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Ecotoxicological information

Toxicity to aquatic plants other than algae

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Administrative data

Endpoint:
toxicity to aquatic plants other than algae
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
2004-10-20 - 2004-12-15
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2004
Report date:
2004

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 221 (Lemna sp. Growth Inhibition Test)
Version / remarks:
2002
Deviations:
no
GLP compliance:
yes
Remarks:
No details available.

Test material

Constituent 1
Details on test material:
Not applicable.
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
- Name of test material (as cited in study report): Fe(Na)EDDMHA
- Appearance: Black, solid
- Storage condition of test material: Room temperature, protected from moisture and light

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
No details available.

Test solutions

Vehicle:
yes
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
Stock solution: 184.2 mg test item/L, freshly prepared with dilution water
Dispersion treatment: Agitation
Test concentration (nominal): 184.2 mg test item/L

Test organisms

Test organisms (species):
Lemna minor
Details on test organisms:
TEST ORGANISM
- Common name, Strain: Duckweed, Lemna minor, Lemnaceae, Arales, Arecidae, Monocotyledonae
- Source (laboratory, culture collection): ÖKOTOX MOSER & PICKL GBR, Postfach 720207, D-70578 Stuttgart
- Method of cultivation: The species was bred in the testing facility. Density was kept low to prevent conglomerates of plants on the surface. At least once per week, plants were transferred to freshly prepared growth medium. Growth media and breeding vessels were autoclaved before use to enable the breeding of axenic cultures.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
7 d
Post exposure observation period:
No post exposure observation period described.

Test conditions

Hardness:
No details available.
Test temperature:
24 +/- 2 °C
pH:
No details available.
Dissolved oxygen:
No details available.
Salinity:
Not applicable.
Nominal and measured concentrations:
184.2 mg/L (nominal)
Details on test conditions:
TEST SYSTEM
- Test vessel: Crystallization dishes with a volume of 500 mL, covered with glass tops and filled with 200 mL test solution were used in the test.
- No. of colonies per vessel: 3
- No. of fronds per colony: 4
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3

GROWTH MEDIUM
- Standard medium used: yes

OTHER TEST CONDITIONS
- Light intensity and quality: Continuous fluorescent light, 6500 - 10000 lx (corresponding to 85 - 125 µE⋅m-2/s) on the surface of the test medium. Difference of light intensity at any measured incubation place was less than 15 % from the mean value.
Reference substance (positive control):
yes
Remarks:
Zinc chloride

Results and discussion

Effect concentrationsopen allclose all
Duration:
7 d
Dose descriptor:
EC50
Effect conc.:
> 184.2 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: biomass growth
Remarks on result:
other: n.a.
Duration:
7 d
Dose descriptor:
LOEC
Effect conc.:
> 184.2 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: biomass growth
Duration:
7 d
Dose descriptor:
NOEC
Effect conc.:
184.2 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: biomass growth
Duration:
7 d
Dose descriptor:
EC50
Effect conc.:
> 184.2 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: n.a.
Duration:
7 d
Dose descriptor:
LOEC
Effect conc.:
> 184.2 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
7 d
Dose descriptor:
NOEC
Effect conc.:
184.2 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
7 d
Dose descriptor:
EC50
Effect conc.:
> 184.2 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: biomass dry weight
Remarks on result:
other: n.a.
Duration:
7 d
Dose descriptor:
LOEC
Effect conc.:
> 184.2 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: biomass dry weight
Duration:
7 d
Dose descriptor:
NOEC
Effect conc.:
184.2 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: biomass dry weight
Details on results:
No further details are available.
Results with reference substance (positive control):
No details reported.
Reported statistics and error estimates:
The NOEC and LOEC were determined by calculation of statistical analysis statistical significance of log biomass integrals, growth rates and
log biomass dry weight. One Way Analysis of Variance (ANOVA) and DUNNETT’S test (biomass integrals and growth rates) were carried out for the determination of statistically significant differences compared to control replicates. When running a One Way Analysis of Variance a Normality Test and an Equal Variance Test were done first. P-values for both Normality and Equal Variance Tests were 0.05. The α-value (acceptable probability of incorrectly concluding that there is a difference) was α=0.05. For log biomass dry weight equal variance test failed and DUNNETT’S test with TOXSTAT was carried out for the determination of statistically significant differences compared to control replicates.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
Guideline validity criteria were met.
Conclusions:
The study is regarded as a valid guideline study conducted under GLP compliance. Effects on the growth of the monocotyledonae Lemna minor were tested. No effects were found at the nominal limit concentration of 184.2 mg/L (log biomass integrals, specific growth rate and log biomass dry weight; 0 – 7 d).
The EC50-values for inhibition of log biomass growth (EbC50), specific growth rate (ErC50) and log biomass dry weight (EdwC50) were > 184.2 mg/L, the NOEC was 184.2 mg/L and the LOEC was > 184.2 mg/L.
Executive summary:

The effects of the test item on growth of the monocotyledon species Lemna minor were determined according to the principles of OECD Guideline 221. The test item contained 54.3 % Fe(Na)EDDHMA, a structural analogue of FeNa-EDDHA, from which 5.2 % is Fe chelated by o,o-EDDHMA. The aim of the study was to determine the effects of the test item on the growth of Lemna minor over 7 days under static exposure conditions. Based on a preliminary test, a limit test with nominal 184.2 mg test item/L was carried out. Three replicates were investigated for the test concentrations and the control. Frond numbers were assessed on days 0, 2, 5 and 7. Inhibition of log biomass growth, specific growth rate and log biomass dry weight were determined. The concentrations of the a.i. Fe(Na)EDDHMA were analysed on days 0 (freshly prepared solution) and 7 (old solution) via HPLC. The recovery rates of the active ingredient FeNa-EDDHMA was 97 % in the fresh solution and 88 % in the old solution supporting the use of nominal concentrations. Environmental parameters, water temperature and pH-value were determined to be within the acceptable limits.

The EC50-values for inhibition of log biomass growth (EbC50), specific growth rate (ErC50) and log biomass dry weight (EdwC50) were greater than 184.2 mg/L, the NOEC was 184.2 mg/L and the LOEC was greater than 184.2 mg/L.