Reaction mass of Octyl-3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazole-2-yl)phenyl]propionate and 2-Ethylhexyl-3-[3-tert-butyl-4-hydroxy-5-(5-chloro-2H-benzotriazole-2-yl)phenyl]propionate

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:

From July 20, 1993 to August 30, 1993

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Principles of method if other than guideline:

ABC Protocol No. 9207 as approved by CIBA-GEIGY, Ltd. and the ABC Laboratories' study director

GLP compliance:

yes

Details on test solutions:

- Source (laboratory, culture collection): Department of Botany, Culture Collection of Algae, University of Texas at Austin

Test organisms (species):

Scenedesmus sp.

Details on test organisms:

- Test vessel: 250-mL Erlenmeyer flask
- Test volume: 100 mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3
- Light intensity and quality: approximately 8600 lux

Test type:

static

Total exposure duration:

72 h

Nominal and measured concentrations:

Nominal concentrations: Control (0.0), Vehicle Blank (acetone), 0.10, 1.0 and 10 mg/L

Details on test conditions:

- Test vessel: 250-mL Erlenmeyer flask
- Test volume: 100 mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3
- Light intensity and quality: approximately 8600 lux

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 10 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

cell number

A 72-hour screen with Scenedesmus subspicatus exposed to TINUVIN 109 was conducted at test concentrations of 0.10, 1.0, and 10 mg/L along with a control and vehicle blank (acetone). Test concentrations were based on the solubility of TINUVIN 109 in algae nutrient media. Logarithmic phase growth was confirmed at 72 hours with a mean count of 7.3 × 10⁵and 4.5 × 10⁵cells/mL in the control and vehicle blank replicates, respectively, that were 52- and 26-fold increases, respectively, from the initial 1.4 × 10⁴and 1.7 × 10⁴cells/mL. After 72 hours, algal cell counts for the 0.10-, 1.0-, and 10-mg/L test levels were 142, 133, and 91 % of the vehicle blank population, respectively. No oily surface film was noted in the 10 mg/L test solution at 72 hours.

Conclusions:

According to ABC Protocol No. 9207 and the ABC Laboratories' study director, the EC50 and the NOEC of TINUVIN 109 was greater than 10 mg/L and 10 mg/L respectively.

Executive summary:

This test using the procedures outlined in ABC Protocol No. 9207 as approved by CIBA-GEIGY, Ltd. (1993) and the ABC Laboratories' study director (1993). A 72-hour screen with Scenedesmus subspicatus exposed to TINUVIN 109 was conducted at test concentrations of 0.10, 1.0, and 10 mg/L along with a control and vehicle blank (acetone). Test concentrations were based on the solubility of TINUVIN 109 in algae nutrient media. The results as below:

1)     72-hour EC50 was greater than 10 mg/L (95% confidence limits could not be determined)

2)     72-hour no-observed effect concentration was determined to be 10 mg/L

 

Description of key information

For Scenedesmus subspicatus, the 72-hour EC50 of TINUVIN 109 was greater than 10 mg/L and the NOEC of TINUVIN 109 was 10 mg/L .

Key value for chemical safety assessment

EC10 or NOEC for freshwater algae:

10 mg/L

Additional information

A 72-hour screen with Scenedesmus subspicatus exposed to TINUVIN 109 was conducted at test concentrations of 0.10, 1.0, and 10 mg/L along with a control and vehicle blank (acetone). Test concentrations were based on the solubility of TINUVIN 109 in algae nutrient media. The results as below:

1)     72-hour EC50 was greater than 10 mg/L (95% confidence limits could not be determined)

2)     72-hour no-observed effect concentration was determined to be 10 mg/L