Hexamethylene diisocyanate

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1999

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP guideline study with acceptable restrictions.

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

GLP compliance:

yes

Analytical monitoring:

yes

Vehicle:

no

Details on test solutions:

Because of the rapid hydrolysis a water accommodated fraction (WAF) was prepared by direct weighing of Desmodur H rein into water:
- 100 mg of the test item were diluted in 1 litre of dilution water
- treated for 60 s at 8000 rpm with an ultra-turrax
- stirred for 24 hours on a magnetic stirrer
- finally undissolved particles removed by filtration using folded filters (pore size 7-12 µm)

The resulting solution was analyzed to its TOC content and was the only concentration used in the test.

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM:
- supplier: Bio International B.V. (Netherlands)
- body length: 2.5 - 3.5 cm
- medication: none
- mortalities during acclimatization: < 2 %
- keeping water: synthetic fresh water in accordance with ISO

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

total hardness 14.1 °dH (251.5 mg/l CaCO3)

Test temperature:

The temperature varied between 21.3 – 21.7 °C (daily monitoring)

pH:

pH-values varied between 8.0 – 8.2 (daily monitoring)

Dissolved oxygen:

Oxygen concentration varied between 8.0 – 8.5 mg/l (daily monitoring)

Salinity:

No data

Nominal and measured concentrations:

Nominal concentration of test substance : 70 mg/l (Analytical value after 0 h: 46 mg/l, after 96 h: 45 mg/l, resp.)

Details on test conditions:

TEST SYSTEM:
- keeping water: synthetic fresh water according to ISO 7346
- photoperiod: 16 hours light, 8 hours dark
- temperature: 20 - 24 °C
- ventilated
- no feeding during test
- test vessel: glass aquarium, 5 l test media
- number of fish per test vessel: 10
- test concentration: 70 mg/l plus one control
- test parameter: mortality (recorded daily)

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

>= 82.8 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks on result:

other: arithmetic mean of the analytical values of day 0, 1, 2, 3 and 4 d

Details on results:

The above test result refers to a concentration of the test substance which was calculated directly from analytically determined TOC values.

Validity criteria fulfilled:

yes

Remarks:

The mortality in the controls did not exceed 10% by the end of the test. •The dissolved oxygen concentration remained above 60% of the air-saturation value throughout the exposure period. •The pH did not vary by more than 1 unit

Executive summary:

An acute toxicity study was performed on hexamethylenediisocyanate (HDI) in accordance with the EU Method C.1 and under GLP. Considering the variable composition of the test substance, a Water Accommodated Fraction procedure was used (100 mg of the test substance was added to 1L of water). Fish (species: Danio rerio) were exposed to the WAF under static conditions (Bayer AG, 2000).

The endpoint is lethal concentration. The 96 -h LC0 was found to be >= 82.8 mg/l. (nominalconcentration). The result relates to the arithmetic mean of analytical values. Based on the results of this study, HDI would not be classified as harmful to fish in accordance with the classification system of the EU (Directive 67/548/EC). This toxicity study is classified as acceptable and satisfies the guideline requirement.

 

Results Synopsis:

Danio Rerio:

Body Length = 2.5 3.5 cm

Test Type Static

Limit Test

96h-LC0 >= 82.8 mg/L

Basis for effect: mortality

Description of key information

The acute toxicity has been determined for fish with 96 h-LC0 of >= 82.8 mg/l

(Brachydanio rerio). The test result refers to concentration of the test substance which was calculated directly from analytically determined TOC-value. The test was conducted according to Council Directive 92/69/EEC C.1 (1992) (Bayer AG, 2000). A water accommodated fraction was prepared for testing by stirring the substance in water with Ultra turrax 60 sec/8000 rpm, 24 hours magnetic stirrer and filtration. Only one concentration was tested. The pH of the test solution was around 8.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

LC50

Effect concentration:

82.8 mg/L

Additional information

Disregarded study:

For fish (Danio rerio) a LC 50 > 22 mg/l after 96 h was obtained. The study was conducted according to the German standard "Letale Wirkung beim Zebrabaerbling (Brachydanio rerio) LC0, LC50, LC100, 48-96h", UBA-Verfahrensvorschlag, Mai 1984 (Bayer AG, 1992). This study is not regarded as being reliable. In all tests, the temperature is stated to be higher then recommended in the test guideline. After 1 hour of stirring the hydrolysis process was still ongoing at least in the vessels with the higher hexamethylene diisocyanate (HDI) concentrations as was obvious by “remaining oily droplets (HDI) at the water surface”. Therefore the lethal effects might not be caused by HDI itself but by the matter of fact that non-dissolved particles in the test substance impinged on the gill breathing of fish.