Reaction mass of cyclohexanol and cyclohexanone

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Non-GLP guideline study without analytical test item concentration verification

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

no

Remarks:

The study was not performed according to GLP. However, the quality of the test carried out in this laboratory is highly reliable, with experimental conditions rigorously similar to those recommended in the OECD guidelines.

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Great waterflea
- Source: BIOAGRI Ambiental - Laboratorio de Analise de Ecotoxicidade
- Age at study initiation (mean and range, SD): less than 24 hours
- Feeding during test: no

ACCLIMATION
- Type and amount of food: P. subcapitata
- Feeding frequency: daily 10E6 cells per daphnid

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

237 mg/L CaCO3

Test temperature:

19.3 -19.9 mg O2/L

pH:

7.49 - 7.92

Dissolved oxygen:

6.46 - 8.47 mg O2/L

Nominal and measured concentrations:

Nominal initial concentrations: control, 125, 250, 500, 1000, 2000 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: borosilicate glass, 120 mL, completely filled
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: M4 medium
- Intervals of water quality measurement: after 0 and 48 hours


OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 24 hour darkness

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): mobility

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

366.02 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% CL: 326.28 - 410.61 mg/L

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- EC50: 1.39 mg/L after 24 hours of exposure (95% CL: 1.17 - 1.64 mg/L)

Executive summary:

The acute toxicity of the reaction mass to daphnia magna was assessed in an experimental study according to OECD guideline 202 (Daphnia acute immobilization test). The test organisms were exposed the nominal initial concentrations of 0, 125, 250, 500, 1000, 2000 mg/L (test item) for 48 h and the immobility of the test organisms was observed during the test period. As reference substance potassium dichromate was used. The EC 50 (24 h) for the reference substance was 1.39 mg/l. The EC50 (48 h) for the test item was 366.02 mg/l.

Description of key information

The EC50 (48h) for the reaction mass was 366.02 mg/l. Different values for the single components were achieved.

 

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

366.02 mg/L

Additional information

The acute toxicity of the reaction mass to aquatic invertebrates was assessed in an experimental study according to OECD 202 (Rhodia, 2009). The test organisms were exposed to the nominal initial concentrations of 0, 125, 250, 500, 1000, 2000 mg/L (test item) for 48 h and the immobility of the test organisms was observed during the test period. As reference substance potassium dichromate was used. The EC 50 (24 h) for the reference substance was 1.39 mg/l. The EC50 (48 h) for the test item was 366.02 mg/l.

In two published studies the acute toxicity of the singel component cyclohexanone to daphnia magna (Bringmann 1977,1982) was assessed over 24 h. The EC 50(24h) was determined for 800 and 820 mg/l.

The acute aquatic toxicity of the second component cyclohexanol was assessed in a GLP study according to OECD guideline 202. Analysis of the freshly prepared test concentrations at 0 and 24 hours showed the measured test concentrations to range from 81% to 107% of the nominal values. However, analysis of the old or expired test preparations sampled at 24 and 48 hours showed a marked decline in the measured test concentrations ranging from 49% to 105% of nominal. These results were in line with the preliminary stability analyses indicating that the test solutions were unstable under the test conditions employed. Due to the volatile nature of the test item, losses via this route are possible. After 48 h an EC50 of 17 mg/l was identified referred to the nominal concentrations (SafePharm, 2003).