Registration Dossier

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Fish toxicity, freshwater, acute: LC50 > 100 mg/L

Invertebrates toxicity, freshwater, acute: EC50 > 500 mg/L

Invertebrates toxicity, freshwater, long-term: NOEC = 100 mg/L

Algae toxicity, freshwater, acute: EC50 > 1.000 mg/L

Toxicity to micororganisms, activated sludge, acute: EC10 = 125 mg/L

Additional information

Data obtained by Read-Across from ε-caprolactam:

As key study for PNEC derivation the chronic study concerning toxic effects of epsilon-Caprolactam on invertebrates was identified. From the NOEC of 100 mg/l the PNEC was derived. For the PNEC STP the NOEC of the OECD 209 study of 125 mg/l was used for further risk assessment.

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Data obtained by Read-Across from sodium hydroxide:

At concentrations reported in publications and study reports, the toxicity has been assumed to be

due to hydroxide only, because at these effect concentrations the concentration of sodium is too low

to explain the effects. However, it should be realised that the results of toxicity tests with NaOH

depend on the buffer capacity of the test medium. In a highly buffered test medium the hydroxyl ion

will be neutralized and the observed toxicity will be low, while in a poorly buffered test medium the

pH will increase rapidly and therefore the observed toxicity will be relatively high (see also section

2.1). Besides the direct effects (pH change) NaOH could also have indirect effects. The pH change

could influence the speciation of other chemicals and therefore increase and/or decrease the toxicity

e.g. NH3 is more toxic than NH4 +.