Hydrocarbons, C9-C10, aromatics, >1% naphthalene

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study according to Official Jounal of the European Communities No. L251 Part C: C2 Acute toxicity for Daphnia

Justification for type of information:

Hydrocarbons, C9-C10, aromatics, >1% Naphthalene are a combination of Hydrocarbons, C9 Aromatics and Hydrocarbons, C10-C12 Aromatics. Read across data is available for Hydrocarbons, C9 Aromatics and Hydrocarbons, C10-C12 Aromatics and the worst case scenario for each end point has been presented.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 10, 3, 1, 0.4, control mg/l
- Sample storage conditions before analysis: all samples were analyzed on the day taken

Vehicle:

not specified

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Test material and dilution water were stirred in sealed vessels for 24 hrs. The mixture was then allowed to settle for 1 hr. The aqueous phase was then drawn off and used as the test medium.
- Controls: yes

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Water flea
- Source: ICI Brixham Laboratory
- Age at study initiation (mean and range, SD): =< 24 hrs
- Method of breeding: Cultures started with animals less than 24 hours old, and discarded when 28 days old. Young are removed daily, and animals for testing removed 23 hours after last removal. Test young are from 15-28 day cultures from at least the third brood.

ACCLIMATION
- Acclimation period: Daphnids are placed in fresh culture medium for at least one hour prior to test for observation.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Post exposure observation period:

48 hrs

Hardness:

186 mg/ml CaCO3

Test temperature:

20.6-21.7°C

pH:

7.9-9.4

Dissolved oxygen:

7.9-9.4 mg/l

Nominal and measured concentrations:

Nominal: 10, 3, 1, 0.4, control mg/l
Measured: 7.3, 3.2, 1.4, <1.0, <0.5 mg/l

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: 250 ml glass beakers, filled with 240 ml of solution
- 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: Reconstituted fresh water made from Millipore filtered water made according to EPA-660/3-75-009. A soil extract was prepared by autoclaving 100 g soil/l filtered water for 15 min at 120°C. Solids are then removed by filtration and added to the fresh water at 20 ml/l.


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : mobility during 15 second period at 24 and 48 hrs

Key result

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

3.2 mg/L

Nominal / measured:

nominal

Basis for effect:

mobility

Remarks on result:

other: 2.6-4.0 mg/l

Duration:

24 h

Dose descriptor:

EL50

Effect conc.:

4.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 3.8-4.3 mg/L

Details on results:

- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: An oily sheen was observed on the surface of the highest loading treatment (67.2 mg/l) only on day 1 of the study. These were believed to have had no significant effect on the study outcome.

Nominal loading (mg/L)	Daphnia Total Mortality (at 24, 48 hrs)
control	0,0
0.4	0,0
1.0	0,0
3.0	0,8
10.0	10,10

Validity criteria fulfilled:

yes

Conclusions:

The 48-hr EL50 for Daphnia magna is 3.2 mg/L (WAF).

Executive summary:

This test was conducted to determine the acute aquatic toxicity of Hydrocarbons, C9, aromatics to the aquatic invertebrate Daphnia magna. 20 daphnids per concentration (10 per test vessel) were exposed to 0, 0.4, 1, 3, or 10 mg/l (WAF) of test substance. The daphnids were exposed for 48 hrs in a static test. The daphnids were observed at 24 and 48 hrs after the start of exposure for mobility. Based on immobilization, the 48-hr EL₅₀ for Daphnia magna is 3.2 mg/L (WAF).

Description of key information

There is no data available for this substance. However,key data is available for structural analogues Hydrocarbons C9 aromatics. The data is read across to this substance based on analogue read across and a discussion and report on the read across strategy is provided as an attachment in IUCLID Section 13.

Key information is summarised below:

Hydrocarbons, C9-C10, aromatics, >1% Naphthalene are a combination of Hydrocarbons, C9 Aromatics and Hydrocarbons, C10-C12 Aromatics. Read across data is available for Hydrocarbons, C9 Aromatics and Hydrocarbons, C10-C12 Aromatics and the worst case scenario for each end point has been presented.

The test was conducted to determine the acute aquatic toxicity of Hydrocarbons, C9, aromatics to the aquatic invertebrateDaphnia magna. Based on immobilization, the 48-hr EL₅₀forDaphnia magnais 3.2 mg/L (WAF).

This data is used for read across to Hydrocarbons, C9-C10, aromatics, >1% Naphthalene.

Additional information

The data used to characterize the acute aquatic toxicity of C9 aromatics hydrocarbons are from a short-term toxicity study with Daphnia magna following standard test guidelines. These results indicate that C9 aromatics hydrocarbons causes moderate acute toxicity to freshwater invertebrates at 21.3 mg/L (48-hour EL₅₀), based on nominal loading of the test substance in water, and 6.14 mg/L (48-hour EC₅₀), based on measured concentrations.

 

This data is used for read across to Hydrocarbons, C9-C10, aromatics, >1% Naphthalene.