((4S,4aR,7S,7aR)-4,7-dimethylhexahydrocyclopenta[c]pyran-1(3H)-one

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

November 2020 to May 2021

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Batch Number CH-DA-01-18

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

Preparation and application of test solution
-Method: Water Accommodated Fractions

Test organisms (species):

Daphnia magna

Details on test organisms:

Sourced from ephippia supplied by Cheshire Eco Solutions, from MicroBioTests. The ephippia were incubated no more than 96h prior to test commencement, therefore the neonates were less than 24h old at the test commencement.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Remarks on exposure duration:

Observations of the test animals were carried out at 24h and 48h for the definitive test.

Test temperature:

20 oC +/- 2 oC

pH:

6-9

Dissolved oxygen:

> 3 mg/L

Nominal and measured concentrations:

Nominal concentrations: 10, 18, 32, 56, 100, 180, 320, 560 and 1000 mg/L

Details on test conditions:

TEST SYSTEM
-Test Vessel: 100 mL capacity borosilicate glass crystallising dishes
-Type: Closed
-Volume of solution: 50 mL
-Type of flow-through: Static
-No. organisms per vessel: 10 animals per vessle
-No. vessels per concentration (replicates): 2 vessels per concentration
-No. vessels per control (replicates): 2 vessels per control

TEST MEDIUM/WATER PARAMETERS
-Source/preparation of dilution water: ISO reconstituted water (as specified in OECD 2020)
-Intervals of water quality measurement carried out at each concentration at 0h and 48 h

EFFECT PARAMETERS MEASURED: Immobilisation

OTHER TEST CONDITIONS
-Photoperiod: 16h light / 8h dark

RANGE FINDING STUDY
-Test concentrations: 1,000, 100, 10 and 1 mg/L
-Results used to determine conditions for the definitive study: yes

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

56 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

212 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

274 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Control mortality was 2.5%

Results with reference substance (positive control):

-Results with reference substance valid? Yes
-Relevant effect levels: yes
-Limit test: no
Dose-response test: yes
24h EC50: 1.4 mg/L

Nominal Conentration (mg/L)	Number immobile at 24h		Number immobile at test termination (48h)		Total exposed
	Replicate a	Replicate b	Replicate a	Replicate b
10	0	0	0	0	20
18	0	0	0	0	20
32	0	0	0	0	20
56	1	0	2	1	20
100	0	0	2	2	20
180	2	2	3	5	20
320	6	7	8	9	20
560	10	10	10	10	20
1000	10	10	10	10	20

Validity criteria fulfilled:

yes

Conclusions:

The 48-hour EC 50 was 212 mg/L and the 48-hour NOEC was 56 mg/L. The substance does not meet the criteria for classification as toxic to the aquatic environment according to Regulation (EC) 1272/2008.

Executive summary:

The short-term toxicity of dihydronepetalactone to aquatic invertebrates was determined during a GLP-compliant study performed according to OECD Testing Guideline 202.

Since the substance was poorly water soluble, Water Accomodated Fractions (WAF) were prepared.  Results are expressed on the initial loading of the test substance required to produce effects.

The species was Daphnia magna.

A range-finding test was performed to determine the concentrations to be used during the definitive test.  As a result, concentrations of 10, 18, 32, 56, 100, 180, 320, 560 and 1000 mg/L were used during the definitive test.

The 48-hour EC50 was 212 mg/L and the 48-hour NOEC was 56 mg/L.  The substance did not meet the criteria for classification as toxic to the aquatic environment according to Regulation (EC) 1272/2008.

Description of key information

The short-term toxicity of dihydronepetalactone to aquatic invertebrates was determined during a GLP-compliant study performed according to OECD Testing Guideline 202.

Since the substance was poorly water soluble, Water Accomodated Fractions (WAF) were prepared.  Results are expressed on the initial loading of the test substance required to produce effects.

The species was Daphnia magna.

A range-finding test was performed to determine the concentrations to be used during the definitive test.  As a result, concentrations of 10, 18, 32, 56, 100, 180, 320, 560 and 1000 mg/L were used during the definitive test.

The 48-hour EC50 was 212 mg/L and the 48-hour NOEC was 56 mg/L.  The substance did not meet the criteria for classification as toxic to the aquatic environment according to Regulation (EC) 1272/2008.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

212 mg/L