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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:
24 AUG - 27 AUG 1993
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP - Guideline study
Qualifier:
according to guideline
Guideline:
EU Method C.3 (Algal Inhibition test)
GLP compliance:
yes
Analytical monitoring:
yes
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Liquid ethylchlorid (liquid at 4 °C) was given in excess in 4 °C cold VE-water. The vessel was closed with a septum and incubated over 5 days at 4°C.
Preparation of test concentrations: head-space-vessels of 20 mL volume were filled with 10 mL nutrient solution and closed with as septum. All used instruments were cooled to 8°C. Adequate amounts of the stock solution were injected to each of the test vessels. The whole process was conducted at 8°C.
- Controls: water control
Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM
- Common name: green algae
- Source (laboratory, culture collection): originally obtained from "Institut für Wasser-, Boden- und Lufthygiene, Berlin", in-house culture
- Age of inoculum (at test initiation): 3 days
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Test temperature:
24 +/- 2 °C
pH:
Test start: 8.3 - 8.6
Test end: 9.2 - 9.7
Nominal and measured concentrations:
nominal: 0, 20, 40, 80, 160, 320 and 640 mg/L
mean measured: 0, 7.7, 12, 30, 68, 132 and 319 mg/L
Details on test conditions:
TEST SYSTEM
- Type of flow-through (e.g. peristaltic or proportional diluter): static test
- Initial cells density: 2 x 10 exp 4 cells/mL
- Control end cells density: 49 x 10 exp 4 cells/mL
- No. of vessels per control (replicates): 17
- No. of vessels per vehicle control (replicates): 17


GROWTH MEDIUM
- Standard medium used: yes according to guideline 92/69/EWG


OTHER TEST CONDITIONS
- Photoperiod:continuous illumination
- Light intensity and quality: approximately 8000 lux


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: [counting chamber; electronic particle counter; fluorimeter; spectrophotometer; colorimeter]: photometer at 685 nm
Reference substance (positive control):
no
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
118 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
9.4 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate

 

Cell density (104cells/mL)

Mean measured concentration
[mg/L]

Test period (h)

0 h

24 h

48 h

72 h

Control

2

6

16

49

7.7

2

5

14

35

12

2

5

13

32

30

2

5

12

26

68

2

5

9

15

132

2

4

9

9

319

2

3

5

5

Description of key information

ErC50(72 h):118 mg/L (meas. geom. mean)

ErC10 (72 h): 9.4 mg/L (meas. geom. mean)

Key value for chemical safety assessment

EC50 for freshwater algae:
118 mg/L
EC10 or NOEC for freshwater algae:
9.4 mg/L

Additional information

The acute toxicity of chloroethane (CAS 75-00-3) to aquatic algae was tested in a guideline study following EU method C.3. Scenedesmus subspicatus was exposed to measured test concentrations of 7.7, 12, 30, 68, 132 and 319 mg/L under static conditions. The test concentrations were prepared by giving ethylchlorid in excess in VE-water. The vessels were closed with a septum and incubated over 5 days at 4°C. The test concentrations were prepared by filling head-space-vessels (20 mL volume) with 10 mL nutrient solution. The vessels were closed with a septum. At test termination EC50 (72 h) values of 118 mg/L (measured, geom. mean) were determined. The EC10 (72 h) value was 9.4 mg/L (measured, geom. mean).