Manganese sulphate

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

0.03 mg/L

Assessment factor:

50

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

0.088 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 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. Note that this LC50 is quoted in terms of mg Mn/L and hence to calculate the equivalent LC50 for MnSO4(NO3)2 it is necessary to make an adjustment based on the relative molecular weights of Mn compared with MnSO4. The molecular weight of Mn is 55 and that of MnSO4 is 151 . It is therefore necessary to multiply the LC50 measured in mg Mn/L by a factor of 2.75 to obtain the LC50 for Mn(NO3)2. Multiplying 3.2 by 2.75 = 8.79. Hence, the lowest L(E)C50 for MnSO4 is 8.79 mg/L.

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 1.51 mg/L of MnSO4 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 MnSO4.

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 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 MnSO4.

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 and the EC50is >1000 mg/L.

Conclusion on classification

Self-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 8.79 mg/L of MnSO4 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 1.51 mg/L of MnSO4 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.

Harmonised classification

Manganese sulphate is classified as Chronic 2 (H411) in Annex VI of the CLP Regulation (index no.025-003-00-4).