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Environmental fate & pathways

Distribution modelling

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distribution modelling
Type of information:
calculation (if not (Q)SAR)
Migrated phrase: estimated by calculation
Adequacy of study:
key study
Study period:
14 May to 20 December 2001
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study undertaken using accepted software program.

Data source

Reference Type:
study report
Report Date:

Materials and methods

calculation according to Mackay, Level III
Calculation programme:
Fugacity Model v. 2.20
air - biota - sediment(s) - soil - water

Test material

Details on test material:
- Name of test material (as cited in study report):Chlorendic Anhydride- Name of test material (as cited in study report): Chlorendic Acid

Study design

Test substance input data:
Chlorendic Anhydride- Molar mass: 370.83 g/mol- Data temperature: 25°C- Water solubility: 0.0982g/m3 (estimated WSKOW v.1.33)- Vapour pressure: 9.47E-03 (estimated by MPBPWIN v1.30)- log Pow:4.37 (estimated by KOWWIN v1.63)- Mineral matter - water partition coefficient Log Koc = 0.92- Melting point: 233°C- Reaction half-life estimates for- Air: 23.521 hours; Estimated using AOPWIN v1.88. This program estimates reaction with both hydroxyl radicals and ozone. Because the reaction rate of the latter was not significant its contribution has not been included. It is likely that the half-life in bulk air would be much lower because of reaction with atmospheric water.- Water: 2.78E-03 hours- Soil: 2.78E-03 hours- Sediment: 2.78E-03 hours; Hydrolysis on dissolution has been assumed and an arbitrary half life of 10s (2.78E-03 hours) used as input.- Suspended sediment: 2.78E-03 hours- Aerosols: 2.78E-03 hours- Aquatic biota: 2.78E-03 hoursChlorendic Acid- Molar mass: 388.85 g/mol- Data temperature: 25°C- Water solubility: 499 g/m3 (Test method OECD 105, VCL370/013652)- Vapour pressure: 4.053E-06 (estimated by MPBPWIN v 1.30)- log Pow: 1.39 (Test Method OECD 107, VCL370/013652)- Mineral matter - water partition coefficient- Melting point: 181.33°C (estimated by MPBPWIN v 1.30)- Reaction half-life estimates for- Air: 15.688 hours; Estimated using AOPWIN v1.88. This program estimates both reaction with hydroxyl radicals and ozone. Because the reaction rate of the latter was not significant its contribution has not been included.- Water: 4320 hours; No test data on aqueous hydrolysis rates were available and HYDROWIN v1.65 was unable to estimate a rate but hydrolysis is expected to be slow (compound with high degree of halogenation) Chlorendic anhydride (present as the acid) was shown to be not biodegradable in an inherent biodegradability test conducted at HLS (VCL372/013650) and BIOWIN v3.65 estimated that the acid would be recalcitrant to ultimate biodegradation (although primary biodegradation could be expected in weeks). On the basis of the BIOWIN output the Level III fugacity model run as part of the Syracuse programme suite uses half lives of 4320 h for the water, soil and sediment compartments. Accordingly these values were also used in this study.- Soil: 4320 hours- Sediment: 4320 hours- Suspended sediment: 4320 hours- Aerosols: 15.688 hours; No data were available therefore because of the high interface/volume ratio the value for air was used. - Aquatic biota: 4320 hours
Environmental properties:
The parameters that define the model environment are:Volume of each environmental compartment (m3)Density ofeach environmental compartment (kg/m3)Organic carbon content of soil and sediments (g/g)Lipid content (kg/m3)Transport velocities between compartments (m/h)

Results and discussion

Percent distribution in media

Air (%):
Water (%):
Soil (%):
Sediment (%):
Other distribution results:
The distibution results are for chlorendic acid.

Applicant's summary and conclusion

Chlorendic anhydrideThe only simulation run was for emission of the anhydride to air. Under these conditions nearly all (>99.9 percent) of the anhydride in the system was in the air compartment. Anhydride was rapidly removed from the system and the mean residence time was only 14.8 hours. The simulation results probably overestimated concentrations in air because no account was taken of reaction with atmospheric water.Chlorendic acidAs expected the simulation results showed that the acid was much more persistent in the environment than the anhydride. They also showed deposition of the acid from air onto soil and water, transport from soil to water but little deposition from water into the sediment compartment. The primary route of loss from the system was advection from the water compartment but degradation in the soil and water compartments was also significant. There were a number of uncertainties regarding the values used for model inputs so the results should be treated with appropriate caution.