Acetic acid, oxo-, sodium salt, reaction products with ethylenediamine and hydroxybenzenesulfonic acid monosodium salt, iron sodium salts

Toxicity to aquatic algae and cyanobacteria

Description of key information

Fe(3K)EDDHSA (EC 462-490-6), Scenedesmus subspicatus, OECD 201: ErC50(72h) > 100 mg/L, EbC50(72h) > 100 mg/L, NOEC(72h) >= 100 mg/L.
Fe(Na)EDDHA (CAS 84539-55-9), Desmodesmus subspicatus, OECD 201: ErC50(72h) > 294 mg/L, NOECr(72h): 8.2 mg/L, EbC50(72h): 27.3 mg/L, NOECb(72h): 2.4 mg/L .

Key value for chemical safety assessment

EC50 for freshwater algae:

294 mg/L

EC10 or NOEC for freshwater algae:

8.2 mg/L

Additional information

Ecotoxicological effects towards aquatic algae and cyanobacteria of Fe(3Na)EDDHSA (CAS 84539-54-8) were not investigated experimentally. Read across from the structurally similar substances Fe(3K)EDDHSA (EC 462 -490 -6) and Fe(Na)EDDHA (CAS 84539-55-9) was performed to fulfil this relevant endpoint under REACH (for further details, please refer to the separate read-across statement).

The toxic effects of Fe(3K)EDDHSA (EC 462-490-6) on the growth of single-cell green algaeScenedesmus subspicatusas representatives of primary producers in freshwater plankton over a 72 hour static exposure period were determined according to the principles of OECD Guideline 201 (L`Haridon, 2000). A preliminary study was conducted with test substance concentrations of 0.01, 0.1, 1 and 10 mg/L. Since no growth inhibition has had occurred, the definitive experiment was conducted as limit test with a single test concentration of 100 mg/L. A constant illumination (7000 - 7450 lux) was applied and no aeration was performed, since the cultures were constantly agitated. The initial cell concentration was 1 x 10E4 cells/mL, cell numbers were counted after 24, 48 and at the end of the test, using a Mallassez cell counter. The specific growth rate is defined as the natural log of the cell number (ln no. of cells/mL) over specific time intervals. The biomass is defined as the number of cells per mL of solution x time in hours and therefore represents an area (cells.mL/h). The biomass at 72 h is determined using the trapezoidal method from the number of cells observed at all time intervals. As results, the ErC50(72h) as well as the EbC50(72h) are greater than 100 mg/L. The NOEC at 72 h is greater or equal to 100 mg/L, based on the specific growth rate and biomass data. As no inhibition was observed at 100 mg/L and the measured concentrations of the test substance were within +/- 20 % of the nominal value at the beginning and the end of the test, the study was considered as complete.

The toxic effects of Fe(Na)EDDHA on the growth of single-cell green algae as representatives of primary producers in freshwater plankton over a 72 hour static exposure period were determined according to the principles of OECD Guideline 201 and EU Method C.3 (Salinas, 2010). The following nominal concentrations based on test substance mass without a correction for purity were used: 3.2, 10, 32, 100, 320 mg/L. The analytically determined concentrations of the test substance in the test water were in a range of 89 - 102 % of the nominal concentration at start of exposure and decreased to 63 - 86 % of the nominal concentration at the end of exposure. Therefore mean measured concentrations were considered to be an accurate representation of exposure levels throughout the exposure period. The 72 hour EC50 value for Desmodesmus subspicatus CHODAT (SAG 86.81) was greater than 294 mg/L and the NOEC was 8.2 mg/L based on mean measured concentrations and growth rate. The 72 hour EC50 based on yield and mean measured concentrations was 27.3 mg/L and the NOEC was 2.4 mg/L.