Magnesium

Endpoint summary

Additional information

Environmental fate and pathways

 

Environmental Fate/Exposure Summary: 

Magnesium is an essential nutrient for humans, animals, and plants. Magnesium is approx 2% of soil in the earth's crust, eighth in abundance, and widely distributed in the environment in a variety of rock and minerals, such as igneous (e.g., olivine), metamorphic (e.g.,montmorillonite), and sedimentary rocks (e.g., magnesite, brucite, dolimite). Rocks and minerals contain a higher percentage of magnesium than do soils resulting from the loss of magnesium due to weathering. Magnesium salts, which make up 17% of sea salt, are released to the atmosphere as sea spray.

The production and use of magnesium compounds as refractories (e.g., olivine), as chemical intermediates, and in construction materials(e.g,magnesium oxide) may result in their release to the environment through various waste streams while the production and use of magnesium compounds in environmental applications (e.g., magnesium hydroxide), agriculture (e.g., magnesium sulfate), and ice control (e.g., magnesiumchloride) result in their direct release to the environment. Magnesium compounds, as ionic salts, will exist solely in the particulate phase in the ambient atmosphere. Particulate-phase magnesium compounds may be removed from the air by wet and dry deposition. Magnesium compounds in soil are removed by weathering. As soils weather, soil magnesium compounds become more soluble. Below pH 7.5, most magnesium minerals are too soluble to persist in soils.

Volatilization of magnesium compounds from moist soil surfaces is not an important fate process because these compounds are ionic and will not volatilize. 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.

If released into water,magnesium compounds may be removed by incorporation into sediment. For example, a small amount of magnesium is ion exchanged for calcium on clay minerals in ocean sediment. Also small amounts of magnesium carbonate are deposited with calcite in seawater. There is also significant uptake of magnesium by sediment in which sulfate reduction is taking place. The avg Kd value for magnesium sorption on sediments is 1.3 cu m/kg, which suggests that magnesium ions are weakly sorbed.

Volatilization of magnesium compounds from water surfaces is not an important fate process because these compounds are ionic and will not volatilize. Magnesium is widespread in living cells and does not bioconcentrate in aquatic organisms. Occupational exposure to magnesium compounds may occur through inhalation and dermal contact with these compounds at workplaces where magnesium compounds are produced or used. Monitoring data indicate that the general population is exposed to magnesium compounds via inhalation of ambient air, ingestion of food and drinking water, and dermal contact with compounds and consumer products containing magnesium compounds. The average daily intake of magnesium for a 25-30 yr man is 288 mg/day. (SRC)

 

TERRESTRIAL FATE:

 Magnesium compounds are removed from soils by weathering. A major portion of soil magnesium consists of weathered primary minerals and secondary aluminosilicates in which Mg+2 ions are substituted for Al+3 ions. Silicates and aluminosilicates minerals undergo rapid surface exchange of H+ for Mg+2 ions followed by slow dissolution. As soils weather, H4SiO4 declines and magnesium silicates become more soluble. Increases in soil CO2 levels will increase the solubility of the magnesium silicates while decreasing the solubility of dolomite (CaMgCO3). In submerged soils where CO2 levels are high, dolimite will be the most stable mineral phase. Below pH 7.5, most magnesium minerals are too soluble to persist in soils. However in alkaline soils that have high concns of soluble H4SiO4, some magnesium silicates may actually form (e.g., talc, serpentine, sepiolite and chrysotolite)(1,2).

(1) Aikawa JK; pp. 1025-1034 in Metals and Their Compounds in the Environment. Merian E, ed. Weinheim, Germany: VCH (1991)

(2) Bodek I et al (eds); Environmental Inorganic Chemistry. Elmsford, NY: Pergamon Press pp. 6.5-1 to 6.5-10 (1988)]

Based on estimated Koc value of13.22 L/kg, indicates that magnesium is expected to have very high mobility in soil.

Volatilization of magnesium from moist soil surfaces is not expected to be an important fate process given a estimated Henry's Law constant of 1.065E-037 atm-m3/mole (1.079E-032 Pa-m3/mole) . The estimated Henrys Law Constant (25 deg C) measured by calculation from EPI SuiteTM v4.1, HENRYWIN v3.20 Program was 1.065E-037 atm-m3/mole , which is almost zero.

Volatilization of magnesium compounds from water surfaces is not an important fate process because these compounds are ionic and will not volatilize

 The estimated Biodegradetion show that magnesiumis expected to degrade rapidly in both aerobic and anaerobic conditions.

The estimated Biodegradetion was measured by calculation from EPI SuiteTM v4.1Program and no Biodegradation was predicted . This is Exposure Assessment Tools and Models made from EPA (Environmental Protection Agency) .

Ready Biodegradability Prediction: YES

These rates suggest that biodegradation may be an important environmental fate process in soil

 

AQUATIC FATE:

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(2). High-temperature alteration of basalts at hydrothermal vents apparently constitute the most important sink for magnesium in seawater(1).

(1) Bodek I et al, eds; Environmental Inorganic Chemistry. Elmsford, NY: Pergamon Press pp. 6.5-1 to 6.5-10 (1988)

2) Pettine M et al; Sci Tot Environ 145: 243-265 (1994)

Based on on estimated Koc value of 13.22 L/kg, indicates that magnesium is not expected to adsorb to suspended solids and sediment.

Volatilization from water surfaces is not expected based upon a Henry's Law constant of  1.065E-037 atm-m3/mole (1.079E-032 Pa-m3/mole).

According to, an estimated BCF of3.162L/kg wet-wt , from Log Kow estimated:-0.57and regression-derived equations, suggest the potential for bioconcentration in aquatic organisms is low.

Magnesium is widespread in living cells(1) and does not bioconcentrate in aquatic organisms.
(1) Aikawa JK; pp. 1025-1034 in Metals and Their Compounds in the Environment. Merian E, ed. Weinheim, Germany: VCH (1991)] 

 The estimated Biodegradetion show that magnesium is expected to degrade rapidly in both aerobic and anaerobic conditions.

The estimated Biodegradetion was measured by calculation from EPI SuiteTM v4.1Program and no Biodegradation was predicted . This is Exposure Assessment Tools and Models made from EPA (Environmental Protection Agency) .

Ready Biodegradability Prediction: YES

These rates suggest that biodegradation may be an important environmental fate process.

 

ATMOSPHERIC FATE:

 As ionic salts, magnesium compounds will exist solely in the particulate phase in the ambient atmosphere. Particulate-phase magnesium compounds may be removed from the air by wet and dry deposition.

 

Stability

 

Phototransformation in air

Phototransformation in air is not expected to be an important environmental fate process since this compound lacks functional groups that is susceptible under environmental conditions, magnesium massive as an inorganic compound cannot broken down by photons.Magnesium do not contain chromophores that absorb at wavelengths >290 nm and therefore Magnesium massive is not expected to be susceptible to direct photolysis by sunlight. Magnesium does not react with dry air but slowly gets tarnished in most air due to the formation of a thin film of the oxide.

Hydrolysis

 

According to “ANNEX VIII- STANDARD INFORMATION REQUIREMENTS FOR SUBSTANCES MANUFACTURED OR IMPORTED IN QUANTITIES OF 10 TONNES OR MORE , study for Hydrolysis as a function of pH does not need to be conducted if:

-the substance is ready biodegradable.

-the substance is highly insosuble in water

As magnesium is ready biodegradable (according EPI SuiteTM v4.1 and Biodegradation was predicted) a Hydrolysis study does not need to be conducted.

Magnesium as an ingot is insoluble in pure cold water. Hydrolysis is not expected to be an important environmental fate process since this compound lacks functional groups that hydrolyze under environmental conditions.

Magnesium does not decompose water in cold but decomposes boiling water or steam.

Mg + H₂O ( steam) ——→ MgO + H₂       

Hydrolysis is a chemical reaction during which molecules of water (H2O) are split into hydrogen cations (H+, conventionally referred to as protons) and hydroxide anions (OH−) in the process of a chemical mechanism).

This substance, which is metal-containing inorganic substance, is not anticipated to hydrolyze readily in water at neutral pHs.

 

Phototransformation in water

 

Expert Judgement

If released into water, magnesium is not expected to adsorb to suspended solids and sediment based upon the estimated Koc value of 13.22 L/kg  . Volatilization from water surfaces is not expected to be an important fate process based upon this compound's estimated Henry's Law constant is1.065E-037 atm-m3/mole.

Magnesium as an ingot is insoluble in pure cold water, but reacts with hot water to form Mg(OH)2 under the evolution of hydrogen gas. Reacts with seawater forming the chloride and sulphate.

On this basis phototransformation in water is not expected .

 

Therefore testing for Phototransformation in water does not need to be performed.

 

Phototransformation in soil

 

Expert Judgement

 

 If released to soil, magnesium is expected to have very high mobility based upon an estimated Koc of 13.22. Volatilization from moist soil surfaces is not expected to be an important fate process based upon an estimated Henry's Law constant of1.065E-037 atm-m3/mole.

 Henry's Law constant indicates that volatilization from moist soil surfaces may occur may occur slowly.

    

 Therefore testing for Phototransformation in soils does not need to be performed.

 

Biodegradation

Biodegradation in water: screening tests

 

The estimated Biodegradetion was measured by calculation from EPI SuiteTM v4.1 Program and Biodegradation was predicted . This is Exposure Assessment Tools and Models made from EPA (Environmental Protection Agency) .

 

 

Biowin1 (Linear Model Prediction)   : Biodegrades Fast

Biowin2 (Non-Linear Model Prediction): Biodegrades Fast

Biowin3 (Ultimate Biodegradation Timeframe): Weeks

Biowin4 (Primary Biodegradation Timeframe): Days

Biowin5 (MITI Linear Model Prediction)   : Biodegrades Fast

Biowin6 (MITI Non-Linear Model Prediction): Biodegrades Fast

Biowin7 (Anaerobic Model Prediction): Biodegrades Fast

Ready Biodegradability Prediction: YES

 

SMILES : [Mg]

EC Name: MAGNESIUM

CAS Name: MAGNESIUM

Molecular Formula: Mg

MOL WT : 24.3039

 

 

------+-----+--------------------------------------------+---------+---------

TYPE | NUM |      Biowin1 FRAGMENT DESCRIPTION        | COEFF | VALUE

------+-----+--------------------------------------------+---------+---------

MolWt| * | Molecular Weight Parameter                      |        | -0.0125

Const| * | Equation Constant                                       |        | 0.7475

============+============================================+=========+=========

RESULT  |   Biowin1 (Linear Biodeg Probability)     |        | 0.7350

============+============================================+=========+=========

 

------+-----+--------------------------------------------+---------+---------

TYPE | NUM |      Biowin2 FRAGMENT DESCRIPTION        | COEFF | VALUE

------+-----+--------------------------------------------+---------+---------

MolWt| * | Molecular Weight Parameter                     |        | -0.3738

============+============================================+=========+=========

RESULT  | Biowin2 (Non-Linear Biodeg Probability)  |        | 0.9331

============+============================================+=========+=========

 

A Probability Greater Than or Equal to 0.5 indicates --> Biodegrades Fast

A Probability Less Than 0.5 indicates --> Does NOT Biodegrade Fast

 

------+-----+--------------------------------------------+---------+---------

TYPE | NUM |      Biowin3 FRAGMENT DESCRIPTION        | COEFF | VALUE

------+-----+--------------------------------------------+---------+---------

MolWt| * | Molecular Weight Parameter                     |        | -0.0582

Const| * | Equation Constant                                     |        | 3.1992

============+============================================+=========+=========

RESULT  | Biowin3 (Survey Model - Ultimate Biodeg) |        | 3.1410

============+============================================+=========+=========

 

------+-----+--------------------------------------------+---------+---------

TYPE | NUM |      Biowin4 FRAGMENT DESCRIPTION        | COEFF | VALUE

------+-----+--------------------------------------------+---------+---------

MolWt| * | Molecular Weight Parameter                     |        | -0.0380

Const| * | Equation Constant                                     |        | 3.8477

============+============================================+=========+=========

RESULT  |  Biowin4 (Survey Model - Primary Biodeg) |        | 3.8098

============+============================================+=========+=========

 

Result Classification:  5.00 -> hours    4.00 -> days   3.00 -> weeks

(Primary & Ultimate)   2.00 -> months   1.00 -> longer

 

------+-----+--------------------------------------------+---------+---------

TYPE | NUM |      Biowin5 FRAGMENT DESCRIPTION        | COEFF | VALUE

------+-----+--------------------------------------------+---------+---------

MolWt| * | Molecular Weight Parameter                     |        | -0.0783

Const| * | Equation Constant                                     |        | 0.7121

============+============================================+=========+=========

RESULT  | Biowin5 (MITI Linear Biodeg Probability) |        | 0.6338

============+============================================+=========+=========

 

------+-----+--------------------------------------------+---------+---------

TYPE | NUM |      Biowin6 FRAGMENT DESCRIPTION        | COEFF | VALUE

------+-----+--------------------------------------------+---------+---------

MolWt| * | Molecular Weight Parameter                     |        | -0.7599

============+============================================+=========+=========

RESULT  |Biowin6 (MITI Non-Linear Biodeg Probability)|        | 0.8539

============+============================================+=========+=========

 

A Probability Greater Than or Equal to 0.5 indicates --> Readily Degradable

A Probability Less Than 0.5 indicates --> NOT Readily Degradable

 

 

------+-----+--------------------------------------------+---------+---------

TYPE | NUM |      Biowin7 FRAGMENT DESCRIPTION        | COEFF | VALUE

------+-----+--------------------------------------------+---------+---------

Const| * | Equation Constant                                       |        | 0.8361

============+============================================+=========+=========

RESULT  |  Biowin7 (Anaerobic Linear Biodeg Prob)  |        | 0.8361

============+============================================+=========+=========

 

A Probability Greater Than or Equal to 0.5 indicates --> Biodegrades Fast

A Probability Less Than 0.5 indicates --> Does NOT Biodegrade Fast

 

Ready Biodegradability Prediction: (YES or NO)

----------------------------------------------

Criteria for the YES or NO prediction: If the Biowin3 (ultimate survey

model) result is "weeks" or faster (i.e. "days", "days to weeks", or

"weeks" AND the Biowin5 (MITI linear model) probability is >= 0.5, then

the prediction is YES (readily biodegradable). If this condition is not

satisfied, the prediction is NO (not readily biodegradable). This method

is based on application of Bayesian analysis to ready biodegradation data

(see Help). Biowin5 and 6 also predict ready biodegradability, but for

degradation in the OECD301C test only; using data from the Chemicals

Evaluation and Research Institute Japan (CERIJ) database.

 

 

Biodegradation in water and sediment: simulation tests

 

According to “ANNEX IX- STANDARD INFORMATION REQUIREMENTS FOR SUBSTANCES MANUFACTURED OR IMPORTED IN QUANTITIES OF 100 TONNES OR MORE”, a ready biodegradability study does not need to be performed if the substance is ready biodegradable. As magnesium is ready biodegradable a ready biodegradability study does not need to be conducted.

The estimated Biodegradetion was measured by calculation from EPI SuiteTM v4.1Program and Biodegradation was predicted . This is Exposure Assessment Tools and Models made from EPA (Environmental Protection Agency) .

 

Biodegradation in soil

 

According to “ANNEX IX- STANDARD INFORMATION REQUIREMENTS FOR SUBSTANCES MANUFACTURED OR IMPORTED IN QUANTITIES OF 100 TONNES OR MORE”, a ready biodegradability study does not need to be performed if the substance is ready biodegradable. As magnesium is ready biodegradable a ready biodegradability study does not need to be conducted.

The estimated Biodegradetion was measured by calculation from EPI SuiteTM v4.0 Program and Biodegradation was predicted . This is Exposure Assessment Tools and Models made from EPA (Environmental Protection Agency) .

 

Bioaccumulation

 

This substance has a limited potential to bioaccumulate (based on log Kow used :, Log Kow estimated : -0.57, and predicted bioconcentration factors, log BCF =0.500  (EPIWIN/BCF Program).

The estimated BCF of3.162L/kg wet-wt was measured by calculation from EPI SuiteTM v4.1 Program.

These values would suggest very low bioaccumulation potential.

This is Exposure Assessment Tools and Models made from EPA (Environmental Protection Agency).

 

BCFBAF Program (v3.01) Results:

==============================

SMILES : [Mg]

EC Name: MAGNESIUM

CAS Name: MAGNESIUM

Molecular Formula: Mg

MOL WT : 24.3039

 

 

--------------------------------- BCFBAF v3.01 --------------------------------

Summary Results:

Log BCF (regression-based estimate): 0.50 (BCF = 3.16 L/kg wet-wt)

Biotransformation Half-Life (days) : 0.0166 (normalized to 10 g fish)

Log BAF (Arnot-Gobas upper trophic): -0.04 (BAF = 0.904 L/kg wet-wt)

 

Log Kow (experimental): not available from database

Log Kow used by BCF estimates: -0.57

 

Equation Used to Make BCF estimate:

Log BCF = 0.50

 

Correction(s):                   Value

Correction Factors Not Used for Log Kow < 1

 

Estimated Log BCF = 0.500 (BCF = 3.162 L/kg wet-wt)

 

Magnesium is widespread in living cells(1) and does not bioconcentrate in aquatic organisms.

Bioaccumulation: aquatic / sediment

 

This substance has a limited potential to bioaccumulate (based on log Kow used :, Log Kow estimated : -0.57 , and predicted bioconcentration factors, log BCF = 0.500  (EPIWIN/BCF Program).

The estimated BCF of 3.162 L/kg wet-wt was measured by calculation from EPI SuiteTM v4.1 Program.

These values would suggest very low bioaccumulation potential.

This is Exposure Assessment Tools and Models made from EPA (Environmental Protection Agency).

 

BCFBAF Program (v3.01) Results:

==============================

SMILES : [Mg]

EC Name: MAGNESIUM

CAS Name: MAGNESIUM

Molecular Formula: Mg

MOL WT : 24.3039

 

--------------------------------- BCFBAF v3.01 --------------------------------

Summary Results:

Log BCF (regression-based estimate): 0.50 (BCF = 3.16 L/kg wet-wt)

Biotransformation Half-Life (days) : 0.0166 (normalized to 10 g fish)

Log BAF (Arnot-Gobas upper trophic): -0.04 (BAF = 0.904 L/kg wet-wt)

 

Log Kow (experimental): not available from database

Log Kow used by BCF estimates: -0.57

 

Equation Used to Make BCF estimate:

Log BCF = 0.50

 

Correction(s):                   Value

Correction Factors Not Used for Log Kow < 1

 

Estimated Log BCF = 0.500 (BCF = 3.162 L/kg wet-wt)

 

 

Bioaccumulation: terrestrial

 

This substance has a limited potential to bioaccumulate (based on log Kow used :, Log Kow estimated : -0.57, and predicted bioconcentration factors, log BCF =0.500  (EPIWIN/BCF Program).

The estimated BCF of3.162 L/kg wet-wt was measured by calculation from EPI SuiteTM v4.1 Program.

These values would suggest very low bioaccumulation potential.

This is Exposure Assessment Tools and Models made from EPA (Environmental Protection Agency).

 

BCFBAF Program (v3.01) Results:

==============================

SMILES : [Mg]

EC Name: MAGNESIUM

CAS Name: MAGNESIUM

Molecular Formula: Mg

MOL WT : 24.3039

 

 

--------------------------------- BCFBAF v3.01 --------------------------------

Summary Results:

Log BCF (regression-based estimate): 0.50 (BCF = 3.16 L/kg wet-wt)

Biotransformation Half-Life (days) : 0.0166 (normalized to 10 g fish)

Log BAF (Arnot-Gobas upper trophic): -0.04 (BAF = 0.904 L/kg wet-wt)

 

Log Kow (experimental): not available from database

Log Kow used by BCF estimates: -0.57

 

Equation Used to Make BCF estimate:

Log BCF = 0.50

 

Correction(s):                   Value

Correction Factors Not Used for Log Kow < 1

 

Estimated Log BCF = 0.500 (BCF = 3.162 L/kg wet-wt)

 

 

===========================================================

Whole Body Primary Biotransformation Rate Estimate for Fish:

===========================================================

------+-----+--------------------------------------------+---------+---------

TYPE | NUM | LOG BIOTRANSFORMATION FRAGMENT DESCRIPTION | COEFF | VALUE

------+-----+--------------------------------------------+---------+---------

L Kow| * | Log Kow = -0.57 (KowWin estimate)       | 0.3073 | -0.1755

MolWt| * | Molecular Weight Parameter                 |        | -0.0675

Const| * | Equation Constant                         |        | -1.5058

============+============================================+=========+=========

RESULT  |       LOG Bio Half-Life (days)            |        | -1.7801

RESULT  |           Bio Half-Life (days)            |        | 0.01659

NOTE    | Bio Half-Life Normalized to 10 g fish at 15 deg C  |

============+============================================+=========+=========

 

Biotransformation Rate Constant:

kM (Rate Constant): 41.77 /day (10 gram fish)

kM (Rate Constant): 23.49 /day (100 gram fish)

kM (Rate Constant): 13.21 /day (1 kg fish)

kM (Rate Constant): 7.428 /day (10 kg fish)

 

Arnot-Gobas BCF & BAF Methods (including biotransformation rate estimates):

Estimated Log BCF (upper trophic) = -0.044 (BCF = 0.9044 L/kg wet-wt)

Estimated Log BAF (upper trophic) = -0.044 (BAF = 0.9044 L/kg wet-wt)

Estimated Log BCF (mid trophic)  = -0.026 (BCF = 0.9423 L/kg wet-wt)

Estimated Log BAF (mid trophic)  = -0.026 (BAF = 0.9423 L/kg wet-wt)

Estimated Log BCF (lower trophic) = -0.022 (BCF = 0.9505 L/kg wet-wt)

Estimated Log BAF (lower trophic) = -0.022 (BAF = 0.9505 L/kg wet-wt)

 

Arnot-Gobas BCF & BAF Methods (assuming a biotransformation rate of zero):

Estimated Log BCF (upper trophic) = -0.035 (BCF = 0.9217 L/kg wet-wt)

Estimated Log BAF (upper trophic) = -0.035 (BAF = 0.9221 L/kg wet-wt)

 

Transport and distribution

Adsorption / desorption

 

According to “ANNEX IX- STANDARD INFORMATION REQUIREMENTS FOR SUBSTANCES MANUFACTURED OR IMPORTED IN QUANTITIES OF 100 TONNES OR MORE , an adsorption study need not be conducted if:

— based on the physicochemical properties the substance can be expected to have a low potential for adsorption (e.g. the substance has a low octanol water partition coefficient), or

— the substance and its degradation products decompose rapidly.

 

Octanol/Water Partition Coefficient ofmagnesiumis low (log Kow =-0.57)

 

If released into water,magnesiumis not expected to adsorb to suspended solids and sediment based upon the Koc. The Koc ofmagnesiumcan be estimated to be13.22.This estimated Koc value suggests thatMagnesiumis expected to have very high mobility in soil.

 

The estimated Soil Adsorption Coefficient was13.22L/kg measured by calculation from EPI SuiteTM v4.1 Program. This is Exposure Assessment Tools and Models made from EPA (Environmental Protection Agency

These results suggest thatmagnesiumhas high soil mobility and does not have a high potential for adsorption to soil

 

 

KOCWIN Program (v2.00) Results:

 

SMILES : [Mg]

EC Name: MAGNESIUM

CAS Name: MAGNESIUM

Molecular Formula: Mg

MOL WT : 24.3039

 

--------------------------- KOCWIN v2.00 Results ---------------------------

 

 

Koc Estimate from MCI:

---------------------

First Order Molecular Connectivity Index ........... : 1.000

Non-Corrected Log Koc (0.5213 MCI + 0.60) .......... : 1.1211

Fragment Correction(s) --> NONE                     :  ---

Corrected Log Koc .................................. : 1.1211

 

Estimated Koc: 13.22 L/kg  <===========

 

Koc Estimate from Log Kow:

-------------------------

Log Kow (Kowwin estimate) ......................... : -0.57

Non-Corrected Log Koc (0.8679 logKow - 0.0004) ..... : -0.4951

Fragment Correction(s) --> NONE                     :  ---

Corrected Log Koc .................................. : -0.4951

 

Estimated Koc: 0.3198 L/kg  <===========

 

Henry's Law constant.

The estimated Henrys Law Constant (25 deg C) measured by calculation from EPI SuiteTM v4.1, HENRYWIN v3.20 Program was  1.065E-037 atm-m3/mole (1.079E-032 Pa-m3/mole) , which is almost zero.

This is Exposure Assessment Tools and Models made from EPA (Environmental Protection Agency).

Distribution modelling.

 

The concentrations in water and sediment are effectively independent of the compartment into which the emissions occur. Concentrations in air and soil depend on what compartment emissions occured to and are quite variable. Only emissions to air contribute to atmospheric concentrations whilst deposition in soil comes approximately 50/50 from direct emissions to soil and indirectly from emissions to air.

 

Mackay fugacity modelling (level 3) indicates that, taking into account degradation and using inflow parameters which are consistent with the known production tonnage of this substance in, fugacity coefficient indicates that environmental concentrations in water are predicted to be 1.41e-006 (atm), in air (atm) 2.6e-032 and soil 3.36e-006 (atm) and sediment to be  1.28e-006 (atm).

These are negligible low levels. This can be considered a worse case prediction as it assumes all product is emitted with no emission control systems used.

 

Other distribution data

 

These results suggest for magnesium that direct and indirect exposure from distribution in media is unlikely.

Based on low vapor pressure and low estimated log Pow, expected to

partition to water. Not expected to partition to air, sediments or biota.

 

Therefore testing for distribution in media does not need to be performed.

 

The estimated STP Fugacity Model and Volatilization From Water were measured by calculation from EPI SuiteTM v4.1 Program. This is Exposure Assessment Tools and Models made from EPA (Environmental Protection Agency) .

 

Volatilization From Water

=========================

 

Chemical Name: MAGNESIUM

 

Molecular Weight   : 26.32 g/mole

Henry's Law Constant: 0.0245 atm-m3/mole (estimated by Bond SAR Method)

 

                                             RIVER     LAKE

      

                                         ---------        ---------

Water Depth    (meters):       1                1

Wind Velocity   (m/sec):       5                0.5

Current Velocity (m/sec):     1                0.05

 

HALF-LIFE (min ) :             32.15            2932

HALF-LIFE (hours) :           0.5358         48.86

HALF-LIFE (days ) :           0.02232        2.036

 

 

STP Fugacity Model: Predicted Fate in a Wastewater Treatment Facility

======================================================================

(using 10000 hr Bio P,A,S)

PROPERTIES OF: MAGNESIUM

-------------

Molecular weight (g/mol)                              26.32

Aqueous solubility (mg/l)                              0

Vapour pressure (Pa)                                   0

(atm)                                                            0    

(mm Hg)                                                      0

Henry 's law constant (Atm-m3/mol)         0.0245

Air-water partition coefficient                    1.00198

Octanol-water partition coefficient (Kow)  0.269153

Log Kow                                                         -0.57

Biomass to water partition coefficient        0.853831

Temperature [deg C]                                   25

Biodeg rate constants (h^-1),half life in biomass (h) and in 2000 mg/L MLSS (h):

-Primary tank        0.04       17.05      10000.00

-Aeration tank      0.04       17.05      10000.00

-Settling tank        0.04       17.05      10000.00

 

STP Overall Chemical Mass Balance:

---------------------------------

                                                  g/h              mol/h         percent

 

Influent                              1.00E+001        3.8E-001       100.00

 

Primary sludge                  2.47E-002        9.4E-004        0.25

Waste sludge                    1.46E-002        5.5E-004        0.15

Primary volatilization       1.30E-001        4.9E-003        1.30

Settling volatilization       3.48E-002        1.3E-003        0.35

Aeration off gas               8.84E+000        3.4E-001       88.44

 

Primary biodegradation  1.74E-003        6.6E-005        0.02

Settling biodegradation  5.09E-005        1.9E-006        0.00

Aeration biodegradation 6.84E-004       2.6E-005        0.01

 

Final water effluent          9.49E-001        3.6E-002        9.49

 

Total removal                  9.05E+000        3.4E-001       90.51

Total biodegradation     2.47E-003         9.4E-005        0.02