Benzenamine, 4-[(4-aminophenyl)(4-imino-2,5-cyclohexadien-1-ylidene)methyl]-, N-Me derivatives, molybdatephosphates

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Study period:

April 2000

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
This read-across is based on the hypothesis that source and target substances have the same type of toxicological effects based on common underlying mechanisms (ECHA, 2015b). All substances have the same organic structural group (colorant) with different compositions of the inorganic group (metallic salt). Read-across is in this case based on the hypothesis that source and target substances have similar toxicological properties because they degrade to the similar chemical substances (ECHA, 2015c). This prediction is supported by physicochemical and toxicological data on the substances.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Name Source Substance Target Substance
Chemical name Benzenamine, N,N-dimethyl-, oxidized, molybdatetungstatephosphates Benzenamine, 4-[(4-aminophenyl)(4-imino-2,5-cyclohexadien-1-ylidene)methyl]-, N-Me derivatives, molybdatephosphates
IUPAC name reaction product of:
(a) [4-[bis[4-(dimethylamino)phenyl]methylene]cyclohexa-2,5-dien-1-ylidene]-dimethyl-ammonium
(b) [4-[[4-(dimethylamino)phenyl]-[4-(methylamino)phenyl]methylene]cyclohexa-2,5-dien-1-ylidene]-dimethyl-ammonium
(c) [4-[bis[4-(methylamino)phenyl]methylene]cyclohexa-2,5-dien-1-ylidene]-dimethyl-ammonium
(d) phosphomolybdic acid
CAS No 101357-19-1 67989-22-4
EC No 309-916-8 268-006-8
Molecular weight range ≥ 2200 ≤ 3300 3800 - 7300
Molecular formula Reaction mass of C25 H30 N3. P Moy Wz O40 (y + z = 12), C24 H28 N3. P Moy Reaction mass of (C25H30N3)x.O3.P2O5.(MoO3)y; (C24H28N3)x.O3.P2O5.(MoO3)y and (C23H26N3)x.O3.P2O5.(MoO3)y
Wz O40 (y + z = 12) and C23 H26 N3. P Moy Wz O40 (y + z = 12) x = 6-10
y = 10-24
Structural formula

3. ANALOGUE APPROACH JUSTIFICATION
The target substance CAS 67989-22-4 is an organometallic multi-constituent substance. The source substance CAS 101357-19-1 has the same organic constituent (see table above) as the target substance consisting of triphenylmethan and three dimethylamine moieties. The inorganic Part B is very similar between source and target substances, consisting of the elements O, Mo, P and W in different compositions. These differences are expected to behave very similar. The target and source substances are thus considered suitable for the analogue approach based on structural similarity.

Qualifier:

according to guideline

Guideline:

ISO 8692 (Water Quality - Fresh Water Algal Growth Inhibition Test with Scenedesmus subspicatus and Selenastrum capricornutum)

Deviations:

not specified

GLP compliance:

not specified

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: 0345N/982432
- Stability in water: at least 96hours

Analytical monitoring:

no

Details on sampling:

- Concentrations: 0.1, 1, 10, 100mg/L in ISO-medium

Vehicle:

not specified

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: growing cultures of algae were exposed to concentrations of 0.1, 1, 10, 100mg/L in ISO-medium for 72 hours

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

TEST ORGANISM
- Common name: Pseudokirchnerialla subcapitata
- Strain: not specified
- Source (laboratory, culture collection): not specified

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Remarks on exposure duration:

not specified

Post exposure observation period:

not specified

Hardness:

not specified

Test temperature:

controlled but not specified in report

pH:

controlled but not specified in report

Dissolved oxygen:

not specified

Salinity:

not specified

Conductivity:

not specified

Nominal and measured concentrations:

nominal

Details on test conditions:

TEST SYSTEM
- Initial cells density: 1 x 10e4 cells/mL
- Control end cells density: 147.2 x 10e4 cells/mL
- No. of vessels per concentration (replicates): triplicate
- No. of vessels per control (replicates):triplicate
GROWTH MEDIUM
- Standard medium used: yes
OTHER TEST CONDITIONS
- Sterile test conditions: yes/no
- Adjustment of pH:
- Photoperiod:
- Light intensity and quality:
- Salinity (for marine algae):
EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: spectrophotometer
TEST CONCENTRATIONS
- Test concentrations: 0, 0.1, 1, 10, 100 mg/L

Reference substance (positive control):

no

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

< 0.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

>= 0.1 - <= 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

- Exponential growth in the control (for algal test): yes
- Algal cell growth was completeyl inhibited and the growth amd the growth rate completely reduced at 0345N concentrations prepared at 1mg/L and higher

Results with reference substance (positive control):

none

Reported statistics and error estimates:

not specified

Validity criteria fulfilled:

yes

Conclusions:

The results show that a discharge of 0345N causes acute toxicity to algal growth

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

April 2000

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

ISO 8692 (Water Quality - Fresh Water Algal Growth Inhibition Test with Scenedesmus subspicatus and Selenastrum capricornutum)

Deviations:

not specified

GLP compliance:

not specified

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: 0345N/982432
- Stability in water: at least 96hours

Analytical monitoring:

no

Details on sampling:

- Concentrations: 0.1, 1, 10, 100mg/L in ISO-medium

Vehicle:

not specified

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: growing cultures of algae were exposed to concentrations of 0.1, 1, 10, 100mg/L in ISO-medium for 72 hours

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

TEST ORGANISM
- Common name: Pseudokirchnerialla subcapitata
- Strain: not specified
- Source (laboratory, culture collection): not specified

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Remarks on exposure duration:

not specified

Post exposure observation period:

not specified

Hardness:

not specified

Test temperature:

controlled but not specified in report

pH:

controlled but not specified in report

Dissolved oxygen:

not specified

Salinity:

not specified

Conductivity:

not specified

Nominal and measured concentrations:

nominal

Details on test conditions:

TEST SYSTEM
- Initial cells density: 1 x 10e4 cells/mL
- Control end cells density: 147.2 x 10e4 cells/mL
- No. of vessels per concentration (replicates): triplicate
- No. of vessels per control (replicates):triplicate
GROWTH MEDIUM
- Standard medium used: yes
OTHER TEST CONDITIONS
- Sterile test conditions: yes/no
- Adjustment of pH:
- Photoperiod:
- Light intensity and quality:
- Salinity (for marine algae):
EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: spectrophotometer
TEST CONCENTRATIONS
- Test concentrations: 0, 0.1, 1, 10, 100 mg/L

Reference substance (positive control):

no

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

< 0.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

>= 0.1 - <= 1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

- Exponential growth in the control (for algal test): yes
- Algal cell growth was completeyl inhibited and the growth amd the growth rate completely reduced at 0345N concentrations prepared at 1mg/L and higher

Results with reference substance (positive control):

none

Reported statistics and error estimates:

not specified

Validity criteria fulfilled:

yes

Conclusions:

The results show that a discharge of 0345N causes acute toxicity to algal growth

Reference 3

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
This read-across is based on the hypothesis that source and target substances have the same type of toxicological effects based on common underlying mechanisms (ECHA, 2015b). All substances have the same organic structural group (colorant) with different compositions of the inorganic group (metallic salt). Read-across is in this case based on the hypothesis that source and target substances have similar toxicological properties because they degrade to the similar chemical substances (ECHA, 2015c). This prediction is supported by physicochemical and toxicological data on the substances.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Name Source Substance Target Substance
Chemical name Benzenamine, N,N-dimethyl-, oxidized, molybdatetungstatephosphates Benzenamine, 4-[(4-aminophenyl)(4-imino-2,5-cyclohexadien-1-ylidene)methyl]-, N-Me derivatives, molybdatephosphates
IUPAC name reaction product of:
(a) [4-[bis[4-(dimethylamino)phenyl]methylene]cyclohexa-2,5-dien-1-ylidene]-dimethyl-ammonium
(b) [4-[[4-(dimethylamino)phenyl]-[4-(methylamino)phenyl]methylene]cyclohexa-2,5-dien-1-ylidene]-dimethyl-ammonium
(c) [4-[bis[4-(methylamino)phenyl]methylene]cyclohexa-2,5-dien-1-ylidene]-dimethyl-ammonium
(d) phosphomolybdic acid
CAS No 101357-19-1 67989-22-4
EC No 309-916-8 268-006-8
Molecular weight range ≥ 2200 ≤ 3300 3800 - 7300
Molecular formula Reaction mass of C25 H30 N3. P Moy Wz O40 (y + z = 12), C24 H28 N3. P Moy Reaction mass of (C25H30N3)x.O3.P2O5.(MoO3)y; (C24H28N3)x.O3.P2O5.(MoO3)y and (C23H26N3)x.O3.P2O5.(MoO3)y
Wz O40 (y + z = 12) and C23 H26 N3. P Moy Wz O40 (y + z = 12) x = 6-10
y = 10-24
Structural formula

3. ANALOGUE APPROACH JUSTIFICATION
The target substance CAS 67989-22-4 is an organometallic multi-constituent substance. The source substance CAS 101357-19-1 has the same organic constituent (see table above) as the target substance consisting of triphenylmethan and three dimethylamine moieties. The inorganic Part B is very similar between source and target substances, consisting of the elements O, Mo, P and W in different compositions. These differences are expected to behave very similar. The target and source substances are thus considered suitable for the analogue approach based on structural similarity.

Reason / purpose for cross-reference:

read-across source

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Batch no 982432 supplied by Client
- Expiration date of the lot/batch: 01 July 2022
- Purity test date: Not supplied

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Room temperature in the dark
- Stability under test conditions: stable
- Solubility and stability of the test substance in the solvent/vehicle: poorly soluble
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium: Not specified

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: None
- Preliminary purification step (if any): None
- Final dilution of a dissolved solid, stock liquid or gel:
- Final preparation of a solid: WAF'sprepared in Elendt M7 medium at nominal concentrations

Analytical monitoring:

yes

Details on sampling:

- Concentrations:
- Sampling method: Not speicied
- Sample storage conditions before 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)
- Nominal amounts of test item (10, 32, 20, 64 and 200 mg) were each separately added to the surface of 10, 10, 2.0, 2.0 and 2.0 liters of culture medium to give the 1.0, 3.2, 10, 32 and 100 mg/L loading rates respectively. After the addition of the test item, the culture medium was stirred by magnetic stirrer using a stirring rate such that a vortex was formed to give a dimple at the water surface. The stirring was stopped after 95 hours and the mixtures allowed to stand for 1-Hour. Visual observations made on the WAFs indicated that a significant amount of dispersed test item was present in the water column and hence it was considered justifiable to remove the WAF by filtering through a glass wool plug (2 to 4 cm in length). A wide bore glass tube, covered at one end with Nescofilm was submerged into the vessel, sealed end down, to a depth of approximately 5 cm from the bottom of the vessel. A length of Tygon tubing was inserted into the glass tube and pushed through the Nescofilm seal. A glass wool plug was inserted into the opposite end of the tubing and the WAF removed by mid-depth siphoning (the first 75 to 100 mL discarded). Microscopic observations of the WAFs were performed after filtering and showed no micro-dispersions of test item to be present.

Test organisms (species):

other: Lemna gibba

Details on test organisms:

TEST ORGANISM
- Common name: Lemna gibba
- Strain: N/a
- Source (laboratory, culture collection): Culture obtained from Bayer CropScience AG, 40789 Monheim, Germany in 2007
- Age of inoculum (at test initiation):
- Method of cultivation:Maintained in the lab under standard test conditions

ACCLIMATION
- Acclimation period:7 days
- Culturing media and conditions (same as test or not): yes
- Any deformed or abnormal cells observed: no

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

7 d

Test temperature:

24 ± 1 ºC throughout the test.

pH:

5.6 – 5.7 on Day 0 to pH 6.4 – 6.5 on Day 7

Details on test conditions:

TEST SYSTEM
- Test vessel: 500 mL glass conical flasks
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: fill volume 250 mL
- Aeration: No
- Type of flow-through (e.g. peristaltic or proportional diluter): N/a
- Renewal rate of test solution (frequency/flow rate): N/a
- Initial cells density:
- Control end cells density:
- No. of organisms per vessel: 3 colonies
- No. of vessels per concentration (replicates): three
- No. of vessels per control (replicates): three
- No. of vessels per vehicle control (replicates): n/a

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

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water:
- 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:
- 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:

EL50

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.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

7 d

Dose descriptor:

LOELR

Effect conc.:

32 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.:

59 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

7 d

Dose descriptor:

NOELR

Effect conc.:

3.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

7 d

Dose descriptor:

LOELR

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Validity criteria fulfilled:

yes

Conclusions:

A study was performed to assess the effect of the test item on the growth of the freshwater plant Lemna gibba. Due to the low aqueous solubility and complex nature of the test item for the purposes of the test the test item was prepared as a Water Accommodated Fraction (WAF). Lemna gibba was exposed to WAFs of the test item over a range of nominal concentrations of 1.0, 3.2, 10, 32 and 100 mg/L loading rate WAF (three replicate flasks per concentration) for a period of 7 days, under constant illumination at a temperature of 24 ± 1 °C. The number of fronds in each control and treatment group was recorded on Days 0, 2, 4 and 7 along with observations on plant development.
Chemical analysis of the test preparations on Day 0 (fresh media) showed measured test concentrations to range from less than the limit of quantification (LOQ) of the analytical method, determined to be 0.048mg/L, to 0.39 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.
The NOEL in terms of inhibition of yield calculated from dry weight was considered to be 3.2 mg/L loading rate WAF. Correspondingly the LOEL was considered to be 10 mg/L loading rate WAF.

Reference 4

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

08 February 2018 to 28 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
- Source and lot/batch No.of test material: Batch no 982432 supplied by Client
- Expiration date of the lot/batch: 01 July 2022
- Purity test date: Not supplied

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Room temperature in the dark
- Stability under test conditions: stable
- Solubility and stability of the test substance in the solvent/vehicle: poorly soluble
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium: Not specified

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: None
- Preliminary purification step (if any): None
- Final dilution of a dissolved solid, stock liquid or gel:
- Final preparation of a solid: WAF'sprepared in Elendt M7 medium at nominal concentrations

Analytical monitoring:

yes

Details on sampling:

- Concentrations:
- Sampling method: Not speicied
- Sample storage conditions before 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)
- Nominal amounts of test item (10, 32, 20, 64 and 200 mg) were each separately added to the surface of 10, 10, 2.0, 2.0 and 2.0 liters of culture medium to give the 1.0, 3.2, 10, 32 and 100 mg/L loading rates respectively. After the addition of the test item, the culture medium was stirred by magnetic stirrer using a stirring rate such that a vortex was formed to give a dimple at the water surface. The stirring was stopped after 95 hours and the mixtures allowed to stand for 1-Hour. Visual observations made on the WAFs indicated that a significant amount of dispersed test item was present in the water column and hence it was considered justifiable to remove the WAF by filtering through a glass wool plug (2 to 4 cm in length). A wide bore glass tube, covered at one end with Nescofilm was submerged into the vessel, sealed end down, to a depth of approximately 5 cm from the bottom of the vessel. A length of Tygon tubing was inserted into the glass tube and pushed through the Nescofilm seal. A glass wool plug was inserted into the opposite end of the tubing and the WAF removed by mid-depth siphoning (the first 75 to 100 mL discarded). Microscopic observations of the WAFs were performed after filtering and showed no micro-dispersions of test item to be present.

Test organisms (species):

other: Lemna gibba

Details on test organisms:

TEST ORGANISM
- Common name: Lemna gibba
- Strain: N/a
- Source (laboratory, culture collection): Culture obtained from Bayer CropScience AG, 40789 Monheim, Germany in 2007
- Age of inoculum (at test initiation):
- Method of cultivation:Maintained in the lab under standard test conditions

ACCLIMATION
- Acclimation period:7 days
- Culturing media and conditions (same as test or not): yes
- Any deformed or abnormal cells observed: no

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

7 d

Test temperature:

24 ± 1 ºC throughout the test.

pH:

5.6 – 5.7 on Day 0 to pH 6.4 – 6.5 on Day 7

Details on test conditions:

TEST SYSTEM
- Test vessel: 500 mL glass conical flasks
- Type (delete if not applicable): closed
- Material, size, headspace, fill volume: fill volume 250 mL
- Aeration: No
- Type of flow-through (e.g. peristaltic or proportional diluter): N/a
- Renewal rate of test solution (frequency/flow rate): N/a
- Initial cells density:
- Control end cells density:
- No. of organisms per vessel: 3 colonies
- No. of vessels per concentration (replicates): three
- No. of vessels per control (replicates): three
- No. of vessels per vehicle control (replicates): n/a

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

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water:
- 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:
- 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:

EL50

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.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

7 d

Dose descriptor:

LOELR

Effect conc.:

32 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.:

59 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

7 d

Dose descriptor:

NOELR

Effect conc.:

3.2 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Key result

Duration:

7 d

Dose descriptor:

LOELR

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Validity criteria fulfilled:

yes

Conclusions:

A study was performed to assess the effect of the test item on the growth of the freshwater plant Lemna gibba. Due to the low aqueous solubility and complex nature of the test item for the purposes of the test the test item was prepared as a Water Accommodated Fraction (WAF). Lemna gibba was exposed to WAFs of the test item over a range of nominal concentrations of 1.0, 3.2, 10, 32 and 100 mg/L loading rate WAF (three replicate flasks per concentration) for a period of 7 days, under constant illumination at a temperature of 24 ± 1 °C. The number of fronds in each control and treatment group was recorded on Days 0, 2, 4 and 7 along with observations on plant development.
Chemical analysis of the test preparations on Day 0 (fresh media) showed measured test concentrations to range from less than the limit of quantification (LOQ) of the analytical method, determined to be 0.048mg/L, to 0.39 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.
The NOEL in terms of inhibition of yield calculated from dry weight was considered to be 3.2 mg/L loading rate WAF. Correspondingly the LOEL was considered to be 10 mg/L loading rate WAF.

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L

EC10 or NOEC for freshwater algae:

10 mg/L