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

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

06 Apr - 15 Apr 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

2004

Qualifier:

according to guideline

Guideline:

EPA OPP 72-2 (Aquatic Invertebrate Acute Toxicity Test)

Version / remarks:

1982

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

1992

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1010 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)

Version / remarks:

draft 1996

GLP compliance:

yes (incl. QA statement)

Remarks:

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

Analytical monitoring:

yes

Details on sampling:

Watersamples from start and end of exposure were retained for analysis. Immediately after preparation of the test solutions and again after 48 hours of static exposure, duplicate samples containing 20 mL of the pooled media from test vessels of each testing group were taken.
In advance, sample containers were filled with 5 mL acetonitrile and shaken in order to rinse the adsorptive surface of the glass. After shaking the solvent remained in the bottle and test-water-samples (20 mL) were added to a total sample volume of 25 mL.
The samples were adjusted to pH 3 by adding appropriate amounts of ophosphoric acid and afterwards stored below -18°C until being measured.

Vehicle:

yes

Details on test solutions:

Initially, the test substance was dissolved in dimethylformamide. Therefore, a primary stock solution was prepared by replenishing 5364.7 mg AE1887196 (tech.) with DMF (dimethylformamide) up to 10mL, corresponding to a 500g a.s./L stock solution. From this solution, sub dilutions were establi hed in the following sub dilution steps:
stock solution B > 5 mL stock solution A + 5 mL DMF = 250 g a.s/ L
stock solution C > 5 mL stock solution B + 5 mL DMF = 125 g a.s/ L
stock solution D > 5 mL stock solution C + 5 mL DMF = 62.5 g a.s/ L
stock solution E > 5 mL stock solution D + 5 mL DMF = 31.3 g a.s/ L
Each solution was hand shaken until visible homogeneity was achieved. From each of these stock solutions 100 μL were taken and carefully added to an amount of 1000 mL test water in order to establish the concentrations 3.13, 6.25, 12.5, 25.0 and 50.0 mg a.s./L
The test solutions were stirred for at least 26 minutes (25.0 and 50.0 mg a.s./L) respectively 36 minutes (3.13, 6.25, 12.5 mg a.s./L) whereas stirring of the 25.0 and 50.0 mg a.s./L solutions was interrupted twice for 5 minutes of ultrasonication.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Waterflea
- Clone: Genotype No. 2 calssified by Dr. Bradley, University of Sheffield, Department of Zoology, report of February 3, 1988. Renamed later as "type B"
- Source: Bayer laboratory stock breeding
- Age at study initiation: First instars < 24 hours old
- Method of breeding: The culture has been maintained in 2000 mL containers (50 to 100 daphnids percontainer) in weekly renewed aqueous media, being placed in an climate-controlled environment under study conditions. The daphnids were fed three times per week with living cells of the green alga Desmodesmus subspicatus.
- Feeding during test: No

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

14 German degrees = 249 mg/L CaCO3

Test temperature:

20.6°C - 21.0°C

pH:

7.9

Dissolved oxygen:

8.2 - 8.4 mg/L

Salinity:

578 μS/cm

Nominal and measured concentrations:

Nominal (mean measured): 3.13 (3.14), 6.25 (6.28), 12.5 (12.4), 25.0 (23.4) and 50.0 (35.3) mg a.s./L

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 mL glass beakers (DIN 12332)
- Type: covered with transparent glass plates
- Material, size, fill volume: Glass, fill volume 50 mL
- Aeration: none
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 6
- No. of vessels per control (replicates): 6
- No. of vessels per vehicle control (replicates): 6

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Artificial water, type Elendt M7, repared as defined by the underlying OECD / EEC guidelines
- Total organic carbon: < 2.0 mg/L
- Particulate matter: < 5.0 mg/L
- Metals (mg/L): below detection limits
- Pesticides: below detection limit
- Intervals of water quality measurement: Temperature, dissolved oxygen, pH and conductivity were measured at test initiation and at 48 h

OTHER TEST CONDITIONS
- Photoperiod: 16:8 hours light-dark cycle
- Light intensity: max 1200 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
After 24 and 48 hours, behaviour of the water fleas was visually evaluated by counting mobile daphnids.

Reference substance (positive control):

yes

Remarks:

K2Cr2O7; performed separately in February 2010

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 50 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

act. ingr.

Basis for effect:

mobility

Details on results:

No immobilities or other effects on behaviour occurred in untreated control within 48 hours of exposure.

Results with reference substance (positive control):

24 hour EC50 = 0.73 mg/L , which meets the range defined by OECD 202 (0.6 mg/L - 2.1 mg/L)

Concentrations in the exposure media at start and end of the study revealed recoveries within 92 and 101 % of nominal for concentrations up to 25 mg a.s./L whilst for the highest tested concentration of 50 mg a.s./L only a recovery of 72 / 69 % of nominal was found. Nevertheless, since already 12,5 mg a.s./L caused turbidity after administration to the test water, the existence of undissolved active substance indicated exceeding of the maximum saturation concentration.

Due to the limited solubility in water, in the current study the biological effects concentrations for Daphnia magna were predominantly located above the maximum saturation concentration. Administration of test item concentrations up to an expected EC50 concentration was inhibited by strong precipitation of the test item.

Since the highest tested concentration of 50 mg a.s./L caused effects distinctly below 50% immobilisation, and since precipitation of the test item in the tested aqueous concentrations avoided a reliable dose-response relation, statistical EC50 calculations were not applicable.

Table 1: Number of immobilized daphnids

Concentration mg a.s./L	24h	48h
control	0%	0%
Solvent control	0%	0%
3.13	0%	0%
6.25	0%	16.7%
12.5	0%	20.0%
25	0%	6.7%
50	10%	33.3%

 

Table 2: Recoveries based on nominal concentration

Concentration mg a.s./L	Test start	Test end
3.13	101%	100%
6.25	101%	100%
12.5	100%	98%
25	95%	92%
50	72%	69%

 

Description of key information

Daphnia magna EC50 (48h) > 50 mg/L (nominal) 

The test item was initially suspended in solubilizer.

Additional information

One study is available on the short-term toxicity of triafamone (CAS No. 874195-61-6) to the waterflea Daphnia magna (Bruns, 2010; 2013). The study was performed according to OECD guideline 202 and GLP, with analytical monitoring of the test item concentration. Due to the moderate water solubility (approx.33 mg/L) the test item was initially dissolved in dimethylformamide. No immobilities or other effects on behaviour occurred in the solvent control within 48 hours of exposure. Concentrations in the exposure media at start and end of the study revealed recoveries within 92 and 101 % of nominal for concentrations up to 25 mg a.s./L whilst for the highest tested concentration of 50 mg a.s./L only a recovery of 72 / 69 % of nominal was found. Nevertheless, since already 12,5 mg a.s./L caused turbidity after administration to the test water, the existence of undissolved active substance indicated exceeding of the maximum saturation concentration. Due to the limited solubility in water, the effect concentrations for Daphnia magna were predominantly located above the maximum saturation concentration. Administration of test item concentrations up to an expected EC50 concentration was inhibited by strong precipitation of the test item. Since the highest tested concentration of 50 mg a.s./L caused effects distinctly below 50% immobilisation, and since precipitation of the test item in the tested aqueous concentrations avoided a reliable dose-response relation, statistical EC50 calculations were not applicable.