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Environmental fate & pathways

Additional information on environmental fate and behaviour

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Administrative data

Endpoint:
additional information on environmental fate and behaviour
Type of information:
calculation (if not (Q)SAR)
Remarks:
Migrated phrase: estimated by calculation
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Calculation using the validated Unit World model, to assess the removal of zinc from the water column, referring to established reference conditions for EU regional waters.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report date:
2010

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
The removal from the water column of zinc is calculated by the Unit World Model, a screening level model used to assess the long-term fate and effects of chemicals through simultaneous consideration of chemical partitioning, transport, reactivity, speciation, bioavailability and exposure routes.
GLP compliance:
not specified

Test material

Constituent 1
Chemical structure
Reference substance name:
Zinc
EC Number:
231-175-3
EC Name:
Zinc
Cas Number:
7440-66-6
Molecular formula:
Zn
IUPAC Name:
zinc
Constituent 2
Reference substance name:
Reference substance 001
Details on test material:
Calculations done for "Zn", assumed to be added in soluble form to a water body (worst case). So results are relevant to all soluble and also less soluble zinc compounds

Results and discussion

Any other information on results incl. tables

Zinc removal under different water chemistries:

-At 136 µg/l loading rate, zinc is removed from the water column for 70% after 3 days. Removal is the same at pH 6 and pH 8. At pH 7, it is a bit faster (70% removal after 2.5 days).

Zinc remopval under different loading rates:

-at pH 6, 413 µg/l loading rate, zinc is removed 70% after 3.5 days.

-at pH 6, 82µg/l and 136 µg/l loading rate, zinc is removed 70% after 3 days.

It is noted that these were first checks on removal rates, done in a small volume, with limited depth. Calculations done for reference real-world regional water conditions were done subsequently and reported in Mutch 2010b.

  

The system was dosed with one single dose of soluble zinc salt. This represents a worst case situation for metal release and persistence in the water column.

Applicant's summary and conclusion

Conclusions:
model calculations allow to assess the removal of zinc from the water column
Executive summary:

The removal of zinc from a water column was assessed using the Unit World Model, and referring to a small volume of water, to check the effect of a) loading and b) pH. Both variables had limited effect on the removal time of zinc from the water column.