Hydrocarbons, C10, aromatics, <1% naphthalene

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

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:

A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Vehicle:

no

Details on test solutions:

Individual treatment concentrations were prepared as water accommodated fractions (WAF). Control and dilution water were laboratory prepared algal nutrient medium. Test substance was mixed with dilution water in sealed vessels for approximately 24 hours, and the mixtures were allowed to settle for approximately 1 hour prior to drawing off the aqueous phase for testing.

Test organisms (species):

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

Details on test organisms:

Algal cells obtained from testing laboratory cultures. Original algal cultures obtained from American Type Culture Collection (ATCC 22662).

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

Temperature was 22 to 24 Deg C.

pH:

The pH ranged from 7.2 to 7.7 at test initiation and 7.2 to 10.2 at test termination.

Dissolved oxygen:

Not applicable

Salinity:

freshwater

Nominal and measured concentrations:

Nominal loading rates were 0.1, 0.4, 1.0, 3.0, and 10 mg/L. Only the 0 and 72 hours samples from the 3.0 and 10 mg/L treatments were analyzed yielding mean measured concentrations of 3.2 and 8.2 mg/L, respectively.

Details on test conditions:

Lighting was continuous at approximately 3000 lux.

Test vessels were sealed 300 ml conical flasks that were completely filled with test solution. The treatment and control flasks were inoculated with algal cells to yield initial concentrations ranging from 3200 to 5000 cells/ml. Uninoculated flasks were used to determine particle counts without algal cells. Biomass was calculated as area under the growth curve.

Reference substance (positive control):

no

Key result

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 1 - < 3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 1 - < 3 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.:

ca. 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

ca. 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

See Tables Below

Reported statistics and error estimates:

EL50 values estimated by visual inspection of data to determine range of loading rates, which bracketed a 50% reduction in biomass and growth rate. ANOVA and Williams test used to determine NOELs.

Nominal Loading	72 h
(mg/L)	% Inhibition
Control	N/A
0.1	-14.0
0.4	-27.0
1.0	-8.0
3.0	97.0
10.0	100.0

Nominal Loading	Conc.	Conc.
(mg/L)	0 hr (cells/mL)	72 hr (cells/mL)
Control	3.2xE3	3.7xE5
0.1	4.6xE3	4.2xE5
0.4	5.3xE3	4.7xE5
1.0	5.4xE3	4.0xE5
3.0	5.2xE3	9.3xE5
10.0	3.5xE3	0.0

Validity criteria fulfilled:

yes

Conclusions:

The hydrocarbons, C10, aromatics, >1% naphthalene, freshwater 72-hr EL50 value for Pseudokirchneriella subcapitata (formerly Selenastrum capricornutum) is 1.0 to 3.0 mg/l based on both growth rate and biomass. The hydrocarbons, C10, aromatics, >1% naphthalene, freshwater 72-hr NOELR (No Observed Effect Loading Rate) value for Pseudokirchneriella subcapitata is approximately 1.0 mg/l based on both growth rate and biomass.

Executive summary:

The hydrocarbons, C10, aromatics, >1% naphthalene, freshwater 72-hr EL50 value for Pseudokirchneriella subcapitata (formerly Selenastrum capricornutum) is 1.0 to 3.0 mg/l based on both growth rate and biomass. The hydrocarbons, C10, aromatics, >1% naphthalene, freshwater 72-hr NOELR (No Observed Effect Loading Rate) value for Pseudokirchneriella subcapitata is approximately 1.0 mg/l based on both growth rate and biomass.

Description of key information

There is no data available for Hydrocarbons, C10, aromatics, <1% naphthalene. However, data is available for a structural analogue, Hydrocarbons, C10 aromatics, >1% naphthalene andpresented in the dossier. This data is read across to based on analogue read across and a discussion and report on the read across strategy is provided as an attachment in IUCLID Section 13.

Water accommodated fractions of hydrocarbons, C10, aromatics, >1% naphthalene, produced a freshwater 72-hr EL₅₀ value for Pseudokirchneriella subcapitata (formerly Selenastrum capricornutum) of 1.0 to 3.0 mg/L based on both growth rate and biomass. The 72-hr NOELR (No Observed Effect Loading Rate) value for Pseudokirchneriella subcapitata is approximately 1.0 mg/L based on both growth rate and biomass.

 

In a supporting study, water accommodated fractions of hydrocarbons, C10, aromatics, >1% naphthalene, produced a freshwater 72-hr EL₅₀ value for Pseudokirchneriella subcapitata (formerly Selenastrum capricornutum) of 11 mg/L and 8.5 mg/L based on growth rate and biomass, respectively. The 72-hr NOELR (No Observed Effect Loading Rate) value for Pseudokirchneriella subcapitata is 2.5 mg/L based on both growth rate and biomass.

Additional information

Water accommodated fractions of hydrocarbons, C10, aromatics, >1% naphthalene, produced a freshwater 72-hr EL₅₀ value for Pseudokirchneriella subcapitata (formerly Selenastrum capricornutum) of 1.0 to 3.0 mg/L based on both growth rate and biomass. The 72-hr NOELR (No Observed Effect Loading Rate) value for Pseudokirchneriella subcapitata is approximately 1.0 mg/L based on both growth rate and biomass.