Waste hazard properties HP 4 ‘Irritant’ and HP 8 ‘Corrosive’ by pH, acid/base buffer capacity and acid/base concentration
Résumé
European “Technical Recommendations” have proposed, with the use of substance concentrations, the use of a pH (≤2 or ≥11.5) to classify waste for the hazard properties HP4 ‘Irritant’ and HP8 ‘Corrosive’. The document add unfortunately that the buffer capacity must be “not low” to classify as hazardous. Buffer capacity refers to a 2018 UK classification guide referring to the ‘corrosive’ level of a method proposed in 1988 for substances and preparations but not retained in EU regulations, but well in its Guidance. The product method uses the pH unclearly associated or not to a 1% concentration. The different methods of classifying products and wastes in terms of corrosivity or irritation are expressed as acid/base concentration and compared. The “corrosive” level of 1988 corresponds to an average strong acid/base concentration ≥14.4%, i.e. 14 times less severe than CLP (acid/base concentration ≥0.44-0.15% for pH only or ≥1% for pH and concentration). The “pH only” method corresponds to the lowest concentration of acid/base and is the most severe. These methods were applied to five hazardous alkaline wastes (pH ≥11.5). The “pH only” method is the only that classifies all waste in accordance with the European List of Waste. To avoid innovation and divergence between products and waste, it seems preferable to use the product regulations “pH only” or eventually “pH and concentration” for HP4 and HP8. Fortunately, the elimination of the danger HP 4 and HP 8 from acidic or alkaline waste can be obtained by neutralization, including for alkaline wastes with CO2.
Domaines
Sciences de l'environnement
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