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Dredging sediments can be implemented as primary resources in several civil engineering applications, on the condition that the release of anthropogenic compounds meets environmental requirements. The remediation of sedimentary wastes constitutes therefore, a key step before valorization consideration in circular economy schemes. This study focused on Zn removal from clayey river sediments dredged in northern France (Lille, Saint-Omer and Aire-Sur-La Lys) using a Thermo-Evolved Red Mud (TERM) and a Slag Based Hydraulic Binder (SBHB). The first step consisted in investigating Zn-trapping mechanisms prior to TERM and SBHB application as Zn-stabilizers. Results underlined poorer metal retention within the most organic sediment (high fatty acids and polycyclic aromatic molecules concentrations), emphasizing the minor role of the organic fraction typology during Zn-trapping. The pollutant displayed its best binding yields within the sediment with the highest interstitial pH and specific areas, which stressed out the preponderant influence of alkalinization ability and particles size distribution. In a second step, the spiked sediments were treated with TERM and SBHB, which resulted in a substantial lowering of Zn release at 12% of stabilizer/sediment ratio. Even though the organic content role was not preeminent during the pollutant trapping, it appeared here influential as delays in removal efficiencies were observed for the most endowed sediment. Two preferential geochemical pathways were adopted during the remediation operations with significant promotive roles of basic background pH. Indeed, Zn removal with TERM consisted mainly in sorptive mechanisms involving exchanges with Ca and Mg ions, whereas binding onto SBHB was principally achieved through precipitation phenomena. [ABSTRACT FROM AUTHOR]

To investigate the influence of the duration-temperature pairs chosen for laboratory thermal maturations on the evolution of the organic matter (OM) and porosity of the clay-rich source rocks with increasing maturity, long duration (104 days) thermal maturations, bulk, molecular geochemical OM characterization (Rock Eval, GC-TCD, GC/MS) and nitrogen adsorption porosimetry were applied on six type II mudstones from the Kimmeridge Clay formation. These results were compared with shorter duration experiments (72 h) previously carried out. The results show that the increase in the duration of thermal maturation experiments enhanced the degradation of heavy polar OM components into saturated and aromatic hydrocarbons, leading to the production of similar amounts of extractible OM (EOM) enriched in saturated and aromatic hydrocarbons. Then, in preventing the early breaking of low energy bonds, the lower temperature used for the longer duration experiments led to a less pronounced early cracking of OM resulting in a different timing of gas generation. This process did not influence the general evolution of the pore volume, which increased during gas generation. Whatever the duration-temperature pair chosen for maturation experiments highly oil-prone samples formed lower pore volumes during gas generation. Increasing the duration of thermal maturation seemed, nevertheless, to influence the amplitude and the timing of pore alteration events that occur during gas generation, leading to slightly different pore size distributions and pore volumes between short and long duration experiments. However, these differences remain limited, suggesting that results from different time-duration experiments can be easily compared. • Long and short-duration thermal maturation experiments are compared. • Longer duration experiments enhance the degradation of polar organic components. • Longer duration experiments exhibit slightly different gas concentrations. • Duration-temperature pairs do not greatly influence the evolution trend of porosity. • Duration-temperature pairs influence pore size distributions and pore volumes. [ABSTRACT FROM AUTHOR]

Hemp (Cannabis sp.) has been a fundamental plant for the development of human societies. Its fibers have long been used for textiles and rope making, which requires prior stem retting. This process is essential for extracting fibers from the stem of the plant, but can adversely affect the quality of surface waters. The history of human activities related to hemp (its domestication, spread, and processing) is frequently reconstructed from seeds and pollen detected in archaeological sites or in sedimentary archives, but this method does not always make it possible to ascertain whether retting took place. Hemp is also known to contain phytocannabinoids, a type of chemicals that is specific to the plant. Here we report on the detection of one of these chemicals, cannabinol (CBN), preserved in a sediment record from a lake in the French Massif Central covering the past 1800 yr. The presence of this molecule in the sedimentary record is related to retting. Analysis of the evolution of CBN concentrations shows that hemp retting was a significant activity in the area until ca. A.D. 1850. These findings, supported by pollen analyses and historical data, show that this novel sedimentary tracer can help to better constrain past impacts of human activities on the environment. [ABSTRACT FROM AUTHOR]

This work investigates the relation between the molecular composition of the organic matter (OM), hydrocarbon generation, and porosity of artificially matured mudstones from the Kimmeridge Clay formation. Anhydrous thermal maturations, geochemical characterization (gas chromatography-mass spectrometry, gas chromatography with a thermal conductivity detector), scanning electron microscopy observations, and nitrogen adsorption measurements were carried out. The results were compared to the calculated OM porosity after maturation. Our results reveal that samples richer in phytoplanktonic OM generated more abundant oils enriched in alkanes and lighter aromatic hydrocarbons (i.e., biphenyls and naphthalenes) that are more able to fill the adjacent pores of the mineral matrix during maturation. Both the calculated and the observed OM porosity increases during maturation, but the measured rock pore volume shows a non-linear evolution related to the amount of gas generated and the ensuing ability of the rock to preserve the pores. The secondary cracking of highly oil-prone samples generated larger amounts of C 1 -C 5 gases but lower pore volumes, less well preserved. OM composition and its ability to generate oil and gas seem therefore to affect the pore volume. These variations are nevertheless small compared to the effect of thermal maturity, which remains the major process controlling the evolution of porosity. During gas generation, high C 2 -C 5 concentrations are generated compared to methane. The short thermal maturation duration of our experiments may have delayed the conversion of C 2 -C 5 hydrocarbons to methane. In addition, slight differences in the concentrations of saturated and aromatic components and markedly different pore volumes and pore size distributions exist between artificially and naturally matured rocks. The conditions of artificial maturations may thus impact the thermal transformations of OM, emphasizing the necessity to investigate the role of the artificial maturation kinetics on OM and porosity., Competing Interests: The authors declare no competing financial interest., (Copyright © 2020 American Chemical Society.)

A total of 207 volatile compounds were identified in extracts of four French labeled brandies: Armagnac, Cognac, Calvados, and Mirabelle. Relative levels of all components were determined using GC-MS after integration of a selected peak of the mass spectrum of each. Each type of brandy could be clearly discriminated using PLS-DA statistical analyses based on these levels. French Mirabelle spirit, which was studied for the first time, was characterized by higher levels of many aldehydes and acetals and by the presence of compounds having an odd number of carbons together with benzaldehyde and some of its derivatives. Many possible derivatives of acrolein and high amounts of butan-2-ol were rather specific for the volatile composition of Calvados. The most important difference between the two wine-based samples seemed to be directly linked to the distillation system used. Many furanic compounds are specific to Cognac, whereas two or three compounds such as 1-(ethoxyethoxy)-2-methylbutane and gamma-eudesmol were specific to Armagnac. These two brandies presented rather high distributions of isobutanol and isopentanols, whereas Mirabelle and Calvados compositions offer more concentrated aliphatic linear alcohols.

Four oleanane-related aromatic triterpenoids isolated from an archeological piece of oak wood have been identified by NMR studies. Their structures give clue to a novel diagenetic transformation pathway of 2,3-oxygenated higher plant triterpenoids in the environment.