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Ecotoxicological information

Toxicity to microorganisms

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Reference
Endpoint:
activated sludge respiration inhibition testing
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Justification for type of information:
See attached document below.
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Key result
Duration:
3 h
Dose descriptor:
NOEC
Effect conc.:
790 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Conclusions:
Based on a worse case approach taking into account the highest toxicity observed to activated sludge with the 2 source substances [Sodium sulfate (CAS 7757-82-6) and calcium sulfate (CAS 7778-18-9)], the 3h-NOEC value of 790 mg/L was attributed to the target substance "Sulphates of potassium, sodium and calcium, by-product from fermentation”. Even if a microorganism toxicity test is not available for potassium sulphate, an adverse effect is not suspected for this source substance, due to the very high EC50/NOEC obtained with the 2 other salts (same category in OECD program) and the total absence of adverse effects observed with these 3 salts to all tested aquatic organisms.
Executive summary:

The results of the toxicity to microorganisms are indicative of a similar vey low toxicity of sodium sulfate (CAS 7757-82-6) and calcium sulfate (CAS 7778-18-9), with a 37d-NOEC = 8000 mg/L and a 3h-NOEC = 790 mg/l respectively.

Based on a worse case approach taking into account the highest toxicity observed to activated sludge with the 2 source substances, Sodium sulfate and Calcium sulfate, the 3h-NOEC value of 790 mg/L was attributed to the target substance "Sulfates of potassium, sodium and calcium, by-product from fermentation”. Even if a microorganism toxicity test is not available for potassium sulphate, an adverse effect is not suspected for this source substance, due to the very high NOEC obtained with the 2 other salts (same category than potassium sulfate in the OECD program) and the total absence of adverse effects observed with these 3 salts to all tested aquatic organisms.

Description of key information

Based on a worse case approach taking into account the highest toxicity observed to activated sludge with the 2 source substances [Sodium sulfate (CAS 7757-82-6) and calcium sulfate (CAS 7778-18-9)], the 3h-NOEC value of 790 mg/L was attributed to the target substance "Sulfates of potassium, sodium and calcium, by-product from fermentation”. Even if a microorganism toxicity test is not available for potassium sulphate, an adverse effect is not suspected for this source substance, due to the very high EC50/NOEC obtained with the 2 other salts (same category in the OECD program) and the total absence of adverse effects observed with these 3 salts to all tested aquatic organisms.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:
790 mg/L

Additional information

The results of the toxicity to microorganisms are indicative of a similar vey low toxicity of sodium sulfate (CAS 7757-82-6) and calcium sulfate (CAS 7778-18-9), with a 37d-NOEC = 8000 mg/L and a 3h-NOEC = 790 mg/l respectively.

Based on a worse case approach taking into account the highest toxicity observed to activated sludge with the 2 source substances, Sodium sulfate and Calcium sulfate, the 3h-NOEC value of 790 mg/L was attributed to the target substance "Sulfates of potassium, sodium and calcium, by-product from fermentation”. Even if a microorganism toxicity test is not available for potassium sulphate, an adverse effect is not suspected for this source substance, due to the very high NOEC obtained with the 2 other salts (same category than potassium sulfate in the OECD program) and the total absence of adverse effects observed with these 3 salts to all tested aquatic organisms.

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