4,4-dimethyloxazolidine

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:

26 November - 14 December 2001

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Report date:

2002

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

1984

Deviations:

yes

Remarks:

see "Principles of method if other than guideline"

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.5400 (Algal Toxicity, Tiers I and II) (January 2012)

Version / remarks:

1996

Deviations:

yes

Remarks:

see "Principles of method if other than guideline"

Principles of method if other than guideline:

Between the 72- and 96-hour cell counts in the range-finding test, the temperature in the growth cabinet increased to 27°C for a maximum of 10 hours, which is above the recommended temperature range of 24+-1°C.

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

4,4-dimethyloxazolidine

EC Number:

257-048-2

EC Name:

4,4-dimethyloxazolidine

Cas Number:

51200-87-4

Molecular formula:

C5H11NO

IUPAC Name:

4,4-dimethyl-1,3-oxazolidine

Test material form:

liquid

Specific details on test material used for the study:

- Name: BIOBAN CS-1135 (4,4-dimethyl-oxazolidine)
- Source and lot/batch No.of test material: Dow Chemical Company, 1H25 DF87
- Purity: 76%

Sampling and analysis

Analytical monitoring:

no

Details on sampling:

Samples of each test concentration and the control were collected in amber glass jars at time 0,72 and 96 hours. Samples, along with appropriate chain-of custodies, were transported to Maxxam Analytics Inc. for chemical analyses.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION OF TEST SOLUTIONS
Range-finding test: A stock solution of 1000 mg/L was prepared by mixing 101.3 mg of the test substance in 100 mL of filtered nutrient solution. The solution was then placed on a magnetic stir plate and agitated for just over 4 hours.
Definitive test: A 10 mg/L stock solution was prepared, by mixing 10.1 mg of the test substance in 1000 mL filtered nutrient solution and stirring for 10 minutes.

Test organisms

Test organisms (species):

Selenastrum sp.

Details on test organisms:

TEST ORGANISM
- Test species: Uni-algal cultures of Selenastrum capricornutum Printz 1913
- Source (laboratory, culture collection): Axenic slope culture of Selenastrum capricornutum, cultured at the ESG International Ecotoxicity Laboratory (Guelph, ON) since 1999.
- Method of cultivation: Cultures are aseptically transferred twice weekly and maintained in temperature and light controlled environments isolated from all testing facilities. Algal growth curves are conducted semi-annually to ensure that algae are in an exponential growth phase.
- Age of test plants: 3-7 days

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Test conditions

Hardness:

not reported

Test temperature:

24 +- 1°C

pH:

7.5+-0.1

Dissolved oxygen:

not reported

Salinity:

not reported

Conductivity:

not reported

Nominal and measured concentrations:

Range-finding test:
Exposure concentrations one order of magnitude apart, were used to determine the range of concentrations required for definitive testing with S. capricornutum. the highest concentration tested was 1,000 mg/L, together with four lower concentrations (i.e. 100 mg/l, 10 mg/L, 1 mg/L, 0.1 mg/L) and a control (100% nutrient solution). S. capricornutum cells (1*10^4 cells/mL +- 1000 cells/mL) were added to each flask (1 replicate per concentration). As per test method, the exposure duration was 96 hours, with daily cell counts.

Definitive testing
A definitive multi-concentration EC50 test was conducted with nominal concentrations of 0.625, 1.25, 2.5, 5 and 10 mg/L plus controls. Each concentration was replicated 5 times. Observations of cell number and appearance were conducted, using a haemocytometer, on a daily basis. After 72 hours, the pH in one replicate sample was measured and the sample was sent for analysis, leaving four replicated remaining for the 96-hour counts. Changes in cell development or appearance, such as cell clumping, cell morphology, cell colour, cell shape, cell size etc. were reported.

Details on test conditions:

TEST SYSTEM
- Test vessel: 250 mL glass flasks with 50 mL of test medium, covered with Jaece non-toxic foam plugs
- Culture medium: Algal growth medium; axenically subcultured into fresh medium twice a week
- Testing medium: Algal growth medium; filter sterilized, but otherwise treated in a non-axenic manner
- Light quality: cool-white fluorescent
- Light intensity: 4+-10% kLux for culturing; 8+-20% kLux for testing
- Photoperiod: 24 hr
- Number of cells per test vessel: 1*10^4 cells/mL

PARAMETERS MEASURED
- Measured endpoints: cell number measured daily using a haemocytometer
- Calculated endpoints: Area under the growth curve, growth rate, cell number
- Statistical endpoints: 72 and 96-hr ECb50 (based on area under the growth curve), 72 and 96-hr ECr50 (based on growth rate), 72 and 96-hr EC50 for cell number, LOEC and NOEC for all three biological endpoints
- number of test concentrations: 5 concentrations, plus control

Reference substance (positive control):

yes

Remarks:

Sodium chloride as reference toxicant

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

3.79 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Effect concentrations 2

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

1.25 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Effect concentrations 3

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

2.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Effect concentrations 4

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

6.57 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 5

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

2.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 6

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

Range-finding test:
Results indicated that the 50% inhibitory effect level and the no effect level for growth inhibition of S. capricornutum was between 1 and 10 mg/L for all endpoint parameters (72 and 96-hour cell number, area under the growth curve and growth rate).

Definitive test:
Results are showed in the table in section "any other information on results".

Any other information on results incl. tables

Test endpoint	EC50 (95% Confidence Intervals) (mg/L)	NOEC (mg/L)	LOEC (mg/L)
Cell number (72 hr)	3.79 (3.51, 4.07)	1.25	2.50
Cell number (96 hr)	5.42 (4.84, 5.98)	2.50	5.00
Area under growth curve (72 hr ECb50)	3.76 (3.46, 4.02)	1.25	2.50
Area under growth curve (96 hr ECb50)	4.20 (3.73, 4.69)	2.50	5.00
Growth rate (0 -72 hr ECr50)	6.57 (6.26, 6.92)	2.50	5.00
Growth rate (0 -96 hr ECr50)	7.14 (6.95, 7.31)	2.50	5.00

Applicant's summary and conclusion

Validity criteria fulfilled:

not specified

Conclusions:

The ecotoxicological evaluation of the effects of 4,4-dimethyl-oxazolidine (CAS 51200-87-4) indicated that the 72 and 96 -hour EC50s for cell number were 3.79 and 5.42 mg/L, respectively. The 72 and 96 -hour EC50s for area under the growth curve were 3.76 and 4.20 mg/L, respectively. The 0 to 72 and 0 to 96 -hour EC50s for growth rate were 6.57 and 7.14 mg/L, respectively. The NOEC and LOEC for 72 -hour cell number and area under the growth curve were 1.25 and 2.50 mg/L, respectively. For the other four endpoint parameters, the NOEC and LOEC were 2.50 and 5.00 mg/L, respectively.

Executive summary:

Ecotoxicological testing of Bioban CS-1135 (CAS 51200 -87 -4) was conducted to determine the growth inhibition of the freshwater green alga, Selenastrum capricornutum Printz, according to the OECD Method 201 (Alga, Growth Inhibition Test, 1984) and in general accordance with OPPTS Method 850.5400 (Algal Toxicity, Tiers I and II, 1996).

Results from the range-finding test indicated that the 50% inhibitory effect level and the no effect level for growth inhibition of Selenastrum capricornutum were between 1 and 10 mg/L for all endpoint parameters (72 and 96 -hour cell number, area under growth curve and growth rate).

The available analytical methods for the test item were not able to extract and quantify this compound. Calculations of all statistical endpoints for the definitive test were conducted using nominal concentrations. The 72 and 96 -hour EC50s for cell number were 3.79 and 5.42 mg/L, respectively. The 72 and 96 -hour EC50s for area under the growth curve were 3.76 and 4.20 mg/L, respectively. The 0 to 72 and 0 to 96 -hour EC50s for growth rate were 6.57 and 7.14 mg/L, respectively. The NOEC and LOEC for 72 -hour cell number and area under the growth curve were 1.25 and 2.50 mg/L, respectively. For the other four endpoint parameters, the NOEC and LOEC were 2.50 and 5.00 mg/L, respectively.