Registration Dossier

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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018
Report Date:
2018

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent

Sampling and analysis

Analytical monitoring:
yes

Test solutions

Vehicle:
yes
Details on test solutions:
The primary stock solution used in the range-finding test was prepared by dissolving 0.0250 g of the test substance in 250 mL with OECD medium, resulting in a concentration of 100 mg.L-1. The stock solution of 10 mg.L-1 was prepared from dilution of the primary stock solution.

The primary stock solution used in the definitive test was prepared by dissolving 0.1 g of the test substance in 1000 mL with OECD medium, resulting in a concentration of 100 mg.L-1. The stock solution of 10 mg.L-1 was prepared from dilution of the primary stock solution.

From these initial stock solutions, a series of dilutions was prepared in order to obtain the desired tested concentrations

Test organisms

Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)

Study design

Test type:
static
Water media type:
brackish water
Limit test:
yes
Total exposure duration:
72 h

Test conditions

Test temperature:
22.1 to 22.3oC
pH:
8.1-8.3
Reference substance (positive control):
yes

Results and discussion

Effect concentrations
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
65.95 mg/L
Details on results:
The 72-hours EyC50 value for alga Pseudokirchneriella subcapitata exposed to 1,3-Difluorobenzene was 29.72 mg.L-1 and the 72-hours ErC50 value was 65.95 mg.L-1. The highest test substance concentration with no observed significant adverse effect (NOEC) on algal growth was 10 mg.L-1 and the lowest test substance concentration at which was observed significant reducing effect on growth (LOEC) was 32 mg.L-1.

Any other information on results incl. tables

Table 12 –Cells Concentration, Yield of Biomass and Yield Inhibition, Growth Rate, and Growth Rate Inhibition of Cells Compared to the Control at 24, 48, and 72 Hours at Each Tested Concentration, in the Definitive Test.

 

Test period (hours)

Nominal concentration (mg.L-1)

Obs*

Cells concentration (cells.mL-1)

Cells concentration average (cells.mL-1)

Yield (y)

(cells.mL-1)

Yield inhibition (Iy) (%)

Growth rate (µ)

(day-1)

Growth rate inhibition (Iµ) (%)

R1

R2

R3

24

Control

NM

30000

20000

30000

26667

21667

0

1.6740

0

0.32

NM

30000

30000

30000

30000

25000

0

1.7918

0

1

NM

20000

30000

30000

26667

21667

0

1.6740

0

3.2

NM

30000

30000

20000

26667

21667

0

1.6740

0

10

NM

30000

20000

30000

26667

21667

0

1.6740

0

32

NM

20000

20000

20000

20000

15000

31

1.3863

17

100

NM

10000

10000

10000

10000

5000

77

0.6931

59

48

Control

NM

160000

140000

160000

153333

148333

0

1.7116

0

0.32

NM

180000

150000

160000

163333

158333

0

1.7432

0

1

NM

150000

170000

180000

166667

161667

0

1.7533

0

3.2

NM

170000

150000

150000

156667

151667

0

1.7223

0

10

NM

150000

170000

160000

160000

155000

0

1.7329

0

32

NM

100000

70000

90000

86667

81667

45

1.4263

17

100

NM

20000

20000

10000

16667

11667

92

0.6020

65

72

Control

NM

680000

700000

710000

696667

691667

0

1.6456

0

0.32

NM

690000

720000

710000

706667

701667

0

1.6504

0

1

NM

720000

690000

700000

703333

698333

0

1.6488

0

3.2

NM

710000

680000

710000

700000

695000

0

1.6472

0

10

NM

700000

720000

670000

696667

691667

0

1.6456

0

32

NM

300000

320000

290000

303333

298333

57

1.3685

17

100

NM

30000

20000

20000

23333

18333

97

0.5135

69

R1, R2 and R3 = replicates.

* NM = None morphological effects observed.

 

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The 72-hours EyC50 value was 29.72 mg.L-1 and the 72-hours ErC50 value was 65.95 mg.L-1. The highest test substance concentration which no observed significant adverse effect (NOEC) on algal growth was 10 mg.L-1 and the lowest test substance concentration at which was observed significant reducing effect on growth (LOEC) was 32 mg.L-1.