Phenol, dodecyl-, branched

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1992-04-07 until 1992-04-10

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1992

Report date:

1992

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Dodecylphenol T

IUPAC Name:

Dodecylphenol T

Constituent 2

Reference substance name:

Phenol, dodecyl-, branched

EC Number:

310-154-3

EC Name:

Phenol, dodecyl-, branched

Cas Number:

121158-58-5

Molecular formula:

C18H30O

IUPAC Name:

4-(3,4,5,6-tetramethyloctan-2-yl)phenol

Details on test material:

- Name of test material (as cited in study report): Dodecylphenol T
- Substance type: technical product
- Physical state: liquid
- Analytical purity: 100%
- Impurities (identity and concentrations): not mentioned
- Composition of test material, percentage of components: not mentioned
- Purity test date: not mentioned
- Lot/batch No.: continuously production; 3630/81325
- Date of production: 1991-04-25
- Stability under test conditions: 1 year
- Storage condition of test material: not mentioned

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

no

Details on test solutions:

1 g test substance was mixed with 1l deionized water, stirred for 18 h and subsequently filtrated

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: Green algae
- Strain: Scenedesmus subspicatus (CHODAT (86.81 SAG))
- Source (laboratory, culture collection): Institut für Wasser-, Boden- und Lufthygiene, Berlin; subsequently in-house breeding
- Method of cultivation: in sterile-aerated Erlenmeyer flasks on light benches

ACCLIMATION
- Acclimation period: A preculture is withdrawn from a stock culture by tranfer 3 days prior to the beginning of the test from which preculture the test cultures are inoculated at a cell density of approximately 20 000 cells/ml.
- Culturing media and conditions (same as test or not): not mentioned
- Any deformed or abnormal cells observed: not mentioned

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Post exposure observation period:

none

Test conditions

Hardness:

Growth/test medium chemistry as described in guideline 92/69/EEC (C.3.), no further details mentioned

Test temperature:

22 °C

pH:

8.5 - 8.7 at the beginning of the test; 9.6 ¿ 9.7 at the end of the test

Dissolved oxygen:

not mentioned

Salinity:

not mentioned

Nominal and measured concentrations:

Stock solution: 0.85 mg/l (WAF)

Details on test conditions:

TEST SYSTEM
- Test vessel: sterile-aerated Erlenmeyes flasks
- Initial cells density: 2x10E4 cells/ml
- Control end cells density: 2x10E4 cells/ml
- No. of vessels per concentration (replicates): 5
- No. of vessels per control (replicates): 8
- No. of vessels per vehicle control (replicates): not applicable

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
no details mentioned

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: not adjusted
- Photoperiod: not specified
- Light intensity and quality: approx. 8000 lux, white

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Cell numbers for exposure times of 24, 48, 72 h
- Determination of cell concentrations: The cell numbers were determined photometrically at a wavelenght of 685 nm
- Chlorophyll measurement: no
- Other: none

TEST CONCENTRATIONS
- Spacing factor for test concentrations: not mentioned
- Range finding study: not mentioned

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.442 mg/L

Nominal / measured:

nominal

Basis for effect:

biomass

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

ca. 0.53 mg/L

Nominal / measured:

nominal

Basis for effect:

biomass

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 0.765 mg/L

Nominal / measured:

nominal

Basis for effect:

biomass

Remarks on result:

other: water solubility under test conditions

Effect concentrations 4

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 0.765 mg/L

Nominal / measured:

nominal

Basis for effect:

growth rate

Remarks on result:

other: water solubility under test conditions

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): no observations made
- Any stimulation of growth found in any treatment: no
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no
- Effect concentrations exceeding solubility of substance in test medium: no

Effective concentrations [mg/l] on the basis of cell growth:
EbC50 (72 h) > 0.765 *
EbC10 (72 h) approx. 0.53
EbC90 (72 h) > 0.765 *
Effective concentrations [mg/l] based on the specific growth rate µ:
ErC50 (0-72 h) > 0.765 *
ErC10 (0-72 h) > 0.765 *
ErC90 (0-72 h) > 0.765 *

* water solubility under test conditions

Results with reference substance (positive control):

no reference substance tested

Reported statistics and error estimates:

no statistical evaluation performed

Any other information on results incl. tables

Table #1: Cell density data:

concentration [mg/L]	cell number (x 10E4 cells/ml) after
	0 h	24 h	48 h	72 h
control	2	4	17	79
0.051	2	4	16	77
0.085	2	4	17	76
0.153	2	3	16	76
0.255	2	4	15	74
0.442	2	4	15	74
0.765	2	4	13	70

Table #2: Growth curves:

concentration [mg/L]	biomass (area under the growth curve)	inhibition of biomass [%]	growth rate µ (0 - 72 h)	inhibition of growth rate [%]
control	55.5	-	1.492	-
0.051	53.5	3.6	1.479	0.9
0.085	54	2.7	1.472	1.3
0.153	52	6.3	1.616	- 8.3
0.255	51	8.1	1.459	2.2
0.442	51	8.1	1.459	2.2
0.765	47	15.3	1.431	4.1

Applicant's summary and conclusion

Validity criteria fulfilled:

yes