Methanesulfonamide, N-[2-[(4,6-dimethoxy-1,3,5-triazin-2-yl)carbonyl]-6-fluorophenyl]-1,1-difluoro-N-methyl-

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:

18 Jun - 15 Jul 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

2006

Qualifier:

according to guideline

Guideline:

other: JMAFF guideline (12 Nou(h)san No 8147 (2000))

GLP compliance:

yes (incl. QA statement)

Remarks:

Ministerium für Arbeit, Gesundheit und Soziales des Landes Nordrhein-Westfalen

Analytical monitoring:

yes

Details on sampling:

Samples were analysed for the test medium of all treatment levels and the control on day 0 and 3.

Vehicle:

yes

Details on test solutions:

1073 mg test substance ad 10 mL dimethylformamid was prepared immediately prior to test initiation. The stock solution was well agitated on a magnetic stirrer for 5 minutes before further use. An adequate amount of the stock solution was transferred to a dilution series to obtain the concentratio levels used in the study.

Details on test organisms:

TEST ORGANISM
- Strain: SAG 61.81
- Source (laboratory, culture collection): Collection of Algal Cultures, Inst. for Plant Physiology, University of Göttingen, Germany
- Age of inoculum (at test initiation): 4 days old, log phase, cell density 10000 cells/mL
- Method of cultivation: 200 μL of a 7-10 days old stock culture was transferred into a 250 mL cotton plugged Erlenmeyer flask containing 50 mL of nutrient medium (Bringmann and Kühn, 1980) once every week. Stock cultures of algae were kept at 22 ± 2°C with 24 h light.

CULTURE
- Culture conditions (same as test or not): same as test

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

21.3 - 22.4°C

pH:

7.8 - 8.2

Nominal and measured concentrations:

Nominal: 0 (control), 0 (solvent control), 0.0300, 0.0960, 0.307, 0.980, 3.13 and 10.0 mg a.s./L
Recovery: Inital 96 % to 108 % of nominal (average 102 %). On day three 92 % to 100 % of nominal (average 95 %)

Details on test conditions:

TEST SYSTEM
- Test vessel: Erlenmeyer flasks with a total volume of 300 mL
- Material, fill volume: glass, 150 mL
- Initial cells density: 10000 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6
- No. of vessels per vehicle control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes, prepared according to the mentioned guideline
- Source/preparation of dilution water: deionized well water
- The stock solutions were sterilized by membrane filtration (mean pore diameter 0.2 μm) and stored at 4°C.
- The pH is adjusted to 8.3 ± 0.2 with NaOH

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Shaking: The shaker table rotated at approximately 100 oscillations per minute
- Photoperiod: continuous light
- Light intensity and quality: 4,440 – 8,880 lux; variation within the test: ± 15 % lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: with counting chamber after 0, 24, 48, and 72 h

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

6.23 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Remarks on result:

other: 95 % CI: 5.29 – 7.51 mg a.s./L

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.096 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Details on results:

Test conditions met all validity criteria, given by the mentioned guideline.
No statistically significant different was determined between the growth rates of the control and the solvent control.

Results with reference substance (positive control):

Positive control results are documented and archived together with strain protocols separatly.

Description of key information

Pseudokirchnerella subcapitata EC50 (72h) = 6.23 mg/L (nominal, based on growth)

Pseudokirchnerella subcapitata NOEC (72h) = 0.096 mg/L (nominal, based on growth)

The test item was initially suspended in solubilizer.

Additional information

One study is available on the toxicity of triafamone (CAS No. 874195-61-6) to the unicellular freshwater green algae Pseudokirchnerella subcapitata (Bruns, 2010). The study was performed according to OECD guideline 201 and GLP, with analytical monitoring of the test item concentration. The measured recovery rates at the end of test were above 90 percent. Therefore it was proven that the test item was stable during the 72 hours test duration and the results can be given as nominal values. Since the substance has a moderate water solubility (approx. 33 mg/L) the test item was initially dissolved in dimethylformamide. No statistically significant different was determined between the growth rates in the controls and the solvent controls. In the treated samples the algae growth was inhibited, which results in an EC50 (72h) value of 6.23 mg/L triafamone. The no observed effect concentration (NOEC) after 72 hours exposure is reported with 0.096 mg/L triafamone.