Registration Dossier

Environmental fate & pathways

Additional information on environmental fate and behaviour

Administrative data

Endpoint:
additional information on environmental fate and behaviour
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
2010-07-26 to 2010-07-31
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Not to GLP or a guideline, but a modern study conducted to a good scientific standard

Data source

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

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
An acidic aqueous solution of manganese nitrate (analysed at 57.2% Mn(NO3)2, as placed on the market, was dissolved in pH-buffered solutions to produce a concentration range of 158-173 mg Mn/L, at pH 4, 7 and 9 at 20°. At 24, 48 and 96 hours, a sample was filtered through a 0.2 micron nylon syringe filter and examined for particulate matter. This step is critical to avoid any possible confounding influence from possible manganese (di)oxide formation (as a result of degradation of the manganese nitrate). This is because prior to ICP analysis, nitric acid is added to the sample, and any traces of oxide would react back to the soluble nitrate, giving the appearance of no degradation. An aliquot of the clear supernatant plus concentrated nitric acid were diluted by a factor of 100 using reverse osmosis water.The concentration of Mn was monitored using ICP-MS over a time period of 96 hours, in order to assess any change over a time period of interest for ecotoxicity in the enviroment.
GLP compliance:
no
Remarks:
Conducted in a facility operating to GLP within the UK National GLP Monitoring Programme.

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Mn(NO3)2
- Physical state: pink liquid
- Composition of test material, percentage of components: 57% Mn nitrate (withing a hydrated substance)
- Lot/batch No.: 07/2008
- Storage condition of test material: room temperature in the dark

Results and discussion

Any other information on results incl. tables

pH 4 and 7 : less than 5% hydrolysis at 20°C.

pH 9 : rate constant 2.54E-06 s-1, half-life 75.9 hr.

Applicant's summary and conclusion

Conclusions:
Manganese dinitrate is stable at pH 4 and 7 at 20°C over a time period of at least 96 hours. Manganese dinitrate is not stable at pH 9, with a half-life of 75.9 hours. At the pH that most aquatic ecotoxicity tests are conducted (pH 7.5-8), manganese dinitrate is considered sufficiently stable at the concentrations and times involved to assign sufficient reliability that the test results are related to the manganese dinitrate and not to any degradation product.