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Short-term toxicity to aquatic invertebrates

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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:
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:
read-across: supporting information
Qualifier:
according to
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).

Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1993
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
The study was given a reliability rating of 1 because it followed a standard test guideline, which describes a procedure to evaluate this endpoint, and the results were reviewed for reliability and assessed as valid. The study was also conducted under GLP.
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:
read-across: supporting information
Qualifier:
according to
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Deviations:
no
GLP compliance:
yes
Analytical monitoring:
yes
Vehicle:
no
Details on test solutions:
Individual treatment solutions were prepared as Water Accommodated Fractions (WAFs). This included adding test substance to glass vessels,
which contained dilution water and mixing for approximately 24 hours with a magnetic stirrer to produce a series of geometrically-spaced
loading rates (mg/L). After mixing, the WAFs were allowed to settle for an hour. Each aqueous phase was then drawn off and transferred to two
150 mL Erlenmeyer flasks which were completely filled. Two further flasks were filled with dilution water only and served as controls.
Test organisms (species):
Daphnia magna
Details on test organisms:
Organisms were supplied by in-house cultures. The laboratory culture is derived from a clone held at ICI Brixham Laboratory. The ICI clone was
itself obtained from the Institut de Recherche Chimique Applique (I.R.Ch.A.), France. Test organisms age = <24 hours old; parents age = 15 - 28
days.
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Hardness:
Water hardness of the control dilution water was 174 mg/L as CaCO3.
Test temperature:
Test temperature was 20 – 22 ºC.
pH:
The pH ranged from 7.7 to 8.1.
Dissolved oxygen:
Dissolved oxygen was 8.3 to 8.6 mg/L for "new" solutions and 8.6 to 8.7 mg/L for "old" solutions.
Salinity:
freshwater
Nominal and measured concentrations:
Nominal treatment levels were control, 0.1, 0.4, 1.0, 3.0 and 10 mg/L, which at t=0 measured non detected (< 2.5 mg/L), NA (not analyzed), NA, NA,
3.3 mg/L and 8.2 mg/L, respectively.
Details on test conditions:
Ten Daphnia magna, less than 24 h old, were added to each flask. The flasks were sealed with black caps that excluded air from the vessel. After
24 and 48 h the numbers of immobilized D.magna were recorded. D.magna were considered to be immobile, if, when the contents of the flask were
swirled they did not swim during a 15 second period of observation.

Photoperiod with a 16 h : 8 h light : dark lighting regime.
Reference substance (positive control):
no
Key result
Duration:
48 h
Dose descriptor:
EL50
Effect conc.:
>= 3 - <= 10 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
See Table in Remarks on Results
Reported statistics and error estimates:
Loading rates causing a 50% effect were determined by visual inspection of the data. They are expressed as being within a range bounded by loading rates that were tested. This is considered more appropriate for test materials that are mixtures of substances of different solubilities than is an interpolative statistical technique.

Nominal Loading Measured Conc  Daphnia Immobilized
(mg/L)  (mg/L)   (@ 24, 48 hrs)*
     
Control  <LoD 0,0
0.1 <LoD  0, 0
0.4 <LoD  0, 0
1.0 <LoD  0, 0
3.0  3.3 – 3.1 ** 0, 0
10.0  8.2 – 7.8 **  10, 10

*10 daphnids added to each of the control and treatment levels (both in duplicate) at test initiation

** Measured concentrations refer to the t=0h (fresh) and t=48 h (old) samples

Validity criteria fulfilled:
yes
Conclusions:
Water accommodated fractions of hydrocarbons, C10, aromatics, >1% naphthalene, produced a 48-hour LL50 value between 3 and 10 mg/L with Daphnia magna.
Executive summary:

Water accommodated fractions of hydrocarbons, C10, aromatics, >1% naphthalene, produced a 48-hour LL50 value between 3 and 10 mg/L with Daphnia magna.

Description of key 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.

The acute toxicity of C9 aromatics hydrocarbons as measured by immobility to the water flea (Daphnia magna) was evaluated in freshwater. Under the conditions of this study C9 aromatics hydrocarbons produced acute toxicity to Daphnia magna 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.

 

Water accommodated fractions of hydrocarbons, C10, aromatics, >1% naphthalene, produced a 48-hour LL50value between 3 and 10 mg/L with Daphnia magna. In a supporting study, water accommodated fractions of hydrocarbons, C10, aromatics, >1% naphthalene, produced a 48-hour LL50 value of 10 mg/L with Daphnia magna.

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

Key value for chemical safety assessment

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.

 

Water accommodated fractions of hydrocarbons, C10, aromatics, >1% naphthalene, produced a 48-hour LL50 value between 3 and 10 mg/L with Daphnia magna.

 

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