Hydrocarbons, C16-C20, n-alkanes, isoalkanes, cyclics, aromatics (2-30 %)

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:

1995

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.

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

EC L383 C2

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

An equilibration trial was performed to determine the time required for the components of the test substance to achieve maximum aqueous solubility. Five glass aspirators were each filled with 22L of main dechlorinated water, leaving a small headspace of air. The test substance was added to four of the vessels at a loading rate of 1000 mg/L, and the contents of the fifth aspirator served as the control. All five vessels were then sealed, and stirred as vigorously as possible without creating a dispersion in the sealed vessels, which contained a small headspace of air to permit stirring. After nominal stirring periods of 24, 48, 72, 96and 198 hours, the WAF solutions were allowed to settle for 1-3 hours, after which a sample of the aqueous layer was extracted and analyzed by GC/FID. The results of the equilibration study showed that equilibrium between the test substance components and the aqueous phase at a loading of 1 g/L was reached in about 72-96 hours.

Vehicle:

no

Details on test solutions:

Test solutions were prepared as water accommodated fractions (WAF). Control and dilution water were reconstituted fresh (hard) water. The nominal loading rates used to prepare the WAFS were based upon range-finding results. This included adding test substance to 15-16 liter glass aspirator bottles, which contained laboratory dilution water, that was filtered (15 um) through activated charcoal. The WAF was stirred for 93-96 hours as vigorously as possible without creating a dispersion in the sealed vessels, which contained a small headspace of air to permit stirring. After mixing, the WAFs were allowed to settle for one hour, after which the aqueous phase was removed for testing. Test vessels were sealed 150 ml erlenmeyer flasks with 10 daphnids per flask. Two replicates per treatment and control were used.

Test organisms (species):

Daphnia magna

Details on test organisms:

D. magna, less than 24 h old, were taken from a laboratory culture, which is derived from a strain obtained via Zeneca Brixham Laboratory from I.R. Ch.A. France. Young were collected from cultures aged between 14 and 28 days

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

no data

Test temperature:

Test temperature was 18.1-19 Deg C.

pH:

The pH ranged from 8.3 to 8.6 during the study.

Dissolved oxygen:

Dissolved oxygen was 9.2-9.3mg/L

Salinity:

freshwater

Nominal and measured concentrations:

WAF concentration (mg/L) of dissolved hydrocarbon (derived from test substance) as determined by GC/FID. Specific hydrocarbon isomers were not identified. Analytical results are based on mass attributable to the test material. Control concentration was <0.02 mg/L at all sampling intervals identified above.

Nominal Loading Measured concentration (mg/L)
(mg/L) time 0 48 hr Mean
100 0.31 0.19 0.24
220 0.31 0.28 0.29
460 0.30 0.31 0.30
1000 0.33 0.24 0.28

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

EL0

Effect conc.:

>= 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

No immobilization was observed in the control and any of the WAF treatments.

48-hr EL0 = 1000 mg/L based upon nominal loading rate

This value is representative of acute aquatic invertebrate toxicity for those C14-C20 (high aromatics) aliphatic category members having an initial minimum boiling point range of 263°C. Since the hydrocarbon constituents for these category members with boiling point values greater than 263 deg C do not show adequate water solubility in equilibrated aqueous solutions, acute aquatic toxicity effects are not expected at the 1000mg/L maximum loading concentration investigated in this study.

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of Hydrocarbons, C16-C20, n-alkanes, isoalkanes, cyclics, aromatics (2-30%), as measured by immobility to the water flea (Daphnia magna) was evaluated in freshwater. Under the conditions of this study, Hydrocarbons, C16-C20, n-alkanes, isoalkanes, cyclics, aromatics (2-30%) did not produce acute toxicity to Daphnia magna at 1000 mg/l, based on nominal loading of the test substance in water.

Executive summary:

The acute toxicity of Hydrocarbons, C16-C20, n-alkanes, isoalkanes, cyclics, aromatics (2-30%), as measured by immobility to the water flea (Daphnia magna) was evaluated in freshwater. Under the conditions of this study, Hydrocarbons, C16-C20, n-alkanes, isoalkanes, cyclics, aromatics (2-30%) did not produce acute toxicity to Daphnia magna at 1000 mg/l, based on nominal loading of the test substance in water.

Description of key information

There is data available for this substance, which is presented in the dossier.

In both the key and supporting study, Hydrocarbons C16-C20, n-alkanes, isoalkanes, cyclics, aromatics (2-30%) did not produce acute toxicity to Daphnia magna at 1000 mg/l, based on nominal loading of the test substance in water.

Additional information

Two studies were available and input as endpoint records. The studies are summarised below.

The study from Shell (1995) examined the short-term toxicity (as measured by immobility) of the test substance Hydrocarbons, C16-C20, n-alkanes, isoalkanes, cyclics, aromatics (2-30%) to Daphnia magna in freshwater. Under the conditions of this study,  Hydrocarbons, C16-C20, n-alkanes, isoalkanes, cyclics, aromatics (2-30%) did not produce acute toxicity to Daphnia magna at 1000 mg/l, based on nominal loading of the test substance in water. The 48h EL50 (mobility) of Hydrocarbons, C16-C20, n-alkanes, isoalkanes, cyclics, aromatics (2-30%) to Daphnia magna is therefore >1000mg/l.

The study from Shell (1993a) examined the short-term toxicity (as measured by immobility) of the test substance Hydrocarbons, C16-C20, n-alkanes, isoalkanes, cyclics, aromatics (2-30%) to Daphnia magna in freshwater. Under the conditions of this study,  Hydrocarbons, C16-C20, n-alkanes, isoalkanes, cyclics, aromatics (2-30%) did not produce acute toxicity to Daphnia magna at 1000 mg/l, based on nominal loading of the test substance in water. The 48h EL50 (mobility) of Hydrocarbons, C16-C20, n-alkanes, isoalkanes, cyclics, aromatics (2-30%) to Daphnia magna is therefore >1000mg/l.