Hydrocarbons, C11-14, n-alkanes, isoalkanes, <2% aromatics

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

March to November 1993

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

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 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

An equilibration study was conducted prior to the study to determine the length of time needed to develop water accommodated fractions (WAFs) at the 1000 mg/L loading level. The aqueous phase of the WAF was analyzed after 1, 24, 48, and 96 hours of stirring. In all samples, the quantity of test substance in solution was less than the limit of detection (0.5 mg/L). Further analysis of test substance in test media a loading level of 1 g/L also showed no detectable amounts of test substance. Consequently, analysis of treatment solutions from the definitive study were not conducted.

Vehicle:

no

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

Organisms used in the test were from a laboratory culture, originally derived from a strain (ATCC 22662) obtained from the American Type Culture Collection, Maryland, Ohio, USA.

Test type:

static

Total exposure duration:

72 h

Post exposure observation period:

None

Test temperature:

23 to 25 degrees C

pH:

7.2 to 8.8

Nominal and measured concentrations:

The nominal loading rate was 1000 mg/L. A control was also tested.

Details on test conditions:

The study was conducted in sealed test systems with no headspace that were not renewed during the study. The test systems used were 300 ml glass Erlenmeyer flasks that were complely filled with test media. Six replicate test systems were established for the treatment level and control. Control and treatment systems were innoculated with a concentration of 5000 cells/ml. Test systems were incubated under constant illumination (approximately 3000 lux) on an orbital incubator.

Reference substance (positive control):

no

Key result

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Key result

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Key result

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Reported statistics and error estimates:

None

Validity criteria fulfilled:

yes

Conclusions:

Growth in an alga culture, as measured by biomass and growth rate, exposed to a 1000 mg/L water accommodated fraction of the test substance was not inhibited when compared to the control after a 72-hour exposure. Therefore, the 72-hr EL50 and NOELR values for these two endpoints are reported as >1000 mg/L and 1000 mg/L, respectively.

Executive summary:

Growth in an alga culture, as measured by biomass and growth rate, exposed to a 1000 mg/L water accommodated fraction of the test substance was not inhibited when compared to the control after a 72-hour exposure. Therefore, the 72-hr EL50 and NOELR values for these two endpoints are reported as >1000 mg/L and 1000 mg/L, respectively.

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

The registration substance Hydrocarbons, C11-C14, n-alkanes, isoalkanes, <2% aromatics, EC number 701-280-3 (target) and the test substance Hydrocarbons, C11-C14, n-alkanes, isoalkanes, cyclics, <2% aromatics (source) are both hydrocarbons with many constituents in common.
The source substance covers the carbon number range of the target substance. The substances therefore have qualitatively similar properties (RAAF Scenario 2 applies).

Reason / purpose for cross-reference:

read-across source

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Description of key information

No data are available for Hydrocarbons, C11-C14, n-alkanes, isoalkanes, <2% aromatics, but measured data are available for Hydrocarbons, C11-C14, n-alkanes, isoalkanes, cyclics, <2% aromatics in which the EL50 was found to be >1000 mg/l and the NOELR was 1000 mg/l.

Additional information

No measured algal acute toxicity data are available for Hydrocarbons, C11-C14, n-alkanes, isoalkanes, <2% aromatics, however data are available for a closely related substance, Hydrocarbons, C11-C14, n-alkanes, isoalkanes, cyclics, <2% aromatics. These data are used as read-across data for Hydrocarbons, C11-C14, n-alkanes, isoalkanes, <2% aromatics.

Growth of algal cultures, as measured by biomass and growth rate, exposed to a water accommodated fraction of Hydrocarbons, C11-C14, n-alkanes, isoalkanes, cyclics, <2% aromatics, was not inhibited over 72 hours. The growth of algae in the the test systems was greater than the controls, which performed normally. Therefore, the 72-hr EL₅₀ values for the two endpoints are reported as >1000 mg/L. The 72-hr NOELR values for biomass and growth rate are reported as 1000 mg/L, respectively.