1,1'-[[3-(dimethylamino)propyl]imino]bispropan-2-ol

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:

(Q)SAR

Adequacy of study:

supporting study

Study period:

May 2022

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

1. SOFTWARE
EPI Suite v4.1
2. MODEL (incl. version number)
ECOSAR v1.11
The following sub-models are covered for this QSAR analysis, all predicting 96 hour EC50 values for freshwater algae:
-Aliphatic Amines
-Neutral Organic SAR
-Aldehydes (Mono)
-Aliphatic Amines-acid
-Neutral Organics-acid
-Neutral Organics
-Aldehydes (Mono)-acid
3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
ECOSAR only requires a chemical structure as SMILES as input. All SMILES codes are available in the attached QPRF.
4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
See attached QMRF.
5. APPLICABILITY DOMAIN
ECOSAR predictions were also made for acute aquatic toxicity to fish and invertebrates. Only for the substance group Neutral organics were algae the most sensitive species. The substances for which algae were the most sensitive species, were flagged by ECOSAR as not being related to an existing ECOSAR class definition. Hence, ECOSAR provided the results for baseline toxicity (i.e. for neutral organics). The results should therefore be used with care. A detailed assessment of the applicability domain of this model can be found in the attached QPRF.
6. ADEQUACY OF THE RESULT
The main purpose of this QSAR analysis, was to assess the aquatic toxicity of the predicted biodegradation products of JeffCat DPA (CAS# 63469-23-8) for use in the PBT/vPvB assessment. All predicted effects concentrations were well above the screening criterion for any of the substances to fulfill the T criterion. Although the modelling results should be interpreted with care, they allow for a very large margin of error and indicate that according to the estimated aquatic toxicity, none of the biodegradation products are expected to fulfill the T criterion. The predictions can be considered appropriate for this use.

Reason / purpose for cross-reference:

other: Record containing the log Kow values (predicted with KOWWIN v1.68) needed for the predicti on of toxicity to algae.

Reason / purpose for cross-reference:

other: Record describing the biodegradation products of DPA (CAS# 63469-23-8) predicted by EAWAG-BBD PPS, for which toxicity to algae is estimated is estimated.

Principles of method if other than guideline:

Estimation of the acute aquatic toxicity to freshwater algae using ECOSAR v4.11.

GLP compliance:

no

Specific details on test material used for the study:

Predictions were made for the 41 biodegradation products predicted by the EAWAG-BBD PPS tool.

Details on test organisms:

Green algae (freshwater)

The table below lists the ECOSAR v4.11 predictions for the compounds for which algae were the most sensitive species. All results are available in the QPRF.

Name	ECOSAR Neutral Organics 96 hr EC50 for green algae (mg/L)
Lactic acid	21338.494
2-Oxopropanoic acid	5378.225

Conclusions:

Overall, a very low aquatic toxicity to algae was estimated for the modelled compounds. The lowest LC50 obtained for green algae within the substances identified as neutral organics, was 21339 mg/L.

Reference 2

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2002-01-28 to 2002-04-05

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

no analytical verification

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes

Specific details on test material used for the study:

- Name of test material (as cited in study report): TOYOCAT-RX4
- Substance type: clear yellowish liquid
- Physical state: liquid
- Analytical purity: 93.1 % (GC)
- Impurities (identity and concentrations): not reported
- Lot/batch No.: 080401
- Expiration date of the lot/batch: 25 October 2002
- Storage condition of test material: at room temperature in the dark

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: due to the substance's good solubility no special treatment other than magnetic stirring for a short period was necessary. Test solutions were prepared from a stock solution of 100 or 1000 mg/L. The lower test concentrations were prepared by subsequent dilutions. The final test solutions were all clear and colourless. After preparation, volumes of 50 mL were added to each replicate of the respective test concentration. Subsequently, adequate volumes of an algal suspension were added to each replicate providing a cell density of 1E+04 cells/mL.
- Evidence of undissolved material (e.g. precipitate, surface film, etc): no, the substance completely dissolved in the test medium at the concentrations tested.

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Strain: NIVA CHL 1
- Source (laboratory, culture collection): not specified
- Age of inoculum (at test initiation): the inoculum was taken from a 4-d preculture and was in the exponential growth phase
- Method of cultivation: Algae stock cultures were started by inoculating growth medium with algal cells from a pure culture on agar. The suspensions were continuously aerated and exposed to light (4000-9000 lux) in a climate room at a temperature of 23 ± 2 °C.

ACCLIMATION
- Acclimation period: 4 days before the start of the test, cells from the algal stock culture were inoculated in culture medium at a cell density of 2E+04 cells/mL. The pre-culture was maintained under the same conditions as used in the test.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Hardness:

24 mg CaCO3/L

Test temperature:

Temperature of test medium at start: 24.1 °C.
Temperature in incubator during exposure was maintained between 22-23 °C.

pH:

Overall pH range at start of testing: 8.3-9.4.
Overall pH range at end of testing: 8.2-9.3.
Increases/decreases always < 1.5 pH unit.

Dissolved oxygen:

not applicable

Salinity:

not applicable

Nominal and measured concentrations:

Nominal concentrations:
- Range finding test: Control + 1.0, 10, 100, 1000 mg/L
- Definitive test: Control + 2.2, 4.6, 10, 22, 46, 100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: all-glass
- Material, size, fill volume: glass, 100 mL, 50 mL
- Aeration: no
- Initial cells density: 1E+04 cells/mL
- Control end cells density: 994000 cells/mL (mean)
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes (M2 medium)

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: tap water purified by reverse osmosis and then passed over activated carbon and ion-exchange cartridges (Millipore Corp., Bedford, Mass., USA)
- Intervals of water quality measurement: pH was measured at beginning and end of test, temperature was monitored daily, no other parameters were monitored

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: no
- Photoperiod: continuous illumination
- Light intensity and quality: TLD-lamps of the type 'cool-white' of 30 Watt, with a light intensity within the range of 7215 to 9286 lux, not varying by more than 20 %.
- Continuous shaking

EFFECT PARAMETERS MEASURED (with observation intervals if applicable):
- Determination of cell concentrations:
* at the beginning of test cells were counted by microscope using a counting chamber
* thereafter (after 24, 48 and 72 h), cell densities were determined by photospectrometric measurement of samples at 720 nm using a Varian Cary 50 single beam spectrophotometer with immersion probe (pathlength = 20 mm) (Varian Nederland BV, Houten, The Netherlands). Algal medium was used as blank.

TEST CONCENTRATIONS
Definitive test:
- Spacing factor for test concentrations: 2.1
Range finding study:
- Test concentrations: 1.0, 10, 100 and 1000 mg/L
- Test conditions: comparable to those applied in the final test
- Results used to determine the conditions for the definitive study: the EC50 for cell growth inhibition and growth rate reduction was between 10 and 100 mg/L

Reference substance (positive control):

yes

Remarks:

K2Cr2O7

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

56 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 95 % CL= 30-104 mg/L

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

22 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

Growth rate:
72-h NOEC = 22 mg/L
72-h LOEC = 46 mg/L
72-h EC10 = 28 mg/L (95% CI = 15-53 mg/L)
72-h EC50 = 56 mg/L (95% CI = 30-104 mg/L)
Biomass:
72-h NOEC = 22 mg/L
72-h LOEC = 46 mg/L
72-h EC10 = 14 mg/L (95% CI = 6.9-27 mg/L)
72-h EC50 = 33 mg/L (95% CI = 17-65 mg/L)

Results with reference substance (positive control):

The 72-h EbC50 for cell growth inhibition was 0.83 mg/L with a 95 % CL of 0.59-1.2 mg/L.
The 72-h ErC50 for growth rate reduction was 1.6 mg/L with a 95 % CL of 1.3-2.0 mg/L.
Both EC50 values lie within the historical ranges.

Reported statistics and error estimates:

ANOVA, Tukey test, Bonferroni t-test (TOXSTAT Release 3.5, 1996) to determine NOEC and LOEC.
Calculation of EC50 and EC10 values was based on linear regression analysis of the percentages of growth inhibition and the percentages of growth rate reduction versus the logarithms of the corresponding nominal concentrations of the test substance.

Analytical verification of test concentrations was not included in the test. As the substance is highly soluble in water (miscible) and does not contain any hydrolysable groups, the nominal test concentration is taken as the actual exposure concentration over the test duration. Stability in aqueous solution was confirmed in a recent acute fish toxicity study (Vaughan, 2012) in which the substance was determined to be stable in test dilution water (not further specified) over a 96h period at 120 mg/L, 15 deg C, pH 7.5-7.9 and a 16h light and 8h dark photoperiod.

Validity criteria fulfilled:

yes

Conclusions:

A 72-h algae growth inhibition test with the unicellular green alga Selenastrum capricornutum (Pseudokirchneriella subcapitata) yielded a 72-h NOEC of 22 mg/L and a 72-h EC50 of 56 mg/L, both based on growth rate.

Reference 3

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2016-11-01 to 2016-12-20

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: "Algal Growth.Inhibition Test" stipulated in the "Testing Methods for New Chemical Substances"

Version / remarks:

(March 31, 2011, No. 0331-7, Phannaceutical and Food Safety Bureau, Ministry ofHealth, Labour and Welfare; March29, 2011, No. 5, Manufacturing Industries Bureau, Ministry ofEconomy, Trade and Industry; No. 110331009, Environmental Policy Bureau, Ministry of the Environment, Japan; latest revision, December 21, 2015, No. 1221- 1, Pharmaceutical and Food Safety Bureau, Ministry of Health, Labour and Welfare; December 9, 2015, No. 1, Manufacturing Industries Bureau, Ministry ofEconomy, Trade and Industry; No. 1512211, Environmental Policy Bureau, Ministry of the Environment., Japan)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

- Chemical name: Reaction product of 3-dimethylaminopropylamine and propylene oxide with 1,1'-[(3-dimethylaminopropyl)imino]-bis-2-propanol and 1-[(3-dimethylaminopropyl)(2-hydroxy-1-methylethyl)amino]-2-propanol as main component
- Name of test material (as cited in study report): DMAPA-2PO
- CAS number: CAS 63469-23-8 (1,1'-[(3-(dimethylaminopropyl)imino)]-bis-2-propanol)
- Molecular formula: C11H26N2O2 (main component)
- Molecular weight: 218.3 (main component)
- Substance type: yellow liquid
- Physical state: liquid
- Analytical purity: 100 %
- Impurities (identity and concentrations): not reported
- Lot/batch No.: 5Y1024
- Expiration date of the lot/batch: NA
- Stability under test conditions: stable

Analytical monitoring:

yes

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The weighed test sample of 100 mg and medium of 1000 mL were mixed, and stirred until being dissolved to prepare the stock solution of 100 mg/L.
Required volume of the stock solution and medium were mixed and stirred to prepare the test solution in the preparation container. The test solution was divided into each test vessel.
- Evidence of undissolved material (e.g. precipitate, surface film, etc): final test solutions were clear and colourless

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Strain: ATCC 22662
- Source (laboratory, culture collection): American Type Culture Collection
- Pre-culture: The algae were counted in pre-culture incubated under the same conditions as the test for 3 days (from November 4 to November 7, 2016) as inoculums, and were added to test vessels to bring the initial cell concentration of 0.75x1E+04 cells/mL.

ACCLIMATION
- Acclimation period: not relevant (except pre-culture 3 days before start of the test)

Test type:

other: Rotary shaking (100 rpm)

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Hardness:

not specified

Test temperature:

22.3-22.5 °C

pH:

t=0h: 7.9-9.5
t=72h: 8.3-8.6

Dissolved oxygen:

not relevant

Salinity:

not relevant

Nominal and measured concentrations:

Preliminary study:
nominal test concentrations: 1.0, 10 and 100 mg/L (100 mg/L analysed)
measured test concentration t = 0 h: 94.5 (pH unadjusted), 100 (pH adjusted) mg/L
measured test concentration t = 72 h: 102 (pH unadjusted), 100 (no algae, pH unadjusted), 107 (pH adjusted), 103 (no algae, pH adjusted) mg/L

Final test:
nominal test concentrations: control, 6.25, 12.5, 25.0, 50.0 and 100 mg/L
measured test concentration t = 0 h: n.d., n.d., 10.9, 22.4, 50.8, 98.1 mg/L
measured test concentration t = 72 h: n.d., n.d., 10.7, 20.9, 50.0, 103 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Sterilized Erlemneyer flask (with gas-permeable Silicosen ®)
- Material, size, headspace, fill volume: 300 mL all-glass flasks filled with 100 mL test solution
- Initial cells density: 7,500 cells/mL
- Control end cells density: 130 x 10,000 cells/mL (mean)
- No. of vessels per concentration (replicates): 6
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: At the pre-culture and algae growth inhibition test, the OECD medium (OECD TG 201; March 23, 2006) prepared with puriified water was used.

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: M2, according to the OECD 201 Guideline, formulated using Milli-RO water.
- Culture medium different from test medium: Yes (M1 versus M2). Three days before the start of the test the algal stock culture (culture in M1) was inoculated in the same culture medium (M2) used in the test. The culture was maintained under the same conditions as used in the test.
- Intervals of measurements: pH was measured at the beginning and at the end of the test. Temperature was continuously measured in a control vessel. At the end of the final test microscopic observations were performed on all test concentrations to observe for any abnormal appearance of the algae.

OTHER TEST CONDITIONS
- Sterile test conditions: no information
- Adjustment of pH:
- Photoperiod: continuous illumination
- Light intensity and quality: Nominal 90 μmol·m-2·s-1 ± 20% (within ± 15% from the average light intensity). Continuous illumination provided by fluorescent lights with wavelength range of 400-700 nm

EFFECT PARAMETERS MEASURED (with observation intervals if applicable):
- Determination of cell concentrations: [counting chamber; electronic particle counter; fluorimeter; spectrophotometer; colorimeter]: Particle counter; Model COULTER Z2 (Beckman Coulter, Inc.), System biological microscope; Model BX41 (Olympus Corporation)
- Effect calculated parameters: specific growth rate and yield

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Range finding study: yes
- Test concentrations: 1.0, 10 and 100 mg/L (setup as preliminary test)
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: analytically confirmed

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

25 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
- Any stimulation of growth found in any treatment: no

Reported statistics and error estimates:

The EC50 was estimated as "larger than the highest test concentration" since no less than 50% of inhibition rate was not obtained within the exposure levels. The EC50 was denoted as EC50 based on growth rate.
Regarding the growth rate, Bartlett's test was done to determine the homogeneity of variance for the data. Then one-way analysis of variance and Dunnett's multiple comparison test was used to determine the significant difference between the control level and exposure levels. The statistical analysis was conducted using computer program (running on Microsoft software "Excel") constructed by our laboratory. NOEC was determined by the results of statistical analysis and cell condition.

Validity criteria fulfilled:

yes

Conclusions:

A 72-h growth inhibition test with the unicellular green alga Pseudokirchneriella subcapitata was performed with the test substance DMAPA-2PO according to the OECD guideline 201 (GLP conditions). The analytically confirmed nominal EC50 for growth rate inhibition (72h-ErC50) was >100 mg/L, and the 72-h NOErC was 25 mg/L. The results of the test can be considered reliable without restrictions.

Description of key information

The study of Yoshikawa (2016) is selected as key study for endpoint coverage. The study is carried out according to the OECD guideline 201, investigating the toxicity of the substance to the unicellular green algae Pseudokirchneriella subcapitata. The 72h-ErC50 and 72h-NOEC were determined to be > 100 mg/L and 25 mg/L respectively. The study is given a Klimisch score of 1 and was conducted under GLP.

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L

EC10 or NOEC for freshwater algae:

25 mg/L

Additional information

Two studies were performed with the test item to investigate the toxicity to aquatic algae.

 

In the first study from Yoshikawa (2016), which was considered as key study, the acute toxicity of the test substance to the unicellular green alga Pseudokirchneriella subcapitata was performed according to the OECD guideline 201 (GLP conditions). The analytically confirmed nominal EC50 for growth rate inhibition (72h-ErC50) was > 100 mg/L. The 72h-NOEC for growth rate inhibition was 25 mg/L.

 

The second study from Migchielsen (2002) was a full test performed according to the OECD guideline 201. A 72-h growth inhibition test with the unicellular green algae Selenastrum capricornutum (Pseudokirchneriella subcapitata) yielded a 72-h NOErC of 22 mg/L and a 72-h ErC50 of 56 mg/L, based on nominal concentrations. The study was considered as supporting as no analytical measurements were performed.

 

Additionally, a QSAR analysis was carried out to assess the aquatic toxicity of the predicted biodegradation products of the substance for use in the PBT/vPvB assessment. Estimations were carried out using ECOSAR v1.11. All predicted effects concentrations were above the screening criterion for any of the substances to fulfill the T criterion (the lowest 96h-LC50 obtained for algae was 42.9 mg/L).