Xanthylium, 3,6-bis(ethylamino)-9-[2-(methoxycarbonyl)phenyl]-2,7-dimethyl-, molybdatetungstatephosphate

Short-term toxicity to aquatic invertebrates

Description of key information

Exposure of Daphnia magna to the test item has been investigated and gave the following results based on the 0-Hour measured test concentrations: 48 hour EC50: 0.99 mg/L

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.99 mg/L

Additional information

Introduction:

A study was performed to assess the acute toxicity of the test item to Daphnia magna. The method followed was designed to be compatible with the OECD Guidelines for Testing of Chemicals (April 2004) No 202, "Daphnia sp., Acute Immobilisation Test" referenced as Method C.2 of Commission Regulation (EC) No. 440/2008.

Methods:

Information provided indicated that the test item was insoluble in water.

 

Preliminary solubility work conducted indicated that it was not possible to obtain a testable solution of the test item using traditional methods of preparation e.g. ultrasonication and high shear mixing.

 

A media preparation trial indicated that a dissolved test item concentration of approximately 0.78 mg/L was obtained from a saturated solution method of preparation indicating this to be the limit of water solubility of this item under test conditions.

Following a preliminary range-finding test, twenty daphnids (4 replicates of 5 animals) were exposed to an aqueous solution of the test item at measured concentrations of 1.0, 3.2, 10, 32 and 100% v/v saturated solution for 48 hours at a temperature of approximately 21°C under static test conditions. The test item solutions were prepared by stirring an excess (50 mg/L) of test item in test water using a propeller stirrer at approximately 1500 rpm for 24 hours. After the stirring period any undissolved test item was removed by filtration (0.2 µm Sartorius Sartopore filter, first approximate 1 liter discarded in order to pre-condition the filter) to produce a saturated solution of the test item. This saturated solution was then further diluted as necessary, to provide the remaining test concentrations.  Immobilization and any adverse reactions to exposure were recorded after 24 and 48 hours.

Results:

Analysis of the test preparations at 0 hours showed measured test concentrations to range from 0.047 to 4.4 mg/L. There was no significant change in the measured concentrations at 48 hours and so the results are based on 0-Hour measured test concentrations only.

Exposure of Daphnia magna to the test item gave the following results based on the 0-Hour measured test concentrations:

Time Point (Hours)	EC50 (mg/L)	95% Confidence Limits (mg/L)			No Observed Effect Concentration (NOEC) (mg/L)	Lowest Observed Effect Concentration (LOEC) (mg/L)
48	0.99	0.70	-	1.4	0.047	0.14