当混合物含有附件 VI 物质且该终点有特定浓度限值 (SCL) 时，在对混合物进行皮肤腐蚀/皮肤刺激或眼损伤/眼刺激分类时，是否应考虑极端 pH 值？

当混合物含有附件 VI 物质且该终点有特定浓度限值 (SCL) 时，在对混合物进行皮肤腐蚀/皮肤刺激或眼损伤/眼刺激分类时，是否应考虑极端 pH 值？

Should extreme pH be considered when classifying a mixture for skin corrosion/skin irritation or eye damage/eye irritation when it contains an Annex VI substance with a specific concentration limit (SCL) for that endpoint?

在设定物质的皮肤腐蚀/皮肤刺激或眼损伤/眼刺激的SCL时，假定已将pH值考虑在内。如果混合物仅包含一种具有SCL的腐蚀性或刺激性成分（酸或碱），即使混合物的pH值极高，也应根据该SCL进行分类。然而，SCL反映的是混合物不包含任何其他可能影响该终点分类的成分的情况。如果混合物中的其他成分会影响刺激性/腐蚀性，则必须将其考虑在内。如果混合物中除具有SCL的物质外，还包含任何其他可能影响混合物腐蚀性或刺激性的物质，则SCL可能无法确定混合物的分类。此类成分可以是表面活性剂、其他酸或碱，它们本身具有腐蚀性或刺激性，或者可能影响具有SCL的物质的腐蚀性或刺激性，例如通过增加皮肤的渗透性。在这种情况下，分类应基于混合物的pH值，除非考虑到酸/碱储备，表明混合物可能不具有腐蚀性，并且体外试验数据证实将其归类为腐蚀性是没有道理的。基于混合物pH值的分类可能比基于SCL的分类更为严格。当适用加和性规则（CLP附件一表3.2.3或3.3.3）或非加和性规则（CLP附件一表3.2.4或3.3.4）时，也可能得出更为严格的分类。

It is assumed that pH has been taken into account when setting an SCL for a substance for skin corrosion/skin irritation or eye damage/eye irritation. When a mixture only contains one corrosive or irritant ingredient (acid or base) with an SCL, the mixture should be classified according to this SCL even if the pH of the mixture is extreme. However, the SCL reflects a situation where the mixture does not contain any other ingredient that might affect the classification for that endpoint. If other ingredients in the mixture affect the irritant/corrosive properties, this has to be taken into account. If a mixture contains any other substances than the one with an SCL, which may affect the corrosive or irritant properties of the mixture, the SCL may not determine the classification of the mixture. Such ingredients can be surfactants, other acids or bases, which either themselves possess corrosive or irritant properties or may be expected to affect the corrosive or irritant properties of the substance with the SCL, for example, by increasing the permeability of the skin. In that case, the classification should be based on the pH value of the mixture, unless consideration of the acid/alkali reserve suggests that the mixture may not be corrosive, and data from in vitro tests confirm that classification as corrosive is not justified. Classification based on the pH value of the mixture may lead to a more severe classification than if based on the SCL. A more severe classification may also result when either the additivity rule (Tables 3.2.3 or 3.3.3 of Annex I to CLP) or non-additivity rule (Tables 3.2.4 or 3.3.4 of Annex I to CLP) applies.