Slimes and Sludges, copper electrolytic

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.

PNEC derivation and other hazard conclusions

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 settled down and precipitated during electro refining. This resulted in relatively high solubilisation potential in water for most of the metals present in the UVCB (eg 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 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 characterisation. Considering the composition of this UVCB, full solubilisation of the various constituting speciation is assumed. The physical form (powder or massive) 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).

 

Table44: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
Zn	Metal ion	Hazard assumed as if UVCB consists of 100% worst-case speciation	See respective PNEC summary in IUCLID and table below
Ba	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
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
Ag	Metal ion	Hazard assumed as if UVCB consists of 100% worst-case speciation	See respective PNEC summary in IUCLID and table below
S, Sn, Te	Sulfate ion	Hazard assumed as if UVCB consists of 100% worst-case speciation	Qualitative assessment conducted

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 Copper intermediates is given in the table below.

 

Table45:Overview of hazard conclusions - Predicted No Effect Concentration (PNEC) takenforward for CSA of the the Copper intermediates

Protection target		Unit		Cu		Pb		As		Ni		Cd		Zn (added)		Mn
Freshwater	μg/L	7.8	6.5	6.5	3.55	0.19	20.6	34
Marine water	μg/L	5.2	3.4	0.5	8.6	1.14	6.1	3.4
Freshwater sediment	mg/kgdw	87	174	64.8	69.2	1.8	235.6	3.3
Marine sediment	mg/kgdw	676	164	4.5	69.2	0.64	113	0.34
Soil	mg/kgdw	88	147	0.3	29.9	0.9	107	3.4
STP	μg/L	230	100	30.4	330	20	52	100,000
Secondary poisoning	mg/kg food	No hazard identified*	10.9	0.5	12.3	0.16	No hazard identified**	No hazard identified

 

 

Protection target		Unit		Cr		Co		Sb		Se		Hg		Ba		Te		Ag
Freshwater	μg/L	4.7	0.51	113	2.67	0.0574	227.8	5.79	0.04
Marine water	μg/L	4.7	2.36	11.3	2	0.0672	/	0.579	0.86
Freshwater sediment	mg/kgdw	31	9.5	11.2	8.2	9.3	792.7	No exposure	438.13
Marine sediment	mg/kgdw	31	9.5	2.24	6.2	9.3	/	No exposure	438.13
Soil	mg/kgdw	3.2	10.9	37	0.1	0.022	207.7	No exposure	0.794
STP	μg/L	10,000	370	2,550	1,500	2.25	50,100	3.2	25
Secondary poisoning	mg/kg	No hazard identified	No hazard identified	Not needed	1	No or insufficient available at present	No or insufficient a available at present	No potential for biocuumulation	No or insufficient available at present

*Based on the copper risk assessment, it was concluded that secondary poisoning is not relevant. The main arguments are: Copper is an essential trace element, well regulated in all living organisms. Difference in copper uptake rates are related to essential needs, varying with the species, size, life stage, seasons... Copper homeostasic mechanisms are applicable across species with specific processes being active depending on the species, life stages…. The use of BAFs are therefore not adequate. There is overwhelming evidence to show the absence of copper biomagnification across the tropic chain in the aquatic and terrestrial food chains. Field evidence has further provided evidence on the mechanisms of action of copper in the aquatic and terrestrial environment and the absence of a need for concern for secondary poisoning. 

**Based on the ICDZ data on bioaccumulation of zinc in animals and on biomagnification (i.e. accumulation and transfer through the food chain), it is concluded that secondary poisoning is considered to be not relevant in the effect assessment of zinc. Major decision points for this conclusion are the following. The accumulation of zinc, an essential element, is regulated in animals of several taxonomic groups, for example in molluscs, crustaceans, fish and mammals. In mammals, one of the two target species for secondary poisoning, both the absorption of zinc from the diet and the excretion of zinc, are regulated. This allows mammals, within certain limits, to maintain their total body zinc level (whole body homeostasis) and to maintain physiologically required levels of zinc in their various tissues, both at low and high dietary zinc intakes. The results of field studies, in which relatively small differences were found in the zinc levels of small mammals from control and polluted sites, are in accordance with the homeostatic mechanism. These data indicate that the bioaccumulation potential of zinc in both herbivorous and carnivorous mammals will be low. Based on the above data, secondary poisoning and the related issues bioaccumulation and biomagnification are not further discussed in this report (Zn RAR).

 

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.

 

Table46:Summary of the information on ecotoxicological information for the purpose ofclassification:

UVCB constituent			Variability composition		Classification acute and chronic aquatic ecotoxicity
Element	Speciation*
Cu	CuSO4	Maximum of typicals	Harmonised and worse self- classification of the speciation, see MECLAS
Ni	NiSO4	Maximum of typicals	Harmonised classification of the speciation, see MECLAS
Pb	Pb compounds	Maximum of typicals	Harmonised and worse self- classification of the speciation, see MECLAS
As	4.13% As, 10.18% As compounds, 85.69% as As2O3	Maximum of typicals	Harmonised classification of the speciation, see MECLAS
Zn	ZnSO4	Maximum of typicals	Harmonised classification of the speciation, see MECLAS
Ba	BaSO4	Maximum of typicals	Self-classification of the speciation, see MECLAS
Co	CoSO4	Maximum of typicals	Harmonised classification of the speciation, see MECLAS
Sn	Sn compounds	Maximum of typicals	Self-classification of the speciation, see MECLAS
Sb	Sb2O3	Maximum of typicals	Harmonised classification of the speciation, see MECLAS
Te	TeO2	Maximum of typicals	Not classified, see MECLAS
Se	Se	Maximum of typicals	Harmonised classification of the speciation, see MECLAS
Ag	Ag (powder)	Maximum of typicals	Self-classification of the speciation, see MECLAS
Bi	Bi sulfate	Maximum of typicals	Not classified, see MECLAS
S	sulfate	Maximum of typicals	Taken into account in corresponding metal sulfates, see MECLAS

* Detailed information on speciation can be found inIUCLID/CSR section 1.2 compositionand IUCLID Section 4.23 Additional Physcio-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 availble ionic and other (metal bearing) species.

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

Hazard to aquatic environment: Acute/chronic Category 1

The classification derived is applicable to the 2 grades of copper slimes.   

The tested sample is representative for copper slime, defined within the concentration ranges outlined under IUCLID section 1.2 (realistic worst-case across industry: maximum of the typicals).

Inputs data were reasonable worst case across industry. The sum of the upper concentration ranges in both grades results in more than 200%, this shows a reasonable worst case scenario across the maximum constituent values. Results on the 2 types of inputs provided the same environmental classification (Tier 1 approach, no T/D data available).