methyl 2-ethoxy-3-[[4-[2-(2H-tetrazol-5-yl)phenyl]phenyl]methyl]benzimidazole-4-carboxylate

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:

August 19, 2004 - September 29, 2004

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

Name: CAN5
Batch No.: February 2004
Active Ingredient(s) l Purity: >99 % 2-ethoxy-1-[[2' -(IH-tetrazol-5-il)biphenyl-4-il]methyl]-1-H -benzimidazol-7 -methylcarboxilate
Certificate of Analysis: not available
Aggregate State at RT: solid (according to IBACON personnel)
Colour: white to yellow
Solubility: in water: < 0.1 ug/L
Stability: (i) technical product: see expiry date; (ii) in water: stable under test conditions
Expiry Date: February 2009
Storage: in original container, at room temperature, in the dark

Analytical monitoring:

no

Details on sampling:

Pre-experiments
Pre-experiments were performed to determine the solubility of the test item in test water and to select suitable methods for the preparati an of a stock solution and the dosage of the test item into the test media.

Range-finding
For the determination of the test concentrations a range-finding test was performed.

Test concentration
100 mg test item/L

Control
In the control, test water was used without addition of the test item.

Vehicle:

yes

Details on test solutions:

Dosage of test item
The test item was not well soluble in test water. To avoid physical effects of undissolved test item on Daphnia no concentrations above the solubilty limit of the test item in test water were tested. Therefore, a stock suspension of 100 mg test item/L was prepared by suspending 50 mg test item in
500 mL test water. The suspension was stirred for 24 hours to dissolve as much test item as possible. Then, the undissolved test item was separated by filtration (0.45 um cellulose nitrate filter). The test media was prepared just before introduction of the Daphnia (= start ofthe test).

Test organisms (species):

Daphnia magna

Details on test organisms:

Introduction
20 Daphnia per control and test concentration, divided into 4 groups of 5 anirnals, each group in 80 mL test medium.

Feeding
The test organisms will not be fed during the test.

Exposure time
48 hours

Test procedure
The test item is considered as stable in test water, so a static test system was chosen.

Species:
Daphnia magna (Straus), clone 5

Age at test start:
6.75 hours to 22.5 hours old

Sex:
Female

origin.
supplied 1997 by the Umweltbundesamt, Institut fur Wasser-, Boden- und Lufthygiene, Berlin, Gennany

Breeding Condition
The Daphnia were bred in the laboratories of IBACON under similar temperature and light conditions as in the test, and in reconstituted water of a similar quality regarding to pH, components of the main ions and total hardness as the test water used in the test. The test organisms were not first brood progeny. The Daphnia of the stock culture were fed at least each working day with green algae (Desmodesmus
subspicatus) freshly grown in the laboratories of IBACON.

Toxic Standard
For the evaluation of the quality of the Daphnia clone and the experimental conditions the substance potassium dichromate p.A. is tested at least twice a year to demonstrate satisfactory test conditions.
Result of the la test reference test:
48-hour EC 50: 2.12 mg potassium dichromate/L
(confidence limits: 1.02 - 4.40 mg/L)
Study completion date: February 19, 2004

Acclimatisation
for 6.75 hours under test conditions.

Test type:

static

Water media type:

other: Reconstitued water

Limit test:

yes

Total exposure duration:

48 h

Post exposure observation period:

The immobility or mortality of the Daphnia was determined by visual controls after 24 and 48 hours. Those animals not able to swim within 15 seconds after gentle agitation of the test beaker were considered to be immobile.

Hardness:

Water Hardness 2.5 mmol/L (= 250.0 mg/L) as CaC03

Test temperature:

20-21 °C

pH:

7.6-7.9

Dissolved oxygen:

The dissolved oxygen concentrations were determined at test start and end in the test media of the only test concentration and the control. The water temperature was measured in one control beaker at the start and the end of the test.

Salinity:

In deionised water analytical grade salts were added to following nominal concentrations:
CaCl2 x 2H2O 2.0 mmol/L (= 294.0 mg/L)
MgSO4 x 7H2O 0.5 mmol/L (= 123.0 mg/L)
NaHCO3 0.75 mmol/L (= 65.0 mg/L)
KCl 0.075 mmol/L (= 5.8 mg/L)
Alkalinity 0.8 mmol/L
Ratio of Ca: Mg = 4 : 1 (based on molarity)
Na : K = 10 : 1 (based on molarity)

Conductivity:

conductivity < 5 µS/cm

Nominal and measured concentrations:

Nominal 100 mg/L

Details on test conditions:

Type and Size:
Glass beakers of l 00 mL volume with 80 mL test medium

Identification:
Each test unit was uniquely identified with study number, treatrnent and replicate number.

Reference substance (positive control):

yes

Remarks:

For the evaluation of the quality of the Daphnia clone and the experimental conditions the substance potassium dichromate p.A. is tested at least twice a year to demonstrate satisfactory test conditions.

Key result

Duration:

24 h

Dose descriptor:

other: Mortality or immobilization

Effect conc.:

ca. 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Mortality or immobilization

Remarks on result:

other: After 24 hours in the control and in the test concentration no mortality or immobilization of the test animals was observed

Key result

Duration:

24 h

Dose descriptor:

NOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Toxicity

Remarks on result:

other: After 24 hours in the control and in the test concentration no mortality or immobilization of the test animals was observed

Key result

Duration:

48 h

Dose descriptor:

other: Mortality or immobilization

Effect conc.:

ca. 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Mortality or immobilization

Remarks on result:

other: After 48 hours in the control and in the test concentration no mortality or immobilization of the test animals was observed

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: Mortality or immobilization

Remarks on result:

other: After 48 hours in the control and in the test concentration no mortality or immobilization of the test animals was observed

Details on results:

Validity Criteria of the Study
Control:
The experiment is valid because the mortality of Daphnia magna in the control did not exceed 10 % and no Daphnia were trapped at the water surface.

Dissolved Oxygen Concentration:
At the end of the test the dissolved oxygen concentration in the test media was > = 2 mg O2/L in the control and test vessels.

Signs of intoxication after 24 hours:
After 24 hours in the control and at all test concentrations no mortality or immobilization of the test animals was observed.

Signs of intoxication after 48 hours:
After 48 hours in the control and at all test concentrations no mortality or immobilization of the test animals was observed.

pH-Values: 6.7 to 7.9
Dissolved Oxygen Concentrations: at least 5.9 mg/L or higher
Water Temperature: 20-21 °C
Behaviour of the Test Item: no remarkable observation.

Validity criteria fulfilled:

yes

Conclusions:

After 24 and 48 hours in the test concentration no mortality or immobilization of the test animals was observed.

Executive summary:

Results after 24 hours

After 24 hours in the control and in the test concentration no mortality or immobilization of the test animals was observed. The 24-hour NOEC of CAN5 to Daphnia magna was determined to be at least nominai 100 mg test item/L. The NOEC might even be higher than this concentration, but concentrations in excess of nominai 100 mg test item/L have not been tested. The 24-hour LOEC were clearly higher than nominal 100 mg test item/L. This value could not be quantified due to the absence of toxicity of CAN5 up to the tested concentration.

Results after 28 hours

After 48 hours in the control and in the test concentration no mortality or immobilization of the test animals was observed. The 48-hour NOEC of CAN5 to Daphnia magna was determined to be at least nominai 100 mg test item/L. The NOEC might even be higher than this concentration, but concentrations in excess of nominai 100 mg test item/L have not been tested. The 48-hour LOEC were clearly higher than nominai 100 mg test item/L. This value could not be quantified due to the absence of toxicity of CAN5 up to the tested concentration.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

100 mg/L

Additional information

Chronic toxicity data are not available for the substance (CAN 5). Short-term toxicity data on Daphnia magna (Daphnia magna in a 48-hour immobilization Test) is available for CAN 5; as a result of this test no effect was observed up to 100 mg/L (higher tested concentration). Therefore, EC50 value is estimated to be higher than 100 mg.

Moreover, the log Kow of CAN5 is ≥ 4.

 

Available data are regarded as conclusive in order to exclude the classification of the substance for this hazard.