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Short-term toxicity to aquatic invertebrates

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Reference
Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Comparable to guideline study with acceptable restrictions
Justification for type of information:
The justification for read across is provided as an attachment in IUCLID Section 13.
Reason / purpose:
read-across: supporting information
Qualifier:
according to
Guideline:
other: As described in: The evaluation of the hazards of harmful substances carried by ships. Joint group of experts on the scientific aspects of marine pollution - GESAMP - reports and studies no. 17, 1982.
Principles of method if other than guideline:
based on discussions in GESAMP/MARPOL meetings held in 1973
GLP compliance:
no
Analytical monitoring:
yes
Details on sampling:
100 mL samples were taken in glass bottles, two mL of carbon disulphide were added. Resulting mixture was shaken for about 3 min. After seperation the solvent layer was drawn off and analysed.
Vehicle:
no
Details on test solutions:
Individual treatment concentrations were prepared seperately by mixing the nominal amount of test substance in freshwater for 24 hours in a conical flask by aid of a magnetic stirrer. The flask was almost completely filled with solution. After mixing, the treatment solutions were allowed to settle for 24 hours, to allow for separation of excess test material. The aqueous solution was then drained off through a stopcock at the base of the flask and tested.
Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: water flea
- Source: testing lab, cultured under standardised conditions
- Age at study initiation (mean and range, SD): <24 hours old; parents age = approximately 21 days old
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
48 h
Test temperature:
20°C
pH:
7.5 to 8.3
Dissolved oxygen:
>50% saturation during the study
Nominal and measured concentrations:
1.0 to 10 mg/L (nominal)
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Type: closed
- Material, size, headspace, fill volume: 250 ml conical flasks
- No. of organisms per vessel: 25
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2
Reference substance (positive control):
not specified
Key result
Duration:
48 h
Dose descriptor:
EL50
Effect conc.:
ca. 2.4 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
0.4 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
test mat.
Basis for effect:
mobility
Reported statistics and error estimates:
Parametric model developed by Kooijman (Kooijman, S.A.L.M. 1981. Parametric analyses of mortality rate in bio-assays. Water Res., 15:107-119).
Validity criteria fulfilled:
yes
Conclusions:
The test substance exhibited a 48-hour EC50 value of 0.4 mg/L, based on measured data, and an EL50 value of approximately 2.4 mg/L, based on nominal data, with Daphnia magna.
Executive summary:

The test substance exhibited a 48-hour EC50 value of 0.4 mg/L, based on measured data, and an EL50 value of approximately 2.4 mg/L, based on nominal data, with Daphnia magna.

Description of key information

EL50 (48 h) = 2.4 mg/L (Daphnia) (freshwater)
LL50 (48 h) = 2.4 mg/L (Mysidopsis) (saltwater)

Key value for chemical safety assessment

Additional information

No studies are available on the acute toxicity to aquatic invertebrates for hydrocarbons, C7-C9, isoalkanes. Based on an analogue approach data are read-across to another isoalkane substance, i.e. 2,2,4-trimethylpentane. A study on 2,3,4-trimethylpentane was conducted by Adema & van den Bos Bakker (1987). Tests were conducted with three different species of freshwater and marine aquatic species including the genera Daphnia, Chaetogammarus, and Mysidopsis. The tests did not follow a standard test guideline, however, they were conducted in a similar way to OECD 202. The acute toxicity, as measured by immobilisation of Daphnia and mortality to Chaetogammarus and Mysidopsis, was evaluated in fresh- and saltwater by using water accomodated fractions (WAFs). Under the conditions of these tests, 2,3,4-trimethylpentane produced acute toxicity to Daphnia and Mysidopsis at 2.4 mg/L and to Chaetogammarus at 5.4 mg/L based on nominal loadings of the test substance in water.