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Ecotoxicological information

Long-term toxicity to fish

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fish early-life stage toxicity
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study scientifically not necessary / other information available
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Description of key information

The chemical safety assessment according to Annex I of Regulation (EC) No 1907/2006 does not indicate the need to investigate further the long-term toxicity to fish.

Key value for chemical safety assessment

Additional information

According to Regulation (EC) No. 1907/2006, Annex IX, Column 2, 9.1.6, long-term toxicity testing shall be proposed by the registrant if the chemical safety assessment according to Annex I indicates the need to investigate further the effects on aquatic organisms.  Experimental data on the chronic aquatic toxicity of soluble silicates are not available. However, soluble silicates have been demonstrated to be not acutely toxic to aquatic organisms. Short-term toxicity tests with fish, aquatic invertebrates, and algae resulted in effect concentrations (EC50 and LC50) above 100 mg/L. Furthermore, soluble silicates have no potential to bioaccumulate in organisms nor is the substance classified for any human health effects which are subject to “T” classification according to REACh legislation. Additionally, dissolved silica is indistinguishable from naturally dissolved silica, which is ubiquitous in the environment. Depending on pH values, reaction with naturally occurring dissolved polyvalent metals such as Ca, Mg, Fe, and Al, will result in insoluble silicates or amorphous silica being formed. These products occur in abundance in natural soils and rocks. In fact, silica is the second most abundant element on earth (HERA, 2005; OECD SIDS, 2004). Silicon is also the primary constituent of the frustules of diatoms and is taken up by diatoms from the ambient water and incorporated into their skeleton (HERA, 2005). Due to the natural adaptation of organisms to silicon, it can be assumed that the additional input of anthropogenic soluble silicates will not lead to an increased hazard potential for aquatic organisms. Chronic aquatic toxicity is therefore not anticipated. In addition, according to the Guidance on information requirements and chemical safety assessment Chapter R.7b: Endpoint specific guidance, R. (ECHA, 2014), long-term testing of fish should only be conducted if it represents the most sensitive taxonomic group. The available short-term toxicity studies on fish and Daphnia determined no adverse effect on any of the trophic levels. The results indicate no higher sensitivity of fish compared to Daphnia.  Overall, according to REACh legislation, Annex IX, 9.1, column 2, studies on the long-term toxicity to fish do not need to be conducted, since the chemical safety assessment showed that soluble silicates are not PBT or vPvB candidates and natural compounds of silicon are ubiquitous in the environment. Short-term aquatic toxicity testing showed no adverse effects in any species below 100 mg/L, which is far in excess of natural occurring concentrations. Hence, due to animal welfare reasons and to avoid unnecessary vertebrate tests, long-term toxicity testing with fish is waived.  


Human & Environmental Risk Assessment on ingredients of European household cleaning products (HERA), 2005: Soluble Silicates – draft- (CAS No.: 1344-09-8, 6834-92-0, 10213-79-3, 13517-24-3, 1312-76-1), p 1 – 64.

OECD SIDS, 2004: SIDS initial assessment report for SIAM 18 – soluble silicates, p. 1 – 43.