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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
72 hours, 4 to 7 March 2003
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline and GLP-compliant study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2003
Report Date:
2003

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.3 (Algal Inhibition test)
Deviations:
no
Qualifier:
according to
Guideline:
EPA OPPTS 850.5400 (Algal Toxicity, Tiers I and II)
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): E-Caprolactone
- Physical state: liquid/ clear, colourless
- Analytical purity: 99.95%
- Lot/batch No.: U 05175
- Stability under test conditions: unlimited
- Storage condition of test material: at room temperature
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
Not applicable

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
Samples were taken at 0 hours (fresh media) and 72 hours (expired media).

Test solutions

Vehicle:
no
Details on test solutions:
The test substance was stirrred in deionised water for about 10 minutes at approximately 20 ± 2 °C.

Test organisms

Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
- Strain number: CHODAT SAG 86.81
- Source: SAG (Collection of algal cultures in Göttingen)

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h

Test conditions

Hardness:
Not applicable
Test temperature:
23 ± 2 °C
pH:
6.9 - 8.2
Dissolved oxygen:
Not applicable
Salinity:
Not applicable
Nominal and measured concentrations:
Nominal: 102, 256, 640, 1600, 4000 mg/L
Measured (mean of 2): 93, 260, 664, 1693, 4204 mg/L
Reference substance (positive control):
no

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
1 217 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
2 616 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
256 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
256 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Reported statistics and error estimates:
Calculation of the integral of biomass growth over the total duration of the test for each concentration level and comparison of values of treated samples in relation to untreated samples.
Calculation of the growth rate over the total duration of the study for each concentration level and comparison of values of treated samples in relation to untreated samples.
The EC values were calculated (linear regression analysis) from the concentration-response relationship.
The LOEC was determined by comparing the means of the calculated biomass or growth rate of the various concentration levels with the control. The Dunnett's One-tailed T test was carried out at a 95% significance level.

Any other information on results incl. tables

Results of the definitive test are compiled below:

Measured fluorescence (relative units)

Time (h)

Flask number

Concentration (mg/L)

0 (control)

4000

1600

640

256

102

0

1

30

31

31

32

31

33

2

31

32

34

33

31

35

3

30

32

32

31

31

34

no

0

0

0

0

0

0

24

1

130

98

130

130

150

130

2

130

95

130

140

140

140

3

130

95

130

140

150

140

no

0

0

0

0

0

0

48

1

660

180

440

630

730

660

2

700

190

420

670

750

680

3

680

190

430

660

780

680

no

0

0

0

0

0

0

72

1

3450

170

930

2720

3330

3380

2

3500

150

780

2450

3800

3590

3

3180

150

730

2350

3970

3630

no

0

0

0

0

0

0

no = not inoculated

Measured fluorescence (relative units)

Time (h)

Flask number

Concentration (mg/L)

0 (control)

4000

1600

640

256

102

0

1

1.5

1.6

1.6

1.6

1.6

1.7

2

1.6

1.6

1.7

1.7

1.6

1.8

3

1.5

1.6

1.6

1.6

1.6

1.7

mean

1.5

1.6

1.6

1.6

1.6

1.7

24

1

6.6

5.0

6.6

6.6

7.6

6.6

2

6.6

4.7

6.6

7.1

7.1

7.1

3

6.6

4.8

6.6

7.1

7.6

7.1

mean

6.6

4.9

6.6

7.0

7.5

7.0

48

1

33.6

6.2

22.4

32.1

37.2

33.6

2

35.7

9.7

21.4

34.2

38.2

34.7

3

34.7

9.7

21.9

33.6

39.8

34.7

mean

34.7

9.5

21.9

33.3

38.4

34.3

72

1

175.9

8.7

47.4

138.7

169.8

172.3

2

178.4

7.6

39.8

124.9

193.7

183.0

3

162.1

7.6

38.7

119.8

202.4

185.1

mean

172.1

8.0

42.0

127.8

118.6

180.1

Calculation of biomass and inhibition of biomass after 72h

Parameter

Flask number

Concentration (mg/L)

0 (control)

4000

1600

640

256

102

Biomass (rel)

1

124

15

49

104

126

122

2

128

14

44

100

138

129

3

119

14

44

97

145

130

mean

120

14

45

100

136

127

Inhibition (%)

 

0.0

88.4

63.2

19.0

-10.3

-2.9

 

Calculation of growth rate and inhibition of growth rate after 72h

Parameter

Flask number

Concentration (mg/L)

0 (control)

4000

1600

640

256

102

Growth rate (rel)

1

0.066

0.024

0.047

0..062

0.065

0.064

2

0.066

0.021

0.044

0.060

0.067

0.064

3

0.065

0.021

0.044

0.060

0.067

0.065

mean

0.065

0.022

0.045

0.061

0.066

0.064

Inhibition (%)

 

0.0

66.1

31.4

7.5

-1.4

1.4

 

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The 72-hour ErC50 (growth rate), EbC50 (integrated biomass) for D. subspicatus exposed to E-Caprolactone under static conditions were 2616 and 1217 mg/L, respectively.
Executive summary:

Desmodesmus subspicatus was exposed to E-Caprolactone at nominal concentrations of 102, 256, 640, 1600 and 4000 mg/L in a static 72 -hour toxicity test carried out according to OECD 201 guidelines. The test design included an untreated control comprising untreated algal growth medium only. Concentrations of E-Caprolactone were verified analytically at test initiation and termination and measured concentrations were 91 - 106% of nominal. The 72 -hour ErC50 and EbC50 endpoints determined were 2616 and 1217 mg/L, respectively. The corresponding 72 -hour NOEC based on inhibition of specific growth rate and inhibition of biomass were both 256 mg/L, respectively.