Low-temperature, mineral-catalyzed air oxidation: a possible new pathway for PAH stabilization in sediments and soils.
Reactivity of polycyclic aromatic hydrocarbons (PAHs) in the subsurface is of importance to environmental assessment, as they constitute a highly toxic hazard. Understanding their reactivity in the long term in natural recovering systems is thus a key issue. This article describes an experimental investigation on the air oxidation of fluoranthene (a PAH abundant in natural systems polluted by industrial coal use) at 100°C on different mineral substrates commonly found in soils and sediments (quartz sand, limestone, and clay). Results demonstrate that fluoranthene is readily oxidized in the presence of limestone and clay, leading to the formation of high molecular weight compounds and a carbonaceous residue as end product especially for clay experiments. As demonstrated elsewhere, the experimental conditions used permitted the reproduction of the geochemical pathway of organic matter observed under natural conditions. It is therefore suggested that low-temperature, mineral-catalyzed air oxidation is a mechanism relevant to the stabilization of PAHs in sediments and soils.
Ghislain
Thierry
T
UMR CNRS 7566 G2R, Nancy-Université, CNRS, B.P. 239, 54506 Vandoeuvre-lès-Nancy, France. Thierry.Ghislain@g2r.uhp-nancy.fr
Faure
Pierre
P
Biache
Coralie
C
Michels
Raymond
R
D000538:Aluminum Silicates / Q000737:chemistry; D002119:Calcium Carbonate / Q000737:chemistry; D002245:Carbon Dioxide / Q000138:chemical synthesis; D002384:Catalysis; D002725:Chloroform / Q000737:chemistry; D000077215:Clay; D005449:Fluorenes / Q000032:analysis / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D019015:Geologic Sediments / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D008903:Minerals / Q000737:chemistry*; D010084:Oxidation-Reduction; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis / Q000737:chemistry*; D011791:Quartz / Q000737:chemistry; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis / Q000737:chemistry*; D013696:Temperature
D000538:Aluminum Silicates; D005449:Fluorenes; D008903:Minerals; D011084:Polycyclic Aromatic Hydrocarbons; D012987:Soil; D012989:Soil Pollutants; D002245:Carbon Dioxide; D011791:Quartz; C007738:fluoranthene; D002725:Chloroform; D002119:Calcium Carbonate; D000077215:Clay