Bottom residues resulting from the synthesis of propene by propane dehydrogenation

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2016

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Hydrocarbons, C4-20, arom.-rich, alkene-manufg. byproduct

EC Number:

310-089-0

EC Name:

Hydrocarbons, C4-20, arom.-rich, alkene-manufg. byproduct

Cas Number:

102242-57-9

IUPAC Name:

102242-57-9

Details on test material:

- Name of test material (as cited in study report): Hydrocarbons, C4-20, arom.-rich, alkene-manufg. byproduct
- Substance type: organic
- Physical state: liquid
- Lot/batch No.: P0160-2015

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: P0160-2015
- Expiration date of the lot/batch: 22 Jan 2017

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: stored in a freezer ( <-18°C).
- Stability under test conditions: stable

Sampling and analysis

Analytical monitoring:

no

Remarks:

Analyses of the test substance preparations were not conducted, since a reliable method for analyses in the required concentration range could not be developed.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
-The test substance is a mixture of sparingly water soluble components. Therefore test solutions were prepared separately for each test concentration as a water accommodated fraction (WAF) using a liquid-liquid saturator technique. For each test solution, a glass aspirator bottle (2-L) with a bottom side-outlet attached to a stopcock was filled with 2-L test media. Prior to use the test substance was homogenized by shaking the container. Then test substance (considering density = 0.8018 g/cm³) was pipetted carefully on the water surface. The bottle was closed and the solution was stirred on a magnetic plate for about 2 days. The stirring was slow (approx. 100 rpm) so that no vortex forms. The undissolved test substance remained on the surface and the required volume of the WAF (1.4-L per test solution) was removed from the bottom port. The WAFs were free of undissolved test substance, confirmed by using a laser light and observing the Tyndall effect.
All stock test solutions appeared colorless and clear.

Test organisms

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Common name: Selenastrum capricornutum and currently renamed as Raphidocelis subcapitata KORSHIKOV
- Source (laboratory, culture collection): Collection of algal cultures in University of Göttingen /Germany
- Method of cultivation: A stock algal culture is maintained continuously at the test facility. Before the exposure an inoculum culture is prepared from the stock culture and incubated for 4 days at 21 – 24 °C (max. temperature difference 2 °C). After this time, the inoculum culture is in exponential growth phase and can be used to initiate the test (study day 0).

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Test temperature:

23.3 – 23.5 °C

pH:

7.9 - 9.8

Nominal and measured concentrations:

loading rate: 0 (control), 6.25, 12.5, 25, 50, 100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Erlenmeyer flasks (nominal volume 250 mL) closed with glass plugs
- Type: closed
- Material, size, headspace, fill volume: approx. 300 mL (Erlenmeyer flasks were completely filled)
- Initial cells density: 0.3 x 104 cells/mL
- Control end cells density:
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6
1 additional uninoculated (without algae) replicate per test group for background fluorescence correction.

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: (OECD medium) was prepared according to OECD Guideline


OTHER TEST CONDITIONS
- Sterile test conditions: An inoculum culture in exponential growth phase was prepared with an aliquot of the stock algal culture added to sterile test media to provide an initial cell density of 0.3 x 104 cells/mL.
- Light intensity and quality: Light intensity was adjusted to the lower end of the acceptable range, to control pH changes due to excessive algal growth in the closed test vessels


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: Algal growth measured as in vivo chlorophyll-a fluorescence (pulsed excitation with light flashes having a wavelength of 430 nm)

TEST CONCENTRATIONS

- Test concentrations: The test concentrations were selected on the basis of a range finding test.
- Results used to determine the conditions for the definitive study: EfluorescenceC50 = between 10 and 100 mg/L (40 mg/L estimated); ErC50 = between 10 and 100 mg/L (33 mg/L estimated);

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

21.6 mg/L

Conc. based on:

other: based on loading rate

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EL10

Effect conc.:

14.7 mg/L

Conc. based on:

other: based on loading rate

Basis for effect:

growth rate

Effect concentrations 3

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

25 mg/L

Conc. based on:

other: based on loading rate

Basis for effect:

growth rate

Results with reference substance (positive control):

- Results with reference substance valid? yes
EC50 values of the reference substance potassium dichromate should be in the range: ErC50 = 0.92 – 1.46 mg/L after 72 hours for Pseudokirchneriella subcapitata.
- The ErC50 (72 h) of potassium dichromate was 0.951 mg/L (Date of the last control experiment: 18 Jan 2016 , project number:60E0063/04E013)

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

In a 72-hour algal growth study, cultures of Pseudokirchneriella subcapitata were exposed to Hydrocarbons, C4-20, arom.-rich, alkene-manufg. byproduct at loading rate of 0 (control), 6.25, 12.5, 25, 50, 100 mg/L under static conditions for in accordance with the OECD 201 guideline. The water pH, temperature and lighting intensity were all maintained within acceptable guideline specifications.
The 72 hour ErC50 (ErL50) value determined in this alga toxicity study was 21.6 mg/L based on the loading rate.
The concentration of test substance in test media could not be verified analytically, therefore the effect concentrations are based on the loading rate used to prepare the test substance WAF solutions. According to guidance in OECD 23, for tests with chemicals that cannot be quantified by analytical methods at the concentrations causing effects, the effect concentration can be expressed based on the nominal concentrations or in the case of water accommodated fractions on the loading rate.acceptable guideline specifications.