7,7-dimethyl-3-oxa-6-azaoctan-1-ol

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Skeletonema costatum testing of the test substance EC 9150A was initiated on 20.05.96 and completed on 23.05.96.

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study conducted in accordance with generally accepted scientific principles, possibly with incomplete reporting or methodological deficiencies, which do not affect the quality of relevant results.

Qualifier:

equivalent or similar to guideline

Guideline:

ISO 10253 (Water quality - Marine Algal Growth Inhibition Test with Skeletonema costatum and Phaeodactylum tricornutum)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

not specified

Details on sampling:

Not stated.

Vehicle:

no

Details on test solutions:

The test substance is soluble in water, and the sample preparation method for water soluble test substances was followed. Standard sample preparation methods are described in Appendix 1 (below):

Appendix 1. Sample Preparation Methods for Toxicity Testing

Water Soluble Test Substances
• Dissolve the test substance in the culture medium. The concentration of this stock solution should correspond with the highest test dosage.
• Mix the stock solution in a 1 I erlenmeyer flask on a magnetic stirrer (~100 rpm) for 2-4 hours. Wrap the erlenmeyer flask in aluminium foil to avoid light exposure and cover the top with parafilm to minimize volatilization.
• If anything has flotated or precipitated, contact the Study Director.
• Prepare the required test dosages with dilutions of the stock solution using graduated pipettes and cylindric/volumetric measuring flasks. Use culture medium for dilutions.

Based on the results from the preliminary test, the following test dosages (nominal whole product) were used for the definitive test: 100; 300; 1000; and 3000 mg/l.

Test organisms (species):

Skeletonema costatum

Details on test organisms:

The strain NIVA BAC 1 was used.
Algal medium 1/2 "f" from Guillard and Ryther (1962) was used.

Test type:

static

Water media type:

not specified

Limit test:

no

Total exposure duration:

72 h

Post exposure observation period:

Not appliacable.

Hardness:

Not stated.

Test temperature:

Temperature in culture cabinet 19.4 - 21.2°C

pH:

pH test start (3000 mg/l): 10.14
pH test end (3000 mg/l): 10.67

Dissolved oxygen:

Not stated.

Salinity:

Not stated.

Nominal and measured concentrations:

The following test dosages (nominal whole product) were used for the definitive test: 100; 300; 1000; and 3000 mg/l.

Details on test conditions:

Growth inhibition test (72 h) with the marine diatom Sketetonema costatum was performed.
Two tests were performed; initially, a preliminary (range finding) test with two parallel test concentrations, followed by a definitive test with 3 parallel concentrations and 6 controls.
Inhibition is measured as a reduction in growth rate, (the growth rate is the increase in cell density per unit time) relative to control cultures grown under identical conditions.

The cell density was measured by fluorescence (Turner 10-100 R fluorometer).

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

170 - 180 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

Lethality-dosage curve for the test substance is presented in Figure 1, and the growth curves are presented in Figure 2 (please see attached background material for figures 1 and 2). The raw data for the definitive test are presented in Appendix 2 (please see attached background material).

The EC50-value was found to be in the range 170 - 180 mg/l (mean value: 175 mg/l) after 72 hours, the EC10-value was estimated to 40 mg/l, the EC90-value was estimated to 230 mg/l and the NOEC- value was estimated to 10 mg/l.

Results with reference substance (positive control):

One test concentration (1.5 mg/l) of the reference substance, 3,5-dichlorophenol, was analyzed on (date). The growth rate inhibition of 1.5 mg/l 3,5-dichlorophenol was 21 % after 72 h.

Reported statistics and error estimates:

None reported.

Validation of Results:

 The test is considered valid if the following requirements are met:

- The control cell density has increased by a factor of more than 16 within 72 hours. This increase corresponds to a growth rate of 0.9 d^-1.

- The control pH has not varied by more than 1.0 units during the test.

- The temperature has been in the range 20.0±2.4°C.

- The light intensity has been in the range 7000-11000 Lux.

- The concentration 1.5mg/l3,5-dichlorophenol was between 20 and 80% growth rate inhibition.

In this test, the control parameters yielded the following values:

- Growth rate of the control: 1.83 d^-1

- pH at the beginning of the test: 10.14

- pH at the completion of the test: 10.67

- Temperature (variations during the test): 19.4 - 21.2 °C

- The light intensity (variation during the test): 7950 - 10050 Lux

- Growth rate inhibition of 1.5mg/l3,5-dichlorophenol: 21%

The test conditions were in accordance with the ISO Standard.

 

Validity criteria fulfilled:

yes

Remarks:

Test requirements were met.

Conclusions:

The toxicity of the test substance, measured as EC50 after 72 hours, was found to be in the range 170 - 180 mg/l. According to the EEC classification system (EEC, 1993), a test substance is classified as very toxic if EC50 < 1 mg/l, as toxic if EC50 = 1 – 10 mg/l and as harmful if EC50 >10 - 100 mg/l. Based on this, the test substance is not classified as harmful.

Executive summary:

Skeletonema costatum testing has been performed on the test substance based on ISO DIS 102 53: "Water Quality Marine Algal Growth Inhibition Test With Skeletonema costatum and Phaeodactylum tricornutum".

The EC50-value for the test substance (nominal whole product) after 72 h was found to be 170 - 180 mg/l (mean value: 175 mg/l). The EC1O-value was estimated to 40 mg/l, the EC90-value was estimated to 230 mg/l and the NOEC value was estimated to 10 mg/l.

The test substance is not classified as harmful according to the EEC classification system.

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

Not reported in the data over 12 years old provided by ECHA.

Reliability:

other: Reliability of study not reported in the data over 12 years old provided by ECHA.

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

not specified

GLP compliance:

yes

Analytical monitoring:

not specified

Details on sampling:

Identity and concentration of auxiliary solvent dispersal: None.

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Test type:

not specified

Water media type:

not specified

Limit test:

yes

Total exposure duration:

72 h

Details on test conditions:

Standard growth medium was used.

Reference substance (positive control):

not specified

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 97 mg/L

Nominal / measured:

not specified

Conc. based on:

not specified

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 97 mg/L

Nominal / measured:

not specified

Conc. based on:

not specified

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

97 mg/L

Nominal / measured:

not specified

Conc. based on:

not specified

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

97 mg/L

Nominal / measured:

not specified

Conc. based on:

not specified

Basis for effect:

biomass

Details on results:

% Concentration loss over test: 0.

Validity criteria fulfilled:

yes

Conclusions:

The EC50 was determined to be be >97 mg/l. The substance is not classified based on these results.

Description of key information

Two toxicity studies on algal are available, one freshwater study in  Desmodesmus subspicatus and one marine study in Skeletonema costatum.
In the freshwater study the EC50-value for the test substance  after 72 h was found to be >97 mg/l and the NOEC value was estimated to 97 mg/l.
In the marine study the EC50-value for the test substance (nominal whole product) after 72 h was found to be 170 - 180 mg/l (mean value: 175 mg/l). The EC1O-value was estimated to 40 mg/l, the EC90-value was estimated to 230 mg/l and the NOEC value was estimated to 10 mg/l.

Key value for chemical safety assessment

EC50 for freshwater algae:

97 mg/L

EC50 for marine water algae:

175 mg/L

EC10 or NOEC for freshwater algae:

97 mg/L

EC10 or NOEC for marine water algae:

10 mg/L