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:
other: OECD guideline study conducted under GLP

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2009
Report Date:
2009

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
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
As noted in the hydrolysis section, oximesilanes quicky hydrolyze to the corresponding oxime and reactive silanols which spontaneously cross link to form high molecular weight silicone polymers. The relevant hydrolysis product is MPKO, the substance that was tested.

Data on selected oximes and oxime silanes are summarized in the attached Table. Although data for each endpoint is not available for all products, the available data show similarities between oxime silanes and their hydrolysis products (oxime). These materials show low toxicity to fish, and daphnia. For algal studies, the toxicity shows a structure activity relationship. The smaller oximes are more toxic to alga, the larger oximes and associated oxime silanes are less toxic. The similarities in response between the oximes and oxime silanes provide additional support of the silicone containing moieties do not contribute to the aquatic toxicity of these materials. Due to the rapid hydrolysis, it is appropriate to use the oxime as surrogate data for the oxime silane.

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Concentrations: 0, 5.6, 10, 18, 32, 56, and 100 mg/l

Test organisms

Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
TEST ORGANISM
- Strain: ATCC 22662
- Source (laboratory, culture collection): laboratory cultures maintained under axenic conditions
- Age of inoculum (at test initiation): 4 days during exponential growth phase


- Culturing media and conditions: same as test
- Any deformed or abnormal cells observed: non observed

Study design

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

Test conditions

Hardness:
not reported
Test temperature:
18-22 degress Celcius
pH:
7.6 - 7.8
Dissolved oxygen:
not reported
Nominal and measured concentrations:
With the exception of the 5.6 mg/l samples, the measured concentrations with 91 - 100% of nomimal
Details on test conditions:
TEST SYSTEM
- Test vessel: 250 ml glass conical flasks closed with foam bungs filled with 100 ml of test solution and 0.75 ml of inoculum culture

- Initial cells density: 0.5 x 10e4 cells/ml
- Control end cells density: at 72 hours, 81.8 x 10e4 cells/ml
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes


OTHER TEST CONDITIONS
- Sterile test conditions: no
- Adjustment of pH: no
- Photoperiod: continuous
- Light intensity and quality: "cool-white" illumination of approximately 6000 lux (nominal)



EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: electronic particle counter

Reference substance (positive control):
no

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
ca. 54 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
32 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
88 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
32 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
growth rate
Details on results:
- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): - none observed
- Any stimulation of growth found in any treatment: none observed
- Effect concentrations exceeding solubility of substance in test medium: none observed
Reported statistics and error estimates:
one way analysis of variance and Duunnett's procedure to identify significant changes from control. Weibull method used to estimate the meane effective concentrations.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The 72 hr ECy50 is 54 mg/l, and the ECr50 is 88 mg/l. The 72 hour no-observed effect concentration was 32 mg/l based on yield and growth rate.