Registration Dossier

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Additional information

Reliable short-term toxicity tests results are available for species of freshwater fish (Oncorhynchus mykiss), invertebrate (Daphnia magna) and algae (Pseudokirchneriella subcapitata). LC50 or EC50 values for the three organisms were 39, 24 and 9 (72 h)/11 mg/l (96 h) respectively, based on mean measured concentrations. NOECs of 1.1 mg/l (72 h) and 2.2 mg/l (96 h) were determined in the algal test, based on mean measured concentrations. The measured data are within the limit of solubility of the substance (510 mg/l), although condensation reactions are expected to occur at concentrations in the range 25-100 mg/l. The test substance was measured in solution but visual observations of particulate material were reported in the fish and invertebrate studies at the higher test concentrations (30 and 50 mg/l for fish and 100 mg/l for invertebrates, based on nominal concentrations).

During the fish test there were no effects seen in the absence of precipitates, so it is inconclusive whether this test shows a silanol dose-response or evidence of physical effects. For the invertebrate test evidence of polymerisation was observed in the highest loading level (100 mg/l, nominal concentration) but the EC50 value is below this concentration and so dose response from lower levels has been attributed to monomeric silanol. No precipitate was observed during the algae test and test solution concentrations were below the concentration where condensations reactions are expected to occur, therefore dose-response is attributed to the test substance.

No long-term data are available for the registered substance.