1,2,4-triazolo[4,3-a]pyridin-3(2H)-one

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

1,2,4-triazolo[4,3-a]pyridin-3(2H)-one

EC Number:

230-191-8

EC Name:

1,2,4-triazolo[4,3-a]pyridin-3(2H)-one

Cas Number:

6969-71-7

Molecular formula:

C6H5N3O

IUPAC Name:

[1,2,4]triazolo[4,3-a]pyridin-3(2H)-one

Details on test material:

Batch number : 09-378
Preparation date : February 19, 2010
Expiry date : July 19, 2010
Storage conditions : Room temperature / dark conditions

Test solutions

Vehicle:

yes

Details on test solutions:

The main test included five different concentrations of test item, namely 1.0, 3.2, 10.0, 31.6 and 100.0 mg/L.

The test medium was prepared as follows: prior to the start of the test, a stock solution of 100.0 mg/L was prepared by direct weighing into reconstituted water. The obtained solution showed brown insoluble particles, therefore it was mixed by the mean of a magnetic stirrer for about 48 hours to achieve the maximum solubilisation of test item and then it was filtered by a cartridge filter (pore diameter 0.45 um) to obtain a clear solution. The test concentrations were then prepared by taking adequate aliquots of obtained solution and diluting them in aerated reconstituted water.
A negative control with only reconstituted water was tested.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

A strain of the freshwater crustacean Daphnia magna Straus was originally supplied by the Italian Health Department (Istituto Superiore di Sanità) in September 2004. Since that time, the clone has been bred in ChemService laboratories in reconstituted water with the same characteristic to the water used in the tests (as for pH, main ions, and total hardness) and under temperature and light conditions identical to those of the tests. The daphnia breeding was daily fed with a fixed amount of green algae Pseudokirchneriella subcapitata (formerly Selenastrum capricornutum) cultivated in the ChemService Laboratory and with a suspension of the yeast Saccharomyces cerevisiae.

At the start of the test, the organisms used in the test were 6-24 hours old and were not first brood progeny.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Test conditions

Hardness:

140 - 250 mg/L as CaCO3

Test temperature:

The incubation temperature was continuously monitored during the course of the study by the means of a data logger. The measured values ranged between 20.1 and 21.5 °C during the test period.

pH:

The pH of the test medium after preparation was in the range 7.41 – 7.98 for test item solutions and 7.30 for control, therefore, the pH of the test medium was not adjusted before the start of the test.

Details on test conditions:

The test was performed in 50 mL glass beakers filled with 40 mL of test medium. The beakers were covered with glass plates to reduce the loss of water and to avoid the entry of dust into the solutions.

For each test concentrations and for the control, 20 daphnids were used divided into four replicates of five daphnids each. The daphnids were randomly distributed to the test vessels at initiation of the test. The daphnid’s loading rate was greater than one daphnid per 2 mL of test solution.

Reference substance (positive control):

yes

Remarks:

potassium chromate (in a test run on December 2009)

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

3.2 mg/L

Nominal / measured:

nominal

Effect concentrations 2

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

10 mg/L

Nominal / measured:

nominal

Effect concentrations 3

Duration:

48 h

Dose descriptor:

IC50

Effect conc.:

80.5 mg/L

Nominal / measured:

nominal

Remarks on result:

other: 45.2 – 123.4

Results with reference substance (positive control):

Effect of potassium dichromate on Daphnia magna:

24 h IC50 (mg/L) Confidence interval (95%, mg/L)
ChemService study 0.71 0.66 – 0.76
Reference data
(UNI EN ISO 6341/99) 0.6 – 2.1

Any other information on results incl. tables

At the end of test period, in the negative control 0% of immobilization was observed and no daphnid was found trapped on the test water surface. These values comply with the validity criteria of the test, that provide a maximum immobilization and/or a maximum number of daphnids trapped in to water surface of 10% in the control medium at the end of the test.

 

The obtained experimental results allowed to calculate the NOEC, the LOEC and the IC₅₀at 24 and 48 h. The results are as follows:

 

Time	NOEC (mg/L)	LOEC (mg/L)
24 h	31.6	100.0
48 h	3.2	10.0

 

Time	IC50(mg/L)	95% Confidence range (mg/L)
24 h	100.0	100.0 – 100.0
48 h	80.5	45.2 – 123.4

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

IC50 24 h = 100.0 mg/L
IC50 48 h = 80.5 mg/L