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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:
2nd September to 5th Septemeber 2013
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Testing was carried out according to OECD 202 guidlines and was GLP compliant.
Justification for data waiving:
other:
Cross-referenceopen allclose all
Reason / purpose:
reference to same study
Reason / purpose:
reference to other study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2013
Report Date:
2013

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
no
Principles of method if other than guideline:
N/A
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
gas under pressure: refrigerated liquefied gas
Details on test material:
Clear, colourless liquid.
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
N/A

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
The incubation period was 72 hours, biomass was measured in samples by counting the number of cells using a miscroscope at 0, 24, 48, and 72 hours. Before the test start pH was measured in all solutions, and again in all replicates after 72 hours.

Test solutions

Vehicle:
no
Details on test solutions:
Fresh stock solution was prepared on the day of the test start. 1000 mg of the test item was added to 1000 ml reversed osmosis water and stirred for 10 minutes. To remove the non-water soluble fraction of the test item from the test solution, the solution was filtered through a 0.45 um cellulose acetate filter (pre-boiled in order to remove any traces of external carbon). The acquired water phase (loading rate 1000 mg/l) was then used as a stock solution, from which the test concentrations were diluted using growth media. Growth media alone was used as the control solution. Nominal loading rates tested were 28, 56, 113, 225, 450 and 900 mg/ l.

Test organisms

Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
The test organism is a laboratory culture of the green alga Pseudokirchneriella subcapitata. The inoculum is taken from Toxicon's culture of P. subcapitata (NIVA CHL 1), which originates from NIVA, Oslo, Norway. A qualification test on the alga culture was performed on the 27th of June 2013 in order to assure the quality of the test organism using potassium dichromate. ErC50 was 0,93 mg/ l, which confirmed that the culture was suitable as a test organism according to OECD 201.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Post exposure observation period:
None

Test conditions

Hardness:
N/A
Test temperature:
21-24±2° C.
pH:
7.9-8.0 at test initiation, 7.4-8.7 at the end of the testing period.
Dissolved oxygen:
N/A
Salinity:
N/A
Nominal and measured concentrations:
28, 56, 113, 225, 450 and 900 mg/ l nominal loading rate. Measured concentrations at 0 hours for the stock solution, 28 and 900mg/l were 220, 17, 200 mg/l respectively, at 72 hours measured concentrations were 14 and 200 mg/l (stock solution was not analysed).
Details on test conditions:
Six replicates were used for the control and three for each of the test solutions. Test bottles were 250 ml glass E-bottles with 100 ml solution, incubated on a shaking table with approximately 100 uE m-2 s-1 continuous illumination and a temperature of 21-24±2° C.
Reference substance (positive control):
yes
Remarks:
potassium dichromate

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
490 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: N/A
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
240 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: N/A
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
113 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: N/A
Details on results:
The criteria for the validity of the test according to OECD 201 were met.
Results with reference substance (positive control):
A qualification test was carried out on the algae culture with potassium dichrominate. This gave an ErC50 of 0.93 mg/I, which confirmed that the culture was suitable as a test organism according to OECD guideline 201.
Reported statistics and error estimates:
An unpaired t-test was applied to determine the highest concentration with no statistical difference to the control (p >0,05).

Any other information on results incl. tables

Table 1. Calculated response variables for the control and the test concentrations (mean ± coefficient of variation) after 72 hours of exposure to the water soluble fraction of the test item Capa 3050.

Concentration mg/I (loading rate)          72h Specific growth rate(/-l) Mean ± CV(%)

Control                                                     1.82±3.8

28                                                             1.84±2.1

56                                                             1.81±3.4

113                                                           1.81±3.6

225                                                           1.69±3.2

450                                                           1.02±3.4

900                                                           0.28±28

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The toxicity of Capa 3050 to the freshwater algae Pseudokirchneriella subcapitata was determined in a 72 hour static test. Algae were exposed to nominal loading rates of Capa 3050 between 28 and 900 mg/l for 72 hours. The 72 hour static ErC50 was 490 mg/l.
Executive summary:

The purpose of the test was to determine the effects of Capa 3050 on the growth of Pseudokirchneriella subcapitata. Exponentially growing cultures of Pseudokirchneriella subcapitata were exposed to Capa 3050 over a period of 72 hours with sampling at 0, 24, 48, and 72 hours. OECD Guidelines 201 were followed for this test. The response was measured as the reduction of growth in a series of loading rates (28, 56, 113, 225, 450 and 900 mg/ l). Stability of Capa 3050 was confirmed in the test media. The 72 hour ErC50 was 490 mg/l based on nominal loading rates.