3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1999-09-27 to 1999-10-01

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study with acceptable restrictions: test substance not stable under test conditions (rapid hydrolysis)

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Version / remarks:

Cited as Directive 92/69/EEC, C.1

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- daily sampling

Vehicle:

no

Details on test solutions:

STOCK AND TEST SOLUTION AND THEIR PREPARATION
- Dispersion: A 1.3 fold amount (100 mg/l) of the maximum water solubility of the test substance in the preliminary test (70 mg/l) was weighed into water, treated for 60 seconds at 8000 rpm with an  ultra-turrax and afterwards stirred on a magnetic stirred for 24 hours. The resulting emulsion 
was filtered using a folded filter of pore size  7-12 um.

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISMS
- Strain: Danio rerio (formerly Brachydanio rerio) HAMILTON BUCHANAN
- Supplier: Bio International B.V. (The Netherlands)
- Age/size/weight/loading:  age 6 months 23 days,  total weight of 10 fish at test end 3.62 g (10 control fish: 4.83 g),   length 2.5 - 3.5 cm
- Keeping water: synthetic fresh water in accordance with ISO
- Pretreatment: no medical pretreatment

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

14.0 degree German hardness

Test temperature:

21.4-21.5 (control: 21.4-21.7) degree C 

pH:

pH: 7.6-8.0 (control: 7.7-8.1)

Dissolved oxygen:

8.2-8.5 = 95.1-98.7 % saturation
(control: 8.3-8.4 mg/l = 96.3-97.4 % saturation)

Nominal and measured concentrations:

70 mg/L (nominal)

Details on test conditions:

DILUTION WATER
- Synthetic fresh water in accordance with ISO
CONTROLS
- Synthetic fresh water in accordance with ISO, Hardness: 14.0 degree German hardness

TEST SYSTEM
- Concentration: 70 mg/l
- Exposure vessel type: 300 x 135 x 200 mm with 5 l test medium,  ventilated
- Number of replicates, fish per replicate: 1 replicate with 10 fish each  for exposed and control
- Photoperiod: 16 hours light / 8 hours dark

TEST PARAMETER
- mortality and visible effects (swimming behavior)
- observations at 2, 24, 48, 72, and 96  hours

Reference substance (positive control):

not specified

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

>= 72 mg/L

Nominal / measured:

nominal

Conc. based on:

other: TOC measurement

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 72 mg/L

Nominal / measured:

nominal

Conc. based on:

other: TOC measurement

Basis for effect:

mortality (fish)

Details on results:

No mortality was observed in control and treated fish. The swimming behavour was found to be normal.

Sublethal observations / clinical signs:

RESULTS: 
- Nominal/measured concentrations: 
  nominal: 70 mg/l; arithmetic mean analytical 72.3 mg/l
  analytical TOC at
   0 h: 48 mg/l; 24 h: 49 mg/l; 48 h: 48 mg/l;
  72 h: 47 mg/l; 96 h: 49 mg/l
  control: always < 2 mg/l

The TOC has to be multiplied with 1.5 to correspond with the amount of test substance.

Validity criteria fulfilled:

yes

Conclusions:

The LC50 (96h) was found to be > 72 mg/L (arithmetic mean of analytical measured values) since no mortalities and abnormal swimming behaviour were
observed during the test. Furthermore, the mean measured concentration of the substance during the test is higher than its maximum determined water solubility of 15 mg/l (23°C).

Executive summary:

A static acute 96-hour fish toxicity limit test according to Directive 92/69/EEC was performed with Danio rerio (Bayer AG 2000). No mortalities and no abnormal swimming behaviour were observed (96h-LC50 >72 mg/L) at the tested concentration (70 mg/L nominal).

Due to fast hydrolysis it is assumed that the observed effect is rather attributed to the hydrolysis product than to the parent substance.

The study was assessed as "reliable with restrictions".

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1996-10-21 to 1996-10-25

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study with acceptable restrictions: Test substance not stable under test conditions (rapid hydrolysis)

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Version / remarks:

Cited as Directive 92/69/EEC, C.1

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- analysis of stock solution twice at 0 h and once after 48 h

Vehicle:

no

Details on test solutions:

STOCK AND TEST SOLUTION AND THEIR PREPARATION
- 1 g test substance was stirred for approx. 18 hours  in water and filtered. Test solutions were prepared daily.

STABILITY OF THE TEST CHEMICAL SOLUTIONS
- Hydrolysis was expected but not quantified. TOC analysis after 24 hours indicated that losses were insignificant (less than 20 % compared to nominal concentrations).

Test organisms (species):

Cyprinus carpio

Details on test organisms:

TEST ORGANISMS
- Supplier: Bio International B.V., Someren (NL)
- Age/size/weight/loading: length 2-3 cm, weight approx. 0.36 g
- kept in dechlorinated tap water in 300 L container
- Feeding: approx. 1 % of body weight daily (TRUOVIT)
- Pretreatment: 14 days quarantine
- Feeding during test: no

Test type:

semi-static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Hardness:

- approx. 11 °dH (German hardness)

Test temperature:

18.1-21.5 °C,
mean:  20 °C

pH:

-  7.7-8.3

Dissolved oxygen:

- 88-100 % saturation

Nominal and measured concentrations:

- 28; 46; 81; 139; 231 mg/l (nominal)   
- 28; 46; 81; 139; 208 mg/l (used for evaluation, highest concentration is the arithmetic mean of measured values)

The maximum concentration of 231 mg/l could not be achieved every day.  Thus the mean of the highest test concentrations was used for 
evaluation.

Details on test conditions:

DILUTION WATER
- Source: drinking water (Gelsenwasser AG)
- Aeration: continuously during test

TEST SYSTEM
- Exposure vessel type: approx. 20 l aquaria with 10 l test solution
- Number of replicates, fish per replicate: one replicate with 10 fish

TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 / 8 hours

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LC0

Effect conc.:

>= 208 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

other: TOC measurement

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 208 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

other: TOC measurement

Basis for effect:

mortality (fish)

Details on results:

No mortality was observed in the control and the treated animals

Sublethal observations / clinical signs:

RESULTS:
- Nominal/measured concentrations: 
 - nominal: 28; 46; 81; 139; 231 mg/l
 - 0 h (first  analysis): 25; 45; 81; 134; 231 mg/l
 - 0 h (second analysis): 27; 44; 78; 138; 178 mg/l
 - 24 h (single analysis): 25; 48; 84; 147; 251 mg/l
- Effect data (mortality): no deaths in exposed or control animals

Validity criteria fulfilled:

not specified

Conclusions:

No effects were observed at the tested concentrations. Hence the LC50 (96 hours) was determined to be >208 mg/L indicating that the test substance does not present a significant hazard to fish.

Executive summary:

In a semi-static acute fish toxicity test according to Directive 92/69/EEC, Hüls AG (1996) observed no mortalities in Cyprinus carpio within 96 hours of exposure to concentrations up to the maximum possible concentration of 208 mg/l (arithmetic mean of analyses for four days). Hence the LC50 (96 hours) was determined as >208 mg/L.

Due to fast hydrolysis it is assumed that the observed effect is rather attributed to the hydrolysis product than to the parent substance.

The study was assessed as "reliable with restrictions".

Description of key information

A static acute 96-hour fish toxicity limit test according to Directive 92/69/EEC was performed with Danio rerio (Bayer AG, 2000). No mortalities or abnormal swimming were observed. The analytical test concentration, which was determined daily by DOC measurements, was 72.3 mg/l. In a semi-static acute fish toxicity test according to Directive 92/69/EEC, Hüls AG (1996) no mortalities in Cyprinus carpio within 96 hours of exposure to concentrations up to the maximum possible concentration of 208 mg/l were observed.

Additional information

The LC50 values for Danio rerio and Cyprinus carpio were determined as >72 mg/L and >208 mg/L, respectively. In view of the low solubility in water (see chapter 4.9) and the liability towards hydrolysis (see chapter 5.1.2) of 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, exposure to well-defined aquatic concentrations is difficult to achieve. Due to fast hydrolysis, the observed effect is expected to be the effect of the hydrolysis product. In the aquatic environment, only the chemically less reactive hydrolysis product is expected to be relevant. The methods used for the determination of the test substance concentration (DOC or TOC) do not differentiate between parent substance and hydrolysis product. Hence the analytical results should be treated with caution.