Pyrolysis light oil from waste plastics

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

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes

Vehicle:

no

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

Unicellular freshwater green alga.
Genus: Desmodesmus
Species: subspicatus
SAG Strain Number: 86.81
Taxonomic position: Chlorophyta - Chlorophyceae
The culture of Desmodesmus subspicatus was obtained in January 2016 by MBM Sci-encebridge GmbH (Institut für Pflanzenphysiologie of Universität Göttingen). The algae are kept as stock culture on solid agar at 2 - 8 °C. From the stock culture, a permanent cul-ture was prepared. From an aliquot of the permanent culture, the pre-culture was prepared.

Water media type:

brackish water

Limit test:

no

Total exposure duration:

72 h

Test temperature:

18.6-20.6ºC

pH:

Blank control: 7.6 (0h)-9.6 (72h)
320 mg/l (nominal): 7.6 (0h)-8.4 (72h)

Details on test conditions:

To minimise potential evaporation of test item, the test was performed in a closed system.
For each treatment, 250 mL of the respective test solution was mixed with the necessary amount of algal pre-culture (0.291 mL) to achieve a cell concentration of 3.1 *103 cells/mL. In this mixture, the pH-value was measured.
For the blank control, 450 mL nutrient medium mixed with the necessary amount of algal pre-culture (0.524 mL) was used instead of test item solution. The test vessels were com-pletely filled with the respective test solution and incubated for 72 hours, shaken on an orbital shaker. Before the start of incubation and every 24 hours, the cell number was de-termined with an electronic particle counter.
At the end of the test, the treatments were examined microscopically in order to assess the appearance of the alga and detect abnormalities (e.g. caused by the exposure to the test item).

Reference substance (positive control):

yes

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

ca. 9.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

ca. 69.54 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

ca. 10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

ca. 32 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Validity criteria fulfilled:

yes

Conclusions:

Growth Rate:
NOEC = 10 mg/L
LOEC = 32 mg/L
EC10= 9.60 mg/L
EC50 = 69.54 mg/L

Key value for chemical safety assessment

EC50 for freshwater algae:

69.54 mg/L

EC10 or NOEC for freshwater algae:

9.6 mg/L