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Ecotoxicological information

Toxicity to aquatic plants other than algae

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Reference
Endpoint:
toxicity to aquatic plants other than algae
Type of information:
other: read across from analogue substance
Adequacy of study:
key study
Study period:
2014
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
performe on analogue substance
Qualifier:
according to guideline
Guideline:
OECD Guideline 221 (Lemna sp. Growth Inhibition Test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Analytical monitoring:
no
Vehicle:
yes
Test organisms (species):
Lemna minor
Details on test organisms:
Exponential growing plant monocolture of Lemna Minor (Umweltbundesamt, D-06813 Dessau-Rosslau, Germany
Test type:
static
Water media type:
freshwater
Total exposure duration:
7 d
Test temperature:
25 ± 1 °C
pH:
5,5 ± 0,2Blank control: 5.5
Nominal and measured concentrations:
The test were performed at concentrations of 20, 200 and 2000 mg/l of the active ingredient. Assuming a purity of 81.8 %, the nominal concentrations of the solutions are 24.5, 245 and 2450 mg/l, respectively.
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: yesTest medium STEINBERG with the following composition: Macroelements mg/lKNO3 350KH2PO4 90K2HPO4*3H2O 16.5MgSO4*7H2O 100Ca(NO3)2*4H2O 295Microelements μg/lH3BO3 120.0ZnSO4*7H2O 180.0Na2MoO4*2HO 44.0MnCl2*4H2O 180.0FeCl3*6H2O 760.0C10H14N2Na2O8*2H2O 1500.0ILLUMINATION: Continuos (3500 - 7500 lux) from Osram Fluora L18W77 (Osarm AG, Winterthur, Switzerland)
Reference substance (positive control):
no
Duration:
7 d
Dose descriptor:
EC50
Effect conc.:
> 2 450 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Reported statistics and error estimates:
The doubling time of frond number in the control must be less than 2.5 days (60 h), corresponding to approximately a 7-fold increase in 7 days and an average specific growth rate of 0.275 d-1.

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.

Effects on frond numbers

With respect to growth rate inhibition for the endpoint frond numbers, the following effects as compared to the untreated controls were observed: 26% at 2450 mg/l and 9% at 245 mg/l. No significant effects were observed at 24.5 mg/l.

With respect to yield inhibition for the endpoint frond numbers, the following effects as compared to the untreated controls were observed: 48% at 2450 mg/l and 20% at 245 mg/l. No significant effects were observed at 24.5 mg/l.

Based on these data the median effect concentrations of Acid Blue 113 to Lemna minor with respect to growth rate (ErC50) for the endpoint frond numbers was estimated to be >2450 mg/l nominal concentration, while the median effect concentration with respect to yield (EyC50) was estimated to be around 2450 mg/l nominal concentration.

The no-observed-effect concentrations of Acid Blue 113 to Lemna minor with respect to growth rate (NOErC) and yield (NOEyC) for the endpoint frond numbers were 24.5 mg/l nominal concentration, as determined by Dunnett's test.

Effects on dry weight

With respect to growth rate inhibition for the endpoint dry weight, the following effects as compared to the untreated controls were observed: 29% at 2450 mg/l, 8% at 245 mg/l and 6% at 24.5 mg/l.

With respect to yield inhibition for the endpoint dry weight, the following effects as compared to the untreated controls were observed: 52% at 2450 mg/l, 18% at 245 mg/l and 14% at 24.5 mg/l.

Based on these data the median effect concentrations of Acid Blue 113 to Lemna minor with respect to growth rate (ErC50) for the endpoint dry weight was estimated to be >2450 mg/l nominal concentration, while the median effect concentration with respect to yield (EyC50) was estimated to be around 2450 mg/l nominal concentration.

Validity criteria fulfilled:
yes
Conclusions:
The analogue substance toxicity to the aquatic plant Lemna Minor were determined following OECD 221. The results showthat the tested item is not toxic to Lemna minor with ErC50 > 2540 mg/l.
Executive summary:

The analogue substance toxicity to the aquatic plant Lemna Minor were determined following OECD 221. The results showthat the tested item is not toxic to Lemna minor with ErC50 > 2540 mg/l.

Description of key information

ErC50 > 2450 mg/l

Key value for chemical safety assessment

EC50 for freshwater plants:
2 450 mg/L

Additional information

The analogue substance toxicity to the aquatic plant Lemna Minor were determined following OECD 221. The results showthat the tested item is not toxic to Lemna minor with ErC50 > 2540 mg/l.