Magnesium dipropan-2-olate

Short-term toxicity to aquatic invertebrates

Description of key information

Magnesium isopropanolate hydrolyses rapedly in contact with moisture or water into isopropanol and magnesium hydroxide. Both hydrolysis products are natural occuring substances and according to the available data are not dangerous for aquatic organisms and no classification is required.

Hydrolysis Product Isopropanol:

The substance was not acutely toxic to Daphnia magna when tested according to a method comparable with OECD guideline 202 (Daphnia sp. Acute Immobilisation Test). An EC50 of 9714 mg/l and above 10 000 mg/l were determined after 24h. An EC50 above 100 mg/l can be expected after an exposure time of 48h.

Hydrolysis product magnesium hydroxide:

The recalculated LC50 (96h) for D. Magna in the key study was determined as 170.86 mg/L with pure, 100% Magnesium hydroxide concentration. In two of the supporting studies, Magnesium chloride was shown to have low toxicity to Daphnia magna with the threshold for Magnesium chloride toxicity to D. magna found to be 0.0078 molar and an LC50 of 3391 mg/l in 25 hours. Magnesium ion was also shown to have low toxicity to Daphnia magna with one supporting study concluding that the EC50 for the Magnesium ion for Daphnia magna was found to be 405.98 mg/l at 24 hours and 343.56 mg/l at 48 hours. Magnesium chloride was also proven to have low toxicity to Daphnia hyaline, having a 48 hour LC50 of 32.0 mg/L, a low toxicity to Cyclops abyssorum, with a 48 hour LC50 of 280 mg/L and Magnesium chloride also has a low toxicity to Eudiaptomus padanus with a 48 hour LC 50 of 180 mg/L. The LC50 for Magnesium chloride on Austropotamobius pallipes pallipes was found to be 480 mg/l in a 96 hr test and 30 day LC50 values of 270 mg/L and 360 mg/L, without and with food, respectively. These values show that Magnesium chloride has low toxicity on Austropotamobius pallipes pallipes. Magnesium sulphate also has a low toxicity for Daphnia magna with an LC50 of 963 mg/l in 24 hours, measured in university lake water. In another supporting study, on the short term toxicity of Magnesium chloride and Magnesium sulphate to Ceriodaphnia dubia, again the conclusion was that Magnesium chloride and Magnesium sulphate, and hence the Magnesium ion, had low toxicity to Ceriodaphnia dubia with the LC50 for Magnesium chloride found to be 880 mg/l after 48 hours and Magnesium sulphate was found to be 1770 mg/l. Magnesium sulphate was found to have a very low toxicity for Lymnaea sp. Eggs with an LC50 of 10530 mg/l in 24hours.

According to the available data, the hydrolysis product magnesium hydroxide can be considered as acutely not harmful to aquatic invertebrates.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

170 mg/L

Additional information

The EC50 of 170 mg/l is related to the key study of the hydrolysis product magnesium hydroxide.