Tin antimony grey cassiterite

Endpoint summary

Description of key information

Tin antimony grey cassiterite consists of antimony, tin, vanadium and oxygen bound in a stable crystalline structure in which all atoms are tightly bound and not prone to dissolution in environmental media. This assumption is validated by available transformation/dissolution data (Klawonn, 2018; Knopf, 2018) that indicate a very low release of the pigment components antimony, tin and vanadium under environmental conditions after 7 and 28 days. The poor solubility of the inorganic pigment tin antimony grey cassiterite is the predominant parameter affecting its fate in the environment. In addition to its poor environmental solubility, the fate of tin antimony grey cassiterite in the environment may further be evaluated by separately assessing the fate of its constituents antimony, tin and vanadium.

 

Degradation: Biotic degradation is not relevant for inorganic substances such as tin antimony grey cassiterite. Abiotic degradation is also not expected to be relevant for the poorly soluble pigment due to the absence of functional groups. Data available for the pigment components antimony, tin and vanadium indicate that abiotic degradation in respective compartments does also not contribute significantly to their fate in the environment. However, the concept of “degradability” was developed for organic substances and is not applicable to inorganic substances. As a surrogate approach for assessing “degradability”, the concept of “removal from the water column” was developed to assess if a metal ion would remain present in the water column upon addition (and thus be able to exert a chronic effect) or would be rapidly removed from the water column. In this concept, “rapid removal” (defined as > 70% removal within 28 days) is considered as equivalent to “rapidly degradable”. The removal of antimony and tin ions from the water column is rapid and its remobilization from the sediment is relatively insignificant (MECLAS, v5.2). Thus, antimony and tin ions are considered equivalent to ‘rapidly degradable” whereas these data have not been generated for vanadium.

 

Transport and distribution: Since tin antimony grey cassiterite is poorly soluble, partitioning of the pigment components into solution in the aquatic, sediment and soil compartment is expected to be very low. Partition coefficients for suspended matter in water for tin, antimony and vanadium of 371,535 L/kg, 3,890 L/kg and 5,754 L/kg, respectively, also indicate that the metals are not very mobile and tend to bind to solid phases. For soil, solid-water partitioning coefficients for tin, antimony and vanadium of 1,905 L/kg, 83 l/kg and 309 l/kg, respectively, were reported (RIVM, 2005).

 

Bioaccumulation and biomagnification: Tin antimony grey cassiterite is poorly soluble in environmental media and the potential to cross biological membranes and to bioaccumulate is expected to be low. Information available for the pigment components tin, antimony and vanadium indicates that the potential for bioaccumulation of tin, antimony and vanadium is also low. Thus, tin antimony grey cassiterite is not expected to bioaccumulate in aquatic, sediment and soil organisms.

 

Reference:

RIVM, 2005: Environmental risk limits for nine trace elements. RIVM report 601501029/2005.