J. Bellocq

Concentrations of PAHs (polycyclic aromatic hydrocarbons) in various marine organisms in relation to those in sediments and to trophic level

Sediments and marine organisms such as mussels (Mytilus galloprovincialis), fish (Mullus barbatus, Serranus scriba), crabs (Polybius henslowi) and shrimp-like crustaceans (mysids, euphausiids) were sampled on European coasts, France, Spain) and analysed for their PAH content by gas chromatography/mass spectrometry (GC-MS). The PAH concentrations determined in the organisms were significantly negatively correlated with logKow values, but to different extents according to the species. This was explained by the greater exposure of the organisms to the lower molecular weight compounds with differences resulting from different feeding habits, habitat, and biotransformation capacities of the organisms in relation to trophic levels. The influence of these observations on the use of different sentinel species in biomonitoring programmes is discussed.

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.

Polycyclic aromatic hydrocarbon (PAH) burden of mussels (Mytilus sp.) in different marine environments in relation with sediment PAH contamination, and bioavailability

Abstract Sediments and mussels (Mytilus edulis, Mytilus galloprovincialis) were sampled in different European coastal environments (Germany, France, Spain) and analysed for their polycyclic aromatic hydrocarbon (PAH) content by Gas Chromatography/Mass Spectrometry (GC-MS). Bioaccumulation factors of individual compounds from the sediment were calculated and discussed according to the compound solubility. The mussels showed different accumulation patterns according to the pollution source they were exposed to (dissolved fraction of PAHs, particulate fraction, petroleum present in the water column). The exposure source also depends on the geographical location of the mussels. In the Mediterranean Sea, the bivalves were mainly exposed to the dissolved fraction of PAHs, while in the Baltic Sea and in the Atlantic Ocean, the PAHs associated to the particles were significant sources.

Relation of the methylated aromatic hydrocarbon distribution pattern to the maturity of organic matter in ancient sediments from the Mahakam delta

The distribution of methyl-phenanthrenes, -anthracenes, -chrysenes and -pyrenes in twelve immature coal samples from the Mahakam delta (Indonesia) have been examined by capillary gas chromatography (CGC) and high resolution Shpolskii spectroscopy (HRS). Gradual changes with increasing depth have been observed for several compound ratios which have been calculated from the relative distributions of the methyl aromatics in each family. A general decrease was observed in the relative proportion of α-substituted compounds (less thermodynamically stable compounds) versus the β-substituted compounds (most thermodynamically stable compounds). These changes reflect the increasing thermal maturation of the sedimentary organic matter which could not be revealed from immature and marginally mature rock samples by vitrinite reflectance data. New maturation indices based on methyl-anthracenes, -chrysenes and -pyrenes are presented and their application to the studied samples is discussed.

Focused microwave-assisted extraction of polycyclic aromatic hydrocarbons and alkanes from sediments and source rocks

Focused microwave-assisted extraction (FMW) of polycyclic aromatic hydrocarbons (PAHs) and n-alkanes from sediments and rocks was compared to conventional extraction methods such as Soxhlet extraction. With the FMW technique, extraction time is reduced to 10 min and the solvent volume is small (∼30 ml). The extraction procedure and analysis was validated on a certified marine sediment standard reference material, then applied to four source rocks of different origins, compositions and analyte concentrations. Recoveries of individual compounds were calculated for both FMW and Soxhlet methods and the results suggested that there was no analyte selectivity. The moisture content of the sample matrix had a positive effect on the extraction recovery of some PAHs with a maximum increase of 30%, whereas n-alkane extraction seems less affected by this factor. The conventional biomarker parameters determined after FMW extraction were the same as those found after Soxhlet extraction. A study of matrix effects on the extraction recovery showed that the recovery of analytes was near 100% if the matrix was ground and above 74%, if the matrix was used without prior grinding

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.

Gas chromatographic retention behaviour of dibenzothiophene derivatives on a smectic liquid crystalline polysiloxane stationary phase

The gas chromatographic retention behaviour, on a smectic liquid crystalline polysiloxane stationary phase, of methyldibenzothiophenes and eighteen C2-dibenzothiophenes (sixteen dimethyldibenzothiophenes and two ethyldibenzothiophenes), out of twenty possible compounds, was investigated. The retention, in addition to vapour pressure and polarity, was greatly influenced by the molecular geometry of the solutes. The major factor affecting this behaviour was the length to breadth ratio (L/B). The elution order of the dimethyldibenzothiophenes was fairly well correlated with L/B values: Roughly, the lower the L/B values, the earlier the dimethyldibenzothiophenes were eluted. However, the solute molecular shape, although of less importance, was also a significant retention-affecting factor, having the contrary effect to L/B values on the elution order. Arc-like molecules (dibenzothiophenes) with groups attached to the outer curved side (i.e., in positions 3 and 4) were retained longer than predicted by L/B values. In contrast, isomers conforming to the arc-like arrangement (i.e., with substituents in positions 1 and 2) were less retained than predicted. The application of these identifications to a crude oil sample is described.

Distribution of methylperylene isomers in selected sediments

Surface and deep sediment extracts, containing perylene compounds, have been examined by High Resolution Shpolskii Spectroscopy. The first identification of the three methylperylene isomers is reported and indicates the predominance of 2-methylperylene among the methylperylene isomer distributions at any maturation stage. Perylene itself was nevertheless always found to be the most abundant perylene compound.

Relationship between rank and distribution of methylaromatic hydrocarbons for condensates of different origins

Abstract Aromatic hydrocarbon fractions from thirty gas condensates have been analysed by capillary GC and high resolution Shpolskii spectroscopy for the determination of the relative distribution in methylphenanthrene (MP), dimethylphenanthrene (DMP) and methylpyrene (MPy) series. The measured maturity indices, MPI, DMPI and MPyI which appeared previously suitable for rocks, coals and crude oils have been tested for the recognition of rank levels of condensates. MPI and DMPI exhibit a remarkedly similar evolution which allows the differentiation of the samples analysed in these works. Such studies extend the applicability of alkylaromatic hydrocarbon ratios to the characterization of maturity level of condensates which range from immature-marginally mature to overmature samples, partially biodegraded or not.

Applicability of low temperature high-resolution fluorescence spectroscopy to the analysis of nitro and amino polycyclic aromatic hydrocarbons

Abstract In order to enable the analysis of nitro and amino polycyclic aromatic hydrocarbon (PAH) isomers in the environment, the applicability of low temperature high-resolution fluorescence spectroscopy (HRFS) using a frozen n -alkane solution (Shpolskii matrix) has been studied. 22 nitro PAHs were treated with potassium borohydride (KBH 4 ) to be reduced into fluorescent amino PAHs, and spectral measurements of reduction products were carried out. Reduction products of 14 nitro PAHs exhibited high-resolution fluorescence spectra. Furthermore, the reproducibility of the reduction reaction and wavelength agreements of the narrow bands in measured spectra were confirmed by comparing spectra obtained at two laboratories in France (the University of Bordeaux I) and Japan (NIRE).