Inorganic residual from kraft or soda pulping separated from green liquor in the chemical recovery cycle.

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Skin sensitisation studies are not available for Green liquor sludge. Therefore assessment of this endpoint shall comprise an assessment of the available other information like human, animal and alternative data of the known constituents of GLS. All constituents of GLS have been used commonly for many decades by the industry and by consumers. However, apart from skin irritation or burns skin sensitisation has normally not been described as secondary effects. Most GLS constituents are ions, which are naturally present in the body and for this reason it is unlikely that they were strong skin sensitisers. Based on the data available, it is concluded that GLS is not currently classifiable as a skin sensitiser, but potential for skin sensitisation effect cannot be completely ruled out.

 

Depending on raw materials and process conditions during production of GLS, the substance may contain also some heavy metals/metalloids at > 0.1% or < 0.1% (Fe, Al, Ni, Cd, Pb, Cr) that have been shown to be also skin sensitisers. Several of these constituents have already hazard classification under the Dangerous Substances Directive 67/548/EEC (see Chapter 3.1 Classification and labelling in Annex I of Directive 67/548/EEC) and under the CLP Regulation (EC) No 1272/2008 on the classification, labelling and packaging of substances and mixtures. There are also occupational limit values related to acute human health effects of constituents of Green liquor sludge. Because concentration of these substances can vary, the companies should have regular control over the levels of hazardous trace elements and compounds. The level of control should reflect the intended downstream uses of GLS and update the chemical safety assessment and risk management measures accordingly.

Migrated from Short description of key information:
Based on phase 1 literature assessment, it is concluded that Green liquor sludge is not currently classifiable as a skin sensitiser, but potential for sensitisation effect cannot be completely ruled out. For these reasons, the level of control should reflect the intended downstream uses of GLS and update the chemical safety assessment and risk management measures accordingly depending on handling and used batches of GLS.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Regarding GLS none of the known > 0.1% constituent is classified as respiratory sensitiser in the CLP List of harmonised classification and labelling of hazardous substances. Trace < 0.1% constituents Cr(VI) and Ni(SO₄) are classified as sensitisers. The analysed concentrations of these metals in the reference GLS sample remain at 54 mg/kg level (as Ni) which is 0,0054 % and for chromium 48mg/kg (0,0048%) (see sections 1.2. and 4.1.1.1 and Annex I of CSR) (VTT 2010). Higher concentrations for Ni (often 100 mg/kg single max. even 1100 mg/kg) and chromium, ca. 300 mg/kg are often reported. However, the reducing conditions of GLS would favor the Cr(III) oxidation state.

Migrated from Short description of key information:
Based on phase 1 literature assessment, it is concluded that GLS is not currently classifiable as a skin sensitizer, but potential for sensitization effect cannot be completely ruled out. All main constituents of GLS have been used extensively for many decades by the industry and by consumers. Based on the data available, it can be concluded that respiratory sensitization of GLS is unlikely. This conclusion may not apply to all possible trace level constituents of GLS. For these reasons, the level of control should reflect the intended downstream uses of GLS and update the chemical safety assessment and risk management measures accordingly depending of handling and used patches for GLS.

Justification for classification or non-classification

Conclusion : no classification for skin or respiratory sensitisation

Justification for non-classification: According to CLP regulation, substances shall be classified as respiratory sensitisers (Category 1) in accordance with the following criteria: (a) if there is evidence in humans that the substance can lead to specific respiratory hypersensitivity and/or (b) if there are positive results from an appropriate animal test.

 Test results from animal studies for GLS are not available. Instead, data is available on the known inorganic constituents (hydroxides, sulfur and oxidised sulfur constituents and carbonates). Irritating and corrosive effects have been reported for skin and pulmonary track for these inorganic ions. However, no allergic response in skin or hypersensitivity of the airways has been reported in such extent that would lead to classification.

When considering the human evidence, the evidence could be referred to a chemical structure related to substances known to cause respiratory hypersensitivity. Mixtures should be classified as a respiratory or skin sensitiser when at least one ingredient has been classified as a respiratory or skin sensitiser and is present at or above the appropriate generic concentration limit (as shown in Table 3.4.3 of the CLP). Evidence from analogous substances, can contribute to the procedure for classification.

 Regarding GLS none of the known > 0.1% constituent is classified as respiratory sensitiser in the CLP List of harmonised classification and labelling of hazardous substances. Trace < 0.1% constituents Cr(VI) and Ni(SO₄) are classified as sensitisers. The analysed concentrations of these metals in GLS remain at 54 mg/kg level (as Ni) which is 0,0054 % and for chromium 48mg/kg (0,0048%) (see sections 1.2. and 4.1.1.1) (VTT 2010). However, the reducing conditions of GLS would favor the Cr(III) oxidation state.

Higher concentrations for Ni (often 100 mg/kg one single max. even 1100 mg/kg) and chromium, ca. 300 mg/kg are often reported.

 

Based on these findings, it is concluded that GLS is not currently classifiable as a sensitiser, but potential for sensitisation effect cannot be completely ruled out. For these reasons, the level of control should reflect the intended downstream uses of GLS and update the chemical safety assessment and risk management measures accordingly depending of handling and used patches for GLS.