Potassium cyanate

Long-term toxicity to fish

Administrative data

Endpoint:

adult fish: sub(lethal) effects

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Justification for type of information:

JUSTIFICATION FOR DATA WAIVING
In accordance with column 2 of REACH Annex IX, the test on long-term toxicity to fish (required in section 9.1.6) does not need to be conducted as the chemical safety assessment according to Annex I indicates no need to investigate further the effects on aquatic organisms.

The following aspects need to be considered:

- the test on ready biodegradability was technically not feasible (see section 5.2.1). Nevertheless, within the aborted read-across study with the structural analogue sodium cyanate, a significant reduction of the TOC was observed after three hours. Without much doubt the cyanate was degraded by abiotic processes and decomposed to CO2 and NH3.

- depending on pH potassium cyanate hydrolyses to CO2 and NH3 (see section 5.1.2)

- The degradation product CO2 is expected to have no adverse effects on aquatic organisms.

- The other degradation product is ammonia. At least for fish and aquatic invertebrates, ammonia is also more toxic than sodium cyanate. Ammonia is natural widely occurring, e.g. as excretion product of aquatic organisms. In addition, ammonia is a degradation product of several substances. The environmental levels of ammonia due to degradation of sodium cyanate are very low. From the water-phase, ammonia is expected to volatilise into air to a certain degree. Under aerobic conditions it is transformed by nitrifying bacteria to nitrite and nitrate. In addition a long-term toxicity to daphnia test, representing the most sensitive species, is available which is sufficient for aquatic long-term toxicity data.