1-[bis[3-(dimethylamino)propyl]amino]propan-2-ol

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:

2012-06-08 - 2012-07-14

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

- Name of test material (as cited in study report): Jeffcat ZR 50
- Physical state: liquid (pale yellow)
- Analytical purity: >99%
- Purity test date: 12.01.2011
- Lot/batch No.: PFW100207
- Expiration date of the lot/batch: not provided
- Storage condition of test material: room temperature in the dark

Analytical monitoring:

yes

Details on sampling:

Duplicate samples for analytical verification of test substance concentrations were taken at 0 and 72 h.
Samples from replicates were pooled.
Samples were stored at -20°C prior to analysis.

Vehicle:

no

Details on test solutions:

- 100 mg/L stock solution prepared through direct addition to culture medium.
- Other concentrations prepared by dilution.
- Stock and test solutions were inverted several times to ensure adequate mixing and homogeneity.

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Strain: CCAP 278/4
- Source (laboratory, culture collection): Culture Collection of Algae and Protozoa (CCAP), SAMS Research Services Ltd., Scottish Marine Institute, Oban, Argyll, Scotland.
- Age of inoculum (at test initiation): 3-5 days, in exponential growth phase
- Method of cultivation: Master cultures were maintained in the lab under constant aeration and constant illumination at 21°C.
- Preculture: Sufficient master culture added to ca. 100 mL volumes of culture media to given initial cell density ca. 1000 cells/mL. Flasks kept under constant agitation (100-150 rpm) and constant illumination (24°C) until algal cell density was ca. 10000-100000 cells/mL (actually 302000 cells/mL).

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Post exposure observation period:

none

Hardness:

ca. 15 mg CaCO3/L

Test temperature:

24 +/- °C

pH:

7.4-9.9 at 0 h
8.0-8.2 at 72 h
pH variation in control < 1.5 pH units during the test (7.4 to 8.0)

Dissolved oxygen:

not applicable

Salinity:

not applicable

Nominal and measured concentrations:

Nominal: control, 6.25, 12.5, 25, 50, 100 mg/L
Measured concentrations were within 92 to 110% of nominal

Details on test conditions:

TEST SYSTEM
- Test vessel: glass conical flasks
- Type (delete if not applicable): stoppered with polyurethane foam bungs to reduce evaporation
- Material, size, headspace, fill volume: glass, 250 mL, 100 mL fill volume
- Initial cells density: 5000 cells/mL (nominal, mean measured = 6040)
- Control end cells density: 688000 cells/mL (mean measured)
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reverse osmosis purified deionised water, pH adjusted to 7.5 with 0.1N NaOH or HCl
- Culture medium different from test medium: no
- Intervals of water quality measurement during the test: pH was determined at 0 and 72 h in each test solution, temperature was recorded daily (incubator)

OTHER TEST CONDITIONS
- Incubated in and INFORS Multitron Version 2 incubator, constantly shaken at approximately 150 rpm
- Adjustment of pH: no (only in non-spiked test medium)
- Photoperiod: continuous illumination
- Light intensity and quality: approximately 7000 lux, warm white lighting (380-730 nm)

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): cell density was determined at 0, 24, 48 and 72 h
- Determination of cell concentrations: Coulter Multisizer Particle Counter

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Range finding study: yes
- Test concentrations in range finding study: 0.10, 1.0, 10 and 100 mg/L
- 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.:

33 mg/L

95% CI:

> 29 - < 37

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

12.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

Growth rate-based:
72-h ErC10 = 16 mg/L
72-h ErC20 = 21 mg/L
72-h LOEC = 25 mg/L
Biomass-based:
72-h EbC10 = 7.7 mg/L
72-h EbC20 = 10 mg/L
72-h EbC50 = 17 mg/L (95% CI = 15-19 mg/L)
72-h NOEC = 6.25 mg/L
72-h LOEC = 12.5 mg/L

Results with reference substance (positive control):

72-h ErC50 = 1.4 mg/L (95% CI = 1.2-1.7 mg/L)
72-h EbC50 = 0.59 mg/L (95% CI = 0.53-0.65 mg/L)
72-h NOEC = 0.25 mg/L
These results were within normal ranges for this reference item.

Reported statistics and error estimates:

- ECx values were calculated using computerised interpolation using the Xlfit software package (IDBS). 95% confidence limits were calculated using the simplified method of evaluating dose-effect experiments (Litchfield and Wilcoxon, 1949).
- One-way ANOVA incorporating Bartlett's test for homogeneity of variance (Sokal and Rohlf, 1981) and Dunnett's multiple comparison procedure for comparing several treatments with a control (Dunnett, 1955) was used for determination of NOEC and LOEC values.

Table 1 - Cell densities and pH values in the definitive test

Nominal concentration (mg/L)		pH	Cell densities* (cells per mL)				pH
		0h	0h	24h	48h	72h	72h
Control	R1	7.4	6.10E+03	2.85E+04	1.62E+05	6.54E+05	8
	R2		6.54E+03	2.25E+04	1.03E+05	6.48E+05
	R3		5.39E+03	2.69E+04	1.41E+05	9.06E+05
	R4		6.11E+03	2.60E+04	1.27E+05	7.47E+05
	R5		6.06E+03	3.17E+04	1.39E+05	5.35E+05
	R6		6.03E+03	3.22E+04	1.62E+05	6.41E+05
	Mean		6.04E+03	2.80E+04	1.39E+05	6.88E+05
6.25	R1	8.5	5.65E+03	2.46E+04	1.07E+05	5.77E+05	8.2
	R2		5.84E+03	2.31E+04	1.20E+05	5.84E+05
	R3		6.13E+03	2.54E+04	1.33E+05	7.12E+05
	Mean		5.87E+03	2.44E+04	1.20E+05	6.24E+05
12.5	R1	8.9	5.87E+03	1.77E+04	8.21E+05	4.27E+05	8.2
	R2		5.49E+03	1.97E+04	9.72E+05	5.27E+05
	R3		5.44E+03	2.01E+04	8.13E+05	4.92E+05
	Mean		5.57E+03	1.92E+04	8.69E+05	4.82E+05
25	R1	9.3	5.47E+03	6.83E+03	3.30E+05	1.78E+05	8.2
	R2		5.57E+03	8.66E+03	4.07E+05	2.02E+05
	R3		5.06E+03	7.95E+03	3.47E+05	1.35E+05
	Mean		5.37E+03	7.81E+03	3.61E+05	1.72E+05
50	R1	9.6	5.60E+03	3.98E+03	1.78E+03	5.30E+03	8
	R2		6.13E+03	2.74E+03	1.43E+03	7.04E+03
	R3		5.36E+03	2.02E+03	3.18E+03	1.71E+04
	Mean		5.70E+03	2.91E+03	2.13E+03	9.80E+03
100	R1	9.9	5.34E+03	1.12E+03	4.00E+02	1.23E+03	8.1
	R2		6.46E+03	1.42E+03	1.79E+03	1.86E+03
	R3		5.39E+03	1.31E+03	7.20E+02	1.01E+03
	Mean		5.73E+03	1.29E+03	9.71E+02	1.37E+03

Validity criteria fulfilled:

yes

Conclusions:

In this study, the test substance's toxicity to growth of the unicellular freshwater alga Pseudokirchneriella subcapitata was observed during 72 h, yielding a growth-rate based EC50 of 33 mg/L and a NOEC of 12.5 mg/L. Measured test substance concentrations were close to nominal. The results of the test can be considered reliable.

Description of key information

A full study was performed under GLP conditions and according to OECD TG 201 (Huntsman, 2012). A NOEC of 12.5 mg/L and an EC50 of 33 mg/L, both based on growth rate, were found for the unicellular green alga selenastrum capricornutum (Pseudokirchneriella subcapitata) after an exposure of 72 hours (Huntsman, 2012).

Key value for chemical safety assessment

EC50 for freshwater algae:

33 mg/L

EC10 or NOEC for freshwater algae:

12.5 mg/L