Ethanaminium, N-[4-[[4-(diethylamino)phenyl][4-(ethylamino)-1-naphthalenyl]methylene]-2,5-cyclohexadien-1-ylidene]-N-ethyl-, molybdatetungstatephosphate

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

06 February 2018 - 14 March 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: OECD Guideline No. 221 “Lemna sp. Growth Inhibition Test (March 2006)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
-Identification: Lumière Blue Cufe 6255F
-CAS Number: 82338-76-9
-EC Number: 279-935-3
-Physical state/Appearance: Blue powder
-Batch: 278PE160900
-Purity: UVCB (treat as 100%)
-Expiry Date: 01 July 2022
-Storage Conditions: Room temperature in the dark



-

Analytical monitoring:

yes

Details on sampling:

-Samples were taken from the control and each loading rate WAF test group from the bulk test preparation on Day 0 and from the pooled replicates on Day 7 for quantitative analysis. All samples were stored frozen prior to analysis. Duplicate samples were taken at each occasion and stored frozen for further analysis if necessary.

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
-Due to the low aqueous solubility and complex nature of the test item, for the purposes of the study the test medium was prepared as a WAF of the test item.

Test organisms (species):

other: Lemna Gibba

Details on test organisms:

TEST ORGANISM
- Common name: Lemna gibba
- Strain:
- Source (laboratory, culture collection): A culture of Lemna gibba was supplied by Bayer CropScience AG, 40789 Monheim, Germany in 2007
- Age of inoculum (at test initiation):
- Method of cultivation: Cultures were maintained in the laboratory by the periodic replenishment of culture medium (Section 3.3).

ACCLIMATION
- Acclimation period:The culture was maintained in the laboratory at a temperature of 24 ± 1 ºC under continuous illumination (intensity approximately 7000 lux) for at least 7 days prior to the start of the test.
- Culturing media and conditions (same as test or not):Yes
- Any deformed or abnormal cells observed:N/a

Test type:

semi-static

Water media type:

other: culture medium

Limit test:

no

Total exposure duration:

7 d

Test temperature:

Temperature was maintained at 24 ± 1 ºC throughout the test

pH:

The pH value of the control cultures (see Table 6) was observed to increase from pH 5.6 – 6.2 on Day 0 to pH 6.5 – 7.1 on Day 7.

Nominal and measured concentrations:

Loading rates of 1.0, 3.2, 10, 32 and 100 mg/L were selected for the definitive test.
Chemical analysis of the test preparations on Day 0 (fresh media) showed measured test concentrations to range from less than the LOQ of the analytical method, determined to be 0.026 mg/L, to 0.037 mg/L. Analysis of the test preparations on Day 7 showed measured test concentrations of less than the LOQ were obtained from all test preparations.

Details on test conditions:

TEST SYSTEM
- As in the range-finding test 500 mL glass conical flasks were used. Three flasks each containing 250 mL of solution were prepared for the control and each treatment group.
The control group was maintained under identical conditions but not exposed to the test item. Each control and test flask was inoculated with 3 colonies of Lemna gibba (total 12 fronds). The flasks were then incubated at 24 ± 1 ºC under constant illumination (intensity approximately 7000 lux) on a black, non-reflective surface for 7 days.

GROWTH MEDIUM
- Standard medium used: yes/
- Detailed composition if non-standard medium was used:

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reverse osmosis purified water (Elga Optima 15+ or Elga Purlab Option R-15 BP)
- Total organic carbon:
- Particulate matter:
- Metals:
- Pesticides:
- Chlorine:
- Alkalinity:
- Ca/mg ratio:
- Conductivity:
- Culture medium different from test medium:
- Intervals of water quality measurement:

OTHER TEST CONDITIONS
- Sterile test conditions: yes/no
- Adjustment of pH: to 5.5 ± 0.2 with either 1M HCl or NaOH
- Photoperiod:
- Light intensity and quality:
- Salinity (for marine algae):

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: [counting chamber; electronic particle counter; fluorimeter; spectrophotometer; colorimeter]
- Chlorophyll measurement:
- Other:

TEST CONCENTRATIONS
- Spacing factor for test concentrations:
- Justification for using less concentrations than requested by guideline:
- Range finding study
- Test concentrations:
- Results used to determine the conditions for the definitive study:

Key result

Duration:

7 d

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

7 d

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks:

Dry weight

Key result

Duration:

7 d

Dose descriptor:

LOELR

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

7 d

Dose descriptor:

NOELR

Effect conc.:

32 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Results with reference substance (positive control):

- Results with reference substance valid? Yes
- NOEC 4.0 mg/L
- LOEC 8.0 mg/L
- Other:A positive control used 3,5-dichlorophenol as the reference item at concentrations of 1.0, 2.0, 4.0, 8.0 and 16 mg/L.
Exposure conditions and data evaluation for the positive control were similar to those in the definitive test.

Validity criteria fulfilled:

yes

Conclusions:

The effect of the test item on the growth of Lemna gibba has been investigated over a 7-Day period a
nd gave the following results:
- EL50:
>100 mg/L Frond number for growth rate
>100 mg/L Dry weight for growth rate
>100 mg/L Frond number for yield
>100 mg/L Dry weight for yield
NOEL:
32 mg/L Frond number for growth rate
32 mg/L Dry weight for growth rate
1.0 mg/L Frond number for yield
3.2 mg/L Dry weight for yield
LOEL:
100 mg/L Frond number for growth rate
100 mg/L Dry weight for growth rate
3.2 mg/L Frond number for yield
10 mg/L Dry weight for yield

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L

EC10 or NOEC for freshwater algae:

32 mg/L