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Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Additional information

General considerations

Ecotoxicological investigations concerning aquatic invertebrates and algae are not available for the target substance Calcium glucoheptonate (CAS 1821694-25-0). However, sufficient data on read-across substances Sodium gluconate (CAS 527-07-01) and Gluconic acid (CAS 526-95 -4) are available and have been used to cover the respective endpoints for the tonnage band of 1 -10 tonnes for the target substance Calcium glucoheptonate. Aquatic toxicity of Calcium glucoheptonate is believed to be similar to that of Sodium gluconate. Glucoheptonates and gluconates are sugar like substances acting in similar manner on aquatic biota (please refer to read-across statement). Sodium and Calcium are macro elements exerting their toxicity potential only at very high dose levels (> 100 mg/L). Since Ca2+ is known as an essential nutrient for plants/algae and is also contained in natural surface waters, a very low toxicity potential is assumed for Calcium glucoheptonate. Aquatic acute and chronic toxicity data on calcium inorganic salts (chloride and sulfate) are much greater than 100 mg/L for three trophic levels. Consecutively, additional toxicity data on the calcium ion are intended not to be included. Providing that considerable amounts of Calcium glucoheptonate (> 100 mg/L) reach aquatic compartment, the amount of calcium will be far under the acute and chronic hazard values established for calcium inorganic salts. So, no harmful effects is expected related to calcium element originated from Calcium glucoheptonate at 100 mg/L and higher. Since it is expected that toxicity of the glucoheptonate ion is similar to the toxicity of gluconate ion, no estimation of EC50/LC50/NOEC etc. (quantitative read-across) is necessary for the target substance Calcium glucoheptonate. Based on this knowledge, the same values as by Sodium gluconate have been taken for Calcium glucoheptonate. This approach is considered for the Chemical Safety Assessment.

In the following, brief summaries of the key and supporting studies with Sodium gluconate and Gluconic acid are shown.

Short-term toxicity to aquatic invertebrates

In another key study, the acute toxicity of the read-across substance Sodium gluconate (CAS 527-07-1) towards Daphnia magna has been determined according to OECD Guideline 202 in compliance with GLP (OECD SIDS, 2004). After the range-finding study (2 vessels/concentration, 10 daphnids/concentration), the definitive test was conducted with test concentrations of 0 (control) and 1000 mg/L (limit test). The measured concentrations of the test substance in the test solution were within +/- 20% of the nominal concentration in all concentrations (HPLC technique has been used). The EC50/NOEC (48 h) value amounts to > 1000 mg/L based on the nominal test concentration.

 

Toxicity to aquatic algae

In another key study, the toxicity of the read-across substance Sodium gluconate (CAS 527-07-1) towards algae has been determined according to OECD Guideline 201 in compliance with GLP (OECD SIDS, 2004). Two tests have been performed. In the first test, 1000 mg/L of the test item have been tested. However, a decrease of the test item concentration was observed and therefore the test could not meet the stability requirements. Conclusively, a second test with 100 and 1000 mg/L test concentration was performed. Desmodesmus subspicatus CHODAT (strain No 86.81 SAG) was used as test organism. An initial cell density of 10 x 10E4 algae/mL was applied. For the second test, 3 flasks with 100 mg/L, 3 flasks with 1000 mg/L and 6 flasks without test item were used. The common OECD procedure has been modified by covering the test vessels with glass petri dishes to prevent contamination by micro-organisms. After 24, 48 and 72 hours, cell concentration was determined using a microscope with a counter chamber (8 fields counted). No cell growth inhibition at 100 mg/L was determined. At 1000 mg/L, 70% cell growth inhibition was observed. For the average specific growth rate, no inhibition at 100 mg/L but 42% inhibition at 1000 mg/L was determined. The cell concentrations in controls increased by a factor of 65.9 after 72 h. As final results and based on growth rate, an EC50 (72 h) of > 100 mg/L and a NOEC (72 h) of 100 mg/L were derived.

As supporting information, the acute toxicity of the read-across substance Sodium gluconate (CAS 527-07-1) towards algae was determined according to OECD Guideline 201 in compliance with GLP (OECD SIDS, 2004).A range-finding test was conducted prior to the definitive test to enable the following concentrations in the definitive test: 0 (control), 100, 180, 320, 560, 1000 mg/L (nominal concentrations). Measured concentrations of the test substance in the test solutions at the beginning of exposure were +/-20 % of the nominal concentrations. As test organism, Pseudokirchnerella subcapitata has been used (Biomass loading: 1 x 10 E04 cells/mL).As final results, the EC50 (72 h) was determined to be > 1000 mg/L while the NOEC (72 h) was set to 560 mg/L based on the growth rate (nominal concentration).

With regard to the second supporting study, acute toxicity of four relatively new chelating agents and their equimolar manganese and cadmium complexes was studied (Silanpää et al., 2003). The chelating agents studied were gluconic acid (GA), β-alaninediacetic acid (ADA), diethylenetriaminepentakismethylenephosphonic acid (DTPMP), and nitrilotriacetic acid (NTA).The bioassay with R. subcapitata using gluconic acid was performed according to a Finnish standard SFS 5072 (1986, Toxicity test with pure culture of algae). At the time of an inoculation, the alga was in its exponential growth phase. During the test, the flasks were shaken in every 24 h. The volume in all tests was 10 mL and illumination intensity was set to 5000 lx. Temperature was maintained at 22 ± 1°C throughout the 72-h test. Two simultaneous experiments were performed for each test concentration and the highest concentration of chelating agents was 1000 mg/L. The growth was estimated with in vivo fluorescence of chlorophyll (Labsystems, Fluoroskan Ascent) and the results obtained from the bioassay are expressed as 72-h EC50 values with 95% confidence interval. The EC50 (72 h) value for gluconic acid is reported as 76 mg/L.R. subcapitataproved the most sensitive to these compounds compared to Daphnia magna and Photobacterium phosphoreum.