1H-1,4,7-Triazonine, octahydro-1,4,7-trimethyl-

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:

28 June 1993 to 02 July 1993

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Study conducted on read-across material

Justification for type of information:

The read-across justification will be provided as soon as possible.

Reason / purpose for cross-reference:

other: Target substance

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal 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

Analytical monitoring:

yes

Details on sampling:

At 0, 24, 48, 72 and 96 hours 10 mL samples from flasks A2 - G2 were taken for determination of the test material. On the same occasions the test material concentration was determined in 10 mL samples taken from the seven blank flasks A7 and 84 - G4 to ascertain the stability of the test material in ISO medium with negligible total organic carbon ie when no algae were present.

Vehicle:

no

Details on test solutions:

0.513 g of the test material was dissolved in 500 mL of distilled water to give a nominal 1.0 g/L stock. Prior to making the stock up to the mark the pH was
adjusted to 7.0 ± 0.5 with 1 M NaOH. A range of test solution concentrations (nominally 10.0 - 180.0 mg/L) were prepared by diluting the stock with ISO algal medium. Each flask contained 200 mL of test solution.

Test organisms (species):

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

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Test temperature:

22 - 24.5 °C

pH:

6.6 - 9.0

Nominal and measured concentrations:

Nominal: 10.0, 18.0, 32.0, 56.0, 100.0 and 180.0 mg/L
Measured (in algal flasks): 9.2, 16, 29.5, 59.0, 99.1 and 178.3 mg/L
Measured (in blank flasks): 10.3, 18.8, 31.5, 57.2, 104.2 and 179.8 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: The test vessels were loosely stoppered and placed according to a randomised distribution in an orbital illuminated incubator
- Material, size, headspace, fill volume: 200 mL
- Initial cells density: 10^4 cells/mL
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- Seven blank flasks without algae were also used in the test.

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: ISO algal medium
- Culture medium different from test medium: no
- Intervals of water quality measurement: The pHs of a representative sample of the test solutions were determined at 0 and 96 hours

OTHER TEST CONDITIONS
- Photoperiod: continuous
- Light intensity and quality: The light intensity was not measured, however the light source used was clearly adequate for the purposes of this study as indicated by the control culture growth.
- Salinity (for marine algae):

EFFECT PARAMETERS MEASURED:
- At 0, 24, 48, 72 and 96 hours the concentration of algal cells in each test vessel was quantified using a Coulter Counter

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

> 180 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

60 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: 95 % limits: 47-80 mg/L

Key result

Duration:

96 h

Dose descriptor:

NOEC

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

not determinable

Details on results:

TEST CONCENTRATIONS
- Analysis indicated that concentrations of the test material at 0 hours were 92-108 % of nominal in all samples. Over the duration of the test the mean measured concentrations in the algal flasks were 89 - 105 % (range 74 - 111 %) of nominal. Comparable values for the blank flasks were 98 - 104 % (range 92 - 116 %) of nominal.
- Effect concentrations were based on nominal concentrations since test solution concentrations remained constant throughout the test.

TOXICITY DATA
- There was a 555 fold mean increase in the cell density of control cultures over 96 hours. The control growth was therefore qualitatively acceptable.
- Calculated 24, 48, 72 and 96 hour EC50s and NOECs:
Growth rate:
24 h: EC50 = > 180 mg/L, NOEC = 32 mg/L
48 h: EC50 = > 180 mg/L, NOEC = 32 mg/L
72 h: EC50 = > 180 mg/L, NOEC = 32 mg/L
96 h: EC50 = > 180 mg/L, NOEC = 10 mg/L

Biomass:
24 h: EC50 = > 180 mg/L, NOEC = 32 mg/L
48 h: EC50 = 132 mg/L (95 % limits: 84 - 302 mg/L), NOEC = 32 mg/L
72 h: EC50 = 66 mg/L (95 % limits: 50 - 94 mg/L), NOEC = 32 mg/L
96 h: EC50 = 60 mg/L (95 % limits: 47 - 80 mg/L), NOEC = -

Table 1: Percentage Inhibition of Test Algal Cultures

Nominal Concentration (mg/L)	Biomass (h)				Growth Rate (h)
	24	48	72	96	24	48	72	96
10.0	7.1	11.1	12.3	17.3	2.9	3.2	2.3	3.5
18.0	17.6	24.4	26.2	28.1	8.9	8.2	5.8	5.5
32.0	2.6	8.3	13.4	23.3	2.8	3.6	3.6	6.5
56.0	32.5	43.3	56.6	54.5	15.7	15.4	16.0	11.9
100.0	26.8	39.2	52.6	52.0	14.1	15.0	15.3	12.1
180.0	41.1	61.7	79.2	81.1	22.5	29.0	33.1	29.0

Validity criteria fulfilled:

not specified

Conclusions:

Under the conditions of this study the 96 hour growth rate EC50 was > 180 mg/L and the NOEC was 10 mg/L, the 96 hour biomass EC50 was 60 mg/L (95 % limits: 47 - 80 mg/L) but the NOEC could not be determined.

Executive summary:

The toxicity of the test material to aquatic algae was investigated in accordance with the standardised guidelines OECD 201, EU Method C.3. and ISO 8692, under GLP conditions.

A range of concentrations of the test material (nominally 10.0 - 180.0 mg/L) were prepared in ISO medium. At 0, 24, 48, 72 and 96 hours samples of test solutions were taken for determination of the test material concentration. Analysis indicated that concentrations of the test material at 0 hours were 92-108 % of nominal in all samples. Over the duration of the test mean concentrations in the algal flasks were 89 - 105 % (range 74 - 111 %) of nominal. Effect concentrations were based on nominal concentrations since test solution concentrations remained constant throughout the test.

Under the conditions of this study the 96 hour growth rate EC50 was > 180 mg/L and the NOEC was 10 mg/L, the 96 hour biomass EC50 was 60 mg/L (95 % limits: 47 - 80 mg/L) but the NOEC could not be determined.

Description of key information

Under the conditions of this study the 96 hour growth rate EC50 was > 180 mg/L and the NOEC was 10 mg/L, the 96 hour biomass EC50 was 60 mg/L (95 % limits: 47 - 80 mg/L) but the NOEC could not be determined.

Key value for chemical safety assessment

EC10 or NOEC for freshwater algae:

10 mg/L

Additional information

The toxicity of the test material to aquatic algae was investigated in accordance with the standardised guidelines OECD 201, EU Method C.3. and ISO 8692, under GLP conditions. The study was awarded a reliability score of 1 in accordance with the criteria set forth by Klimisch et al. (1997).

A range of concentrations of the test material (nominally 10.0 - 180.0 mg/L) were prepared in ISO medium. At 0, 24, 48, 72 and 96 hours samples of test solutions were taken for determination of the test material concentration. Analysis indicated that concentrations of the test material at 0 hours were 92-108 % of nominal in all samples. Over the duration of the test mean concentrations in the algal flasks were 89 - 105 % (range 74 - 111 %) of nominal. Effect concentrations were based on nominal concentrations since test solution concentrations remained constant throughout the test.

Under the conditions of this study the 96 hour growth rate EC50 was > 180 mg/L and the NOEC was 10 mg/L, the 96 hour biomass EC50 was 60 mg/L (95 % limits: 47 - 80 mg/L) but the NOEC could not be determined.