Diallyl 2,2'-oxydiethyl dicarbonate

Long-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

fish early-life stage toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

01 SEP 2020- 03 MAY 2021

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 210 (Fish, Early-Life Stage Toxicity Test)

Version / remarks:

adopted 26. Jul. 2013

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: The test item was delivered at ambient temperature and stored at room temperature until the 20. Jan. 2020. This deviation was assessed as uncritical by the sponsor. Since the 20th of January it was stored in the fridge at -1.1 -12.3 °C.
- Stability and homogeneity of the test material in the vehicle/solvent under test conditions and during storage: homogeneous

Analytical monitoring:

yes

Details on sampling:

Samples for analytical measurement were taken from one replicate per concentration.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A stock solution containing 50 mg/L in dilution water was prepared daily. For this, the loading rate of 43.5 pL (based on a density of 1.15 g/mL, stated in the SDS) was mixed with 1 L dilution water and shaken on an orbital shaker for 1 hour in order to achieve complete dissolution. This stock solution was used for preparation of the lower concentrated stock solutions at the concentrations of 10 mg/L and 1 mg/L.
These stock solutions were mixed with dilution water again. The mixture flowed directly into the aquaria. Flow of stock solutions and dilution water were adjusted to reach the planned concentration of 1 mg/L and 0.1 mg/L in the treatments.

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM
- Source: The original animals were obtained in 2019 from the University Heidelberg and used for breeding and production of eggs.
- Feeding during test : After hatching, around day 7: Powdered flake food (Warm-water fish food); From day 26 until the end of the test: Artemia nauplii
- Frequency: After hatching, around day 7: 1 - 2 times per working day; From day 26 until the end of the test: once each working day.

Test type:

flow-through

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

35 d

Remarks on exposure duration:

at least 30 days post hatch

Hardness:

Hardness of the used dilution water was measured before the start and the end of the test. It is determined to be 35.6 mg CaCO3/L at 0 d and 35 d.

Test temperature:

25.5 - 27.1 °C

pH:

7.2 - 7.7

Dissolved oxygen:

6.9 - 8.3 mg/L

Conductivity:

The conductivity of the dilution water is adjusted to a conductivity of 500 pS by adding electrolyte solutions (sea salt and sodium bicarbonate).

Nominal and measured concentrations:

please refer to 'any other information on results incl. tables'

Details on test conditions:

TEST SYSTEM
- Test vessel: 12 L stainless-steel aquaria
- Renewal rate of test solution (frequency/flow rate):
- No. of fertilized eggs/embryos per vessel: 30 eggs
- No. of vessels per concentration: four replicates
- No. of vessels per control: four replicates

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Reconstituted freshwater was used in the test. Tap water is desalinated by reverse osmosis.

OTHER TEST CONDITIONS
- Adjustment of pH: The pH value of the dilution water is adjusted to pH 7.5 by adding electrolyte solutions (sea salt and sodium bicarbonate).
- Photoperiod: 12/12 hours

RANGE-FINDING STUDY
- Test concentrations: 1 mg/L and 10 mg/L
- Results used to determine the conditions for the definitive study: In a non GLP OECD 210 pre-test using the concentrations 10 mg/L and 1 mg/L, toxicity was observed at the concentration 10 mg/L whereas at the concentration 1 mg/L no toxicity was observed.
Based on the results of the pre-test and under consideration that only a NOEC value had to be established, a limit test was performed instead of a definite test. Accordingly, this study was performed at the concentration of 1 mg/L. For precautionary reasons, the lower concentration of 0.1 mg/L was also tested. Hence, the test was running using the extended limit design, which is acceptable for the determination of a NOEC according to OECD 210.

Reference substance (positive control):

no

Duration:

35 d

Dose descriptor:

NOEC

Effect conc.:

>= 1.06 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

other: hatchability

Duration:

35 d

Dose descriptor:

NOEC

Effect conc.:

>= 1.06 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

other: Post hatch survival

Duration:

35 d

Dose descriptor:

NOEC

Effect conc.:

>= 1.06 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

weight

Duration:

35 d

Dose descriptor:

NOEC

Effect conc.:

0.08 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

length

Duration:

35 d

Dose descriptor:

LOEC

Effect conc.:

> 1.06 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

other: hatchability

Duration:

35 d

Dose descriptor:

LOEC

Effect conc.:

> 1.06 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

other: post hatch survival

Duration:

35 d

Dose descriptor:

LOEC

Effect conc.:

> 1.06 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

weight

Duration:

35 d

Dose descriptor:

LOEC

Effect conc.:

1.06 mg/L

Nominal / measured:

meas. (TWA)

Conc. based on:

test mat.

Basis for effect:

length

Mean of measured Concentrations and % of Nominal, Day 0

Nominal Concentration in mg/L	Mean of measured concentrations in mg/L
	Day 0 Aquaria	% of Nominal	Day 0 Inlet Aquaria	% of Nominal
0.1	0.04	35%	0.11	111%
1	1.32	132%	1.43	143%

 

Mean of measured Concentrations and % of Nominal, Day 7 and Day 14

Nominal Concentration in mg/L	Mean of measured concentrations in mg/L
	Day 7 Aquaria	% of Nominal	Day 14 Aquaria	% of Nominal
0.1	0.05	51%	0.15	154%
1	1.24	124%	1.1	110%

 

Mean of measured Concentrations and % of Nominal, Day 22 and Day 28

Nominal Concentration in mg/L	Mean of measured concentrations in mg/L
	Day 22 Aquaria	% of Nominal	Day 28 Aquaria	% of Nominal
0.1	0.06	62%	0.06	61%
1	0.83	83%	0.95	95%

 

Mean of measured Concentrations and % of Nominal, Day 33

Nominal Concentration in mg/L	Mean of measured concentrations in mg/L
	Day 33 Aquaria	% of Nominal
0.1	0.03	30%
1	0.62	62%

 

Validity criteria fulfilled:

yes

Conclusions:

A slight, but statistically significant difference was observed only for the endpoint length at the concentration of 1.06 mg/L. However, it must be taken into account that this endpoint is very susceptible to outliers and, due to the short length of the fish at the test end of about 10 mm on average, the difference in individual fish length is not very accurate. For the other, more exact endpoints, no toxic effect could be observed compared to the control.
No observations were made which might cause doubts concerning the validity of the study outcome. All validity criteria were met. The result of the test is considered valid.

Executive summary:

The toxicity of Diallyl 2,2'-oxydiethyl dicarbonate was tested in the Early-Life Stage Toxicity Test with Danio rerio following OECD TG 210 and under GLP compliance. One valid experiment was performed.

For each treatment, 30 eggs/fish were exposed to the test item in a flow-through system. The experiment was performed using the two concentrations 1 mg/L and 0.1 mg/L (nominal). Dilution water was added with flow meters. Test item solutions were added with tubing pumps. Test item solutions and dilution water were mixed in the aquarium inlet. Fresh test item solutions were prepared daily.

The concentrations of the test item were measured seven times during the study period of 35 days using LC-MS-MS. The measured concentrations were between 30 % and 154 % of the nominal concentrations. Therefore, the determination of the biological results was based on the time-weighted mean of the measured concentrations, namely 1.06 mg/L and 0.08 mg/L (see annex 2 OECD guidance document No. 23).

A slight, but statistically significant difference was observed only for the endpoint length at the concentration of 1.06 mg/L. However, it must be taken into account that this endpoint is very susceptible to outliers and, due to the short length of the fish at the test end of about 10 mm on average, the difference in individual fish length is not very accurate. For the other, more exact endpoints, no toxic effect could be observed compared to the control.

No observations were made which might cause doubts concerning the validity of the study outcome. All validity criteria were met. The result of the test is considered valid.

The following results for the test item Diallyl 2,2'-oxydiethyl dicarbonate were determined:

Endpoint	NOEC	LOEC
Hatchability	≥ 1.06 mg/L	> 1.06 mg/L
Post hatch survival	≥ 1.06 mg/L	> 1.06 mg/L
Wet Weight	≥ 1.06 mg/L	> 1.06 mg/L
Length	0.08 mg/L	1.06 mg/L

Description of key information

NOEC >= 1.06 mg/Lm Early-Life Stage Toxicity Test , Danio rerio, OECD TG 210, GLP, 1 mg/L and 0.1 mg/L (nominal), flow-through, 35d

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

NOEC

Remarks:

endpoint: hatchability, post-hatch survival and wet weight

Effect concentration:

>= 1.06 mg/L

Additional information

A slight, but statistically significant difference was observed only for the endpoint length at the concentration of 1.06 mg/L. However, it must be taken into account that this endpoint is very susceptible to outliers and, due to the short length of the fish at the test end of about 10 mm on average, the difference in individual fish length is not very accurate. For the other, more exact endpoints, no toxic effect could be observed compared to the control. Hence, the NOEC of >= 1.06 mg/L as derived for the endpoints hathability, post hatch survival and wet weight is considered as key value for the chemical safety assessment.