Flue dust, lead-refining

Ecotoxicological Summary

Additional information

The hazard assessment of inorganic UVCBs for the purpose of classification and derivation of safe effect thresholds (i.e. PNEC) is a cumbersome and complex process. Due to the intrinsic variability of the composition of an UVCB, it is difficult to select a sample that would unambiguously be representative for the (eco)toxicological hazard profile of the UVCB and could subsequently be used for testing. Instead of direct testing, a precautionary approach is taken where the UVCB is treated as a complex metal containing substance containing a number of discrete constituents (metals, metal compounds, non-metal inorganic compounds etc.). For each of these constituents, the hazard profile is used for deriving the proper classification of the UVCB (using the mixture rules) and/or for the derivation of the PNECs of the constituent (forwarded to the risk assessment). Using the PNEC of all individual constituents circumvents indirectly the issue of varying composition of an UVCB as it implicitly assumes that each time the UVCB substance consists of the pure substance, i.e. that each constituent would be present and bioavailable at a 100% concentration in the UVCB substance. This can be considered a conservative approach. A main outcome of the constituents’ based assessment is the selection of all the constituents for which any environmental hazard is identified. This selection defines the scope of the further exposure and risk assessment (CSR, Ch. 9&10).

 

The actual hazard profile of the inorganic UVCB substance and the individual constituents is dependent on the speciation of each and every constituent andhence this information needs to be collected in order to obtain a robust classification or PNEC value used for risk assessment purposes. Different scenarios can be encountered.

·      When the speciation of a constituent is known, this is used as such for the environmental hazard assessment.

·      When the speciation is unknown or few metal species co-exist, the worst-case speciation for the purpose of environmental hazard assessment is selected, i.e. the speciation that would lead to the most severe effects and thus the lowest PNEC.

 

For most metals, it is generally assumed that the Me-ion is the metal species of concern and therefore, the environmental hazard assessment is generally based on Me-ion speciation (ECHA, 2008. Guidance on information requirements and chemical safety assessment; Appendix R.7.13-2: Environmental risk assessment for metals and metal compounds)

 

Selection of the ecotoxicological information for the purpose of classification

 

The UVCB classification is calculated by applying the CLP mixture rules based on the classification of the known or worst-case speciation for each constituent and worst-case constituent concentration in the UVCB (i.e. maximum of the legal entity typical value), using the MeClas tool. Depending on the availability of information, the UVCB classification can be refined following MeClas Tiered approach.

 

Selection of the ecotoxicological information for the purpose of risk assessment

 

For the purpose of the environmental risk assessment for the UVCB, the hazards of each constituent will be assessed and PNEC values for all the constituents for which a hazard has been identified are compiled.

The UVCB is a complex inorganic metals containing substance. The Physico-chemical characterization of the UVCB (see relevant section in IUCLID) demonstrates the presence of different metal species; intermetallic, metal sulphates and metal oxides that are formed as a by-product from refining and smelting of lead containing materials. This resulted in relatively high solubilisation potential in water for most of the metals present in the UVCB (e. g. Cu, Ag, As).

The UVCB is an intermediate, with a very limited life cycle (manufacturing and industrial uses only).Testing the UVCB is difficult because of the large uncertainty involved when selecting representative samples due to the variable elemental concentrations in the composition of the UVCB. Derivation of PNECs for the UVCB as such are therefore difficult to interpretbecause of the uncertainty related to the representativeness of the testing. Also, UVCB exposure cannot be measured or modelled because of the multi-constituent character. For these reasons,the UVCB environmental (hazard) assessment is driven by the assessment of the individual UVCB constituents.

For the purpose of classification, the UVCB is treated as a complex metal containing substance with a number of discrete constituting compounds (metals, metal compounds, non-metal inorganic compounds). The hazard classifications of each compound are then factored into a combined classification of the UVCB as a whole. For environmental endpoints, additivity and/or summation algorithms are applied to quantitatively estimate the mixture’s toxicity to aquatic organisms.

For the purpose of the environmental (risk) assessment, the ecotoxicological information that was taken forward is based on all hazardous constituents of all relevant UVCBs at the site for which quantitative exposure and risk assessment was conducted. For the environment, most often, it is the metal ion that is the toxic driver (ECHA, 2008, R.7.13-2). Consequently, the PNECs expressed as metal ion are the relevant ones to forward to risk characterization. Considering the composition of this UVCB, full solubilisation of the various constituting speciation is assumed. The physical form (powder) does not lead in this case to different release potential of the elements from the UVCB and consequently no different PNECs. When quantitative exposure and risk assessment were conducted on a metal constituent, the ecotoxicological information on this individual metal is reported in the respective summary sheet. The information is taken from the respective REACH IUCLID dossiers (see annex II of this CSR). More information on the scope of the UVCB assessment can be found in the CSR of the UVCB (Chapter 9).

 

Table40:Summary of the information on toxicological information for the purpose of riskassessment:

UVCB constituent			Variability in chemical composition		PNECs
Element	Speciation used for environmental risk assessment
Cu	Metal ion	Hazard assumed as if UVCB consists of 100% worst-case speciation	See respective PNEC summary in IUCLID and table below
Ni	Metal ion	Hazard assumed as if UVCB consists of 100% worst-case speciation	See respective PNEC summary in IUCLID and table below
Pb	Metal ion	Hazard assumed as if UVCB consists of 100% worst-case speciation	See respective PNEC summary in IUCLID and table below
As	Metal ion	Hazard assumed as if UVCB consists of 100% worst-case speciation	See respective PNEC summary in IUCLID and table below
Ag	Metal ion	Hazard assumed as if UVCB consists of 100% worst-case speciation	See respective PNEC summary in IUCLID and table below
Sb	Metal ion	Hazard assumed as if UVCB consists of 100% worst-case speciation	See respective PNEC summary in IUCLID and table below
Se	Metal ion	Hazard assumed as if UVCB consists of 100% worst-case speciation	See respective PNEC summary in IUCLID and table below
Zn	Metal ion	Hazard assumed as if UVCB consists of 100% worst-case speciation	See respective PNEC summary in IUCLID and table below
Cd	Metal ion	Hazard assumed as if UVCB consists of 100% worst-case speciation	See respective PNEC summary in IUCLID and table below
Co	Metal ion	Hazard assumed as if UVCB consists of 100% worst-case speciation	See respective PNEC summary in IUCLID and table below
Cr	Metal ion	Hazard assumed as if UVCB consists of 100% worst-case speciation	See respective PNEC summary in IUCLID and table below

For the purpose of the risk assessment, the hazard conclusions and the metal-specific PNECs (Predicted No Effect Concentration) were collected for each environmental compartment. An overview of the PNECs relevant for the Lead intermediates is given in the table below. PNEC for arsenic metal was not available. Consequently, one was derived based on arsenic oxide using molecular weight conversion. Elements for which no PNEC is reported inTable41have no relevant environmental hazards and for which there is no need to derive environmental threshold. For oxides, hydroxides and sulphates, there is a potential pH-effect on the receiving environmental compartments.

 

Table41:Overview of hazard conclusions - Predicted No Effect Concentration (PNEC) takenforward for CSA of the the Lead intermediates– See respective PNEC summaries.

 

Environmental classification justification

The UVCB is treated as a complex metal containing substance with a number of discrete constituting compounds (metals, metal compounds, non-metal inorganic compounds). The hazard classifications of each compound are then factored into a combined classification of the UVCB as a whole. The classification was derived using Meclas (MEtals CLASsification tool - see www.meclas.eu), a calculation tool that follows classification guidance and implementation in accordance to legal rules and technical guidance from ECHA and CLP. See IUCLID section 13 attachment for MeClas classification conclusions.

 

Table42:Summary of the information on ecotoxicological information for the purpose ofclassification:

UVCB constituent		Variability of elemental composition	Classification acute and chronic aquatic ecotoxicity
Element	Speciation* in composition
As	As2O3/ AsO3	Maximum of typicals	Harmonised classification of the speciation
Cd	CdSO4	Maximum of typicals	Harmonised classification of the speciation
Cr	Cr2O3	Maximum of typicals	Self classification of the speciation
Cu	CuSO4	Maximum of typicals	Harmonised and worst-case self classification of the speciation
Ni	NiSO4	Maximum of typicals	Harmonised classification of the speciation
Pb	Lead compounds with the exception of those specified elsewhere in Annex VI	Maximum of typicals	Harmonised and worst-case self classification of the speciation
S	Metal sulphides/sulphates	Maximum of typicals	Classification: see metal entry
Sb	Sb compounds, with the exception of the tetroxide (Sb2O4), pentoxide (Sb2O5), trisulphide (Sb2S3), pentasulphide (Sb2S5) and those specified elsewhere in Annex VI	Maximum of typicals	Harmonised classification of the speciation
Se	Selenium compounds except cadmium sulphoselenide	Maximum of typicals	Harmonised classification of the speciation
Zn	ZnSO4	Maximum of typicals	Harmonised classification of the speciation
Minors	Sulphide/compounds or metal	Maximum of typicals	Below 0.1% and/or the speciation not impacting classification, see MECLAS report in CSR Annex I

* Detailed information on speciation can be found in IUCLID Section 4.23 Additional Physico-chemical information

Conclusion on classification

The UVCB is a complex inorganic metal containing substance. Its toxicity is related to the degree to which constituents react with water/biological fluids and potentially release soluble, potentially bio available ionic and other (metal bearing) species.

The environmental (self) classification of the UVCB was derived using MeClas (see below).

Hazard to aquatic environment: acute/chronic Category 1

See IUCLID section 13 or CSR Annex 1 for detailed MeClas outprints with the specified input concentrations and resulting classification. Please visit www. meclas.eu for more information about the tool.