Disodium disilicate

Short-term toxicity to aquatic invertebrates

Description of key information

In this study disodium disilicate (delta-crystalline) was found to be toxic to Daphnia magna after 48 h at nominal test item concentrations of 500 mg/L (LOEC48 h) and higher. The EC50 (48 h) was calculated to be 491 mg/L (CI: 454 – 531 mg/L). The NOEC after 48 hours was 250 mg/L. All effect values are given based on the nominal concentrations of the test item disodium disilicate (delta-crystalline).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

491 mg/L

Additional information

The acute immobilization of the test item disodium disilicate (delta-crystalline) (batch number: DEH9001216) to Daphnia magna (STRAUS) was performed according to OECD 202 (2004). 20 test organisms were exposed to each test concentration and control.The study was conducted with 5 nominal test item concentrations ranging from 125 to 2000 mg/L set up in a geometric series with a dilution factor of 2 under static conditions over a period of 48 h. The Silicon content as a component of the test item, disodium disilicate (delta-crystalline), was analysed via UV-spectrophotometry in all test item concentrations,and the pH was controlled after 0 h and 48 h. The recovery rates of Silicon in fresh (0 h) and old media (48 h) of the tested concentration levels were ranging from 88% to 105% of nominal values. Water quality parameters (pH-value and dissolved oxygen concentration), measured at 0 h and 48 h, were determined to be within acceptable limits. The validity criteria of test guidelines were fulfilled.

In this study disodium disilicate (delta-crystalline) was found to be toxic to Daphnia magna after 48 h at nominal test item concentrations of 500 mg/L (LOEC48 h) and higher. The EC50 (48 h) was calculated to be 491 mg/L (CI: 454 – 531 mg/L). The NOEC after 48 hours was 250 mg/L.