Manganese dinitrate

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

0.036 mg/L

Assessment factor:

50

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

0.104 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0 mg/L

Assessment factor:

50

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

56 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

0.011 mg/kg sediment dw

Assessment factor:

50

Extrapolation method:

assessment factor

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

0.001 mg/kg sediment dw

Assessment factor:

500

Extrapolation method:

equilibrium partitioning method

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

25.1 mg/kg soil dw

Assessment factor:

10

Extrapolation method:

assessment factor

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

Aquatic

 

The ecotoxicity and environmental fate data for Mn(NO3)2 includes data generated on Mn(NO3)2 itself, as well as data read-across from MnSO4 and MnCl2. Read-across from MnSO4 and MnCl2 is justified on the following basis:  all of these substances are very soluble in water and hence are bioavailable and all will release Mn2+ ions. From an ecotoxicity standpoint, the nitrate, chloride or sulphate anions are not considered to have a significant influence on the effective toxicity of Mn2+ or have any significant toxicity in their own right, so the anions can be disregarded. Therefore any effect can be attributed to the Mn2+ cation, and so the data from the MnSO4 and MnCl2 ecotoxicity tests is regarded as a suitable surrogate for read-across.

The lowest acute L(E)C50 value from the dataset was obtained in the rainbow trout (Davies & Brinkman 1998). This study was conducted on MnSO4 and the LC50 was 3.2 mg Mn/L. This is equivalent to 10.41 mg/L of Mn(NO3)2 when a molecular weight correction is made.

The lowest chronic NOEC value from the dataset was obtained in the brook trout study (Davies & Brinkman 1998). This study was conducted on MnSO4 and the NOEC was 0.55 mg Mn/L. This is equivalent to 1.790 mg/L of Mn(NO3)2 when a molecular weight correction is made.

Sediment

Chronic endpoints are available for two sediment dwelling organisms,Hyalella Azteca and Chironomus tentans, representing different living and feeding conditions. The lowest of these endpoints is a NOEC of 0.29 mg Mn/L, which is equivalent to 0.22 mg Mn/kg wwt sediment (assuming density of sediment of 1.3 g/cm³) and 0.57 mg Mn/kg dwt sediment (based on a conversion factor of 2.6).

It should be noted that these values are considerably lower than the background concentration of manganese in European environments (452 mg/kg in sediment; “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) and hence has little relevance for assessment of any potential risk from Mn(NO₃)₂.

Terrestrial

There are a wide range of long-term toxicity endpoints available for the soil compartment, that cover three trophic levels. Therefore, the lowest NOEC is used with an AF of 10. In line with the REACH Guidance (R.10.6) the endpoints from soil studies need to be converted from experimental soil to standard soil, taking into account differences in organic matter content (equation R.10-4). Therefore, the lowest overall NOEC is actually 251 mg Mn/kg soil (i.e. NOEC of 207 mg Mn/kg soil, corrected for organic carbon content of 2.8%). It should also be noted that this value is considerably lower than the background concentration of manganese in European environments (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) and hence has little relevance for assessment of any potential risk from Mn(NO₃)_2.

 

STP

Limited effect on sewage sludge was observed in a standard 3hr activated sludge study on MnSO₄. Hence the NOEC for MnSO₄is 560 mg/l (204 mg Mn/L) and the EC₅₀is >1000 mg/L (>364 mg Mn/L). These data are used as a read-across for Mn(NO₃)₂.

Conclusion on classification

According to the 2nd ATP to the CLP Regulation (EU) No 286/2011, environmental classification of readily soluble metal compounds for which suitable ecotoxicity data is available is based upon the acute and chronic ERV.

In this case the lowest acute L(E)C50 value from the dataset was obtained in the rainbow trout (Davies & Brinkman 1998). This study was conducted on MnSO4 and the LC50 was 3.2 mg Mn/L. This is equivalent to 10.41 mg/L of Mn(NO3)2 when a molecular weight correction is made. This is the acute ERV.

The lowest NOEC value from the dataset was obtained in the brook trout study (Davies & Brinkman 1998). This study was conducted on MnSO4 and the NOEC was 0.55 mg Mn/L. This is equivalent to 1.790 mg/L of Mn(NO3)2 when a molecular weight correction is made. This is the chronic ERV.

In cases where both the acute and chronic ERV are greater than 1 mg/L there is no need to classify for either acute or chronic effects.