Silicon carbide

Toxicity to terrestrial plants

Description of key information

When released to the soil system silicon carbide is an inert substance that behaves like other insoluble mineral components of the soil, e.g. sand (the determination of water solubility showed that the substance “can be considered as practically insoluble in water”; see chapter 4.8). This means that the bioavailability of silicon carbide in soil is very low, which accounts for the absence of toxicological effects on soil organisms. This has been demonstrated by the required standard study on acute toxicity (14 days) to earthworms (Eisenia Fetida) performed with silicon carbide (see chapter 6.3.1). Since earthworms are soil-dwelling organisms that feed on soil particles, the study performed covered the exposure via ingestion and contact with soil particles and porewater. The susceptibility of Eisenia spp. to substances is considered to be representative of soil fauna.

Against this background, based on the low bioavailability of silicon carbide and the absence of adverse effects on a representative soil organism, we conclude that the substance has no adverse effects on organisms of the terrestrial compartment. Consequently tests on the toxicity of silicon carbide to soil micro-organisms and plants appear to be dispensable.