2-chloro-N-[[[4-(trifluoromethoxy)phenyl]amino]carbonyl]benzamide

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Study initiated/completed: 12 February 2002 to 04 March 2002.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Version / remarks:

1992

Deviations:

yes

Remarks:

See principles of method if other than guideline section.

Qualifier:

according to guideline

Guideline:

EPA OPP 72-1 (Fish Acute Toxicity Test)

Version / remarks:

1985

Deviations:

yes

Remarks:

See principles of method if other than guideline section.

Qualifier:

according to guideline

Guideline:

EU Method C.1 (Acute Toxicity for Fish)

Version / remarks:

1992

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1075 (Freshwater and Saltwater Fish Acute Toxicity Test)

Version / remarks:

1996

Deviations:

yes

Remarks:

See principles of method if other than guideline section.

Principles of method if other than guideline:

1. The guidelines recommend a temperature of 13 - 17 °C (OECD), 10 - 14 °C (OPPTS) and 11 - 13 °C (EPA). Between hours 48 and 72 a maximum temperature of 14.1°C and between hours 72 and 96 a maximum temperature of 14.6°C was measured with a minimal maximum thermometer. The daily measured temperature ranged from 13.2 to 14.0 °C. This deviation to the guidelines is considered to have no effect on the results of the study.
2. The guidelines recommend to use fish with a length of 5.0 ± 1.0 cm (OECD) and an individual wet weight of 0.5 to 5 g (EPA) and < 3 g (OPPTS). Three of 30 fish were smaller than the range given in the guideline: their length was 3.93, 3.94 and 3.98 cm and their weight was 0.48, 0.44 and 0.44 g, respectively. This deviation to the guidelines considered to have no impact on the interpretation of the results.

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

The test vessels were examined at start of exposure and after 2, 4, 24, 48, 72, and 96 hours for mortality, sublethal effects (behaviour, respiration, appearance), and physical characteristics (i.e. cloudiness, occurrence of precipitate, undissolved test item, particulate matter and film on surface). The pH, dissolved oxygen concentration, and temperature were measured in the control and the test concentrations daily.

Aliquots from the control, solvent control and treated test solution were taken from the test vessels at start of exposure, i.e. at hour 0, after 48 hours of exposure and at the end of exposure, i.e. at hour 96. On each sampling interval, the one aliquot from the control and solvent control and an aliquot from each replicate of the treated test solutions were taken. Aliquots were deep frozen until analysis. The aliquots from the control and the solvent control were not filtered, the test item solutions were stored filtered (Whatman GF/F filter with a nominal pore width of 0.7 µm) and unfiltered. In addition, QC samples were prepared at approximately 25 and 50 µg test item/L on each sampling interval and were analysed together with the test solutions to validate the procedures used.

The samples were concentrated using SPE filled with 1 g of Chromabond C18ec (Machary-Nagel). In general, 100 ml test solution were passed with < 100 mL/h through the conditioned column. After drying the column for at least 10 minutes by passing air through it, the test item was eluted with 5 ml Acetonitrile and made up to 10 mL with MilliQ-water.

Vehicle:

yes

Remarks:

DMF (Dimethylformamide)

Details on test solutions:

A constant flow test item delivery system equipped with syringe pumps for solvent and test item stock solution delivery and membrane pumps for dilution water delivery was employed to maintain a control, a solvent control with 0.1 ml DMF/L and a test concentration of 25 µg triflumuron/L with 0.1 ml DMF/L in the test vessels. The solvent and test item stock solution was added directly into the dilution water stream. The flow rates of stock solution and dilution water were calculated to result in the desired nominal concentrations with a test solution flow rate of 50 ml per minute. The nominal concentration of the test item stock solution was 250 mg test item per liter DMF (Dimethylformamide). The flow rate of the dilution water and the stock solutions was adjusted so that the resulting concentrations were 25 µg test item /L and 0.1 ml DMF/L. Prior to start of the exposure and frequently during the test, the flow rates were controlled for proper delivery rates. The flow rate for each aquarium was 50 mL/min resulting in 7.2 volume exchanges per day for the 10 L test solution volume.

To prepare the two stock solutions for the two sets of standards, triflumuron was diluted in Acetonitrile: MilliQ-water (50:50). These stock solutions were further diluted with Acetonitrile: MilliQ-water (50:50) in order to obtain six concentrations per set with concentrations ranging from 0.05 to 1.64 mg triflumuron/L. The solutions were measured in the following order: first set of standards, quality control samples, test solutions, and second set of standards.

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

Common name: Rainbow trout.

Source: Forellenzucht Hohler- Gasser, Zeiningen, Switzerland.

Acclimatisation: In culture water for more than 14 days prior to testing.

Feed: The fish were fed daily with a commercially prepared fish food diet (Hokovit 502).

Test type:

flow-through

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Hardness:

168 to 176 mg/L as CaCO3

Test temperature:

20°C

pH:

7.19 to 7.32

Dissolved oxygen:

8.48 mg/L.

Nominal and measured concentrations:

Nominal 25 µg test item /L, i.e. at the practical limit of the water solubility.
The mean measured concentration was 24.2 µg active substance (a.s.)/L.

Details on test conditions:

The fish were held in a 400-L polyethylene tank at a photoperiod of 16 hours light and 8 hours dark with a 30 minutes transition period. Within 14 days prior starting the exposure, the fish medium was modified EC reconstituted water (Official Journal of the European Communities, 1992) with a total hardness of 168 to 176 mg/L as CaCO3, an alkalinity of 32 to 35 mg/L as CaCO3, a specific conductivity ranging from 440 to 470 µS/cm, a pH ranging from 7.19 to 7.32, and a dissolved oxygen concentration of 8.48 mg/L. .

A representative sample (n=30) of the fish population were weighed at test termination. The average individual wet weight was 0.73 g (ranging from 0.44 g to 1.01 g) and the mean total length was 4.5 cm (ranging from 3.9 cm to 5.1 cm). In combination with the exposure test solution volume of 10 L this corresponds to a biological loading of 0.73 g/L or 0.10 g/l per 24 hours.

Fish medium consisted of deionized and subsequently reconstituted Horn well water. For deionisation, the well water was passed through a Culligan water softener with a synthetic ion exchange resin and a Culligan Series Reverse Osmosis system. Representative samples of deionised water are analysed twice a year for the presence of pesticides, PCBs, and metals. None of these compounds have been detected at concentrations that are considered toxic in any of the water samples analysed, as in agreement with ASTM standard practice E729-88 (ASTM, 1989). The fish medium was reconstituted according to the formulation given in the Official Journal of the European Communities (1992) using 65 % of the given amounts in order to reduce the hardness. The fish medium was prepared in 4000 litre batches in polypropylene resin tanks and was powerfully recirculated and allowed to "free-fall" to bring the pH and dissolved gases into equilibrium with the atmosphere. The fish medium was allowed to equilibrate for at least 24 hours prior to use. Total hardness, total alkalinity, pH, and specific conductivity of the dilution water were determined after preparing each batch to verify that these parameters were within the acceptable range.

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

>= 24.2 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

> 24.2 µg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

No acute toxicity was found at the practical limit of water solubility of the test item. Since neither sublethal effects nor mortality were observed in the treated test solution, the NOEC is >= 24.2 µg /L.

The quality criteria for the validity of the test were fulfilled since no mortality was observed in the control group, the oxygen concentration was higher than 60% of the air-saturation value and the pH varied by not more than 1 unit.

Sublethal observations / clinical signs:

No sublethal effects nor mortality were observed in the treated test solution, the NOEC is > 24.2 µg a.s./L.

Water quality: The pH ranged from 7.36 to 7.68 and the dissolved oxygen concentrations ranged from 8.09 to 9.97 mg/L (82 to 100 % of the air-saturation value). The temperatures as measured daily with a single point thermometer ranged from 13.2 to 14.0°C. The continuously measured temperature of the control test vessel ranged
from 13.1 to 14.0°C from hour 0 to 48, from 13.2 to 14.1 °C from hour 48 to 72, and from 13.1 to 14.6 °C from hour 72 to 96.

The results of the water quality measurements made during this study established that conditions maintained throughout the 96-hour exposure were satisfactory for the promotion of rainbow trout
survival. During the 96-hour exposure period, biomass loading did not exceed 0.73 g/L or 0.101 g per L per 24 hours.

 

Validity criteria fulfilled:

yes

Conclusions:

This acute toxicity study was performed in rainbow trout (Oncorhynchis mykiss), usinfg flow-through conditions. Fish were exposed for 96 hours to a single nominal concentration of 25 µg/L (measured concentration 24.2 µg/L), stated to be the practical limit of water solubility of triflumuron. No mortality or toxicity was seen at the concentration tested.
100% mortality (96 h) >24.2 µg/L
LC50 (96 h) >24.2 µg/L (mean measured)
NOEC (96 h) >=24.2 µg/L (mean measured)

Executive summary:

Triflumuron Rainbow trout (Oncorhynchus mykiss), mean body length 4.5 cm, mean body weight 0.73 g, 10 fish per replicate, all treatment levels in triplicate) were exposed in a limit test for 96 h under flow-through test conditions to control, solvent control (DMF), and nominal 25 µg test item/L, i.e. at the practical limit of the water solubility.
The mean measured concentration was 24.2 µg test item/L. All results are based on mean measured concentrations of the active substance.

Observations: In the control and solvent control group no adverse effects were observed. No acute toxicity was found at the practical limit of water solubility of the test item.

Since neither sublethal effects nor mortality were observed in the treated test solution, the NOEC is >= 24.2 µg a.s./L.

Description of key information

Acute toxicity study was performed in rainbow trout (Oncorhynchis mykiss), using flow-through conditions. Fish were exposed for 96 hours to a single nominal concentration of 25 µg/L (measured concentration 24.2 µg/L), stated to be the practical limit of water solubility of triflumuron. No mortality or toxicity was seen at the concentration tested.
LC50 (96 h) >24.2 µg/L (mean measured)
NOEC (96 h) >=24.2 µg/L (mean measured)

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

LC50

Effect concentration:

> 24.2 µg/L