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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

For dipotassium hexachloroplatinate, ecotoxicity data are read across from other platinum(IV) substances that also contain a chloro ligand, hexachloroplatinic acid and platinum(IV) chloride. The 72-hour EC50 for biomass and growth rate were estimated to be 1.32 mg Pt L-1 and 3.30 mg Pt L-1, respectively. The 72-hour NOEC was determined to be 0.209 mg Pt L-1 based on biomass and 0.62 mg Pt L-1 based on growth rate. In a second study, the 72-hour EC50 for growth rate and biomass were determined to be 0.96 mg Pt L-1 and 0.52 mg Pt L-1, respectively. The NOEC was determined to be 0.386 mg Pt L-1.

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Additional information

For dipotassium hexachloroplatinate, ecotoxicity data are read across from other platinum(IV) substances that also contain a chloro ligand, hexachloroplatinic acid and platinum(IV) chloride.

An algal growth inhibition test is available for hexachloroplatinic acid following OECD guideline 201 and EU Method C.3 (Pawlowski and Wydra 2005). A static test system was used. Five test concentrations were included and these were analysed using Graphite furnace-AAS method. The mean recovery rates were in the range 83 % to 100 % of the nominal values, apart from the sample with the highest test concentration of 50 mg L-1, where the recovery rate declined to 24 % at the end of the test. This loss was reported to be likely to be caused by centrifugation of samples. However, since the inhibition of algal growth already reached a maximal value at a lower test concentration of 25 mg L-1, results were based on nominal concentrations. No protocol deviations were recorded. All validity criteria were fulfilled. The 72-hour EC50 for biomass and growth rate were estimated to be 3.925 mg test item L-1 (1.32 mg Pt L-1) and 9.808 mg test item L-1 (3.30 mg Pt L-1), respectively. The 72-hour NOEC was determined to be 0.620 mg test item L-1 (0.209 mg Pt L-1) based on biomass and 1.85 mg test item L-1 (0.62 mg Pt L-1) based on growth rate. The 72-hour LOEC values for biomass and growth rate were determined to be 1.85 mg test item L-1 (0.62 mg Pt L-1) and 5.56 mg test item L-1 (1.87 mg Pt L-1), respectively.

A second algal study was conducted with Scenedesmus subspicatus for hexachloroplatinic acid following OECD guideline 201 and EU Method C.3 (Mead and Mullee 2001). Five test concentrations were used and these were analysed using UV digestion and adsorptive stripping voltammetry. Measured test concentrations declined from 81 - 95 % to 68 - 96 % of nominal, and this decline was considered to be due to adsorption to algal cells. Results were based on time-weighted mean measured concentrations in order to give a worst case analysis of the data. The 72-hour EC50 for growth rate and biomass were determined to be 2.4 mg L-1 (0.96 mg Pt L-1) and 1.3 mg L-1 (0.52 mg Pt L-1), respectively. The NOEC was determined to be 0.97 mg L-1 (0.386 mg Pt L-1).

Data are also read across from the platinum(IV) substance platinum(IV) chloride, as supporting data. The algal growth inhibition of platinum (as platinum (IV) chloride) to Pseudokirchneriella subcapitata was assessed in the publication by Bednarova et al. (2012). The study is reliable with acceptable restrictions. It was not conducted to GLP, but followed the standard test guideline OECD 201. Five test concentrations were used. The 72-hour EC50 could not be derived. The 72-hour EC5, EC10 and EC20 values for inhibition of growth rate were determined to be 0.31, 0.58 and 1.12 μM test item (0.18, 0.34 and 0.65 μM Pt, respectively), which corresponds to 0.104, 0.195 and 0.377 mg test item L-1 (0.060, 0.113 and 0.218 mg Pt L-1, respectively). The 72-hour EC5, EC10 and EC20 values for biomass (area under the growth curve) were determined to be 0.04, 0.24 and 0.64 μM test item (0.023, 0.14 and 0.371 μM Pt, respectively), which corresponds to 0.0135, 0.081 and 0.215 mg test item L-1 (0.008, 0.047 and 0.125 mg Pt L-1).