4-tert-butylcyclohexyl acetate

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 14/06/1994 to 16/06/1994

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

This study was performed according to OECD Guideline 202 and EU Method C.2 with GLP statement. All validity criteria were fulfilled but TOC was used as the analytical method.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Remarks:

1996-08-15

Analytical monitoring:

yes

Details on sampling:

No data

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A 100 mg/L stock solution was prepared by dispersing 0.258 g of the test substance in 2.5 litres Elendt M7 medium using a high shear mixer at 14000-15000 rpm for 20 minutes. Test solutions were prepared by adding known volumes of stock to 2 litres Elendt medium.
- Eluate: Elendt M7 medium
- Controls: one control
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): not applicable
- Concentration of vehicle in test medium (stock solution and final test solution): not applicable
- Evidence of undissolved material (e.g. precipitate, surface film, etc): no data

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna (Crustacea: Cladocera).
- Source: no data
- Age at study initiation (mean and range, SD): <24 hour old
- Weight at study initiation (mean and range, SD): no data
- Length at study initiation (length definition, mean, range and SD): no data
- Method of breeding: Cultures were maintained in a synthetic medium with the same chemical composition and similar pH and dissolved oxygen concentration as that used to prepare test solutions. Culture medium consists of 800 mL Elendt M7 medium. The cultures are fed daily with cells of the green algae Chlorella vulgaris. Cultures are reset using 10 neonates, when they become gravid their numbers are reduced from 10 to 5 and the production of neonates results in their daily removal.
- Feeding during test: no

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Remarks on exposure duration:

none

Post exposure observation period:

None

Hardness:

251 +/-2 mg/L as CaCO3

Test temperature:

20.0 +/- 0.9 °C

pH:

7.4 +/- 0.1

Dissolved oxygen:

8.7 +/- 0.4 mg/L

Salinity:

Not applicable

Nominal and measured concentrations:

- Nominal concentrations: 5.6, 10, 18, 32, 56 mg/L
- Measured concentrations: 2.5, 3.4, 6.6, 9.8, 14 mg/L (See table 6.1.3/1 in "Any other information on results incl. tables")

Details on test conditions:

TEST SYSTEM
Each exposure vessel (100 mL glass crystallising dish) was submerged in a 2 litre crystallising dish containing the appropriate test solution. There were 2 vessels at each test concentration (situated in one 2 litre crystallising dish) each nominally containing 10 neonates.

TEST MEDIUM / WATER PARAMETERS
Elendt M7 medium

OTHER TEST CONDITIONS
- Photoperiod: 16 hour light, 8 hour dark
- Light intensity: normal laboratory light intensity

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Immobilisation

TEST CONCENTRATIONS
- Spacing factor for test concentrations: c.a. 1.75
- Range finding study: No
- Test concentrations: Nominal concentrations = 5.6, 10, 18, 32, 56 mg/L

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

5.3 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CL: 4.4-6.4 mg/L

Details on results:

See table 6.1.3/2 in "Any other information on results incl. tables".
- Behavioural abnormalities: At 48 hours, Daphnia at 5.6 mg/L (nominal) were classed as mobile but were affected by the test substance since they exhibited only discontinuous movement through the medium.
- Mortality of control: none

Results with reference substance (positive control):

Not applicable

Reported statistics and error estimates:

None

Table 6.1.3/1: TOC Analysis

Nominal concentration (mg/L)	Nominal TOC concentration (mg/L)	Measured TOC concentration (mg/L)		Mean measured TOC concentration (mg/L)	TOC from test substance* (mg/L)	Concentration of test substance ** (mg/L)
		Day -1	Day 2
0.0	-	9.6	9.7	9.7	-	-
5.6	4.1	11.4	11.5	11.5	1.8	2.5
10	7.3	13.0	11.3	12.2	2.5	3.4
18	13.1	15.7	13.3	14.5	4.8	6.6
32	23.2	18.3	15.3	16.8	7.1	9.8
56	40.7	20.9	18.6	19.8	10.1	14

* Mean background measurement (ie. 9.7 mg/L TOC) has been subtracted from calculated mean values.

** Assuming 72.61% carbon content.

TOC concentrations were determined at 0 hours but cannot be used in the calculation of results since they cannot be adequately audited.

Mean measured concentrations of the test substance were 25 -45% of nominal values. TOC concentrations remained stable during the test. However, the stock used to prepare the test solutions was approximately a third of the nominal stock concentration at -24 hours ie. 22.7 mg/L as TOC. The nominal concentration was 72.6 mg/L. This may have resulted from the low aqueous solubility of the test substance.

Table 6.1.3/2: Effect data

Measured concentration (mg/L)	Number immobile at 24h			% immobile at 24h	Number immobile at 48h			% immobile at 48h
	Replicate		Total		Replicate		Total
	1	2			1	2
Control	0	0	0	0	0	0	0	0
2.5	0	0	0	0	2	2	4	20
3.4	1	0	1	5	3	1	4	20
6.6	4	3	7	33	4*	3	7	33
9.8	10	10	20	100	10	10	20	100
14	10	10	20	100	10	10	20	100

* Replicate 1 at 6.6 mg/L (nominal 18 mg/L) contained 11 neonates.

Validity criteria fulfilled:

yes

Conclusions:

The 48h-EC50 based on measured concentrations was 5.3 mg/L (95% Confidence limits at 4.4 -6.4 mg/L).

Executive summary:

This study was performed according to OECD Guideline 202 and EU Method C.2 with GLP statement, to assess the acute toxicity of the test substance to the freshwater Daphnia magna under static conditions.

Daphnia (10 neonates per vessel) were exposed to a range of nominal concentrations 5.6 -56 mg/L, in duplicate. There was no specific analysis of the test substance. However, TOC (Total Organic Carbon) was taken as an indirect measure. Mean measured concentrations were found to be 2.5 -14 mg/L. The exposure vessels were placed in the test area according to a random distribution and in the temperature range 18.5 -21.0°C and under normal laboratory light intensity with a 16 hour light, 8 hour dark photoperiod.

The 48h-EC50 based on measured concentrations and calculated by the Moving Average method was 5.3 mg/L (95% Confidence limits at 4.4 -6.4 mg/L).

Reference 2

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

No data

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Remarks:

This study was performed according to DIN guideline 38412 Part 11 with GLP statement. Information on purity of the test substance and raw data in control were not provided in this report. Restrictions should be considered.

Qualifier:

according to guideline

Guideline:

other: DIN 38412 Part 11

Deviations:

not specified

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

not specified

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Daphnia magna

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

24 h

Remarks on exposure duration:

none

Key result

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

7 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CL: 4.1-12 mg/L

Duration:

24 h

Dose descriptor:

other: The highest concentration tested without observed effect

Effect conc.:

2.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Table 6.1.3/1: Results

Nominal concentration (mg/L)	After 24 hours
	mobile	immobile	% immobile
2.6 4.0 5.5 7.7 11 15.4 22	19 14 12 10 7 4 0	1 6 8 10 13 16 20	5 30 40 50 65 80 100

Validity criteria fulfilled:

not specified

Conclusions:

The 24h-EC50 was determined to be 7 mg/L (95% confidence limit: 4.1 - 12 mg/L) based on nominal concentrations.

Executive summary:

This study was performed according to DIN guideline 38412 Part 11 with GLP statement, to assess the acute toxicity of the test substance to Daphnia magna during 24 hours in static conditions.

One control and seven test substance concentrations were performed. Nominal concentrations were 2.6, 4.0, 5.5, 7.7, 11, 15.4 and 22 mg/L. Measured concentrations were not determined.

Based on percentage of immobilisation and nominal concentrations, the highest concentration tested without observed effect and the 24h-EC50 were determined to be 2.6 mg/L and 7 mg/L (95% confidence limit: 4.1 - 12 mg/L), respectively.

No information on purity of the test substance and raw data in control were provided in this report. Thus, validity criteria cannot be verified.

Description of key information

OECD Guideline 202, EU Method C.2, GLP, key study, validity 2:

48h-EC50 = 5.3 mg/L (95% Confidence limits = 4.4 -6.4 mg/L).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

5.3 mg/L

Additional information

To assess the short-term toxicity of the registered substance to aquatic invertebrates Daphnia magna, two studies are available. Among this data, one study is assessed as the key study (Marshall, 1994) and the other study as supporting (Scholz, 1995).

According to the key study, performed in compliance to OECD Guideline 202 and EU Method C.2 with GLP statement, the freshwater Daphnia magna were exposed to a range of mean measured concentrations of 2.5 – 14 mg/L substance (two vessels per test concentration, with 10 neonates per vessel) under static conditions. The 48h-EC50 based on measured concentrations was 5.3 mg/L (95% Confidence limits at 4.4 -6.4 mg/L).

In the supporting study (Scholz, 1995), the test duration was only 24 hours and no analytical measurements were performed. Furthermore, some information were missing and validity criteria cannot be verified.