2,2'-(vinylenedi-p-phenylene)bis[5-methylbenzoxazole]

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:

February from 14th to 16th, 2001

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

adopted 4 April 1984

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

adopted 25 April 1984

GLP compliance:

no

Analytical monitoring:

no

Details on test solutions:

Due to the limited water solubility of the test material in the respective concentrations, it was moderately stirred in Daphnia medium tor 24 h at room temperature. After this incubation time, the undissolved materials were removed by filtration. The resulting water accomodated fraction was used in the test.

Test organisms (species):

Daphnia magna

Details on test organisms:

ACCLIMATION
- Acclimation period: daphnia, which had been selected in size, were acclimatized to the reconstituted water for 4 hours before introduction into the test media.

BREEDING
- Vessel: parental and young Daphnia were held in 250 l glass aquaria.
- Photoperiod: 16 h per day.
- Temperature: 20 ±.2 °C
- Medium: continuously aerated reconstituted water (lSO 6341 (5)); prepared with distilled water (conductivity < 1.5 µS/cm). The final test medium contained 25 ml/l of each of the following four stock solutions: CaCl2 x 2 H2O 11.76 g/l; MgSO4 x7 H2O 4.93 g/l; NaHCO3 2.59 gll; KCl 0.23 g/l. The sum of the ca and Mg ions in this solution is 2.5 mmol/I. The ratio of ca:Mg ions is 4:1 and of Na:K ions is 10:1. The total alkalinity of this solution is 0.8 mmol/l. The bottom of the aquaria is covered with gravel (<1.5 cm). Every month, 25 % of the total volume of the aquaria is replaced by fresh water.
- Feed: 15 g sera micropan (sera GmbH, D-52525 Heinsberg) homogenized in 1 l deionised water.
- Frequency of feeding: once a day, except weekends.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test temperature:

20.0 ± 0.5 °C

pH:

Test vessels: 7.0 - 7.9
Control: 7.1 - 7.7

Dissolved oxygen:

Test vessels: 6.2 - 6.9 mg/l
Control: 6.7 - 6.9 mg/l

Details on test conditions:

TEST SYSTEM
- Test vessel: 100 ml flasks, all-glass, with 50 ml of test medium.
- Aeration: no.
- No. of organisms per vessel: 20 per vessel
- No. of vessels per concentration: 2 replicates.
- No. of vessels per control: 3 replicates.

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reconstituted water (lSO 6341), not aerated.

OTHER TEST CONDITIONS
- Adjustment of pH: the pH was not adjusted before the test.
- Photoperiod: 16 h photoperiod a day, supplied by overhead white fluorescent tubes.

PARAMETERS MEASURED
- Temperature: determined in a control flask at the start and at the end of the test.
- Oxygen, pH: determined in all vessels prior to the addition of Daphnia to the test medium and at the end of the test.

EFFECT EVALUATED
Those individuals not able to swim within 15 s after gentle agitation of the test vessel were considered to be immobile.
Observations of immobile Daphnia were made atter 24 and 48 h of exposure.

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

loading rate

Basis for effect:

mobility

Details on results:

Since no effects were observed, the full test was omitted.
For the evaluation of the test the nominal content of the test solution was used, assuming the test compound to be stable in water over 48 h.
At all loading rates no significant effects (<10 % immobilization) were observed after 24 and 48 h of exposure.

No significant toxic effects were also observed in the control after 24 and 48 h of exposure, respectively.

Vessel	No of organisms	lmmobile Daphnia		% immobilization
		24 hrs	48 hrs	24 hrs	48 hrs
Control (A)	20	0	1	0	5
Control (B)	20	0	1	0	5
Control (C)	20	0	1	0	5
Test item 1 mg/l (A)	20	1	1	5	5
Test item 1 mg/l (B)	20	0	0	0	0
Test item 10 mg/l (A)	20	0	0	0	0
Test item 10 mg/l (B)	20	0	1	0	5
Test item 100 mg/l (A)	20	0	0	0	0
Test item 100 mg/l (B)	20	0	0	0	0

Conclusions:

ELr50 (48h) > 100 mg/l (nominal)

Executive summary:

The acute toxicity of the substance to Daphnia magna was investigated under static exposure conditions over a period of 48 h. A screening test with nominal concentrations of 100, 11 and 1 mg/l, respectively, was performed.

40 individual Daphnia divided in 2 test vessels were exposed to each concentration of the test substance.

Due to the limited water solubility of the test material, test item in concentrations of 1, 10 and 100 mg/l was moderately stirred in Daphnia medium for 24 h at room temperature. After this incubation time, the undissolved materials were removed by filtration. The resulting water accomodated fractions were used in the tests. No chemical analysis of the test media was conducted.

For the valuation of the test the nominal content of the test solution was used, assuming the test compound to be stable in water over 48 h.

At all loading rates no significant effects (<10 % immobilization) were observed after 24 and 48 h of exposure. No significant toxic effects were also observed in the control after 24 and 48 h of exposure, respectively.

Based on these results of the study, it can be concluded that the 24 and 48 h EC0 values of the substance with respect to the loading rate is equal/higher than 100 mg/l. The EC50 value after 24 and 48 h of exposure is higher than 100 mg/l with respect to the loading rate.

Conclusion

ELr50 (48h) > 100 mg/l (nominal)

Description of key information

Not harmful/toxic to aquatic invertebrates, after short-term exposure.

Additional information

The acute toxicity of the substance to Daphnia magna was investigated under static exposure conditions over a period of 48 h. A screening test with nominal concentrations of 100, 11 and 1 mg/l was performed. Due to the limited water solubility of the test material, test item in concentrations of 1, 10 and 100 mg/l was moderately stirred in Daphnia medium tor 24 h at room temperature. After this incubation time, the undissolved materials were removed by filtration. The resulting water accomodated fractions were used in the tests. No chemical analysis of the test media was conducted. At all loading rates no significant effects (<10 % immobilization) were observed after 24 and 48 h of exposure. No significant toxic effects were also observed in the control after 24 and 48 hours of exposure.

In order to support the study outcomes, data on the structural analogue Similar Substance 01 has also been taken into conderation. The read across approach can be considered as suitable and appropriate to investigate the potential for aquatic toxicity of Fluorescent Brightener 002 (the read across approach is detailed in section 13).

The acute toxicity of Similar Substance 01 to Daphnia magna was investigated under static exposure conditions, over a period of 48 h. The only applied test concentration was 100 mg/l nominal concentration; the final test concentration was prepared by dilution of a stock solution of the test substance. No chemical analysis of the test media was conducted. At the nominal concentration assayed less than 10 % of the Daphnia were immobile after 24 and 48 hours of exposure.

In both the cases, no acute adverse effects were recorded at the highest tested dosages; thus, the substance resulted to be not harmful/toxic to aquatic invertebrates, after short-term exposure.