(1α,2α,5α)-2,2,6-trimethylbicyclo[3.1.1]heptan-2-ol

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

effects on growth of green algae

Type of information:

experimental study

Adequacy of study:

key study

Study period:

13.02.2003 - 09.09.2003

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

1984

GLP compliance:

yes (incl. QA statement)

Details on sampling:

- Concentrations: Nominal concentrations of the test item were: 0 mg/L (control), 6.5, 13, 25, 50, and 100 mg/L. Mean measured concentrations were: ND (none detected; control), 5.78, 12.4, 22, 44.8, and 91.2 mg/L mg/L. The mean measured concentrations ranged from 88 to 95% of nominal concentrations.
-Preparation of Samples: A portion of each solution was transferred into a 1 L glass beaker and a 1 L portion of dilucion water was also transferred to a glass beaker to serve as a control.
- Sampling method: At 24, 48, and 72 hours, three treatment vessels and six control vessels were randomly selected to allow daily determination of the number of algal cell/mL.
-Sample storage conditions before analysis: The test substance was contained in a 500 mL amber glass bottle at room temperature in the dark.

Details on test solutions:

A 100 mg/L stock solution was prepared by weighing 0.2003 g of test substance into a 2,000 mL Class A glass volumetric flask and adjusting to the line volume with dilution water. This stock solution was mixed for 4.5 h with a magnetic stirrer at room temperature. A series of solutions was prepared by bringing 65, 130, 250, 500, and 1,000 mL of the 100 mg/L stock solution to 1,000 mL with dilution water.

Test organisms (species):

other: Selenastrum capricornutum

Details on test organisms:

TEST ORGANISM
- Common name: Green alga
- Source (laboratory, culture collection): the Culture Collection of Algae at the University of Texas
- Age of inoculum (at test initiation): 14 days

Test type:

static

Water media type:

freshwater

Total exposure duration:

72 h

Test temperature:

24.2 to 24.4 °C

pH:

Initial: pH 7.4 to 7.5
Final: pH 7.8 to 10.0

Nominal and measured concentrations:

Nominal concentrations: 6.5, 13, 25, 50, 100 mg/L
Mean measured concentrations: 5.78, 12.4, 22, 44.8, 91.2 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: glass 40 mL vial
- Type (delete if not applicable): closed
- Initial cells density: 10 000 algal cells/mL
- No. of vessels per concentration (replicates): 11
- No. of vessels per control (replicates): 20
- Source: Culture Collection of Algae at the University of Texas at Austin and delivered to T.R. Wilbury Laboratories in 2001

ACCLIMATATION
- Acclimation period: 14 days

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

63.8 mg/L

95% CI:

>= 59.4 - <= 68.5

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

22 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

38.8 mg/L

95% CI:

>= 33.3 - <= 41.8

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

biomass

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

5.78 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Details on results:

The algal population grew at an acceptable rate in the control resulting in an average of 310,000 cells/mL after 72 h.
No effects in size differences, unusual cell shapes, colors, flocculations, adherence of cells to test containers, or aggregation of cells were noted.

Reported statistics and error estimates:

- The NOEC was calculated using one-way analysis of variance (ANOVA) and Bonferroni's test (TOXSTAT 3.3).
- The effective concentrations and NOEC were determined using the mean measured concentration of the test item.

Validity criteria fulfilled:

yes

Conclusions:

The toxicity of the test substance to the unicellular freshwater green alga Selenastrum capricornutum was determined according to the principles of OECD 201 (1984). After 72 hours the EC50 was determined to be 63.8 mg/L by using the average specific growth rate.

Executive summary:

The toxicity of the test substance to the unicellular freshwater green alga Selenastrum capricornutum was determined according to the principles of OECD 201 (1984). The study was conducted under static conditions. Five concentrations were tested, the nominal concentrations were: 6.5, 13, 25, 50, and 100 mg/L. Mean measured concentrations were: 5.78, 12.4, 22, 44.8, and 91.2 mg/L. These mean measured concentrations ranged from 88 to 95% of the nominal concentrations and were used to calculate median effective concentrations.

Algae were distributed among twenty replicates of each control and eleven replicates of each treatment at the rate of approximately 10,000 cells/mL. Exposure of algae to the test substance for 72 h resulted in a EC50 of 63.8 mg/L growth rate. Meanwhile, the NOEC was determined as 22 mg/L.

Description of key information

- ErC50 (72 h) = 63.8 mg/L (Selenastrum capricornutum, OECD 201)

- NOErC (72 h) = 22 mg/L (Selenastrum capricornutum, OECD 201)

Key value for chemical safety assessment

EC50 for freshwater algae:

63.8 mg/L

EC10 or NOEC for freshwater algae:

22 mg/L

Additional information

The toxicity of the test substance to the unicellular freshwater green alga Selenastrum capricornutum was determined according to the principles of OECD 201 (1984). The study was conducted under static conditions. Five concentrations were tested, the nominal concentrations were: 6.5, 13, 25, 50, and 100 mg/L. Mean measured concentrations were: 5.78, 12.4, 22, 44.8, and 91.2 mg/L. These mean measured concentrations ranged from 88 to 95% of the nominal concentrations and were used to calculate median effective concentrations.

Algae were distributed among twenty replicates of each control and eleven replicates of each treatment at the rate of approximately 10,000 cells/mL. Exposure of algae to the test substance for 72 h resulted in a EC50 of 63.8 mg/L growth rate. Meanwhile, the NOEC was determined as 22 mg/L.