Reaction products of N,N'-ethane-1,2-diylbis(1,3-propanediamine), cyclohexane, peroxidized 4-butylamino-2,2,6,6-tetramethylpiperidine and 2,4,6-trichloro-1,3,5-triazine

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:

1997-05-30 - 1997-12-26

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study (OECD test guideline 201)

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Test item concentrations were determined in the control and all test treatments at test initiation, at 24 hours (old and new solutions), and test termination. Water samples (100 mL percomposited test solution) were taken using volumetric pipets.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Stock solution: Solution was prepared by sonicating a solution with a nominal concentration of 100 mg/L (actually three separate 500-mL volumes of freshwater algal medium to which 0.05 g of test item was added) for 15 minutes and then filtering the solution through a 0.2-µm filter to remove any undissolved test substance.
- This solution was analyzed and utilized as the stock for preparing the five test concentrations.
- Blank: A dilution water control was maintained concurrently
(- Evidence of undissolved material: All test chambers were filled with appropriate test solutions (without filtration) and allowed to sit over the weekend to permit the test substance to coat the glassware. These solutions were discarded when the test was initiated and fresh solutions were added).

TEST CONCENTRATIONS
Nominal: control, 0.011, 0.022, 0.045, 0.090, and 0.179 mg test item/L
Actual: control (<0.020), <0.020, 0.021, 0.040, 0.077, and 0.142 mg test item/L (mean, day 0 and 4)

REPLICATES: Each test concentration was tested in 5 replicates (plus a chemical "blank" flask), the blank control in 8. The extra replicates in all test concentrations and the control were for chemistry sampling on day 3.

RANGE-FINDING TEST
A static range-finding test was conducted at nominal concentrations of 0.10, 1.00, 10.0, 100 and 1000 mg test item/L prior to performing the main test.

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Strain: Green Algae (Selenastrum capricornutum)
- Source: University of Texas
- Initial cell density: approximately 10000 cells/mL
- Method of cultivation: freshwater algal medium under continuous illumination (and continuously agitated at approximately 100 rpm)
- Cultures were maintained at approximately 24 ± 2°C prior to test initiation.
- Inoculum culture was 5 days old at test initiation

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

23.1 to 25.0°C

pH:

initial pH: 7.2 to 7.5
pH at end: 7.1 to 9.9

Nominal and measured concentrations:

Nominal concentrations (based on loading concentration): 0 (control), 6.25, 12.5, 25, 50, 100 mg/L
Nominal concentrations (based on water accomodated fraction): 0 (control), 0.011, 0.022, 0.045, 0.090, and 0.179 mg/L
Mean measured concentrations: control (0.028), <0.020, <0.020, 0.029, 0.045, and 0.083 mg/L (day 0 and 3)
Mean measured concentrations: control (<0.020), <0.020, 0.021, 0.040, 0.077, and 0.142 mg mg/L (day 0 and 4)

Details on test conditions:

TEST SYSTEM
- Test vessel: 250 mL Erlenmeyer flasks
- Type: covered with gas exchange caps
- Fill volume: 100 mL
- Aeration: Algae were incubated on a lab-shaker (approximately 100 rpm)
- Initial cells density: approximately 10000 cells/mL
- Control end cells density: ~355E4 cells/mL
- No. of organisms per vessel: ~355E6 cells
- No. of vessels per concentration: 5 replicates (plus a chemical "blank" flask)
- No. of vessels per blank control: 8 replicates

GROWTH MEDIUM
- Freshwater algal growth medium

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Town water (Jupiter, Florida)
- Total organic carbon: < 1.0 mg/L
- Pesticides: < 2.21 µg/L
- Ca/Mg ratio: ~6.7:1

OTHER TEST CONDITIONS
- Sterile test conditions: no
- Adjustment of pH: prior to addition of the test item, pH 7.4
- Photoperiod: continuously
- Light intensity and quality: 81.9 – 134 µmol/m²/s
- Temperature: 24 +/- 2 °C

EFFECT PARAMETERS MEASURED
- Determination of cell concentrations: by means of a cell counter at 24, 48 and 72 hours
- Temperature: daily
- pH: at start (0 h) and at the end (72 h)

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2

Reference substance (positive control):

no

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

>= 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: WAF

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: WAF

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.083 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks:

and biomass

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 0.083 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks:

and biomass

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

0.142 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks:

and biomass

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

> 0.142 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks:

and biomass

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks:

and biomsss

Remarks on result:

other: WAF

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks:

and biomass

Remarks on result:

other: WAF

Executive summary:

In a 96 hour acute toxicity study, cultures of the green algae Selenastrum capricornutum were exposed to the test item (as described in section 1.2) at nominal concentrations of 0, 6.25, 12.5, 25.0, 50.0, and 100 mg test item/L (based on loading concentration of 100 mg/L) or 0. 0.011, 0.022, 0.045, 0.090, and 0.179 mg/L (based on concentration of 0.179 mg/L in water accomodated fraction) under static conditions. No growth inhibition was observed in the test. There were no compound related phytotoxic effects. The EC50 was > 0.083 mg test item/L (corresponding to a nominal concentration of > 100 mg/L) for 72 hours and the NOEC was 0.083 mg test item/L, related to the analytically verified concentrations. The EC50 was > 0.142 mg test item/L (corresponding to a nominal concentration of > 100 mg/L) for 96 hours and the NOEC was 0.142 mg test item/L, related to the analytically verified concentrations. This toxicity study is classified as acceptable and satisfies the guideline requirements for a toxicity study on Freshwater Alga and Cyanobacteria, Growth Inhibition Test (OECD TG 201).

Description of key information

The EC50 as well as NOEC was > 0.142 mg/L  for 96 hours based on the analytically verified concentrations (corresponding to a nominal concentration of > 100 mg/L). 

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L

EC10 or NOEC for freshwater algae:

100 mg/L

Additional information

The toxicity to algae was assessed according to OECD guideline 201 . The green algae Selenastrum capricornutum were exposed to the test substance for 96 hours at nominal concentrations of 0, 6.25, 12.5, 25.0, 50.0, and 100 mg test substance/L (based on loading concentration of 100 mg/L) or 0. 0.011, 0.022, 0.045, 0.090, and 0.179 mg/L (based on concentration of 0.179 mg/L in water accomodated fraction) under static conditions. No growth inhibition was observed in the test. There were no compound related phytotoxic effects. The EC50 was > 0.083 mg test substance/L (corresponding to a nominal concentration of > 100 mg/L) for 72 hours and the NOEC was 0.083 mg test substance/L, related to the analytically verified concentrations. The EC50 was > 0.142 mg test substance/L (corresponding to a nominal concentration of > 100 mg/L) for 96 hours and the NOEC was 0.142 mg test substance/L, related to the analytically verified concentrations.