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1) This study was to evaluate the test substance for its ability to generate acute toxic effects in Cyprinus carpio during an exposure period of 96 hours.

The definitive test was performed with carp exposed to concentrations ranging from 0.1 to 100 mg/l in a static system. Acetone was used as a solvent in the stock solution.

The 96h-LC50 for carp is > the nominal concentration of 100 mg/l. The maximum solubility was estimated to be between 10 and 100 mg/l. Hence, the testing of concentrations> 100 mg/l was not considered to be relevant.

The BWZ of TK 12146, Accelerator DY 9577 for acute toxicity in fish is <4.

2)This study was performed to assess the acute toxicity of the test item to Daphnia magna. The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (April 2004) No 202, "Daphniasp., Acute Immobilisation Test" referenced as Method C.2 of Commission Regulation (EC) No. 440/2008.

 

Following a preliminary range-finding test, twenty daphnids (4 replicates of 5 animals) were exposed to an aqueous solution of TK 12146 at nominal concentrations of 10, 18, 32, 56 and 100% v/v saturated solution for 48 hours at a temperature of approximately 20°C under static test conditions. The test item solutions were prepared by stirring an excess (50mg/L) of test item in test water using a propeller stirrer at approximately 1500 rpm for24hours. After the stirring period any undissolved test item was removed by filtration (0.2 µm Gelman Acrocap filter, first approximate 100 mL discarded in order to pre-condition the filter) to give a 100% v/v saturated solution. This saturated solution was then further diluted as necessary, to provide the remaining test concentrations. Immobilization and any adverse reactions to exposure were recorded after 24 and 48 hours.

 

Exposure of Daphnia magnato the test item gave the following results based on the 0-Hour measured test concentrations:

Time Point

(Hours)

EC50
(mg/L)

No Observed Effect Concentration (NOEC) (mg/L)

Lowest Observed Effect Concentration (LOEC) (mg/L)

48

>0.75

0.22

0.40

 

3) The study was performed to assess the effect of TK 12146 on the growth of the green alga Pseudokirchneriella subcapitata. The method followed that described in the OECD Guidelines for Testing of Chemicals (2006) No 201, "Freshwater Alga and Cyanobacteria, Growth Inhibition Test" referenced as Method C.3 of Commission Regulation (EC) No 761/2009.

 

The test item was very slightly soluble in water. Preliminary solubility work conducted indicated that it was not possible to obtain a testable solution of the test item using traditional methods of preparation e.g. ultrasonication and high shear mixing.

 

A preliminary media preparation trial indicated that a dissolved test item concentration of approximately 0.65 mg/L was obtained from a saturated solution method of preparation indicating this to be the limit of water solubility of this item under test conditions.

 

Following a preliminary range-finding test,Pseudokirchneriella subcapitatawas exposed to solutions of the test item at nominal concentrations of 6.25, 12.5, 25, 50 and 100% v/v saturated solution (three replicate flasks per concentration) for 72 hours, under constant illumination and shaking at a temperature of 24 ± 1 °C. The test item solutions were prepared by stirring an excess (50 mg/L) of test item in culture medium using a propeller stirrer at approximately 1500 rpm for 24 hours. After the stirring period any undissolved test item was removed by filtration (0.2 µm Gelman Acrocap filter, first approximate 500 mL discarded in order to pre-condition the filter) to produce a 100% v/v saturated solution of the test item. This saturated solution was then further diluted as necessary, to provide the remaining test groups.

 

Exposure ofPseudokirchneriella subcapitatato the test item gave the following results based on the geometric mean measured test concentrations:

 

Response Variable

EC10(mg/L)

EC20(mg/L)

EC50(mg/L)

95% Confidence Limits (mg/L)

No Observed Effect Concentration (NOEC) (mg/L)

Lowest Observed Effect Concentration (LOEC) (mg/L)

Growth Rate

0.049

0.073

0.13

0.12

-

0.15

0.022

0.074

Yield

0.048

0.054

0.068

0.063

-

0.073

0.022

0.074

  This study showed that the EC50is greater than the limit of solubility.

4) TK 12146, ACCELERATOR DY 9577 was investigated for its ability to inhibit the cell multiplication of the bacteria species Pseudomonas putida according to DIN 38412 Part L 8 (March 1991) and NEN-EN-ISO 10712 (1996).

Suspensions of Pseudomonas putida were exposed to concentrations ranging from 312.5 to 10,000 mg TK 12146, ACCELERATOR DY 9577 per litre. After incubation the extinction values of the bacterial cell suspensions were measured. No toxicity was observed.

Based on the results of the test presently performed, the toxicity threshold value (EC10) of TK 12146, ACCELERATOR DY 9577 was over 10,000 mg/l.

The "Bewertungszahl" (Assessment figure or value for bacterial toxicity) is therefore < 1.9 (Bewertung wassergefahrdender Stoffe, 1989).

The EC50 value for the reference substance, 3,5-dichlorophenol, tested during the same experiment was 29 mg/l. Since this was within the accepted range of 10-30 mg/l for the EC50 and the multiplication factor of the bacteria within the test was over 60, it was concluded that the test conditions were optimal and the results obtained were valid.