N,N-Bis(2-hydroxyethyl)-C12-18(even numbered, C18 unsaturated) alkyl-1-amine oxides

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:

6 - 20 March 1990

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study performed under GLP and according to guideline with some deviations.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1990

Report date:

1990

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

yes

Remarks:

To maintain a constant pH, concentrations of KH2PO4 & NaCO3 were increased, this is assumed not to have affected the study outcome, as confirmed by the reference compound. No measurement of actual concentrations.

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Ethanol, 2,2'-iminobis-, N-coco alkyl derivs., N-oxides

EC Number:

263-180-1

EC Name:

Ethanol, 2,2'-iminobis-, N-coco alkyl derivs., N-oxides

Cas Number:

61791-47-7

Molecular formula:

not applicable

IUPAC Name:

N,N-Bis(2-hydroxyethyl)-C12-18(even numbered) alkyl-1-amine oxides

Details on test material:

The following test substance data were submitted by the sponsor:
- chemical name : Cocobis(2-hydroxyethyl)amine oxide
- CAS-reg. no. : 61791-47-7
- batch/lot no. : 900110
- active amine oxide content : 30.5% (CoA is enclosed in study report):
Free amine (%): 0.3
Free peroxide (%): 0.13
pH (10+90% water): 7.1
Colour Gardner: < 2
- CRL code : T90-02-01.5

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
- appearance : liquid
- boiling point : approx. 100°C (water)
- chemical stability : stable at test conditions
- water solubility : soluble at test concentrations
- storage until required : at ambient conditions in the dark
- biodegradability : readily biodegradable

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Details on test solutions:

For the definitive test stock solution of 1 g/litre, was prepared by dissolving the test substance in deionized water. The selected test
concentrations were prepared by dilution of this stock solution in the inoculated test medium.

Test organisms

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

The test was carried out with the unicellular green algae; Selenastrum capricornutum ATCC 22662. This strain was maintained on mineral salts
agar slants in the light at room temperature. The test was inoculated with algae taken from an exponentially growing pre-culture using the mineral
salts medium.

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:

No data

Test temperature:

22.5 - 23.0 C

pH:

6.8 - 7.8

Dissolved oxygen:

No data

Nominal and measured concentrations:

The nominal test concentrations of the test were 0.063 - 0.125 - 0.250 - 0.5 - 1.0 mg/litre.

Details on test conditions:

The culturing apparatus is a cabinet in which the temperature is maintained between 22 and 24C, and continuous uniform
illumination is provided i n the spectral range of 400 to 700 nm. The light intensity is in the range of 6000 to 10000 lux which
is obtained by using seven 30 W fluorescent lamps (colour temperature of approximately 4300 K ) , at a distance of 0.35 m
from the algal culture. The culture flasks were rotated continuously at 100 rpm to prevent sedimentation of the algae.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.3 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Remarks on result:

other: 95% CI 0.25-0.35 mg/L

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.95 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 0.83 - 1.15 mg/L (95% CL)

Details on results:

The growth of S. capricornutum is stimulated at low concentrations. These concentrations are not considered for the determination
the concentration/effect relationship. The ErC50 and EbC50 (0-72 h) of the test item are 0.95 (95% confidence limits 0.83 - 1.15)
and 0.86 (95% confidence limits 0.73 - 1.06) mg/litre respectively. The NOEC determined for the test item is 0.25 mg/litre.

Results with reference substance (positive control):

The extinctions of potassium dichromate give an ErC5O and EbC50 (0-72 h) of potassium dichromate of 0.56 and 0.69 mg/litre, respectively. These values of the reference compound are in accordance with data of an international interlaboratory test showing that the test organisms have not
changed significantly and that the slight modification of the mineral salts medium did not influence the result.

Reported statistics and error estimates:

The EC50 values were computed from the best fitted line (least square method) through the points given by the probit of the
percentage inhibition and the logarithm of the concentration of the test substance. The EC50 value calculated with the area
under the growth curve is termed EbC50 (0-72 h) whereas the EC value calculated with the specific growth rate is termed ErC50.
Confidence limits were computed based on Fieller's theorem. All computations were performed with.the software package SAS.

Any other information on results incl. tables

Inhibition algal growth and growth rate. Growth rate is recalculated from data fig 2 of report.

Conc substance (in mg/L)	% inhibition growth	% inhibition growth rate
0.063	0.9	0
0.125	- 114	- 19
0.250	- 73	- 14
0.500	20.6	19
1.0	61.8	52.4

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The ErC50 and EbC50 (0-72h) of the test item are 0.95 (95% confidence limits 0.83 - 1.15) and 0.86 (95% confidence limits 0.73 - 1.06) mg/litre respectively. The NOEC determined of the test item is 0.25 mg/litre. Assuming the product contains 100% pure technical active ingredient and the toxicity can be allocated to the active substance only, the ErC50, EbC50 and NOEC would be 0.29, 0.26 and 0.08 mg/L respectively for the amine oxide.

Executive summary:

In this study the toxicity of the test item to algae was investigated according to OECD guidance and GLP. A range finder and a reference compound were also investigated. Based on nominal concentrations only, the ErC50 and EbC50 (0-72 h) of Aromox C/12-W are 0.95 (95% confidence limits 0.83 - 1.15) and 0.86 (95% confidence limits 0.73 - 1.06) mg/litre respectively. The NOEC determined of the test item is 0.25 mg/litre.