Hydrocarbons, C9-C10, n-alkanes, isoalkanes, cyclics, <2% aromatics

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:

August to December 1996

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: This robust summary has a reliability rating of 1 because the study followed a standard guideline, followed GLP guidelines, and was conducted without deviations that would invalidate the study.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Samples for analysis of new and old test solutions were taken new at 0 hours (test initiation) and old at 48 hours (test termination).

Vehicle:

no

Details on test solutions:

The water accommodated fractions of the test material were prepared by stirring the test material at each loading level in the exposure solution for 44 hours with a 1.5 to 2 hour settling period, after which each aqueous phase was removed and added to a test system. A second 10 mg/L WAF was stirred for 25 hours with a 1.5 to 2 hour settling period because the original WAF vessel developed a leak as it was stirring. An equilibration study was conducted over a period of 72 hours prior to the definitive study to determine the approximate length of time needed to stir the test substance in the test media to acheive a saturated solution. Results suggested that a stirring period of 20 to 28 hours would be sufficient to reach equilibrium.

Test organisms (species):

Daphnia magna

Details on test organisms:

Organisms used in the test were from a laboratory culture were less than 24 hour old. The source of the culture was from Zeneca Brixham Laboratory from I.R.Ch.A., France.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

None

Hardness:

155 mg/L CaCO3

Test temperature:

19.3 to 19.7 degrees C

pH:

7.1 to 8.2

Dissolved oxygen:

9.1 to 9.2 mg/L

Nominal and measured concentrations:

Nominal loading rates were 1.0, 2.2, 4.6, 10, 22, 46, and 100 mg/L. A control was also included. Based on analyses of new and old test solution samples taken new at 0 hours (test initiation) and old at 48 hours (test termination), the nominal/measured (mean) concentration values were: control/<0.02 mg/L; 1.0/0.11 mg/L; 2.2/0.22 mg/L; 4.6/0.18 mg/L; 10/0.25 mg/L; 22/0.44 mg/L; 46/0.47 mg/L; and 100/0.56 mg/L.

Details on test conditions:

The study was conducted in closed test systems that were not renewed during the study. The test systems used were 150 ml glass Erlenmeyer flasks. The control and treatment level was evaluated in replicate test systems. Ten organisms, less than 24 hours old, were exposed in each of the control and treatment solution flasks and were not fed during the study.

Reference substance (positive control):

no

Duration:

24 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

24 h

Dose descriptor:

LL0

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Key result

Duration:

48 h

Dose descriptor:

EL50

Effect conc.:

> 22 - < 46 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EL0

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

A total of 20 daphnids were added to the control and treatment solutions. Immobility results are as follows:

Loading Rate % Immobility
(mg/L) 24 hr 48 hr
Control 0 0
1.0 0 0
2.2 0 0
4.6 0 0
10 0 0
22 5 25
46 10 65
100 25 75

Reported statistics and error estimates:

Effect levels were estimated by visual inspection of the data, which is thought to be more appropriate than interpolative statistical analysis if the data are based on water accommodated fractions of a complex test substance with low water solubility.

Validity criteria fulfilled:

yes

Conclusions:

Water accommodated fractions (WAFs) of the test substance produced a 48-hour EL50 range of >22 to <46 mg/L and a LL0 value of 10 mg/L with Daphnia magna. There was no mortality in the control.

Executive summary:

Water accommodated fractions (WAFs) of the test substance produced a 48-hour EL50 range of >22 to <46 mg/L and a LL0 value of 10 mg/L with Daphnia magna. There was no mortality in the control.

Description of key information

The water accommodated fraction (WAF) of hydrocarbons, C9-C10, n-alkanes, isoalkanes, cyclics, <2% aromatics, produced a 50% effect (immobility) with Daphnia magna at a loading of >22-<46 mg/L after a 48-hour exposure.

Additional information

The water accommodated fraction (WAF) of hydrocarbons, C9-C10, n-alkanes, isoalkanes, cyclics, <2% aromatics, produced a 50% effect (immobility) with Daphnia magna at a loading of >22 -<46 mg/L after a 48-hour exposure.