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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:
read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
From September 08, 1986 to September 11, 1986
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
KL 2 due to RA and no analytical dose verification.
Justification for type of information:
Refer to the section 13 for details on the category justification.
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
no
GLP compliance:
no
Remarks:
(Pre GLP study; however, GLP comparable quality conditions followed)
Analytical monitoring:
not specified
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION:
- Method: First a stock solution of 10 g of the test substance per litre was prepared in water. From this solution appropriate aliquots were pipetted into the test vessels and filled up to final volumes of 100 mL with mineral nutrient.
- Controls: Nutrient medium with algal culture without test material
- Chemical name of vehicle: Water
Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM
- Source (laboratory, culture collection): Pflanzenphysiol, Institut der Universitat Gottingen
- Age of inoculum (at test initiation): A culture of the original delivery was carried on for 6 months

ACCLIMATION
- Acclimation period: Preincubation for about 3-4 d in test medium without test substance
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Post exposure observation period:
None
Test temperature:
24.0-25.0 °C
Nominal and measured concentrations:
0.3 - 1,000 mg/L (nominal)
Details on test conditions:
TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: 300 mL conical flasks containing 100 mL liquid volume
- Initial cells density: 1.0E+04 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3

GROWTH MEDIUM
- Standard medium used: Yes (mineral nutrient according to DIN 38412 part 9)

OTHER TEST CONDITIONS
- Light intensity and quality: Continuous uniform illumination with approximately 2,000 lux (daylight-spectrum)
- Stirring: At 500 rpm

EFFECT PARAMETERS MEASURED (with observation intervals if applicable):
- Determination of cell concentrations at 24, 48 and 72 h
Reference substance (positive control):
not specified
Key result
Duration:
72 h
Dose descriptor:
other: EbC0
Effect conc.:
ca. 0.3 mg/L
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Basis for effect:
cell number
Key result
Duration:
72 h
Dose descriptor:
other: EbC50
Effect conc.:
ca. 1.1 mg/L
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Basis for effect:
cell number
Key result
Duration:
72 h
Dose descriptor:
other: ErC50
Effect conc.:
ca. 8.7 mg/L
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Basis for effect:
growth rate
Details on results:
See Table 1 for details
Reported statistics and error estimates:
Probit method was used to determine EbC50 and ErC50 and t-test was used determine EbC0.

Table 1.Cell concentrations and pH values after various time intervals

Substance concentrations (mg product/L)

Algae cell concentrations (/mL)

Incubation time (h)

24

48

72

0

8.4E+04

7.2E+05

2.3E+06

0.3

8.2E+04

6.7E+05

2.0E+06

1.0

3.9E+04

3.3E+05

1.3E+06

3.0

2.2E+04

5.8E+04

6.2E+05

10

2.3E+04

2.1E+04

4.5E+04

30

1.9E+04

2.7E+04

2.0E+04

100

1.0E+04

5.0E+03

5.0E+03

300

1.0E+04

5.0E+03

5.0E+03

1000

1.0E+04

5.0E+03

5.0E+03

Validity criteria fulfilled:
not specified
Remarks:
(Coefficient of variation for growth rate not reported)
Conclusions:
Under the study conditions, 72 h EbC0, EbC50 and ErC50 of the read across substance were found to be 0.3, 1.1 and 8.7 mg/L, respectively.
Executive summary:

A study was conducted to determine the toxicity of the read across substance, C12-18 and C18-unsatd. MEA, to the green algae Scenedesmus subspicatus according to OECD Guideline 201, in compliance with GLP. Algae were exposed to the test substance at concentration ranges of 0.3 to 1000 mg/L for 72 h under static conditions. The algae cell concentrations were determined at 24, 48 and 72 h. The inhibitory effect on algae biomass growth and growth rate was calculated subsequently. No analytical dose verification was conducted. Under the study conditions, the nominal 72 h EbC0, EbC50 and ErC50 were found to be 0.3, 1.1 and 8.7 mg/L, respectively (Gode, 2001).

Description of key information

Key value for chemical safety assessment

EC50 for freshwater algae:
8.7 mg/L

Additional information

A study was conducted to determine the toxicity of the read across substance, C12-18 and C18-unsatd. MEA, to the green algae Scenedesmus subspicatus according to OECD Guideline 201, in compliance with GLP. Algae were exposed to the test substance at concentration ranges of 0.3 to 1000 mg/L for 72 h under static conditions. The algae cell concentrations were determined at 24, 48 and 72 h. The inhibitory effect on algae biomass growth and growth rate was calculated subsequently. No analytical dose verification was conducted. Under the study conditions, the nominal 72 h EbC0, EbC50 and ErC50 were found to be 0.3, 1.1 and 8.7 mg/L, respectively (Gode, 2001).