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Ecotoxicological information

Endpoint summary

Administrative data

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Additional information

Urea phosphate will directly dissociate into urea and phosphoric acid in aqueous environment. Considering all data, this shows that urea phosphate is of very low toxicity to aquatic organisms with effect values all above 100 mg/L when the duration of exposure was as specified within the current guidelines.

Toxicity to fish

Urea: The 96 hour LC50of urea to B. barnawas > 9100 mg/L. The NOEL was 4961 ppm.

Phosphoric acid: The median lethal pH (96 hr) was 3 -3.35 for Lepomis macrochirus. Mortality is caused by low pH values, when adjusted to environmentally relevant pH values, phosphoric acid does not cause acute adverse effects.

No long-term toxicity data are available: Urea and phosphoric acid do have a very high water solubility and its chemical properties do not indicate bioaccumulation. In addition, urea is of inherently low toxicity to fish species: it is a normal product of protein catabolism and therefore fish have evolved effective excretion mechanisms. Additionally, exposure will be limited by the action of microorganisms and incorporation of urea into the nitrogen cycle.

 

Toxicity to aquatic invertebrates 

The 24 hour EC50 for urea in Daphnia was reported to be >10000 mg/L; urea is not acutely toxic to daphnids.

The 48h-EC50 for phosphoric acid in Daphnia was >100 mg/L.

No long-term toxicity data are available: Urea and phosphoric acid do have a very high water solubility and its chemical properties do not indicate bioaccumulation. In addition, urea is of inherently low toxicity to invertebrate species: it is a normal product of protein catabolism and therefore fish have evolved effective excretion mechanisms. Additionally, exposure will be limited by the action of microorganisms and incorporation of urea into the nitrogen cycle.

 

Toxicity to algae

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 hour EC50 for phosphoric acid with Desmodesmus Subspicatus (the pH was adjusted to neutral (pH 7.5)) was >100mg/L and NOEC=100 mg/L.

Toxicity to Micro-organisms

The 3-hour EC50 value for urea phoshate to activated sludge was >100 mg/L with a NOEC of 100 mg/L.