[No public or meaningful name is available]

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)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Test guideline 3

Qualifier:

according to guideline

Guideline:

ISO 6341 (Water quality - Determination of the Inhibition of the Mobility of Daphnia magna Straus (Cladocera, Crustacea))

Test guideline 4

Qualifier:

according to guideline

Guideline:

other: Guidance document on aquatic toxicity testing of difficult substances and mixtures, OECD series on testing and assessment number 23, December 14, 2000

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Samples were taken from the undiluted filtrate and the control. The filter containing the undissolved test substance residue was also retained for possible analyses. Frequency: at t=0h and t=48h; volume: 2ml from the approximate centre of the test vessels; storage: samples were stored in a freezer until analysis.

Test solutions

Vehicle:

yes

Details on test solutions:

Preparation of test solutions started with an aqueous mixture that was prepared at a loading rate of 100mg/l. The mixture was magnetically stirred for two days and subsequently filtered through a 0.45µm membrane filter (Whatman RC55) until all undissolved material was removed. The resulting clear and colourless filtrate was used as highest test concentration. Two lower concentrations were prepared by subsequent dilution in test medium (containing 1 and 10% of the filtrate).

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

Straus, at least third generation, obtained by acyclical parthenogenesis under specified breeding conditions

Study design

Test type:

static

Limit test:

yes

Remarks on exposure duration:

Medium: several chemicals, trace elements, macro nutrients and vitamins dissolved in tap water purified by reverse osmosis. Combined limit/range-finding test.

Test conditions

Hardness:

180mg/l expressed as CaCO3

Test temperature:

19.9 - 20.8°C

pH:

7.9 - 8.1

Dissolved oxygen:

8.3 - 9.3µg/l

Details on test conditions:

number of daphnids: control and filtrate: 20 per concentration, filtrate dilutions: 10 per concentration; loading: 5 per vessel containing 80mg of test solution; light: 16hours of photoperiod daily; no feeding; no aeration of test solutions; introduction of daphnids: +/- half an hour after preparation of the test solutions

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

4.8 µg/L

Nominal / measured:

meas. (geom. mean)

Basis for effect:

mobility

Remarks:

including mortality

Effect concentrations 2

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 4.8 µg/L

Basis for effect:

mobility

Remarks:

including mortality

Remarks on result:

other: No EC50 could be calculated because the test substance proved to be non-toxic (EC50 > maximum soluble concentration).

Effect concentrations 3

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 4.8 µg/L

Basis for effect:

mobility

Remarks:

including mortality

Remarks on result:

other: No EC50 could be calculated because the test substance proved to be non-toxic (EC50 > maximum soluble concentration).

Details on results:

Calibration curves were constructed using five concentrations. Linear regression analysis was performed using the least squares method with a 1/concentration weighting factor. The coefficient of correlation (r) was >0.99 for each curve.

Results with reference substance (positive control):

The 24h-EC50 was 0.52mg/l with a 95% confidence interval between 0.48 and 0.60mg/l.
The 48h-EC50 was 0.38mg/l with a 95% confidence interval between 0.34 and 0.45mg/l.
The sensitivity of this batch of D. magna was in agreement with the historical data collected at Notox.

Any other information on results incl. tables

The 48h-EC50 is related to a concentration measured in a 0.45µm filtered solution prepared at a loading rate of 100mg/l. This was a factor of at least 3 above the limit of solubility in water (0.0016mg/l). Hence, due to the limited solubility in test medium, concentration levels toxic for Daphnia magna could not be reached.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

In the control, no daphnids became immobilised. The oxygen concentration at the end of the test was >=3mg/l in control and test vessels. No protocol deviations. No deviations from standard operating procedures that affected the integrity of the study.

Conclusions:

Due to the high log Pow (>4), the low water solubility (<1mg/l), the 48EC50 and 72LC50 which might both be >100mg/l and the non-readily biodegradability, the substance should be classified for 'chronic aquatic toxicity' (DSD: R53, CLP: cat.4).