2-[[4-[ethyl(2-hydroxyethyl)amino]phenyl]azo]-6-methoxy-3-methylbenzothiazolium chloride

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:

26.-28.11.1991

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)

Version / remarks:

Part I, 1984

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

No data.

Vehicle:

no

Details on test solutions:

No data.

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: water flea
- Strain/clone: n.a.
- Source: daphnids were bred in the laboratories of the TF Product Ecology under standardized conditions
- Age of parental stock (mean and range, SD): < 24 h

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

136 mg/L CaCO3
Alkalinity: 0.8 mmol/L

Test temperature:

21 °C

pH:

7.8 - 8.2

Dissolved oxygen:

Test media were saturated with oxygen at the beginning of the test.

Salinity:

no data

Conductivity:

no data

Nominal and measured concentrations:

nominal: 0.1, 0.18, 0.32, 0.58 and 1.0 ppm
measured mean concentration: 0.08, 0.14, 0.25, 0.45, 0.78 ppm

Details on test conditions:

TEST SYSTEM
- Test vessel: beaker
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: 250 ml beakers containing 100 ml test medium
- Aeration: no
- Type of flow-through (e.g. peristaltic or proportional diluter): n.a.
- Renewal rate of test solution (frequency/flow rate): /
- No. of organisms per vessel: 10
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 2

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: bidistilled water
- Alkalinity: 0.8 mmol/L
- Ca/mg ratio: 4:1
- Intervals of water quality measurement: at beginning and at end of the test

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16 h light, 8 h dark
- Light intensity: no data

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : mobility after 24 and 48 h

VEHICLE CONTROL PERFORMED: yes (blank control)

RANGE-FINDING STUDY
- Test concentrations: no details reported
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

0.17 other: ppm

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95% confidence limit

Remarks:

0.14 - 0.19

Duration:

48 h

Dose descriptor:

EC0

Effect conc.:

0.08 other: ppm

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

0.45 other: ppm

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Test evaluations were done according to the guidelines by visual assessment of the mobility of the daphnids after 24 and 48 hours.
The EC50 was calculated by using the Probit model and by graphical determination on logarithmic probability paper.
The concentration of the test substance at the beginning and at the end of the test was analysed by the analytical Service Klybeck.

Results with reference substance (positive control):

EC50 (24 h) = 0.9 ppm (range: 0.8 - 1.5 ppm)

1) Analytical results of test substance measurements:

Nominal concentration [ppm]	Concentration start [ppm]	Concentration end [ppm]	Mean value* [ppm]
0.10	0.08	0.07	0.08
0.18	0.14	0.13	0.14
0.32	0.26	0.23	0.25
0.58	0.47	0.42	0.45
1.00	0.80	0.75	0.78

* used for calculation of EC₅₀ value

2) Oxygen concentration and pH

The oxygen concentration and the pH was controlled at the beginning and at the end of the test.

Start:        - Oxygen: saturated

- pH: 8.0 (highest test concentration)

- Temp.: 21° C

End:

Nominal Conc. [ppm]	0.1	0.18	0.32	0.58	1.0	Blanc
Oxygen [%]	96	96	96	97	96	97
pH	7.9	7.8	7.9	7.9	7.9	7.7
Temp. [°C]	21	21	21	21	21	21

 

3) Influence of the Test Item on the immobilisation of Daphnia magna:

Nominal concentration [ppm]	No. of animals	No. of responses		Immobility [%]*
		24 h	48 h	24 h	48 h
0 (Blank)	10	0	0	0	0
	10	0	0
0.08	10	0	0	0	0
	10	0	0
0.14	10	1	4	5	20
	10	0	0
0.25	10	9	9	95	95
	10	10	10
0.45	10	9	10	90	100
	10	9	10
0.78	10	10	10	100	100
	10	10	10

 * calculated for 20 animals

Validity criteria fulfilled:

yes

Conclusions:

The 48-h EC50 of the test item to Daphnia magna under the conditions of the OECD test guideline 202 is 0.17 ppm.

Executive summary:

The 48h acute toxicity of the test item to Daphnia magna was studied under static conditions. Daphnids were exposed to 0 (blank control), 0.08, 0.14, 0.25, 0.45, 0.78 ppm (measured concentration). Mortality/immobilisation were observed daily.  The 48h EC₅₀was 0.17 ppm. The 48h EC₀ based on mortality/immobilisation was 0.08 ppm. 

 

Based on the results of this study, the test item would be classified in category Chronic 1 in accordance with the classification system of the GHS.

 

This study is classified as acceptable and satisfies the guideline requirements for an acute toxicity study with freshwater invertebrates.

 

Results Synopsis

Test Organism Age (e.g. 1^stinstar): < 24 h

Test Type: Static

 

EC₀:  0.08 ppm

EC₅₀:  0.17 ppm                       95% C.I.:  0.14 -0.19 ppm

Endpoint(s) Effected:  mortality/immobilisation

Description of key information

The 48h acute toxicity of the test item to Daphnia magna was studied under static conditions in accordance with OECD test guideline 202. Daphnids were exposed to 0 (blank control) and mean measured concentrations of 0.08, 0.14, 0.25, 0.45, 0.78 ppm. The 48h EC₅₀ was 0.17 ppm. 

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.17 mg/L