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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Ecotoxicological information

Toxicity to aquatic plants other than algae

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Administrative data

Link to relevant study record(s)

Reference
Endpoint:
toxicity to aquatic plants other than algae
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Qualifier:
according to guideline
Guideline:
OECD Guideline 221 (Lemna sp. Growth Inhibition Test)
GLP compliance:
no
Remarks:
published data
Analytical monitoring:
yes
Details on sampling:
Samples for chemical analysis were taken at the start of the tests and at the end from control, lowest and highest test concentrations.
Vehicle:
no
Details on test solutions:
Stock solutions were prepared by ultrasound treatment for 15 minutes and stirring over night in the dark at room temperature.
Test solutions were prepared as dilutions of the stock solution directly before test start.
Test organisms (species):
Lemna minor
Details on test organisms:
TEST ORGANISM
- Common name: Lemna minor
- Strain: clone St, Landlot number 9441
- Source (laboratory, culture collection): in-house batch culture, from Friedrich-Schiller University Jena, K.-J. Appenroth
- Method of cultivation: Steinberg medium modified acc. R. Altenburger (annex OECD 221)
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
7 d
Test temperature:
24 +/- 2°C
pH:
5.6/6.9; 6.2
Nominal and measured concentrations:
Nominal concentrations: 0.008 - 0.2 mg/L
Details on test conditions:
TEST SYSTEM
- Test vessel: crystallizing dishes
- Material, size, headspace, fill volume: Fill volume 200 mL
- Control end cells density: no data
- No. of colonies per vessel: 4
- No. of fronds per colony: 3
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes, Steinberg medium modified acc. R. ALtenburger (annex OECD 221)


OTHER TEST CONDITIONS
- Photoperiod: continuous
- Light intensity and quality: photosynthetically active radiation (85 - 135 µE/m²xs)
Key result
Duration:
7 d
Dose descriptor:
EC50
Effect conc.:
0.024 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
frond number
growth rate
Key result
Duration:
7 d
Dose descriptor:
EC10
Effect conc.:
0.008 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
frond number
growth rate
Duration:
7 d
Dose descriptor:
EC50
Effect conc.:
0.013 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
biomass
Duration:
7 d
Dose descriptor:
EC10
Effect conc.:
0.004 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
biomass
Reported statistics and error estimates:
Results of the standard biotests were modeled as concentration–response curves in the free software R version 2.11.1 using the drc package. Effects (as percentage of control for continuous data and as proportion for binomial data) were fitted against log-transformed concentrations (x) using the 4-parameter log–logistic model (function LL.4) given in Equation 1 in publication, with the parameter c relating to the lower and d relating to the upper limit of the curve and b relating to the slope. The EC50 was directly iteratively determined as the model parameter. Whereas for the continuous response data obtained for L.
minor, the 4-parameter model was used. Further effect concentrations, EC20 and EC10, were estimated by the ED function in drc and confidence intervals (95%) for all point estimates were determined using the delta method in drc.
Concentration–response modeling was based on nominal test concentrations.

Chemical analysis of the test solutions confirmed that recovery of nominal climbazole concentrations was moderate for all aquatic biotests mentioned in the publication, at 68% to 85% for initial and 62% to 74% for aged test solutions. However, based on initially


measured test concentrations, recovery at test end reached 81% to 99%. Hence, there was only a little loss of climbazole during


the static exposure.


The mean recovery the substance in the this test was 70.5% (information from the author). Thus, the ErC10 (growth rate) based on the measured concentrations were used for the hazard assessment.

Validity criteria fulfilled:
yes
Remarks:
frond number doubling time < 2.5 days: OK (1.8)
Conclusions:
The 7-d ErC50 and 7-d ErC10 based on the growth rate and frond number of the test item to Lemna minor were determined to be 0.0239 and 0.0079 mg/L, respectively.
Executive summary:

A published study on the biological effect of the substance to the aquatic plant Lemna minor is available. mg/l climbazole (98% purity) using Steinberg medium. Based on preliminary range-finding test, the nominal exposure concentrations in the definitive test were 0.008, 0.0031, 0.0125, 0.05 and 0.2 mg/L. Test solutions were prepared by ultrasonic mixing for 15 minutes and continuous stirring overnight in the dark. A static regime was employed with 3 replicates per test concentration and 6 control replicates. Static test conditions were within protocol guidelines. The test media pH was 5.6-6.2. Study observations were recorded and noted smaller frond of darker colouration and clustered colonies at higher test concentrations. The concentrations were determined by High Performance Liquid Chromatography (HPLC) and resulted in a recovery of 70.5% of the nominal concentrations. The 7-d ErC50 and 7-d ErC10 based on the growth rate and frond number of the test item to Lemna minor were determined to be 0.0239 and 0.0079 mg/L, respectively. The ErC10 of this test is considered for the hazard assessment and classification.

Description of key information

The 7-d ErC50 and 7-d ErC10 based on the growth rate and frond number of the test item to Lemna minor were determined to be 0.0239 and 0.0079 mg/L, respectively. The ErC10 of this test is considered for the hazard assessment and classification.

Key value for chemical safety assessment

EC50 for freshwater plants:
0.024 mg/L
EC10 or NOEC for freshwater plants:
0.008 mg/L

Additional information