The aim of this study is to investigate the distributions of polycyclic aromatic hydrocarbons (PAHs) in sediment and water (suspended particles and dissolved phase) samples collected from Dapeng Bay(coast¡Bbay¡Bwetland and mangrove). Chemical fingerprinting techniques and statistical analysis were applied to delineate the possible sources of PAHs in sediment and water samples. The average concentrations of total PAHs (£U51PAHs) ranged from 143 to 1595 ng/g dry weight (dw) in the sediments. Total PAH (£U46PAHs) concentrations varied from 11 to 38 ng/L in dissolved phase and from 1.4 to 15ng/L (252 to 772 ng/g dw) in suspended particulate phase, respectively. Comparing with sediment quality guidelines (SQGs), the total PAH concentrations in all sediment samples were below the criteria, suggesting that no adverse biological effects would arise from the PAHs in these sediments. The partition coefficients¡]KOC¡^values of PAHs were higher than predicted values. It might be attributed to soot particles which have extremely high sorption capacities. Total organic carbon¡]POC¡^and black carbon (BC) were significantly correlated with combustion PAH concentrations in Dapeng Bay. Combustion PAHs (Flt¡ÏPyr¡ÏBaA¡ÏChr¡ÏBbF¡ÏBkFa¡ÏBeP¡ÏBaP¡ÏIP¡ÏBghiP) concentrations were significantly correlated with black carbon (BC) in mangroves sediment cores and wetland A. In addition, total PAH concentrations were significantly correlated with combustion PAHs concentrations in dissolved phase. In suspended particulate phase, total PAH concentrations and combustion PAHs concentrations were significantly correlated with suspended solid (SS). Results from diagnostic ratios and hierarchical cluster analysis (HCA) both indicate that PAHs in the coast of Dapeng Bay were mainly from petrogenic sources, but from petrogenic and pyrogenic mixed sources in the wetland and mangrove inside the Dapeng Bay. In addition, the origin of perylene in Dapeng Bay and coastal sediments was mainly from the biogenic and pyrogenic, while it was from biogenic origin in wetland A and wetland B. However, the origin of perylene in mangrove M1 and mangrove M2 tended to be diagenetic.

This study investigated the concentration distributions of polyclic aromatic hydrocarbons (PAHs) in the sediment cores collected from Fang-Liao submarine canyon. Chemical fingerprinting techniques and statistical analysis were applied to delineate the possible sources of the PAHs in deposited sediment core samples. It is noteworthy that all cores were not dated; therefore the deposition age could not estimate from the depth of deposition directly. The average concentrations of polyclic aromatic hydrocarbons (£U51PAHs) were found ranged from 229 to 638 (ng/g dry wt) in the sediment cores in Fang-Liao submarine canyon. In addition, the low molecular weight PAHs (2-3 ring PAHs) were found dominant in the PAH composition pattern of most samples. Total PAH concentrations were significantly correlated with total organic carbon (TOC) in all the sediment cores. Compared with sediment quality guidelines (SQGs), the PAH concentrations of all sediment samples were lower than those outlined in the criteria, that suggests no evident adverse biological effects caused by PAHs. Results also showed that total PAH concentration of surface sediments (0-2 cm) decreased with the water depth. Identification of PAHs sources suggests that all up-cores were dominated by petrogenic sources, but all down-cores except for S17 and S18 were dominated by pyrogenic sources or mixed sources. In contrast, biogenic sources were found dominant in S17 and S18 as they were characterized by higher ratio of perylene/£Upenta-PAHs(%). Compared with literature, the sediment cores of Fang-Liao submarine canyon were moderately polluted with PAHs. Analysis of diagnostic ratios and hierarchical cluster analysis (HCA) as well as principal component analysis (PCA) all indicate PAHs sources of Fang-Liao submarine canyon were mainly from petroleum and petroleum combustion sources for site of S3,S5,S7,S8 and S17; while pyrogenic or mixed sources for site of S1,S2,S9,S18 and S33.

Contrairement aux idées reçues, le sol est une ressource naturelle non renouvelable menacée. La réhabilitation des friches industrielles polluées aux HAP, toxiques et persistants, représente donc un enjeu majeur. Les techniques traditionnelles ne sont pas toujours très appropriées, c’est pourquoi ce travail vise à étudier la pertinence de l’oxydation chimique in situ, habituellement utilisé pour le traitement de nappes contaminées par des polluants moins récalcitrants (COHV, BTEX). Il s’inscrit dans le cadre du projet OXYSOL (ANR-PRECODD) destiné à construire une filière complète de traitement in situ et de refonctionnalisation. Ce travail a consisté à étudier et optimiser ces performances en travaillant avec la terre d’une ancienne cokerie. Ensuite, l’objectif a été de mettre en évidence les principaux paramètres limitants en utilisant différentes terres polluées contrastées. Tout d’abord, les expériences en systèmes fermés ont conduit à sélectionner les deux oxydants les plus adaptés: le réactif de Fenton et le persulfate activé. Ensuite, l’oxydation a été étudiée en systèmes ouverts de l’échelle du laboratoire à l’échelle pilote afin d’optimiser les conditions d’injection. Les résultats obtenus, comparables à ceux en systèmes fermés, ont mis en évidence le caractère très limitant de la faible disponibilité des HAP ainsi que l’existence d’une fraction impossible à atteindre (taux d’abattement inférieur à 50%). Enfin, les derniers résultats ont corroboré la relation entre l’âge de la pollution, la disponibilité des HAP et les performances de l’oxydation chimique. Par ailleurs, ils ont permis d’expliquer et hiérarchiser les effets limitants de différents paramètres (disponibilité des HAP, teneur en carbone organique, en carbonate, pH, structure des HAP et mode d’injection) en fonction de l’oxydant utilisé. Les recherches effectuées soulignent l’importance d’étudier les performances de l’oxydation chimique directement avec la terre prélevée sur le site pollué. / Contrary to general belief, soil is a threatened nonrenewable natural resource. Consequently, the restoration of brownfields contaminated with PAHs, that are toxic and persistent contaminants, is a major challenge. Usual techniques are not always appropriate, so the aim of this work is to study the relevance of in situ chemical oxidation (ISCO), usually used for groundwater treatment contaminated with less recalcitrant pollutants (CVOCs, BTEX). It is a part of OXYSOL project aiming at the conception of a global treatment pathway including in situ remediation and soil construction. This work was to study and optimize oxidation efficiency with the soil of a former coking plant. Then, objective was to highlight main limiting factors using different contrasting soils. First, experiments were run in batch systems to select both most suitable oxidants: Fenton's reagent and activated persulfate. Then oxidation was performed in flow systems from the bench to the pilot scale in order to optimize injection parameters. Results, comparable to those obtained in batch systems, showed that oxidation efficiency was strongly limited because of low PAHs availability and highlighted presence of unavailable PAHs (degradation ratio lower than 50%). The last results confirmed the relationship between pollution aging, PAHs availability and chemical oxidation performance. Moreover, they help to understand and compare the influence of different limiting factors (PAHs availability, organic carbon content, carbonate content, pH, PAHs structure and injection method) depending on the oxidant. The research underlined the need to investigate chemical oxidation performance with soil samples collected from contaminated sites and not with spiked soils.