Manganese sulphide

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

0.011 mg/L

Assessment factor:

50

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

0.049 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.001 mg/L

Assessment factor:

500

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

100 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

1.53 mg/kg sediment dw

Assessment factor:

500

Extrapolation method:

assessment factor

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

0.153 mg/kg sediment dw

Assessment factor:

5 000

Extrapolation method:

assessment factor

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

6.2 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

ENVIRONMENTAL HAZARD ASSESSMENT INCLUDING DERIVATION OF PNECS

Aquatic

A standard acute toxicity study with Daphnia was conducted as a limit test at 100% v/v saturated solution (equivalent to 6.1 mg/l) and showed no effects. Therefore the 48 Hour EC50 was greater than 6.1 mg/l, and the NOEC was 6.1 mg/l. A standard acute toxicity study with fish was conducted with MnS at concentrations of at 1, 10 and 100% v/v saturated solution and showed some mortality at the highest mean measured test concentration of 13 mg/l. The 96 Hour LC50 was greater than 13 mg/l and the NOEC was 7.8 mg/l. In an algal growth inhibition test the 72h E_rC50 was 4.9 mg/l, with a NOEC of 2.6 mg/l. These results were based on mean measured test concentrations. An 8 day chronic study on Daphnia gave a NOEC = 0.54 mg/l, also based on mean measured test concentration.

 

Table1: PNEC aquatic

		Value		Assessment factor		Remarks/Justification
PNEC aqua – freshwater (mg/l)		0.0108		50		Two chronic NOEC values in algae and Daphnia are available. The Daphnia NOEC of 0.54 mg/l is selected as the key value.
PNEC aqua - marine water (mg/l)		0.00108		500		Two chronic NOEC values in algae and Daphnia are available. The Daphnia NOEC of 0.54 mg/l is selected as the key value. An additional assessment factor of 10 applies to the marine compartment.
PNEC aqua – intermittent releases (mg/l)		0.049		100		Lowest L(E)C50 value from fish, Daphnia and algal studies. The key value is ErC50 = 4.9 mg/l from the algal growth study.

 

It should be noted that the PNECS aquatic freshwater and marine water are lower than the background concentration of manganese in European environments (15.9 µg Mn/L in surface water; “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 have very limited relevance for assessment of any potential risk from MnS. PNEC aqua for intermittent releases, however, is higher than this and is therefore relevant.

 

Sediment

No experimental data on sediment toxicity exist. The data are not requiredas the hazard assessment performed during the chemical safety assessment concludes that the substance is not classified and the risk assessment concludes that the compound is of no immediate concern to the environment. PNEC sediment is calculated by the equilibrium partitioning method.

Table2: PNEC sediment

		Value		Assessment factor		Remarks/Justification
PNEC sediment (mg/kg w.wt.)		1.53 0.153 (when the assessment factor for ingestion is applied)		50 (aquatic factor) 10 (ingestion of bound substance)		Equilibrium partitioning based on freshwater aquatic PNEC and Kd value of 650 ml/g. The tenfold safety factor is added to account for ingestion of compound bound to sediment
PNEC marine sediment (mg/kg w.wt.)		0.0153		500 (aquatic factor) 10 (ingestion of bound substance)		Equilibrium partitioning based on marine aquatic PNEC and Kd value of 650 ml/g. The tenfold safety factor is added to account for ingestion of compound bound to sediment

It should be noted that this value is 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 MnS.

Terrestrial

No experimental data on terrestrial toxicity exist. The data are not requiredas 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. PNEC soil is calculated by the equilibrium partitioning method.

 

Table3: PNEC soil

		Value		Assessment factor		Remarks/Justification
PNEC soil (mg/kg.w.wt.)		6.2 0.62 (when the ingestion assessment factor is applied)		10 (ingestion of bound substance)		Equilibrium partitioning based on aquatic PNEC and Kd value of 650. The tenfold safety factor is added to account for ingestion of compound bound to soil

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 MnS.

 

STP

No effects on sewage sludge were observed in a standard 3hr study on MnS. Hence the NOEC for MnS is 1000mg/l.

 

Table4: PNEC sewage treatment plant

		Value		Assessment factor		Remarks/Justification
PNEC stp (mg/l.)		100		10		Activated sludge Respiration/inhibition test. NOEC -= 1000mg/l

 

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 MnS is not considered to require any further assessment of PBT properties.

Conclusion on classification

According to the 2nd ATP to the CLP Regulation (EU) No 286/2011, the methodology for determining the environmental classification of metal compounds that have limited solubility, is based on the assumption that the ecotoxicological effects are determined by the fraction of dissolved metal. On this basis, relevant ecotoxicological information generated with a soluble metal compound expressed in terms of mg metal ion per litre) are compared with the level of metal ion released from the sparingly soluble metalcompound under investigation (as determined during transformation/dissolution protocol testing).

This approach to determining the classification takes precedence over the aquatic toxicity data that has been generated on the substance itself. 

The relevant ecotoxicological values (environmental reference values, ERV) for manganese were established by considering the database of available studies conducted with soluble manganese compounds (i.e. manganese dichloride, manganese sulphate, and manganese nitrate). The database was refined through application of suitable relevance and reliability criteria. From the resulting studies, the short term toxicity study with the lowest L(E)C50 was selected as the acute ERV for manganese (3.2 mg Mn/L; Davies & Brinkman, 1998 - Rainbow trout study with MnSO4), and the long term toxicity study with the lowest NOEC was selected as the chronic ERV for manganese (0.55 mg Mn/L; Davies & Brinkman, 1998 - Brook trout study with MnSO4). Both studies were conducted on standard species, and were assessed to be of adequate relevance and reliability for use in hazard determination of manganese. Summaries of these studies are included in this dataset.

 

The acute and chronic ERV values were compared to the levels of Mn release, as determined through transformation/dissolution protocol testing with Manganese sulphide (Rodriguez, 2010). During the transformation/dissolution protocol test with Manganese sulphide at initial test substance loading rates of 1, 10 and 100 mg/L, the level of manganese measured in the pH 6 media, following a 7 day exposure period, were 536.8, 4439.0 and 18181.8 µg Mn/L, respectively. The level of manganese measured in the pH 6 media following 28 days exposure, at the 1 mg/L test material loading rate, was 417.3 µg Mn /L.

 

Since the level of Mn release following a 7 day exposure of Manganese sulphide to environmentally relevant water, at the 1 mg/L loading rate is lower than the acute ERV, Manganese sulphide does not require classification in terms of acute aquatic toxicity. Since the level of Mn release following a 28 day exposure of Manganese sulphide to environmentally relevant water, at a loading rate of 1 mg/L, was lower than the chronic ERV, Manganese sulphide does not require classification in terms of chronic aquatic toxicity.