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Ecotoxicological information

Short-term toxicity to fish

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Description of key information

With high probability acutely not harmful to fish.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish
Effect concentration:
180 mg/L

Marine water fish

Marine water fish
Effect concentration:
179 mg/L

Additional information

The assessment of the short-term toxicity to fish is based on the available data from studies with several freshwater and saltwater species:

The selected key studies (Calamari et al., 1980) for freshwater fish were performed according to IRSA (1980) with Oncorhynchus mykiss in soft and in hard water. The test concentrations were analytically verified. The resulting 96-h LC50 values were 180 mg/L (nominal) for soft water and 380 mg/L (nominal) for hard water, respectively.

The key data are supported by the results of several freshwater and marine studies as summarized in the following table:



Test Species

Duration / Dose Descriptor

Effect Concentration [mg/L]


NITE (1997)

OECD 203

Oryzias latipes

96-h LC50

> 100

nominal; analytically verified; limit test

OECD 204

14-d LC50

> 92


Dawson et al. (1977)

No guideline specified*

Lepomis macrochirus

96-h LC50



Menidia beryllina (marine species)

96-h LC50



Wellens H. (1982)

UBA, Document I 5.3-97125-2/6

Danio rerio

96-h LC50

> 1000


McCain & Peck (1976)

APHA (1965)**

Vala mugil engeli (marine species)

96-h LC50


nominal; geometric mean of LC0 and LC100***

Gambusia affinis

(marine species)

96-h LC50


nominal; geometric mean of LC0 and LC100***

Tilapia sp.

(marine species)

96-h LC0


nominal; only LC0 reported

*Study meets generally accepted scientific principles, acceptable for assessment.

**American Public Health Association (1965). Standard Methods for the Examination of Water and Wastewater, 12th ed. New York, USA.

*** The calculation of the LC50 is not done in a proper way since the geometric mean between LC0 and LC100 was used. This is only correct if there is no effective concentration between LC0 and LC100. In this case, there is a concentration in between.

The stability of morpholine (CAS 110-91-8) in the test medium has not been analytically confirmed in all supporting studies, but is considered to be stable due to the high water solubility (completely miscible), the moderate vapour pressure (VP = 9.8 hPa, at 20 °C) and the low Henry´s law constant (HLC, uncharged: 0.0115 Pa*m3/mol, at 25 °C) of the substance.



Summing up the available freshwater and saltwater data, morpholine is assessed to be with high probability not acutely harmful to fish.