviour

Remarks:

and pathological symptoms

Effect concentrations 7

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

31.25 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

behaviour

Remarks:

and pathological symptoms

Details on results:

The live weight of the earthworms was measured individually at the day of application (day 0) and at day 14.
Mortality, behaviour and morphological changes of the earthworms were recorded 7 and 14 days after application.
No noteworthy earthworm mortality was observed at 31.25, 62.5, 125 and 250 mg/kg soil dry weight after 14 days of exposure. However, earthworm mortalities of 100 % occurred at 500 and 1000 mg/kg soil dry weight.
No significant symptoms or changes in the earthworm behaviour were observed at the test item concentrations of 31.25 mg/kg soil dry weight. However, at 62.5, 125 and 250 mg/kg soil dry weight significant pathological symptoms and behavioural changes were observed.
The earthworm biomass after 14 days of exposure to the test item was not statistically significantly reduced at 31.25 and 62.5 mg/kg soil dry weight. However, at 125 and 250 mg/kg soil dry weight the biomass of the survivors was statistically significantly reduced compared to the control.
The no observed effect concentration (NOEC) concerning mortality was set at 250 mg/kg soil dry weight and the LC50 was determined to be at 304 mg/kg soil dry weight. The NOEC with respect to pathological symptoms and behavioural changes was determined to be at the test item concentration of 31.25 mg/kg soil dry weight. The NOEC for biomass reduction is set at the test item concentration of 62.5 mg/kg soil dry weight.
All validity criteria of the test guideline were fulfilled.

Results with reference substance (positive control):

LC50=50.1 mg/kg soil dw (95CI: 45.8-55.5 mg/kg soil dw)
NOEC=30 mg/kg soil dw

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Earthworm mortalities of 100 % were observed at the test item concentrations of 500 and 1000 mg/kg soil dry weight. Significant pathological symptoms and behavioural changes occurred up from 62.5 mg/kg soil dry weight. The biomass of the survivors was significantly reduced at 125 and 250 mg/kg soil dry weight.
Consequently, the no observed effect concentration (NOEC) concerning mortality was set at 250 mg/kg soil dry weight and the LC50 was determined to be at 304 mg/kg soil dry weight. The NOEC with respect to pathological symptoms and behavioural changes was determined to be at the test item concentration of 31.25 mg/kg soil dry weight. The NOEC for biomass reduction of the survivors is set at the test item concentration of 62.5 mg/kg soil dry weight.

Executive summary:

The acute toxicity of Tributylphenol to earthworm Eisenia fetida was determined in a 14 day test according to OECD207.

Earthworm mortalities of 100 % were observed at the test item concentrations of 500 and 1000 mg/kg soil dry weight. Significant pathological symptoms and behavioural changes occurred up from 62.5 mg/kg soil dry weight. The biomass of the survivors was significantly reduced at 125 and 250 mg/kg soil dry weight.

Consequently, the no observed effect concentration (NOEC) concerning mortality was set at 250 mg/kg soil dry weight and the LC50 was determined to be at 304 mg/kg soil dry weight. The NOEC with respect to pathological symptoms and behavioural changes was determined to be at the test item concentration of 31.25 mg/kg soil dry weight. The NOEC for biomass reduction of the survivors is set at the test item concentration of 62.5 mg/kg soil dry weight.