Camille Pasquet echantillonne un sol en Nouvelle Caledonie
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L’article “Alternative dry separation of PM10 from soils for characterization by kinetic extraction: example of New Caledonian mining soils” par Pasquet, C.; Gunkel-Grillon, P.; Laporte-Magoni, C.; Serres, A.; Quiniou, T.; Rocca, F.; Monna, F.; Losno, R.; van Oort, F.; Chateau, C. vient d’être publié dans la revue Environmental Science and Pollution Research. [pdf]
Camille Pasquet, étudiante en thèse en co-direction Dijon – Nouméa (camille.pasquet@etudiant.univ-nc.nc) a mis au point une méthode simple et rapide permettant de séparer les plus fines particules contenues dans les sols afin de les analyser. Celles-ci ont une grande importance environnementale car l’érosion éolienne est susceptible de les remobiliser dans l’atmosphère. Les conséquences pour la santé publique peuvent être sévères si ces sols sont enrichis en métaux. C’est précisément le cas de certaines zones de Nouvelle Calédonie qui sont exploitées pour le nickel depuis plus d’un siècle…
Abstract: A simple new device for dry separation of fine particulate matter from bulk soil samples is presented here. It consists of a stainless steel tube along which a nitrogen flow is imposed, resulting in the displacement of particles. Taking into account particle transport, fluid mechanics, and soil sample composition, a tube 6 m long, with a 0.04 m diameter, was found best adapted for PM10 separation. The device rapidly produced several milligrams of particulate matter, on which chemical extractions with EDTA were subsequently performed, to study the kinetic parameters of extractable metals. New Caledonian mining soils were chosen here, as a case study. Although the easily extracted metal pool represents only 0.5-6.4% of the total metal content for the elements studied (Ni, Co, Mn), the total concentrations are extremely high. This pool is therefore far from negligible, and can be troublesome in the environment. This dry technique for fine particle separation from bulk parent soil eliminates the metal-leaching risks inherent in wet filtration, and should therefore ensure safe assessment of environmental quality in fine-textured, metal-contaminated soils.