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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:
other: experimetal study on similar substance
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study well documented, test procedure in accordance with OECD 221 methodes, meets generally accepted scientific principles, acceptable for assessment. GLP compliant with certificate.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2012

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 221 (Lemna sp. Growth Inhibition Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder

Sampling and analysis

Analytical monitoring:
no

Test solutions

Vehicle:
yes

Test organisms

Test organisms (species):
Lemna minor
Details on test organisms:
Exponential growing plant monocolture of Lemna Minor (Umweltbundesamt, D-06813 Dessau-Rosslau, Germany

Study design

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

Test conditions

Test temperature:
25 ± 1 °C
pH:
5,5 ± 0,2
Nominal and measured concentrations:
The test were performed at concentrations of 10, 100 and 1000 mg/l of the active ingredient.
Assuming a purity of 65%, nominal concentrations of 15.4, 154 and 1538 mg/l, respectively, were prepared.
Details on test conditions:
TEST SYSTEM
- Test vessel: 400 ml beaker
- Material, size, headspace, fill volume: glass with 200 ml of test medium

GROWTH MEDIUM
- Standard medium used: yes
Test medium STEINBERG with the following composition:

Macroelements mg/l
KNO3 350
KH2PO4 90
K2HPO4*3H2O 16.5
MgSO4*7H2O 100
Ca(NO3)2*4H2O 295

Microelements μg/l
H3BO3 120.0
ZnSO4*7H2O 180.0
Na2MoO4*2H2O 44.0
MnCl2*4H2O 180.0
FeCl3*6H2O 760.0
C10H14N2Na2O8*2H2O 1500.0

ILLUMINATION: Continuos (3500 - 7500 lux) from Osram Fluora L18W77 (Osarm AG, Winterthur, Switzerland)
Reference substance (positive control):
no

Results and discussion

Effect concentrations
Duration:
7 d
Dose descriptor:
EC50
Effect conc.:
> 1 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate

Any other information on results incl. tables

The number of fronds is counted on day 3, 5 and 7. On day 7 the dry weight is determined by incubating the duckweed at 60° C over night.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The results showthat the tested item is not toxic to Lemna minor with EC50 > 1000 mg/L.
Executive summary:

Effect on frond numbers:The inhibitory effect based on the average specific growth rate and the yield (duckweed biomass production) of the tested item to the duckweedLemna minorwas investigated over a period of 7 d.The test was performed at concentrations of 10, 100 and 1000 mg/l of the active ingredient. Assuming a purity of 70%, nominal concentrations of 15.4, 154 and 1538 mg/l, respectively, were prepared.With respect to duckweed growth rate and yield inhibition for the endpoint frond numbers, no significant effects were observed at all concentrations as compared to the untreated controlsas determined by Dunnett’s test.Based on these data the median effect concentration with respect to growth rate (ErC50) and yield (EyC50) for the endpoint frond numbers of the tested item toLemna minorwas estimated to be >1538 mg/l nominal concentration.The no-observed-effect concentration with respect to growth rate (NOErC) and yield (NOEyC) for the endpoint frond numbers was 1538 mg/l nominal concentration.

Effects on dry weight: With respect to duckweed growth rate inhibition for the endpoint dry weight no significant effects were observed at all concentrations as compared to the untreated controlsas determined by Dunnett’s test.Based on these data the median effect concentration with respect to growth rate (ErC50) for the endpoint dry weight of Direct Black 19 toLemna minorwas estimated to be >1538 mg/l nominal concentration.The no-observed-effect concentration with respect to growth rate (NOErC) for the endpoint dry weight was 1538 mg/l nominal concentration.With respect to duckweed yield inhibition for the endpoint dry weight the following effects as compared to the untreated controls were observed at the respective nominal concentrations: 1538 mg/l (27%) and154 mg/l (20%). No significant effects as determined by Dunnett’s test were observed at 15.4 mg/l.Based on these data the median effect concentration with respect to yield (EyC50) for the endpoint dry weight of the tested item toLemna minorwas estimated to be >1538 mg/l nominal concentration.The no-observed-effect concentration with respect to yield (NOEyC) for the endpoint dry weight was 15.4 mg/l nominal concentration.