Maleic acid

Distribution modelling

Administrative data

Endpoint:

distribution modelling

Type of information:

calculation (if not (Q)SAR)

Remarks:

Migrated phrase: estimated by calculation

Adequacy of study:

key study

Study period:

2004

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Peer reviewed data

Data source

Reference

Reference Type:

secondary source

Title:

Unnamed

Year:

2004

Materials and methods

Model:

calculation according to Mackay, Level I

Calculation programme:

Trent University (1999 & 2004). Fugacity-based Environmental Equilibrium Partitioning Model. Version 2.2.

Release year:

2 002

Media:

air - biota - sediment(s) - soil - water

Test material

Test material information

Constituent 1

Reference substance name:

Maleic anhydride

EC Number:

203-571-6

EC Name:

Maleic anhydride

Cas Number:

108-31-6

Molecular formula:

C4H2O3

IUPAC Name:

furan-2,5-dione

Study design

Test substance input data:

- Molar mass: 116.07 g/mol
- Data temperature: 25 °C
- Water solubility: 407,000 g/m³
- Vapour pressure: 4.8 x 10-3 Pa
- log Pow: -2.61
- Melting point: 84.2 ºC
- Reaction half-life estimates for
- Air: 29.3 hours
- Water: 208 hours
- Soil: 208 hours
- Sediment: 832 hours

Results and discussion

Percent distribution in media

Air (%):

0

Water (%):

100

Soil (%):

0

Sediment (%):

0

Susp. sediment (%):

0

Biota (%):

0

Aerosol (%):

0

Any other information on results incl. tables

    
The material was modeled as a Type 1 chemical, i.e., it was assumed  capable of partitioning into all media. A more correct approach would  have been to model the material as a Type 2 chemical with a Z value of  zero or near-zero in air and an initial estimate of Z in water of 1.0.  This partitioning model would be calculated using the equivalence  approach instead of the fugacity calculation. However, the required  partition coefficients for Type 2 chemicals are not those used for Type 1  chemicals and were not available. Appropriate partition coefficients are  not readily estimated for Type 2 chemicals. In the absence of data,  errors and uncertainty from using estimated parameters would be likely to  counteract any improved accuracy from using a better model. Consequently,  more detailed modeling would be unlikely to significantly affect the  prediction of environmental fate if greater water solubility were assumed  (Zwater = 1.0).


    

    Resulting distributions of maleic acid (resulting from hydrolysis of 
     maleic anhydride) were:    

Level II     

Air:	< 0.01%	    

Water:	  100%    

Soil:	  0.0%    

Sediment:  0.0%

 

    
Resulting distributions of maleic acid (resulting from hydrolysis of  maleic anhydride) were:
Level III
Air:       0.0%
Water:       50%
Soil:        50%
Sediment:  0.02%