1,2,4-triazole-3-thiol

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

As already stated in study plan chapter 4.2, switching from M4-medium (husbandry) to Dilution water (test) has been shown not to cause any detrimental effects for test daphnia, therefore no acclimation period of 48 h was performed. This is a deviation from OECD Guideline No. 202 and EU-Method C.2, which can be considered uncritical.

Deviations:

yes

Remarks:

see Version/remarks

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

1,2,4-triazole-3-thiol

EC Number:

221-656-6

EC Name:

1,2,4-triazole-3-thiol

Cas Number:

3179-31-5

Molecular formula:

C2H3N3S

IUPAC Name:

4H-1,2,4-triazole-3-thiol

Test material form:

solid: crystalline

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

yes

Details on test solutions:

A stock solution containing 10.2 mg/L test item in dilution water was prepared. The lower treatments were prepared by dilution of this stock solution with dilution water.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

Species Daphnia magna
Authority STRAUS
Strain Berlin
Sex female
Age between 0 and 24 hours
Origin Umweltbundesamt Berlin
In-house breeding since 27. September 2007

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Remarks on exposure duration:

24 and 48 hours observation

Test conditions

Hardness:

Parameter Concentration in mg/L
CaCl2*2H2O 293.80
MgSO4*7H2O 123.30
NaHCO3 64.80
KCl 5.80

Test temperature:

19.1 – 20.1 °C

pH:

7.2 -7.7

Dissolved oxygen:

8.4 -9.6 mg/L

Nominal and measured concentrations:

Nominal Concentration Test Item Geometric Mean of
measured concentrations
mg/L mg/L
Blank control --
0.1 0.05
0.22 0.15
0.46 0.37
1 0.86
2.2 2.03

Reference substance (positive control):

yes

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.4 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

Key result

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

0.98 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 3

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

0.15 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 4

Key result

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

0.37 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

One valid experiment was performed.
The study was performed using 5 concentrations ranging from 0.1 to 2.2 mg/L nominal concentration. For each test concentration and the blank control, 20 daphnia were exposed to the test item for 48 hours in a static test system. After 23 and 47 hours, the immobilised daphnia were counted.
Three concentrations showed toxicity between 30 and 100% immobilisation. None of the animals was immobilised in the blank control.
Potassium dichromate K2Cr2O7 (CAS No. 7778-50-9) was used as positive control in a current reference study to assure that the test conditions are reliable.

At the beginning and at the end of the test, the content of the test item in the test solutions was determined using HPLC-UV -determination. The concentrations determined at the start of the test were between 75 % and 82 % of the nominal concentration. At the end of the test the determined concentrations were between 39 % and 104 % of the nominal concentration. Therefore, the determination of the biological results was based on the geometric mean of measured concentrations (see OECD Guideline No. 202).
No observations were made which might cause doubts concerning the validity of the study outcome. All validity criteria were met.
The result of the test is considered valid.

Executive summary:

One valid experiment was performed. The study was performed using 5 concentrations ranging from 0.1 to 2.2 mg/L nominal concentration. For each test concentration and the blank control, 20 daphnia were exposed to the test item for 48 hours in a static test system. After 23 and 47 hours, the immobilised daphnia were counted. Three concentrations showed toxicity between 30 and 100% immobilisation. None of the animals was immobilised in the blank control. Potassium dichromate K₂Cr₂O₇(CAS No. 7778-50-9) was used as positive controlin a current reference study to assure that the test conditions are reliable. At the beginning and at the end of the test, the content of the test item in the test solutions was determined using HPLC-UV-determination. The concentrations determined at the start of the test were between 75 % and 82 % of the nominal concentration. At the end of the test the determined concentrations were between 39 % and 104 % of the nominal concentration. Therefore, the determination of the biological results was based on the geometric mean of measured concentrations (see OECD Guideline No. 202). The following results were determined for the test item 3-Mercapto-1,2,4-triazole (species: Daphnia magna).

 

48h-NOEC= 0.15 mg/L
48h-LOEC = 0.37 mg/L
24h-EC₅₀= 0.98 mg/L
48h-EC₅₀= 0.40 mg/L