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The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Aquatic toxicity testing indicates a low level of toxicity for maleic anhydride. Acute values obtained with non-neutralized test solutions were:

  • 96-hour LC50 in fish = 75 mg/L
  • 48-hour EC50 in daphnids = 37.9 mg/L
  • 72-hour ErC50 in freshwater algae = 65.8 mg/L

Additional information

Studies on the acute aquatic toxicity of maleic anhydride are available for all three trophic levels. Since maleic anhydride rapidly hydrolyses in contact with water (half-life = 0.3 min), the breakdown product maleic acid was also considered in the assessment.

Two key studies, with representative freshwater fish (rainbow trout and bluegill sunfish), showed similar results:

LC50 (fish, 96 h) = 75 mg/L (test substance: maleic anhydride; non-neutralized test solution).

The pH values decreased with increasing test compound concentrations; the observed toxicity is mostly related to acidity.

The test organism most sensitive to maleic acid was Daphnia magna with an EC50 (48 h) of 42.8 mg/L (non-neutralized solution, toxicity partly attributable to pH effect), corresponding to 37.9 mg maleic anhydride/L.

Also a long-term test result (21 days) with maleic anhydride is available for Daphnia magna:

NOEC (Daphnia magna, 21 d) = 10 mg/L (reproduction rate),

EC50 (Daphnia magna, 21 d) = 77 mg/L (reproduction rate).

Due to very limited reporting, the study is considered not reliable hence is not used in the chemical safety assessment of maleic anhydride.

The 72-h ErC50 for growth inhibition in the alga Pseudokirchnerella subcapitata was determined at 74.35 mg maleic acid/L. This ErC50 corresponds to 65.78 mg maleic anhydride/L.