Morpholinium sulphamate

Toxicity to microorganisms

Description of key information

As worst case a EC50 of 200 mg/L was established based on a weight of evidence approach with different read-across substances.

Key value for chemical safety assessment

EC50 for microorganisms:

200 mg/L

Additional information

For the assessment of toxicity to microorganism of morpholinium sulphamate several toxicity to microorganism studies conducted with morpholine, sulphamidic acid and morpholinium sulphamate were considered.

 

Morpholine

A test was performed in order to evaluate the effect of morpholine to the respiration of activated sludge obtained from domestic sewage treatment plant in accordance with OECD TG 209. The duration of the test was 30 min. Activated sludge was used as inoculum. It was taken from a domestic sewage treatment plant and washed before usage. The pH value of the activated sludge was adjusted to pH 7. The dry matter was determined as 5.0 g suspended solids/L The test was performed as limit test at nominal concentration of 1000 mg/L. 3,5-Dichlorophenole was used as reference item. The 30 min EC20 was determined to be greater than 1000 mg/L.

In addition a publication of Bringmann and Kühn the toxicity threshold of morpholine was assessed. Using analogous methods of the cell multiplication inhibition test, the toxicity threshold of 190 compounds including morpholine was determined for bacteria (Pseudomonas putida) and green algae (Scenedesmus quadricuada). Therefore cultures of pseudomonas putida were exposed in 4 different concentration queues of the substance. The dilution sequence was prepared as follows: In a first step 160 mL solution of the substance was prepared. Thereof 80 mL ware filled up to 100 mL with 5 mL Stock solution I and 5 mL stock solution II and 10 mL of bacteria suspension. After 16 h at 25 °C the extinction of the each sample was measured at Hg 436 nm with a coat thickness of 10 mm. The 16 h toxic threshold concentration based on growth inhibition was determined to be 310 mg/L.

Sulphamidic acid

A study was performed in order to evaluate the effect of sulphamidic acid to the respiration of activated sludge obtained from domestic sewage treatment plant in accordance with OECD TG 209. The activated sludge respiration test is a rapid screening method to identify substances which may adversely affect aerobic microorganisms. Duration of the test was three hours. Activated sludge was used as inoculum. It was taken from a domestic sewage treatment plant and washed before usage. The dry matter was determined as 4.77 g suspended solids/L, giving a concentration of 1.6 g suspended solids/L in the test. The study was performed with the nominal concentration of 60; 82, 110, 148 and 200 mg/L. 3,5-Dichlorophenole was used as reference item. The 3 h EC50 was determined to be greater than 200 mg/L.

Conclusion

No study was available for morpholinium sulphamate. Morpholinium sulpahamte is an organic ionic compound which dissociate in water into the corresponding cation morpholine and the corresponding anion sulphamidic acid. The EC50 of sulphamidic acid (200 mg/L) was regarded as worst case for morpholinium sulphamate.