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Aquatic toxicity studies were performed with CAS# 756-12-7 on Daphnia magna and Pseudokirchneriella subcapitata. CAS# 756-12-7 is reactive with water. Test solutions for the key algae and supporting Daphnia studies were made by dissolving CAS# 756-12-7 in water and magnetically stirring the solution until no test substance was visible in the medium. This was completed in a closed flask but a small amount of headspace was present. Test solutions for the key Daphnia study were made by transferring an aliquot of CAS# 756-12-7 via gas-tight syringe to a tightly-closed vial and mixing for ca. 20 minutes. Test containers were sealed to avoid volatilization losses of the test material during the studies. Concentrations of CAS# 756-12-7 and all of its known degradation products except trifluoroacetic acid (CAS# 76-05-1, TFA) were below the limit of detection of the analytical method, i.e. 1 mg/l. Therefore, the ecotoxicological endpoints are expressed in terms of the stoicheometric equivalent concentration of the parent, and which were 55-72% of nominal CAS# 756-12-7 concentrations despite steps taken to avoid sample loss. Based on rapid hydrolysis and high volatility, CAS# 756-12-7 is not expected to be present in the aquatic compartment. The results are summarized in the Table 1(below).

All studies were performed according to accepted international guidelines for testing of chemical and were in compliance with OECD GLP standards. Studies with Pseudokirchneriella subcapitata were performed in accordance with OECD Guideline 201 (Alga, Growth Inhibition Test). Toxicity in the Water flea (Daphnia magna) was measured using OECD Guideline 202 (Daphnia sp. Acute Immobilization Test). Neither CAS# 756-12-7 nor its degradation products, other than TFA, were detected in the test solutions. Therefore, the studies were assigned Klimish rankings of 2 (reliable with restrictions). Nevertheless, because CAS# 756-12-7 is not expected to be present in aquatic systems, the results of these tests are not relevant to conditions in the real environment and are not applicable for Risk Assessment, Classification & Labelling, or PBT Analysis.

Table 1.  Aquatic toxicity results for CAS# 756-12-7



Estimated¹ concentration, parent (95% CI)


Effect Parameter

Daphnia magna (water flea), key

48-hour EC50

39 (36 - 42)


Daphnia magna (water flea), supporting

48-hour EC50

17 (14 - 21)


Pseudokirchneriella subcapitata (green algae), key

72-hour EC50

98 (67.7 - 140)

growth rate

72-hour NOEC


1, estimated concentration of parent is based on measured concentration of trifluoroacetic acid (TFA), molecular weight ratio of parent to TFA, and reaction stoicheometry