Hexan-6-olide

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:

27th February 2003 to 8th May 2003

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Proprietary study conducted according to guidelines and GLP.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

and US EPA OPPTS 850.1010

GLP compliance:

yes

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source: BASF, Daicel, Dow and Solvay
- Substance number: 03/0034-1
- Batch number: U 05175
- Purity test date: 99.95

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: at room temperature
- Stability: the stability of the test substance under storage conditions over the test period was guaranteed by the sponsor, and the sponsor holds this responsibility.

Analytical monitoring:

yes

Details on sampling:

Aliquots of the samples were directly analysed by GC-analysis at test initiation (time 0) and test termination (time 48).

Vehicle:

no

Details on test solutions:

e-Caprolactone in solution with M4-medium: synthetic fresh water (used for culture and test purposes. M4 medium was aerated for approximately 24 hours with oxygen until saturation was reached. The stock solution and dilution was prepared by stirring the test substance in the M4 medium for approximately 10 minutes at 20±2° C. The stock solution was clear and colourless, with a nominal concentration of 1000mg/l. The stock solution was diluted with M4 medium.

Test organisms (species):

Daphnia magna

Details on test organisms:

A clone of Daphnia magna STRAUS 1820 was used. Animals were aged 2-24h at the start of the test (starting with the 3rd generation of parent animals). Stock animals were 2-4 weeks old. They were kept under artificial light, type warm white (OSRAM L58 W31) on a day:night cycle of 16:8h. The animals were not fed during the test.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

No post-exposure observation period.

Hardness:

M4 medium: 2.20-3.20 mmol/l

Test temperature:

19.6-20.1° C

pH:

7.8-8.1

Dissolved oxygen:

7.1-9.7mg/l (M4 medium aerated for 24 hours with oxygen until saturation is reached).

Conductivity:

596 µS/cm

Nominal and measured concentrations:

Nominal: 0, 62.5, 125, 250, 500 and 1000 mg/l.
Measured test initiation (mean two samples): 0, 66.5, 126.1, 252, 481 and 973mg/l.
Measured test termination (mean two samples): 0, 59.4, 124.6, 249, 499 and 980mg/l.

Details on test conditions:

TEST SYSTEM
- Test vessel: 20 ml glass test tubes with flat bottoms filled with 10 ml of medium
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4 and 1 replicate for measurement of pH and oxygen. 1 parallel per test concentration and control without animals for measurement of pH and oxygen at start of experiment, this was thrown away after measurement.
- Biomass loading rate: 0.5 animals/ml

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: M4 medium

OTHER TEST CONDITIONS
- Photoperiod: day:night cycle of 16:8h
- Light intensity: were kept under artificial light, type warm white (OSRAM L58 W31)

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Visual observations were made at 0, 24 and 48h to determine swimming ability; if Daphnia were unable to swim within 15 seconds, even after gentle agitation of the test vessel, they were considered to be immobile.

RANGE-FINDING STUDY
An initial non-GLP range finding study was conducted to determine concentrations for the main test.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

204 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 172-240mg/l

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

125 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

259 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

500 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

No precipitation of test material was observed.
Immobilisation in the control did not exceed 10%.

Results with reference substance (positive control):

The EC50(24h) of the control substance potassium dichromate (non-GLP) was 1.37 mg/l (project number 02/0106/50/13).

Reported statistics and error estimates:

The probit method was used for calculation of the EC50, with 95% confidence limits.

Validity criteria were met:

- in the control the immbolisation observed was ≤10%.

- in the control no Daphnids were captured in a surface film.

- the O₂ concentration was >3mg/l in all tested replicates.

As the analytical results were found be within +/- 80% on the nominal exposure concentrations the results are based on nominal exposure concentrations.

Table 1. Number of immobile Daphnia measured at each timepoint (20 Daphnia exposed in each concentration)

Nominal conc. (mg/L)	Number of immobile Daphnia		% inhibition
	24 hours	48hours	24 hours	48hours
Control	0	0	0	0
62.5	0	0	0	0
125	0	1	0	5
250	7	15	35	75
500	20	20	100	100
1000	20	20	100	100

 

Validity criteria fulfilled:

yes

Conclusions:

The toxicity of the test material to the water flea, Daphnia magna, was determined in a 48 hour acute immobilisation test conducted according to OECD 202 guidelines. The daphnids were exposed to concentrations between 6.25 and 1000mg/l. The 48 hour EC50 was 204 mg/l (with 95% confidence limits: 172 -240mg/l). Validity criteria were fulfilled.

Executive summary:

The toxicity of test material to the water flea, Daphnia magna, was determined in the 48 hour acute immobilisation test conducted according to OECD 202 guidelines. The study was reliable (Klimish 1) and conducted according to GLP standards. The daphnids were exposed to concentrations of the test material between 6.25 and 1000mg/l.

Measured concentrations were within 80% of nominal at 48 hours and therefore nominal concentrations were used.

The 48 hour EC50 was 204 mg/l (with 95% confidence limits: 172 -240mg/l) and NOEC was 125 mg/L.

Description of key information

The toxicity of the test material to the water flea, Daphnia magna, was determined in the 48 hour acute immobilisation test conducted according to OECD 202 guidelines. The daphnids were exposed to concentrations between 6.25 and 1000mg/l. The 48 hour EC50 was 204 mg/l (with 95% confidence limits: 172 -240mg/l).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

204 mg/L

Additional information

The toxicity of test material to the water flea,Daphnia magna, was determined in the 48 hour acute immobilisation test conducted according to OECD 202 guidelines. The study was reliable (Klimish 1) and conducted according to GLP standards. The daphnids were exposed to concentrations of the test material between 6.25 and 1000mg/l.

Measured concentrations were within 80% of nominal at 48 hours and therefore nominal concentrations were used.

The 48 hour EC50 was 204 mg/l (with 95% confidence limits: 172 -240mg/l) and NOEC was 125 mg/L.