Hexamethylene diisocyanate, oligomers, reaction products with 3-methoxypropylamine

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:

From September 05, 2017 to September 07, 2017

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)

Deviations:

yes

Remarks:

see 'Principles of method if other than guideline'

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

yes

Remarks:

see 'Principles of method if other than guideline'

Principles of method if other than guideline:

The following deviation was documented:
- The temperature for the study ranged from 20.5 to 22.2 °C and was therefore higher than stated in the guideline. As no immobility occurred during the test, this deviation
was stated as uncritical. The deviation was assessed and signed by the study director on 07. Sep. 2017.

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

CAS No.: 162492-07-1; EINECS-No.: 500-740-9; Batch No.: 1591ZG-101; Purity: >98 %; Appearance: homogeneous, white powder

Analytical monitoring:

yes

Details on sampling:

23 hours before the start of the test, the adult animals were separated from the young. 0.5 hours before test start, the adults were caught with the help of a glass tube, and the newborn Daphnia, aged between 0 and 20 hours, were sieved from the medium and immediately placed into a beaker containing dilution water. After a settling-in period of 30 minutes, animals which showed no apparent damage were used for the test.
Switching from M4-medium (husbandry) to Dilution water (test) has been shown not to cause any detrimental effects for test Daphnia.

Vehicle:

no

Test organisms (species):

Daphnia magna

Details on test organisms:

Species: Daphnia magna
Variety: STRAUS
Strain: Berlin
Sex: female
Age: between 0 and 24 hours
Origin: Umweltbundesamt Berlin

Animal Husbandry
Daphnia magna is bred in the test laboratory throughout the year. The animals are kept for the use in toxicity tests. They multiply by parthenogenesis, thus being genetically identical.
Vessels: preserving glasses, nominal volume 2 L
Medium: M4-Medium (recipe of ELENDT)
Food: unicellular green algae (Desmodesmus subspicatus)
Medium renewal: twice a week
Photo period: 16/8 hours, using neon tubes
Temperature: 20 ± 2 °C

Test type:

static

Water media type:

other: dilution water

Limit test:

no

Total exposure duration:

48 h

Hardness:

2.502 mmol/L

Test temperature:

20.5 – 22.2 °C

pH:

7.7 - 7.8

Dissolved oxygen:

8.9 - 9.3 mg/L

Salinity:

CaCl2*2H2O: 293.80 mg/L
MgSO4*7H2O: 123.30 mg/L
NaHCO3: 64.80 mg/L
KCl: 5.80 mg/L

Nominal and measured concentrations:

Treatments: 100 mg/L nominal concentration
Because of the poor solubility of the test substance, the measured concentrations were in a very low rage. The measured concentration was 24.2 μg/L at the beginning of the test and 18.9 μg/L at the end of the test. Therefore, the determination of the results was based on the geometric mean of the measured concentrations.

Details on test conditions:

Using a glass tube, the Daphnia were caught and lifted from the beaker. They were put on a small sieve, and the medium surrounding the animals was sucked off using absorbent paper. Immediately after that, the animals were put into the respective test solution. The test vessels were left to stand for 48 hours. After 24 and 48 hours, the immobilized Daphnia were counted. Daphnia are considered immobilised when they do not perform any movements or are only able to move their antennae when the beaker is gently agitated. Daphnia which are trapped at the surface of the test solution are also considered immobilised. The pH, the concentration of dissolved oxygen and the content of the test substance in the test vessels were measured at the beginning and at the end of the test.

Experimental Conditions:
Observation times: 24 and 48 hours
Medium renewal: none
Test vessels: glass beakers, nominal volume 50 mL, tall shape
Replicates (Treatments) 4 vessels, each containing 20 ± 5 mL test solution and 5 Daphnia
Replicates (Blank control) 4 vessels, each containing 20 ± 5 mL dilution water and 5 Daphnia

Reference substance (positive control):

yes

Remarks:

Potassium dichromate K2Cr2O7

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: Corresponding to >21.39 µg/L mean measured geometric concentration

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: Corresponding to 21.39 µg/L mean measured geometric concentration

Details on results:

In the blank control and the treatment, none of the Daphnia were immobilised.

Validity:

- Immobilisation in the controls may not exceed 10 %.

Immobilisation in the controls was 0 %.

- The concentration of dissolved oxygen at the end of the test must be at least 3 mg/L.

The lowest concentration of dissolved oxygen at the end of the test was 9.2 mg/L.

Validity criteria fulfilled:

yes

Conclusions:

Under the study conditions, the 48 h EC50 was determined to be > 100 m/L, corresponding to >21.39 µg/L (mean measured geometric concentration). The 48 h NOEC was 100 m/L, corresponding to 21.39 µg/L (mean measured geometric concentration).

Executive summary:

A study was conducted to determine toxicity of the test substance to Daphnia magna according to OECD Guideline 202 and EU Method C.2, in compliance with GLP. The study was performed using one concentration of the test substance (100 mg/L, nominal). Twenty Daphnia were exposed to the substance for 48 h in a static test system. After 24 and 48 h, the immobilised Daphnia were counted. At this concentration, no immobility was observed. Potassium dichromate K2Cr2O7 was used as positive control in a current reference study to assure that the test conditions were reliable. At the start and at the end of the test, the concentration of the test substance in the solutions was determined using HPLC. Due to poor solubility, the measured concentrations were in the low range: 24.2 µg/L at the beginning of the test and 18.9 µg/L at the end of the test. Under the study conditions, the 48 h EC50 was determined to be > 100 m/L, corresponding to >21.39 µg/L (mean measured geometric concentration). The 48 h NOEC was 100 m/L, corresponding to 21.39 µg/L (mean measured geometric concentration) (Muckle, 2017).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

21.39 µg/L

Additional information

A study was conducted to determine toxicity of the test substance to Daphnia magna according to OECD Guideline 202 and EU Method C.2, in compliance with GLP. The study was performed using one concentration of the test substance (100 mg/L, nominal). Twenty Daphnia were exposed to the substance for 48 h in a static test system. After 24 and 48 h, the immobilised Daphnia were counted. At this concentration, no immobility was observed. Potassium dichromate K2Cr2O7 was used as positive control in a current reference study to assure that the test conditions were reliable. At the start and at the end of the test, the concentration of the test substance in the solutions was determined using HPLC. Due to poor solubility, the measured concentrations were in the low range: 24.2 µg/L at the beginning of the test and 18.9 µg/L at the end of the test. Under the study conditions, the 48 h EC50 was determined to be > 100 m/L, corresponding to >21.39 µg/L (mean measured geometric concentration). The 48 h NOEC was 100 m/L, corresponding to 21.39 µg/L (mean measured geometric concentration) (Muckle, 2017).