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Ecotoxicological information

Toxicity to aquatic plants other than algae

Administrative data

Endpoint:
toxicity to aquatic plants other than algae
Type of information:
experimental study
Adequacy of study:
key study
Study period:
12 – 19 November 2018
Reliability:
1 (reliable without restriction)

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018
Report date:
2019

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 221 (Lemna sp. Growth Inhibition Test)
Version / remarks:
23 March 2006
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Test material form:
solid: particulate/powder

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
Photometric analysis of the test item concentration in the test solutions was performed to
determine exposure concentration and stability of the test item during the test. One analytic sample
of ca. 10 mL was taken from each of the two additional vessels of treatment A, C, E and NC at the
start of the experiment and after 2 d, 4 d and 7 d. The samples were filled into 15 mL falcons and
stored in the fridge (5°C ± 3°C) until measurement.
Replicate 1 of the analytic samples of the treatments A, C, E and NC from day 0, 2, 4 and 7 was
analyzed within ≤ 7 d after sampling. The storage stability of the analytical samples was verified
over a period of 7 d (Validation Study No. 1393, Hydrotox GmbH). The remaining samples were
stored as retain samples in the fridge (5 °C ± 3 °C) until finalization of the study.

Test solutions

Vehicle:
no
Remarks:
No vehicle was used, as test item is soluble in test medium
Details on test solutions:
Steinberg medium

Test organisms

Test organisms (species):
Lemna minor
Details on test organisms:
duckweed Lemna minor obtained from the German Federal Environment Agency (UBA), Berlin-Marienfelde

Study design

Test type:
static
Water media type:
freshwater
Total exposure duration:
7 d

Test conditions

Test temperature:
24.7 to 25.6 °C
pH:
5.5 - 6.6
Nominal and measured concentrations:
nominal active substance concentrations 18.75, 37.5., 75, 150 and 300 mg/L
Reference substance (positive control):
yes

Results and discussion

Effect concentrationsopen allclose all
Key result
Duration:
7 d
Dose descriptor:
EC10
Effect conc.:
19.89 mg/L
Nominal / measured:
nominal
Conc. based on:
act. ingr. (dissolved fraction)
Basis for effect:
frond number
Key result
Duration:
7 d
Dose descriptor:
LOEC
Effect conc.:
<= 18.75 mg/L
Nominal / measured:
nominal
Conc. based on:
act. ingr. (dissolved fraction)
Basis for effect:
frond number
Key result
Duration:
7 d
Dose descriptor:
NOEC
Effect conc.:
<= 18.75 mg/L
Nominal / measured:
nominal
Conc. based on:
act. ingr. (dissolved fraction)
Basis for effect:
frond number
Details on results:
As the measured active substance concentrations are all within ± 20 % of the nominal
concentrations, according to OECD 221 (2006), all results are given in relation to the nominal
active substance concentrations.
The maximum inhibitions at the highest measured test-concentration (100 mg/L) of the Growth rate for Frondnumber
(8.1%), Frondarea (13.5%) and of the Yield for Frondnumber (20.2%), Frondarea (9.1%) were well below 50% inhibition.
Therefore the statistical evaluation for ECx was partially not possible or not meaningful and presented as: > 100 mg/L.
Results with reference substance (positive control):
The EC50(growth rate, frond number) for the reference substance 3,5-Dichlorophenol was 2.8
mg/L (2.3 – 3.3 mg/L 95%-CI) which is in-line with the requirements of the ISO 20079 (2005)
[Lemna, Growth Inhibition Test] of 2.2 – 3.8 mg/.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
EC50 n.d. (7d, growth rate, frondnumber)
EC10 19.89 mg/L (7d, growth rate, frondnumber)