4-isopropylcyclohexanol

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:

Study completion date 15 May 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

4-isopropylcyclohexanol

EC Number:

225-035-0

EC Name:

4-isopropylcyclohexanol

Cas Number:

4621-04-9

Molecular formula:

C9H18O

IUPAC Name:

4-(propan-2-yl)cyclohexan-1-ol

Test material form:

liquid

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

For determination of the appropriate test concentrations for the main test, a range-finding test was performed. The nominal test item concentrations tested were 1.0, 10 and 100 mg/L. For this, three replicates per treatment were tested under identical exposure conditions than those applied for the main test. The test medium of the highest concentration of 100 mg/L was stirred until dissolution for 10 minutes at room temperature. The test media of the two lower concentrations were prepared in a series of further dilution steps. Additional samples were prepared to determine the effect of the light on the test item and a possible adsorption of the test item onto the algae.

Test solutions

Vehicle:

no

Details on test solutions:

Based on the range-finding results the following nominal concentrations of FOLROSIA were selected for the main test: 1.0, 3.2, 10, 32 and 100 mg/L. Additionally, a control (test water without test item) was tested in parallel. The test design included three replicates per test concentration and six replicates of the control.

The measured concentrations of the test item FOLROSIA in the test media of the nominal test concentrations of 1.0 to 100 mg/L were between 92 and 106% of the nominal values at the start of the test. Thus, the correct dosage of the test item could be verified. At the end of the test, 82 to 95% of the nominal values were found. The geometric mean measured exposure concentrations were determined to be 0.87, 2.8, 9.3, 30 and 100 mg/L, respectively, at the 1.0, 3.2, 10, 32 and 100 mg/L (nominal) test concentrations.

Test organisms

Test organisms (species):

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

Details on test organisms:

The test was started using a nominal algal cell density of 5000 cells/mL. The initial cell density was selected according to the recommendations of the OECD test guideline. The algal cell density in the pre-culture was determined using an electronic particle counter (Coulter Counter, Model Z2).

Study design

Test type:

static

Water media type:

other: Reconstituted test water - AAP medium

Limit test:

no

Total exposure duration:

72 h

Test conditions

Hardness:

15 mg/L as CaCO3

Test temperature:

The water temperature during the test was maintained at 22 °C.

pH:

The pH of the test media was in the range of 7.3 to 7.6 during the test period.

Nominal and measured concentrations:

The geometric mean measured exposure concentrations were determined to be 0.87, 2.8, 9.3, 30 and 100 mg/L, respectively, at the 1.0, 3.2, 10, 32 and 100 mg/L (nominal) test concentrations.

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

9.3 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

63 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% CI: 60 - 66 mg/L

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

30 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95% CI: 27 - 33 mg/L

Effect concentrations 4

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

35 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

other: Yield

Remarks on result:

other: 95% CI: 27 - 46 mg/L

Effect concentrations 5

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

8.3 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

other: Yield

Remarks on result:

other: 95% CI: 3.1 - 13 mg/L

Effect concentrations 6

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

2.8 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

other: Yield

Results with reference substance (positive control):

For evaluation of the algal quality and experimental conditions, potassium dichromate is tested as a positive control twice a year to demonstrate satisfactory test conditions. The 72-hour EC50 for growth rate in the reference test IES Study Number 20160277 was 0.9 mg/L (October 2016) and showed that the sensitivity of the test system was within the range recommended by the guideline (72-hour EC50 for the growth rate 0.9 - 1.5 mg/L).

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Executive summary:

A clear concentration-response relationship was observed for both biological endpoints growth rate and yield during the exposure period.

Based on the results of the study, the :

EC50 (growth rate - 72 hr) = 63 mg/L

EC10 (growth rate - 72 hr) = 30 mg/L

NOEC (growth rate - 72 hr) = 9.3 mg/L

EC50 (yield - 72 hr) = 35 mg/L

EC10 (Yield - 72 hr) = 8.3 mg/L

NOEC (yield - 72 hr) = 2.8 mg/L

.