Derivation of Species Sensitivity Distributions (SSDs) for aquatic organisms for manganese

This expert review is intended to provide Species Sensitivity Distributions (SSDs) for thechronic toxicity to aquatic organisms for the manganese metal ion (referred to as ‘manganese’in the remainder of the report) in order to use the resulting endpoint (HC5) for chronicclassification of manganese metal and inorganic manganese compounds under Regulation (EC)No 1272/2008.

Standardly, chronic environmental classification is based on the lowest available reliableendpoint (NOEC or EC10) for aquatic organisms. However, when sufficient data are availableECHA (2008) Guidance on information requirements and chemical safety assessment specifiesin chapter R.10 that extrapolation techniques such as SSDs can be employed under certainpremises.Metal-specificrecommendations from Metals Environmental Risk Assessment Guidance (MERAG, 2016)have been taken into consideration.

Both guidance documents necessitate data from several taxonomic groupswith at least 10 NOEC or EC10 values (and preferably more than 15) to be applied to the SSD.

The manganese data base for aquatic organisms meet these criteria. All studies wereevaluated for their relevance and reliability before being used. Data from studies for whichreliability could not be determined (e.g. due to lack of raw data) were either excluded orconsidered in a weight-of-evidence approach.Where multiple data for one species are available, again recommendations from the guidancedocuments mentioned above was considered to either calculate geometric mean values orconsider only relevant information for that species.

Considering the small difference between derived HC5 values, the reliability based onnormalised width, the essentiality of manganese and the distribution of water hardness inEuropean surface waters, it is considered appropriate to base hazard assessments on the HC5of 0.91 (50% CI: 0.79 – 1.13; 95% CI: 0.53 – 1.49) mg Mn/L as derived for the full data base.

Using these derived values, the experts concluded that no manganese based substance within the Manganese Consortium’s portfolio will be self-classified as hazardous for acute and chronic toxicity.