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EC number: 225-464-3 | CAS number: 4861-19-2
Toxicity to aquatic algae and cyanobacteria
Administrative data
Link to relevant study record(s)
Description of key information
The 192 hour toxicity threshold of blue-green algae urea was 47 mg/L. To some extent urea exhibits toxic action to Microcystis aeruginosa. The 7 day toxicity threshold of urea to Scenedesmus quadricauda was >10000 mg/L. The 72 hr EC50 of Desmodesmus subscpicatus with phosphoric acid was >100 mg/L and the NOEC was 100 mg/L.
Key value for chemical safety assessment
- EC50 for freshwater algae:
- 100
- EC10 or NOEC for freshwater algae:
- 47 mg/L
Additional information
Urea phosphate dissociates directly into urea and phosphoric acid in aqueous environment.
The 192 hour toxicity threshold of blue-green algae to urea was 47 mg/L. To some extent urea exhibits toxic action to Microcystis aeruginosa. The 192 hr toxicity threshold of urea to Scenedesmus quadricauda was >10000 mg/L.
A reliable study was performed according to OECD TG 201 and EC Method C.3 with phosphoric acid. In this limit study, green alga Desmodesmus Subspicatus were exposed to an aqueous solution of phosphoric acid at 100 mg/L under static test conditions for 72h. The pH was adjusted to neutral (pH 7.5). This resulted in ErC50>100 mg/L and NOEC=100 mg/L, based on nominal concentrations. Measured test concentrations ranged from 103% to 106% of nominal at the start of the test, and from 97% to 99% after 72h.
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