Registration Dossier

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

The test substance hydrolyses rapidly and completely in concentrations which are expected to occur in waste waters and surface waters. Products of hydrolysis are formaldehyde and ethylene glycol. Although at high concentrations formaldehyde may partially still be bound onto ethylene glycol (equilibrium), complete hydrolysis is expected in the media of the tests on aquatic toxicity.

Data on ethylene glycol are reported as robust study summaries, while data on formaldehyde are provided as additional information.

Additional information

Data on formaldehyde

Acute toxicity to aquatic organisms

The toxicity to aquatic organisms was tested in several studies covering different trophic levels.

The acute toxicity of formaldehyde to fish ranges from LC50(96 h) = 6.7 - 1020 mg/L (OECD 2002). A lower LC50 value of 1.84 mg/L was obtained in a study using the striped bass (Morone saxatilis) as a test organism. However, due to additional hypoosmotic stress this value is unreliable and not suitable for risk assessment. The lowest reliable effect value of 6.7 mg/L was obtained with the same species. This study was performed in freshwater with fish acclimated to these conditions, although Morone saxatilis is a marine species typically living in coastal waters and bays, but also enters the rivers.

Acute toxicity towards invertebrates was tested with the cladocerans Daphnia magna and Daphnia pulex. One 24 h-EC50 is available but should only be used as additional information since 48 h-values are available from studies according to OECD guideline 202. Further studies using a number of invertebrate species from a wide array of taxa are reported. LC50s range from 0.42 mg/L to 336.8 mg/L, but in the light of new results the validity of the lowest value (Cypridopsis sp. ostracods) has recently been questioned (OECD 2002). Thus, the lowest reliable 48h-EC50 for invertebrates is 5.8 mg/L (D. pulex).

Algal toxicity was found in the same order of magnitude with EC50s (72 h) of 3.48 mg/L and 4.89 mg/L for biomass production and growth rate, respectively. Further algal studies are reported in OECD (2002). With respect to test durations and endpoints these are rated as not suitable for risk assessment.

Algal and Daphnia tests were performed according to the OECD guidelines 201 (algae) and 202 (daphnids), while the fish studies were adhering to national guidelines or were non-guideline studies. Performance was in all cases in accordance with general scientific principles and described in sufficient detail. All studies were conducted without analytical monitoring. However, due to the very low Henry's law constant and the low adsorption potential of formaldehyde in water, losses of test substance due to volatilisation during the test period can be neglected. Therefore, results based on the nominal concentrations can be regarded as valid.

Studies on the toxicity of formaldehyde towards aquatic organisms demonstrated that this substance was acutely toxic to the test organisms.

Chronic toxicity to aquatic organisms

Chronic toxicity towards fish was investigated in a study comparable to OECD guideline 212. According to the Technical Notes for Guidance on data requirement (EC 2000, chapter 3) and EU Technical Guidance Document on Risk Assessment (EC 2003, part II) OECD 212-studies are regarded as long-term tests because the most sensitive stages in fish development are included. The lowest EC50 obtained in this study is 6.9 mg/L. No NOEC was reported and test duration was shorter than recommended by OECD guideline 212.

A recently performed study with Daphnia according to OECD guidelines revealed a 21d NOEC of 6.9 mg/L.