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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Reference
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
no
Principles of method if other than guideline:
This study is a pre-test
GLP compliance:
not specified
Remarks:
The test was conducted according to OECD 201 but the Good Laboratory Practice certificate is not included in the test report.
Analytical monitoring:
yes
Details on sampling:
The test item was stored in a closed vessel at room temperature.
A stock solution of an appropriate concentration in deionised water was prepared. The
stock solution then was used to prepare solutions of the concentrations to be tested.
Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
Desmodesmus subspicatus CHODAT, unicellular freshwater green alga. The culture was
obtained in Feb. 2009 by the „Collection of Alga“, Institute of Plant Physiology of the University
of Göttingen. The alga are kept as stock culture on solid agar at 8 oC. Three or four
days before the start of the test, an aliquot containing a few cells is brought into algal medium
and incubated. The resulting culture is growing exponentially.
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Test temperature:
23 to 26°C
pH:
7.1 to 8.1
Nominal and measured concentrations:
nominal: 0 / 0.1 / 1 / 10 / 100 mg/L
Reference substance (positive control):
no
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
ca. 1 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.:
>= 10 - <= 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC100
Effect conc.:
ca. 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Validity criteria fulfilled:
yes
Conclusions:
NOEC 72 h = 1 mg/L
72h ErC50= 10 – 100 mg/L
72h EbC50= 10 – 100 mg/L
72h EyC50= 10 – 100 mg/L
72h EC100= 100 mg/L
Executive summary:

Pre-test: Study Report following OECD 201 / EN ISO 8692 / EU-Guideline C.3: Toxicity of Lipacide UG against Desmodesmus subspicatus

The aim of this study was to determine the possibility to do an OECD 201 test.

RESULTS

NOEC 72 h = 1 mg/L

72h ErC50= 10 – 100 mg/L

72h EbC50= 10 – 100 mg/L

72h EyC50= 10 – 100 mg/L

72h EC100= 100 mg/L

ANALYTICAL MEASUREMENT OF STABILITY

The stability of the test item in test medium was measured.

A solution of 40 mg/L was measured at t = 0h and 72h. The area at t = 0h was 11 and at t = 72h 6.9, resulting in a recovery of 63%. Therefore it can be stated that the test item is not stable in the test medium for the algal test.

As the test item is not stable and it is not technically possible to use a semi-static protocol for algae, no main study was performed.

Description of key information

A pre-test study report following OECD 201 / EN ISO 8692 / EU-Guideline C.3 : Toxicity of the test substance against Desmodesmus subspicatus was done to determine the possibility to do an OECD 201 test.The test item is not stable and it is not technically possible to use a semi-static protocol for algae, no main study was performed.

Key value for chemical safety assessment

EC50 for freshwater algae:
10 mg/L
EC10 or NOEC for freshwater algae:
1 mg/L

Additional information

ErC50 (72h) = 10 -100 mg/L