Magnesium chloride

Endpoint summary

Description of key information

Short description of key information on bioaccumulation potential result: Magnesium chloride is an easily dissociable magnesium salt and in biological liquid, it is dissociated into the chlorine ion and the magnesium cation. In this context the toxicokinetic information is based on the magnesium cation following oral administration. The principal information is: 

- Magnesium kinetics represent an open system consisting of several compartments: the intestinal tract (absorption compartment), blood (central compartment), cells, skeleton, central nervous system (deep compartments) and faeces, urine, sweat and milk during lactation (excretion).

- At low dietary Mg intakes enteral absorption considerably increases from the normal level of 30-40% up to 80% probably via an active transport system. 

- As in the latter cases Mg uptake depends mostly or exclusively on passive diffusion (10-30%) a Mg deficit will result at intake levels which are sufficient for normal individuals. 

- Mg losses represent an important variable and affect excretion. 

- The dermal absorption can be considered minor compared to oral absorption (in the range of 0.1-1 %).

Key value for chemical safety assessment

Bioaccumulation potential:

no bioaccumulation potential

Additional information

Magnesium chloride is deliquescent, which means that it tends to undergo gradual dissolution and liquefaction by the attraction and the absorption of the moisture from the air. Consequently, in biological liquid, the magnesium chloride is dissociated into the chlorine ion and the magnesium cation: it is hence appropriate to use data from magnesium salt for read-across to magnesium chloride. Moreover, the first adverse effect (mild diarrhoea) to occur is triggered by magnesium concentration rather than by an effect of the chloride ion (SCF, 2001).

 

In this context, the toxicokinetic information is mainly based on the opinion of the Scientific Committee on Food on the tolerable Upper Intake level of Magnesium (SCF, 2001).

The principal data are:

-         Magnesium kinetics represent an open system consisting of several compartments: intestinal tract (absorption compartment), blood (central compartment), cells, skeleton, central nervous system (deep compartments) and faeces, urine, sweat and milk during lactation (excretion).

-         At low dietary Mg intakes, enteral absorption considerably increases from the normal level of 30-40% up to 80% probably via an active transport system (although this has not yet been proved); this system can, however, be completely defective (so-called “primary Mg deficiency”) or insufficient (“poor absorbers”).

-          As in the latter cases, Mg uptake depends mostly or exclusively on passive diffusion (10-30%). A Mg deficit will result at intake levels which are sufficient for normal individuals.

-         Mg losses represent an important variable: diarrhoea or bowel disease adversely affect excretion. Under physiological conditions, healthy kidney can reduce daily Mg excretion from 5 mmol to less than 0.5 mmol within a few days of low Mg intake.

These data are confirmed by some publications and only few are presented as disregarded studies. Indeed, these sources provide valuable information in humans on oral bioavailability of dietary magnesium or of soluble magnesium salts (as MgCl2), which confirm the SCF data (European document).

 

Concerning dermal absorption, no human data are available and on the basis of:

-         The Health Risk Assessment Guidance for metal (HERAG, 2006) indicating that the penetration of the dermis by dissolved metal cations is generally low, i.e. in the range of 0.1 -1%. 

-         The result for acute dermal toxicity with no systemic effect to the limit test.

This dermal absorption can be considered minor compared to oral absorption.