Magnesium

Additional ecotoxological information

Administrative data

Endpoint:

additional ecotoxicological information

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: handbook with reliable values

Data source

Reference

Reference 1

Reference Type:

review article or handbook

Title:

Environmental Inorganic Chemistry.

Author:

Bodek I et al, eds

Year:

1988

Bibliographic source:

Elmsford, NY: Pergamon Press pp. 6.5-1 to 6.5-10 (1988)

Reference 2

Reference Type:

study report

Title:

Unnamed

Year:

1994

Materials and methods

Test guideline

Qualifier:

no guideline followed

GLP compliance:

not specified

Type of study / information:

leaching of magnesium compounds into water.

Test material

Test material information

Constituent 1

Reference substance name:

Magnesium carbonate

EC Number:

208-915-9

EC Name:

Magnesium carbonate

Cas Number:

546-93-0

IUPAC Name:

magnesium carbonate

Test material form:

solid: compact

Results and discussion

Any other information on results incl. tables

 Natural water systems acquire magnesium through weathering reactions, which involve the interaction of water and atmosphere with the earth's crust and subsequent leaching of magnesium compounds into water. The Mg2+ ion is the predominant form of dissolved magnesium. However, some magnesium complexes do form. The magnesium sulfate ion pair complex (MgSO4) is the most significant complex present, representing 2.6% and 11% of the total magnesium content in fresh and sea water, respectively. The concentrations of bicarbonate and carbonate complexes are significant but considerably less than sulfate complexes. Incorporation of magnesium compounds into sediment is an important removal process. For example, a small amount of magnesium is ion exchanged for calcium on clay minerals in ocean sediment. Also small amounts of magnesium carbonate (about 6% of the magnesium supplied by rivers) are deposited with calcite (CaCO3) in seawater. There is significant uptake of magnesium (about 24% of the river input of magnesium) by sediment in which sulfate reduction is taking place(1). The avg Kd value for magnesium sorption on Po River sediments is 1.3 cu m/kg, which suggests that magnesium ions are weakly sorbed on sediments. High-temperature alteration of basalts at hydrothermal vents apparently constitute the most important sink for magnesium in seawater.

Applicant's summary and conclusion

Conclusions:

Natural water systems acquire magnesium through weathering reactions, which involve the interaction of water and atmosphere with the earth's crust and subsequent leaching of magnesium compounds into water. The Mg2+ ion is the predominant form of dissolved magnesium. However, some magnesium complexes do form. The magnesium sulfate ion pair complex (MgSO4) is the most significant complex present, representing 2.6% and 11% of the total magnesium content in fresh and sea water, respectively. The concentrations of bicarbonate and carbonate complexes are significant but considerably less than sulfate complexes. Incorporation of magnesium compounds into sediment is an important removal process. For example, a small amount of magnesium is ion exchanged for calcium on clay minerals in ocean sediment. Also small amounts of magnesium carbonate (about 6% of the magnesium supplied by rivers) are deposited with calcite (CaCO3) in seawater. There is significant uptake of magnesium (about 24% of the river input of magnesium) by sediment in which sulfate reduction is taking place(1). The avg Kd value for magnesium sorption on Po River sediments is 1.3 cu m/kg, which suggests that magnesium ions are weakly sorbed on sediments. High-temperature alteration of basalts at hydrothermal vents apparently constitute the most important sink for magnesium in seawater.