N-isopropylmethacrylamide

Long-term toxicity to fish

Administrative data

Endpoint:

fish early-life stage toxicity

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Justification for type of information:

In accordance with column 2 of REACH Annex IX (9.1. Aquatic toxicity), long-term testing on fish shall be proposed if the chemical safety assessment indicates the need to investigate further the effects on aquatic organisms.
An assessment of the need for long-term testing has therefore been made based on the available information.

The substance is not classified for the environment based on results from acute toxicity tests in three species (fish, daphnia and algae), plus physico-chemical properties such as water solubility and partition coefficient. However, the substance may be considered to have the potential to persist in the aquatic environment as it is not readily biodegradable (14% degradation after 28 days) and has been shown to be hydrolytically stable (estimated half life greater than 1 year at pH 4, 7 and 9).

An acute toxictiy to fish study conducted with a single nominal test concentration of 100 mg /L, resulting in a NOEC of 100 mg /L following 96-h exposure.

With no toxicity observed at a nominal loading rate of 100 mg/l in the acute study, it can be anticipated that no toxic effects would be observed in a long-term study in fish at concentration levels realistic to that which may be present in the environment. In addition, literature data on acute to chronic toxicity ratios indicate that acute LC50: chronic NOEC ratio are generally below 100; it can therefore be anticipated that a chronic NOEC of at least higher than 1 mg/L would be obtained and thus a low concern for chronic aquatic toxicity is anticipated.

In acute studies in fish, daphnia and algae, only the algal study showed the test substance to have any toxic effects at the test concentrations assessed. Although this was a short-term algal test, it can viewed as providing both acute and chronic endpoints, based on the short life cycle of Pseudokirchnerella subcapitata, Therefore, if assessed as a chronic endpoint, the 72 hr NOEC (growth rate) of 125 mg ai /l and the 96 hr NOEC (growth rate) of 250 mg ai/L indicates a low concern for chronic toxicity.

The substances very low log octanol/water partition coefficient (Log10 Pow 0.491) indicates the substance has a very low potential for bioaccumulation in aquatic species, indicating long-term toxicity to invertebrates is not anticipated to be of concern, despite the substances potential to persist in the aquatic environment.

Releases of the substance to the environment are also anticipated to be minimal from its use as a monomer intermediate in the synthesis of polymers. Any potential releases would be through release of waste water. However, the amount and concentration of substance in the waste water is anticipated to be below levels of concern. The lifecycle of the monomer is considered to end when it is reacted into the polymer, so there is no further potential for environmental release.

Based on the above data, it is considered that a long-term study in fish is not required.