Registration Dossier

Environmental fate & pathways

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Administrative data

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Additional information

In the aqueous and terrestrial environment, strontium sulfate dissolves in (pore) water releasing strontium cations and sulfate anions. Sulfate is essential to all living organisms, their intracellular and extracellular concentrations are actively regulated and thus, sulfates are of low toxicity to the environment (OECD SIDS for Na2SO4). Thus, the strontium cation is the moiety of toxicological concern (if any), and the environmental hazard assessment is based on strontium.

Data that were retrieved, suggest that strontium bioconcentration and bioaccumulation is negligible: internal concentrations of soft tissues remain situated between 0.5 and 5.7 μg/g, regardless of the external concentration (9 – 8000 μg/L). Whole body concentrations were considered less relevant due to the potential of strontium to replace Ca in the bones. Reported tissue BAFs vary more than 2 orders of magnitude, but remain below 100. Moreover, an inverse relationship between exposure concentration and BAF has been observed, i. e., decreasing BAFs with increasing Sr-levels in the water column (Moiseenko and Kudryavtseva, 2001).

The data indicate that strontium can is homeostatically controlled by aquatic organisms. The homeostatic control in soft tissues of strontium is observed to continue to function up to the milligramme range of exposure (8 mg/L in seawater; Ueda et al, 1973).

Limited information on transfer of strontium through the food chain indicates that strontium does not biomagnify in aquatic food chains.