Ph. Garrigues

Origin of Polycyclic Aromatic Hydrocarbons (PAHs) in Coastal Marine Sediments: Case Studies in Cotonou (Benin) and Aquitaine (France) Areas

Abstract Polycyclic Aromatic Hydrocarbons (PAHs) were identified and quantified in recent sediments of the Cotonou coastal zones (Benin) in the total concentration range 25–1450 ng g−1, while the Aquitaine sediment samples (France) exhibited total PAH concentrations in the range 4–855 ng g−1. The highest contents of PAHs were found in the harbours, as well in Cotonou as in the Aquitaine region, with the maximum values in the Cotonou harbour. However, the PAH concentrations were comparable with those of slightly contaminated zones. Good correlations observed between a certain number of pairs of isomer PAH concentrations allowed to identify six origin molecular indices that were used to identify the PAH contamination sources in the studied sampling stations: Phe/An, Flt/Py, Chry/BaA, LMW/HMW, Per/∑(PAH), and Per/∑(penta-aromatics). In general, the Cotonou lagoon sampling sites were contaminated mainly by petrogenic PAHs, due to petroleum trade at individual scale along the lagoon, and also waste oils from mechanics shops; the Aquitaine samples were polluted by pyrolytic origin PAHs. Interferences of rather petrogenic and pyrolytic PAH contaminations were noticed in the harbours due to petroleum products deliveries and fuel combustion emissions from the ships staying alongside the quays. Diagenetic origin of perylene was confirmed in this study, but its possible formation by combustion of organic matter was also considered because of the relatively higher concentrations of this PAH in the harbours of Cotonou and of Aquitaine region sediment samples.

Distribution and sources of polycyclic aromatic hydrocarbons in some Mediterranean coastal sediments

The current report shows that the Lazaret Bay (Toulon Harbour) is highly contaminated by polyaromatic hydrocarbons (PAHs). Fourteen PAHs have been detected among the 16 species nominated on the EPA priority list in all the study locations and in the most contaminated one at a concentration of higher than 48μg g−1 of dry sediment. It is also shown that pyrolytic origin is the main source of these compounds in Mediterranean coastal sediments.

Alkylated phenanthrene distributions as maturity and origin indicators in crude oils and rock extracts

Abstract Methylphenanthrene (MP), dimethylphenanthrene (DMP), and trimethylphenanthrene (TMP) distributions have been determined in crude oils and rock extracts from different origins at various stages of thermal maturity. A methodological approach combining Correspondence Factor Analysis and Nonlinear Mapping (NLM) was used for extracting origin/maturity information from these data. It allowed to benefit from the advantages of both methods. The use of such a multivariate data analysis appeared much more efficient than the use of molecular ratios that can be too restrictive and mask specific distribution patterns. This approach performed on the set of natural samples clearly demonstrated the discrimination between the samples through the presence of specific methyl-, dimethyl-, and trimethylphenanthrene isomers as origin/maturity markers. Based on MP, DMP, and TMP distributions, it is possible to distinguish the variations in organic matter type from the effects of thermal maturation. Some substituted phenanthrenes in each isomer series appear as characteristic of the two studied systems: The Aquitaine basin as representative of a marine carbonate environment and the Mahakam delta as representative of a terrestrial environment (higher plants). These compounds could be tentatively related to natural precursors such as triterpenoids or hopanoids.

Banking of environmental samples for short-term biochemical and chemical monitoring of organic contamination in coastal marine environments: the GICBEM experience (1986–1990)

The GICBEM (Groupe Interface Chimie Biologie des Ecosystèmes Marins) program consists of an evaluation of the ecosystem health status in the Mediterranean Sea mainly based on chemical and biochemical approaches. Specific chemical contaminants (polycyclic aromatic hydrocarbons (PAH), polychlorobiphenyls (PCB), heavy metals) in waters, sediments, and related biotransformation indicators in target organisms (mussels, fish) have been selected for a complete survey of the coastal waters. In order to provide an appropriate sampling program for standardization for each sampling cruise, various aspects have been studied: (a) parameters for the choice of the sample sites; (b) ways of collection the samples (waters, sediments, marine organisms); and (c) preparation of the samples for a short term storage on board ship and for further analyses in the ground laboratory. Methods of preparation and storage of the samples are described and could be used to initiate an environmental banking program including both possible retrospective analyses of chemical pollutants and biochemical indicators. Moreover, the correlation between chemicals (PAH) and biochemical (mixed function oxygenase activities) parameters has been studied and this demonstrates the capability of the enzyme activities as reliable pollution biomarkers.

Thermodynamic calculations on alkylated phenanthrenes: geochemical applications to maturity and origin of hydrocarbons

Abstract Enthalpies of formation of alkylated phenanthrenes have been evaluated by molecular mechanics method. These thermodynamic data have been successfully applied as predictive tools in the case of a highly complex class of compounds, the trimethylphenanthrenes, in order to restrict the synthesis work of standards to isomers that are likely to be present in natural samples. The changes in the distributions of isomers at different maturity stages are broadly in agreement with these theoretical calculations.

Alkylated phenanthrene distribution in artificially matured kerogens from Kimmeridge clay and the Brent Formation (North Sea)

Abstract Kerogen and extractible organic matter from immature Kimmeridge clay and Brent coal were heated at different temperatures (270–500°C) under conditions to mimic natural maturation. Aromatic fractions have been examined for their phenanthrene compound distribution. Phenanthrene indices based on methylphenanthrenes (MP) and dimethylphenanthrenes (DMP) exhibit very sensible changes in the applied temperature range. However, at high temperatures (about 450°C and more) possible thermal degradation of phenanthrene compounds produces a decrease in the values of the indices. Experimental data obtained in this study are compared and discussed with data obtained on thermal evolution performed on total rocks. Vitrinite reflectance values measured on artificially matured coals are also tentatively correlated with phenanthrene ratios. Theoretical thermodynamic calculations on MP compounds confirm also the relative thermal stability of the individual isomers.

BIOTA ACCUMULATION OF POLYCYCLIC AROMATIC HYDROCARBONS IN BENIN COASTAL WATERS

The contamination levels of 12 US-EPA polycyclic aromatic hydrocarbons (PAHs) from the tri-aromatics to the hexa- aromatics in biota and sediment of Cotonous lagoon and Benins continental shelf waters are identified in this paper. PAHs were analyzed by gas-chromatography coupled with mass spectrometry (GC-SM). Total lipid contents (TLC) were measured for biota, and total organic carbon content (TOC) for sediment. Total PAH concentrations obtained for organisms ranged between 15 and 102ngg− 1, with mussels accumulating the highest concentrations of PAHs. The lower–molecular-weight (LMW) 3 ring PAHs were predominant in all biota and showed similar distribution patterns. Phenanthrene accounts for 76% of total bioaccumulation factors (BAFs). Biota and sediment accumulation factors (BSAFs) showed that the mussels are exposed to the LMW PAHs more than to the hydrophobic higher-molecular-weight (HMW) PAHs in the Benin coastal waters.

Deposition of Aerosols in Polar Regions-Contamination of the Ice Sheet by Polycyclic Aromatic Hydrocarbons

Abstract As part of the GRIP-GISP programme, sampling of superficial polar ice was carried out in the neve of the Summit station situated in the centre of Greenland, during summer 1991. Twenty-four samples were taken from the first three meters of the ice layer. This is a record of the organic matter concentrations of the air during last five years. This first study concerns the polycyclic aromatic hydrocarbons (PAH) present in the insoluble phase of the ice. It shows that, in the atmosphere, PAH adsorbed on fine particles travel over long distances from industrial regions, especially from Russia and East Europe or, may be, from low latitudes regions to polar regions. Then they are deposited during snow falls and are archived in the ice. All the PAH emitted by fossil fuel combustion are present in the insoluble phase of the ice. However PAH produced by biomass combustion are also present in the ice in essar abundance. On average the total amount of PAH is of the order of a few hundred picogramms per kg of...

Direct Fluorometric Analysis of PAHs in Water and in Urine Following Liquid Solid Extraction

A method for the determination of PAHs in aqueous media based on synchronous fluorescence analysis directly on a solid phase after extraction was evaluated. Tests were conducted for (i) the simultaneous analysis of naphthalene, phenanthrene, anthracene, and pyrene in water at a parts per billion concentration level using a 0V1 sorbing phase block and (ii) the analysis of 1-hydroxyphenanthrene (1-OHPh) and 1-hydroxypyrene (1-OHPy) in human urine using a small sheet cut from a C18 silica fiberglass extraction disk (ENVI-Disk). Because the linear dynamic concentration range is dependent on both the immersion time and the concentration range, in all cases, an optimum immersion time must be determined to preserve linearity of intensity versus concentration. Calibration curves were determined for a concentration lower than 15 ppb in the case of 1-OHPh and at a concentration lower than 1.5 ppb in the case of 1-OHPy. In all cases the limits of detection were estimated to be lower than 0.2 ppb, i.e., for 1-OHPh and 1-OHPy, in the lowest concentration limit these metabolites were found in the urine of persons unexposed or weakly exposed to PAHs.

Resolved Absorption and Fluorescence Spectra of Two Tetrabenzoperylene Isomers in n-Alkane Matrices at Low Temperature. Evidences for Non-Planar Conformations

Abstract Highly resolved Shpolskii absorption and fluorescence spectra of Tetrabenzo (a, cd, f, lm) and –(a, cd, j, lm)perylenes have been obtained in n-hexane and n-octane at 5 K. They have been interpreted in terms of the existence of several non-planar conformers in agreement with theoretical results obtained with the MM2 method.