Registration Dossier

Diss Factsheets

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From October 16, 2017 to October 20, 2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
not specified
GLP compliance:
yes (incl. QA statement)
Analytical monitoring:
yes
Details on sampling:
To demonstrate that test vessels were dosed with nominal exposure concentrations of test substance, whole test vessels were analysed for both dissolved and undissolved test substance using the high-performance liquid chromatography mass spectrometry method. At the start of the test, additional sacrificial test vessels were used for sampling and at the end of the test one replicate of the culture medium control and each test concentration was sampled. The method of whole sample analysis was used due to the low solubility of the compound.
Vehicle:
yes
Remarks:
AAP medium
Details on test solutions:
Preparation of test solutions
The study was run with a culture medium control and nominal exposure concentrations of 0.0625, 0.125, 0.25, 0.5 and 1.0 mg/L. A primary stock concentrate of test substance, with a nominal concentration of 10 mg/L, was prepared by weighing a nominal 0.01 g of test substance and making up to 1000 mL volume with the culture medium AAP in a volumetric flask. The resultant stock was observed to be a clear and colourless solution and was used to prepare the test solutions. This was achieved by adding the relevant volumes of the primary stock to AAP media and making up to 1000 mL volume in a volumetric flask. The control consisted of culture medium only. In all cases the final solutions contained nutrients. The test solutions were all observed to be clear and colourless. The appropriate test solution (100 mL volume) was dispensed to each test and blank vessel.
Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
The test species was the unicellular green alga Pseudokirchneriella subcapitata strain CCAP 278/4 from laboratory cultures maintained under axenic conditions. A 3 d old culture of the alga in the exponential growth phase was used as inoculum for the test. The culture was grown in the medium, and under the environmental conditions, described for the test.
Test type:
not specified
Water media type:
other: AAP-medium
Limit test:
no
Total exposure duration:
72 h
Test temperature:
22 ± 2ºC
pH:
7.30 to 7.66
Nominal and measured concentrations:
1 mg/L highest concentration (Based on non-GLP range finding test)
0, 0.0625, 0.125, 0.25, 0.5 and 1.0 mg/L (nominal)
0, 0.055, 0.11, 0.24, 0.43 and 0.79 mg/L (measured)
Details on test conditions:
Appratus
The test vessels were glass conical flasks of 250 mL nominal capacity closed with foam bungs. Each flask contained 100 mL of test solution. The cultures were incubated at 22  2°C (the nominal test temperature), under continuous "cool-white" illumination of approximately 6000 lux, with nominal orbital shaking at 160 rpm.
Reference substance (positive control):
no
Key result
Duration:
72 h
Dose descriptor:
other: ErC50
Effect conc.:
ca. 0.184 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat. (total fraction)
Basis for effect:
growth rate
Key result
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
ca. 0.11 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat. (total fraction)
Basis for effect:
other: growth rate and biomass
Key result
Duration:
72 h
Dose descriptor:
LOEC
Effect conc.:
ca. 0.24 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat. (total fraction)
Basis for effect:
other: growth rate and biomass
Key result
Duration:
72 h
Dose descriptor:
other: EyC50
Effect conc.:
ca. 0.172 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat. (total fraction)
Basis for effect:
biomass
Key result
Duration:
72 h
Dose descriptor:
other: ErC10
Effect conc.:
ca. 0.123 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat. (total fraction)
Basis for effect:
growth rate
Key result
Duration:
72 h
Dose descriptor:
other: EyC10
Effect conc.:
ca. 0.115 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat. (total fraction)
Basis for effect:
biomass

Results:

Analytical data

The limit of quantification of test substance in this study was 0.004 mg/L. All analytical values are quoted to two significant figures and percentages to the nearest integer. On the basis of the analytical data the mean measuredconcentrations were used for the calculation and reporting of results.

Biological data

Algal cell particle densities (cell particles per unit volume) were measured as a surrogate for biomass.

Growth rates

The growth rate (0 to 72 h) was calculated for each replicate culture. The results obtained from these growth rate analyses, based on mean measured test concentrations, were as follows:

Test substance

(mg/L)

NOEC

0.11

LOEC

0.24

ErC50

0.184

ErC20

0.138

ErC10

0.123

Yield

This response was defined as the biomass at the end of the test minus the starting biomass. For the purposes of calculation, the cell particle density count (cell particles per unit volume) was an acceptable surrogate for biomass.The EC50, EC20and EC10values with their associated confidence intervals were subsequently calculated using the Linear Interpolation method.The results obtained from these statistical analysis, based on mean measured test concentrations, were as follows:

 

Test substance

(mg/L)

NOEC

0.11

LOEC

0.24

EyC50

0.172

EyC20

0.129

EyC10

0.115

Additional biological data

The microscopic observations, made at the end of the test, showed that compared to the control the algal cells sampled from the nominal 0.0625, 0.125, 0.25 mg/L test concentrations appeared normal. No cells were observed in samples from the 0.5 and 1.0 mg/L test concentrations.

Validity criteria

The validity criteria specified in the OECD 201 guideline are;

1) To achieve ≥16 fold exponential increase in biomass in the control replicates within the 72 h test period. In this test,cell particle density increase (measured as a surrogate for biomass) was 83 over the 72 h for the control.

2) The mean coefficients of variation for control replicate sectional (daily) specific growth rates must not exceed 35% and in this test, was determined to be 4%.

3) The replicate coefficient of variation of average specific growth rates during the whole test period in the control replicate cultures must not exceed 7% and in this test, was calculated to be 1.5%.

Based on the study results, it was concluded that the study has fulfilled validity criteria.

Validity criteria fulfilled:
yes
Conclusions:
Under the study conditions, 72 h ErC50, ErC10, EyC50, EyC10, NOEC and LOEC values for the test substance with freshwater green algae, were determined to be 0.184, 0.123, 0.172, 0.115, 0.11 and 0.24 mg/L (measured), respectively.
Executive summary:

A study was conducted to determine the acute toxicity potential of the test substance, 'di-C16-18 satd. and C18-24-unsatd. AAEMIM-MS' (active: 101%), to freshwater green algae (Pseudokirchneriella subcapitata), according to OECD Guideline 201, in compliance with GLP. Six replicates of the culture medium control and triplicates of each concentration of the test substance were employed. Three replicate algal cultures, with a nominal cell density of approximately 0.5E4 cells/mL, were exposed to test substance at nominal concentrations of 0, 0.0625, 0.125, 0.25, 0.5 and 1.0 mg/L in AAP medium for 72 h. One 100 mL volume of Coulter electrolyte, inoculated in the same manner, had a cell density of 0.593E4 cells/mL and was used for growth calculations. The exposure levels of test substance in aqueous samples of test media were monitored using a HPLC method of analysis. Based on whole sample extraction (dissolved and undissolved), the measured concentration of the test substances were found to be 0, 0.055, 0.11, 0.24, 0.43 and 0.79 mg/L. The test results were expressed in terms measured concentration of test substance. Algal cell particle densities (cell particles per unit volume measured as a surrogate for biomass) and growth rate were calculated for each replicate culture. The ErC50 and ErC10 values for growth rate was found to be 0.184 and 0.123 mg/L respectively, whereas, EyC50 and EyC10 values for cell particle density was found to be 0.172 and 0.115 mg/L respectively. The NOEC and the LOEC values were found to be 0.11 mg/L and 0.24 mg/L, respectively, for both growth rate and cell particle densities. The study was considered to have met all the validity criteria. Under the study conditions, 72 h ErC50, ErC10, EyC50, EyC10, NOEC and LOEC values for the test substance with freshwater green algae, were determined to be 0.184, 0.123, 0.172, 0.115, 0.11 and 0.24 mg/L (measured), respectively (Scymaris, 2017).

Description of key information

Based on the results of the study, the 72 h ErC50, ErC10, EyC50, EyC10, NOEC and LOEC values of the test substance, 'di-C16-18 satd. and C18-24-unsatd. AAEMIM-MS' for toxicity to freshwater green algae, were determined to be 0.184, 0.123, 0.172, 0.115, 0.11 and 0.24 mg/L (measured), respectively.

Key value for chemical safety assessment

EC50 for freshwater algae:
0.184 mg/L
EC10 or NOEC for freshwater algae:
0.123 mg/L

Additional information

A study was conducted to determine the acute toxicity potential of the test substance, 'di-C16-18 satd. and C18-24-unsatd. AAEMIM-MS' (active: 101%), to freshwater green algae (Pseudokirchneriella subcapitata), according to OECD Guideline 201, in compliance with GLP. Six replicates of the culture medium control and triplicates of each concentration of the test substance were employed. Three replicate algal cultures, with a nominal cell density of approximately 0.5E4 cells/mL, were exposed to test substance at nominal concentrations of 0, 0.0625, 0.125, 0.25, 0.5 and 1.0 mg/L in AAP medium for 72 h. One 100 mL volume of Coulter electrolyte, inoculated in the same manner, had a cell density of 0.593E4 cells/mL and was used for growth calculations. The exposure levels of test substance in aqueous samples of test media were monitored using a HPLC method of analysis. Based on whole sample extraction (dissolved and undissolved), the measured concentration of the test substances were found to be 0, 0.055, 0.11, 0.24, 0.43 and 0.79 mg/L. The test results were expressed in terms measured concentration of test substance. Algal cell particle densities (cell particles per unit volume measured as a surrogate for biomass) and growth rate were calculated for each replicate culture. The ErC50 and ErC10 values for growth rate was found to be 0.184 and 0.123 mg/L respectively, whereas, EyC50 and EyC10 values for cell particle density was found to be 0.172 and 0.115 mg/L respectively. The NOEC and the LOEC values were found to be 0.11 mg/L and 0.24 mg/L, respectively, for both growth rate and cell particle densities. The study was considered to have met all the validity criteria. Under the study conditions, 72 h ErC50, ErC10, EyC50, EyC10, NOEC and LOEC values for the test substance with freshwater green algae, were determined to be 0.184, 0.123, 0.172, 0.115, 0.11 and 0.24 mg/L (measured), respectively (Scymaris, 2017).