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EC number: 265-314-4 | CAS number: 65036-46-6
Toxicity to aquatic plants other than algae
Administrative data
Link to relevant study record(s)
- Endpoint:
- toxicity to aquatic plants other than algae
- Type of information:
- read-across from supporting substance (structural analogue or surrogate)
- Adequacy of study:
- key study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- guideline study
- Justification for type of information:
- Read-across from the alternative salt form of the registered substance is justified as per the document attached in section 13.
- Reason / purpose for cross-reference:
- read-across source
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 221 (Lemna sp. Growth Inhibition Test)
- Deviations:
- no
- Guideline:
- other: Commission Regulation (EU) 2016/266
- Deviations:
- no
- Test organisms (species):
- Lemna gibba
- Test type:
- static
- Water media type:
- freshwater
- Limit test:
- no
- Total exposure duration:
- 7 d
- Nominal and measured concentrations:
- Nominal: 0 (control), 10, 22, 46, 100, 220 mg/L
Initial measured: 0 (control), 2.517, 6.892, 16.225, 36.043, 91.817 mg/L - Key result
- Duration:
- 7 d
- Dose descriptor:
- EC10
- Effect conc.:
- > 91.817 mg/L
- Nominal / measured:
- meas. (initial)
- Conc. based on:
- test mat.
- Basis for effect:
- growth rate
- Duration:
- 7 d
- Dose descriptor:
- EC20
- Effect conc.:
- > 91.817 mg/L
- Nominal / measured:
- meas. (initial)
- Conc. based on:
- test mat.
- Basis for effect:
- growth rate
- Key result
- Duration:
- 7 d
- Dose descriptor:
- EC50
- Effect conc.:
- > 91.817 mg/L
- Nominal / measured:
- meas. (initial)
- Conc. based on:
- test mat.
- Basis for effect:
- growth rate
- Duration:
- 7 d
- Dose descriptor:
- NOEC
- Effect conc.:
- >= 91.817 mg/L
- Nominal / measured:
- meas. (initial)
- Conc. based on:
- test mat.
- Basis for effect:
- growth rate
- Duration:
- 7 d
- Dose descriptor:
- LOEC
- Effect conc.:
- > 91.817 mg/L
- Nominal / measured:
- meas. (initial)
- Conc. based on:
- test mat.
- Basis for effect:
- growth rate
- Duration:
- 7 d
- Dose descriptor:
- EC10
- Effect conc.:
- > 91.817 mg/L
- Nominal / measured:
- meas. (initial)
- Conc. based on:
- test mat.
- Basis for effect:
- biomass
- Duration:
- 7 d
- Dose descriptor:
- EC20
- Effect conc.:
- > 91.817 mg/L
- Nominal / measured:
- meas. (initial)
- Conc. based on:
- test mat.
- Basis for effect:
- biomass
- Duration:
- 7 d
- Dose descriptor:
- EC50
- Effect conc.:
- > 91.817 mg/L
- Nominal / measured:
- meas. (initial)
- Conc. based on:
- test mat.
- Basis for effect:
- biomass
- Duration:
- 7 d
- Dose descriptor:
- NOEC
- Effect conc.:
- >= 91.817 mg/L
- Nominal / measured:
- meas. (initial)
- Conc. based on:
- test mat.
- Basis for effect:
- biomass
- Duration:
- 7 d
- Dose descriptor:
- LOEC
- Effect conc.:
- > 91.817 mg/L
- Nominal / measured:
- meas. (initial)
- Conc. based on:
- test mat.
- Basis for effect:
- biomass
- Details on results:
- Signs of phytotoxicity were observed in the treatment groups 10 mg/L and higher on day 5 and in treatment groups 22 mg/L and higher on day 7.
The toxicity results of the main study are consistent with the results from preliminary tests. - Results with reference substance (positive control):
- The EC50(7d) of the reference substance 3,5 Dichlorphenol was 7.10 mg/L.
- Conclusions:
- The growth inhibition test on Lemna Gibba on the source substance showed signs of phytotoxicity in the treatment groups >10 mg/L on day 5 and in treatment groups >22 mg/L on day 7. The EC10 for the registered substance is 91.817 mg/L based on initial measured concentration.
Reference
Table 1: Effect concentrations based on nominal concentration (mg/L) after
7 days for the response variable average specific growth rate
| Effect concentration [mg/L] | Average specific growth rate based on frond number [mg/L] |
Average specific growth rate based on dry weight [mg/L] |
| ErC10 (95% CL) |
>220 - |
>220 - |
| ErC20 (95% CL) |
>220 - |
>220 - |
| ErC50 (95% CL) |
>220 - |
>220 - |
| NOErC | ≥220 | ≥220 |
| LOErC | >220 | >220 |
– insufficient data for calculation
Table 2: Effect concentrations based on initial measured concentration (mg/L) after
7 days for the response variable average specific growth rate
| Effect concentration [mg/L] | Average specific growth rate based on frond number [mg/L] |
Average specific growth rate based on dry weight [mg/L] |
| ErC10 (95% CL) |
>91.817 - |
>91.817 - |
| ErC20 (95% CL) |
>91.817 - |
>91.817 - |
| ErC50 (95% CL) |
>91.817 - |
>91.817 - |
| NOErC | ≥91.817 | ≥91.817 |
| LOErC | >91.817 | >91.817 |
– insufficient data for calculation
Table 3: Effect concentrations based on nominal concentration (mg/L) after 7 days for the response variable yield
| Effect concentration [mg/L] | Yield based on frond number [mg/L] |
Yield based on dry weight [mg/L] |
| ErC10 (95% CL) |
>220 - |
>220 - |
| ErC20 (95% CL) |
>220 - |
>220 - |
| ErC50 (95% CL) |
>220 - |
>220 - |
| NOErC | ≥220 | ≥220 |
| LOErC | >220 | >220 |
Table 4: Effect concentrations based on initial measured concentration
(mg/L) after 7 days for the response variable yield
| Effect concentration [mg/L] | Yield based on frond number [mg/L] |
Yield based on dry weight [mg/L] |
| EyC10 (95% CL) |
>91.817 - |
>91.817 - |
| EyC20 (95% CL) |
>91.817 - |
>91.817 - |
| EyC50 (95% CL) |
>91.817 - |
>91.817 - |
| NOEyC | ≥91.817 | ≥91.817 |
| LOEyC | >91.817 | >91.817 |
– insufficient data for calculation
Table 5: Signs of phytotoxicity were observed in the treatment groups 10 mg/L
and higher on day 5 and in treatment groups 22 mg/L and higher on day 7
| Nominal concentration [mg/L] | Vessel No. | Morphological changes, signs of phytotoxicity | ||
| Day 2 | Day 5 | Day 7 | ||
| o (control) | 1-6 | 0 | 0 | 0 |
| 10 | 7-9 | 0 | 8 | 0 |
| 22 | 10-12 | 0 | 8 | 9(++) |
| 46 | 13-15 | 0 | 8 | 6(+) |
| 100 | 16-18 | 0 | 8 | 3, 6(++) |
| 220 | 19-21 | 0 | 8 | 6 |
Explanation of abbreviations:
0: No findings
1: frond or root yellowing (chlorosis)
2: fronds humped or swollen (gibbosity)
3: small fronds
4: shortened roots
5: no roots
6: plants fragmented (fronds and/or roots)
7: dead white plant tissue (necrosis)
8: plants colored by test substance (roots are yellowish)
9: plants increased (fronds and/or roots)
(+): slight effects
(++): medium effects
(+++): strong effects
Description of key information
In an OECD 221 Lemna growth inhibition study on the read-across substance, 7 day ErC50 values for the growth rate based on initial concentrations were >91.817 mg/L. The EyC50 for the yield was determined to be >91.817 mg/L.
Key value for chemical safety assessment
- EC50 for freshwater plants:
- 91.817 mg/L
- EC10 or NOEC for freshwater plants:
- 91.817 mg/L
Additional information
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