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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
Study period:
4 February 1992 to 24 January 1994
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Version / remarks:
OECD Guideline No. 201 and EEC Directive 67 /549 Annex VIII, Part C (87 /302/EEC).
Deviations:
no
GLP compliance:
yes
Analytical monitoring:
no
Vehicle:
no
Test organisms (species):
Scenedesmus sp.
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
72 h
Key result
Duration:
72 h
Dose descriptor:
other: ErC50
Effect conc.:
640 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
125 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: area under the curve
Validity criteria fulfilled:
yes
Conclusions:
In the current testing conditions, exposure of Scenedesmus subspicatus to peroxidase for 72 hours in concentrations up to 976 mg enzyme concentrate dry matter/L produced the following EC50 and NOEC values:
ErC50 (24 - 72 h): 624.6 mg enzyme concentrate dry matter/L, equivalent to 176.6 mg active enzyme protein/L.
EbC50 (72 h): 312.3 mg enzyme concentrate dry matter/L.
"No observed effect level" for 72 hour AUC: 122 mg enzyme concentrate dry matter/L, equivalent to 34.5 mg active enzyme protein/L.
"No observed effect level" for the 24-72 hour growth rate: 488 mg enzyme concentrate dry matter/L, equivalent to 138 mg active enzyme protein/L.
Executive summary:

Scenedesmus subspicatus was exposed to peroxidase for a period of 72 hours. The study was conducted according to OECD Guideline No. 201 and EEC Directive 67 /549 Annex VIII, Part C (87 /302/EEC). Five algeal cultures with an initial cell density of 1.1 x 10^5 cells/mL were exposed to peroxidase in concentrations 61, 122, 244, 488 and 976 mg enzyme concentrate dry matter/L.There were 5 concentrations plus 1 control in each triplicate. The cultures were incubated for 72 hours under continuous illumination.


The cell densities of the control and test cultures were determined at 0, 24, 48 and 72 hours by direct counting with the aid of a haemacytometer.


The growth inhibition test showed the following values:


EbC50 (72 h): 312.3 mg enzyme concentrate dry matter/L (95 % confidence limits 283 - 351.4 mg enyzme concentrate dry matter/L); equivalent to 88.3 mg active enzyme protein/L.


ErC50 (24 - 72 h): 624.6 mg enzyme concentrate dry matter/L (95 % confidence limits 546.6 - 712.5 mg enzyme concentrate dry matter/L); equivalent to 176.6 mg active enzyme protein/L.


"No observed effect level" for 72 hour AUC: 122 mg enzyme concentrate dry matter/L; 34.5 mg enyzme concentrate dry matter active enzyme protein/L.


"No observed effect level" for the 24-72 hour growth rate: 488 mg enzyme concentrate dry matter/L; 138 mg active enzyme protein/L.

Description of key information

The toxicity to aquatic algae and cyanobacteria of the present target substance, Glucose oxidase IUBMB 1.1.3.4, has not been determined but another enzyme (Peroxidase, IUBMB 1.11.1.7) has been analyzed and used as a source substance for read-across.


Exposure of Scenedesmus subspicatus to peroxidase for 72 hours in concentrations up to 976 mg enzyme concentrate dry matter/L produced the following EC50 and NOEC values:


ErC50 (24 - 72 h): 624.6 mg enzyme concentrate dry matter/L, equivalent to 176.6 mg active enzyme protein/L.


EbC50 (72 h): 312.3 mg enzyme concentrate dry matter/L.


"No observed effect level" for 72 hour AUC: 122 mg enzyme concentrate dry matter/L, equivalent to 34.5 mg active enzyme protein/L.


"No observed effect level" for the 24-72 hour growth rate: 488 mg enzyme concentrate dry matter/L, equivalent to 138 mg active enzyme protein/L.

Key value for chemical safety assessment

EC50 for freshwater algae:
624.6 mg/L

Additional information