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Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

ENVIRONMENTAL FATE PROPERTIES

Summary of degradation

MnO is inorganic and hence the ready biodegradation and hydrolysis tests are not relevant. This is because there is no carbon to be evolved and no chemical bonds to be broken, respectively. The water solubility of MnO is 0.85 mg/l at 20°C and a transformation dissolution study has shown that the concentration of manganese dissolved and/or transformed is 8803.1 µg/l after 7 days from 100mg/L loading (i.e around ten times the water solubility). Not surprisingly these limit values are rather higher than the background concentration of manganese in European environments (15.9 µg Mn/L in surface water, 452 mg/kg in sediment, 428.6 mg/kg in soil; “Probabilistic Distribution of Manganese in European Surface Water, Sediment and Soil and Derivation of Predicted Environmental Concentrations (PEC)”, Parametrix, 2009 and supported by GEMAS data).

Volatilisation

Data on volatilisation are not available for the substance. MnO is a solid and hence not volatile.

Distribution modelling

No distribution modelling data exist.

Summary of environmental distribution

The 72hr adsorption/desorption study (OECD 106) on MnCl2 (a more soluble/readily available form of Manganese (Mn2+)) in 35 different soil types illustrate that adsorption is pH sensitive. A median Kd of 994 ml/g was determined for all soil types used (pH range 3.0-8.5).

 

Summary and discussion of bioaccumulation

The data are not required as the hazard assessment performed during the chemical safety assessment concludes that the substance is not classified and is of no immediate concern to the environment. Furthermore, manganese is an essential trace nutrient in animals and is required for the photosynthetic process in plants. Hence unacceptable bioaccumulation is highly unlikely to occur in any organism due to their ability to regulate intake and loss from natural sources.

Secondary poisoning

Bioaccumulation of MnO is not expected to occur. Hence no secondary poisoning risk exists.

Assessment of PBT/vPvB Properties - Comparison with the Criteria of Annex XIII

According to the Guidance on information requirements and chemical safety assessment, Chapter R.11: PBT assessment, “the PBT and vPvB criteria of Annex XIII to the regulation do not apply to inorganic substances”. Therefore MnO is not considered to require any further assessment of PBT properties.

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