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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:
other information
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Test procedure is in accordance with generally accepted scientific standards and described in sufficient detail. Due to incorporation of removal of Zeolite A in the wastewater treatment process, the predicted environmental distribution appears realistic, except for a significant underestimation of the fraction in the sediment which is compensated for by an overpredicted fraction in the water. Generally, the application of modelling calculations seems problematic for zeolites as many substance parameters have to be estimated for the model. In reality, it must be assumed that zeolites will settle rather fast to the bottom of aquatic systems, i.e. to the sediment.

Data source

Reference Type:
study report

Materials and methods

other: EUSES-exposure simulation according to the HERA scenario
Calculation programme:

Model input parameters by user:

Molecular weight (g/mol): 2190
Log Kow: -1 c)
Water solubility (g/l): 0,001 a)
Vapor pressure (Pa): 1 x 10-6 c)
Melting Point (°C): 300 a)
Half-life in Air (d): 1000000 b)
Half-life in Water (d): 63 a)
Half-life in Soil (d): 1000000 b)
Half-life in Sediment (d): 4200000 b)
Temperature (°C): 12

a)=measured b)=default c)=estimated

Input data calculated by the model:
Henry Constant (Pa m³ /mol) 0.00219
Air-Water partitioning coeff.(dimensionless) 9.24E-07
Organic Carbon-Water partitioning coeff.(l/kg) 0.195
Soil Solids-Water partitioning coeff. (l/kg) 0.0039
Sediment Solids-Water partitioning coeff.(l/kg) 0.0098
Suspended Particles-Water partitit.coeff.(l/kg) 0.0195
air - biota - sediment(s) - soil - water

Test material

Constituent 1
Chemical structure
Reference substance name:
Zeolite, silica and titanium based, crystalline, synthetic, non fibrous
EC Number:
Molecular formula:
[SiO4/2]x [TiO4/2]y * wH2O, with x can range from 0.50 to 0.99, y can range from 0.01 to 0.5 and x+y=1 and w can range from 0 to 120
Zeolite, silica and titanium based, crystalline, synthetic, non fibrous

Results and discussion

Any other information on results incl. tables

The results obtained in the EUSES calculations are shown in Table 1.

Table 1: Concentrations and distribution of Zeolite A in the four dominant media based on Level III calculations
                                               Concentration (PEC)  Distribution
                                               [mg/l][mg/kg]                [%]
Natural soil (total)
                       2.66E-03        0.08%
Agricultural soil (total)
       1.1                  59.7%
Industrial/urban soil (total)
               0.00266           0.01%
Surface Water (total)
                          0.75                     39.9%
Sediment (total)
                   0.45                     0.31%
                                  1.02E-06 0.00%

Applicant's summary and conclusion