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The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

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Environmental fate & pathways


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Administrative data

Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study meets generally accepted scientific principles

Data source

Reference Type:
Ion exchange and hydrolysis of Type A zeolite in natural waters
Allen HE, Cho SH and Neubecker TA
Bibliographic source:
Water Res., 17 , 1871-1879

Materials and methods

Principles of method if other than guideline:
A suspension of a surface modified zeolite in different waters was studied for hydrolysis as indicated by loss of both particulate aluminum and particulate silicon.
GLP compliance:
not specified

Test material

Constituent 1
Reference substance name:
Automatically generated during migration to IUCLID 6, no data available
Automatically generated during migration to IUCLID 6, no data available
Details on test material:
- Name of test material (as cited in study report): Type A Zeolite
- Framework: cuboidal
- Related CAS number: 1318-02-1
- Analytical purity: no data
- surface modified with Ca

Study design

Analytical monitoring:
Duration of test
30 d
Initial conc. measured:
ca. 7 other: µmol/L (particulate aluminium and silicon concentration)

Results and discussion

Transformation products:
Dissipation DT50 of parent compound
ca. 2 mo

Any other information on results incl. tables

Type A Zeolite hydrolysed extensively in the test waters at rates which were strongly dependent on hydrogen ion concentration (see Table 2).

Table 2: Increasing hydrolysis of Zeolite A within 3 days in synthetic test water with decreasing pH
 pH                         % zeolite
 8.2                         44%
 7.1                         59%
 6.3                         72%

Hydrolysis results for the synthetic water and different natural waters are given as estimated hydrolytic half-lifes (see Table 3).

Table 3: Estimated hydrolytic half-lifes of Zeolite A in different natural waters
 water type                                      t1/2 [d]
 Lake Michigan                                   27
 Lake Michigan                                   31
   + 15% sewage effluent
 Ohio River                                       n.d.
 Miami River                                  ca. 150
 Raccoon Creek                    1
 Raccoon River                    slow
 Town River                                       2
 Synthetic water                  60
   (EPA Guidelines)

The results indicate that hydrolysis of Zeolite A does occur in the environment. The rate of this reaction depends on the pH and the silicate concentration in the water. The half-life of 60 d observed in the synthetic water with a high pH and high silicate concentration is very likely an overestimation of the hydrolysis half-life. Therefore, it yields a conservative prediction of Zeolite A persistance under most circumstances.

Applicant's summary and conclusion