Wastewater-based epidemiology (WBE) provides near real-time insight into population exposure to chemicals and microbial targets but lacks retrospective depth because monitoring depends on the initiation of sampling. Here, we demonstrate that sediments accumulated in settling basins constitute multi-year, time-integrated archives of wastewater composition that can extend WBE into the past. Four sediment cores collected in 2024 from a large combined-sewer desilting basin in Paris, undisturbed since 2020, were analyzed across stratigraphic layers corresponding to discrete depositional events. A total of 44 targeted pharmaceuticals, illicit drugs, and lifestyle markers were quantified, with concentrations ranging from tens of ng g−1 to several µg g−1. Stable WBE microbial targets were consistently detected, whereas SARS-CoV-2 was not detected. Reorganization of layers by depositional age revealed reproducible multi-year patterns and consistent parent/metabolite relationships. Contaminant preservation was strongly modulated by sediment geochemistry and compound properties, with organic matter and mineral phases jointly controlling partitioning and favoring retention of neutral and cationic molecules. Despite discontinuous, event-driven accumulation and pronounced matrix heterogeneity, recurring stratigraphic structures across independent cores demonstrate that sediments provide a semi-quantitative record of wastewater composition over discrete time windows. These findings establish urban sewer sediments as complementary, retrospective observatories of public health.

Organic matter (OM) dynamics in mangrove forests have been studied extensively in terms of the capacity of their soils to store organic carbon. While delta 13C, delta 15N, and C/N values for mangrove soils and sources are well reported, other indicators of OM maturity and composition are lacking. In this study, soil OM decomposition processes were investigated for a semi-arid bay head mangrove forest in New Caledonia. Mangrove tissues and 20-cm soil cores were collected in monospecific stands of Avicennia marina and Rhizophora stylosa. The isotopic compositions of the samples were assessed, along with their molecular compositions (lignin-derived phenols and neutral carbohydrates). Rock-Eval analysis was also performed on the samples to investigate OM characteristics. Results showed that stable isotope ratios and Rock-Eval parameters followed similar vertical trends beneath both species indicating the influence of depth on OM state. However, the more anoxic conditions beneath R. stylosa limited OM decomposition as shown by the lower TpS2 values (indicator of OM thermal stability). Neutral carbohydrates and, surprisingly, lignin-derived phenols, were lost at higher rates than bulk organic carbon beneath both mangrove species. Selective degradation of individual compounds was observed, and species-dependent variations associated with the redox conditions and the OM sources were identified. We suggest that lignin was degraded, even in anoxic environments, because of the amount of labile lignocellulosic components in the soil. These findings enhance our understanding of OM dynamics in mangrove ecosystems, shedding light on the mechanisms underlying carbon cycling and their implications for global carbon storage and ecosystem management.

Rock-Eval (R) pyrolysis is dedicated to rapidly determining the quality and quantity of organic matter (OM) in environmental and geological samples. It has been proposed that detailed examination of S2 pyrograms acquired from a Flame Ionization Detector during the programmed pyrolysis of samples can provide complementary information to classical Rock-Eval (R) parameters. Previous mathematical deconvolution of the S2 pyrogram has been suggested to semi-quantify distinct thermal fractions that are assumed to be distinct in terms of chemical and/or biological lability. To date, there is no direct molecular support for such an assumption. This work proposes a methodological approach based on coupling a temperature-programmed pyrolyser to a standard mass spectrometer (Py-MS). A set of reference soil samples was analysed. The set was completed by dissolved OM, source rock and coal samples in order to test the relevance of this methodological approach to various OM types. Data analysis was based on Tpeak values defined at temperatures of maximum m/z fragment production during the temperature ramp. These Tpeak values were grouped into clusters of distinct m/z values for which a chemical attribution is proposed owing to an extensive literature survey. For the soil samples, all the pyrolytic fractions described in the literature from mathematical deconvolution of the S2 pyrogram were identified except for the most thermolabile fraction (280-320 degrees C). Fragments with Tpeak values between 330 and 390 degrees C were mainly attributed to proteins, lignin and carbohydrates. Tpeak values found in the 391-499 degrees C range corresponded to m/ z fragments attributed to aliphatics, lignin and aromatics while fragments with Tpeak values higher than 480 degrees C were assigned solely to aromatics. In all samples, these fragments displayed a singular pattern of decreasing m/z with increasing temperature, the significance of which remains to be fully elucidated. This preliminary study provides key methodological guidelines for re-exploring Py-MS applications to disentangle the chemical nature of OM.

If natural and cultivated soils have been widely investigated, urban soils are still poorly understood, especially in terms of the microbial diversity they harbor and its roles in providing soil functions and ecosystem services. This paper presents data collected from urban soils sampled at 135 sites from the medium-sized city of Blois (France), which correspond to different land uses randomly distributed in the city. In total, eight types of land use were identified, undergoing four levels of management intensity and positioned either in or out of the Loire floodplain. This data collection describes the main soil physicochemical characteristics (texture, pH, water status, chemical contents), plant traits (root functional traits) as well as abundances of broad taxonomic groups (bacterial, archaeal, and fungal), and of microbial functional groups involved in soil C, N, and P cycling, microbial diversity (sequencing of Bacteria, Archaea, and Fungi), and different microbial activities (respiration, activities linked to the nitrogen cycle, extracellular enzymatic activities, and potential methanogenesis). The dataset summarized in this article improves our knowledge about physicochemical and (micro)biological characteristics of urban soils and can be used as a reference for future studies of urban soils.

Pharmaceutical products (PPs) are found in several compartments of the environment, and are mostly emitted by wastewater treatment plants effluents. Their occurrence in the particulate phase, in opposition with the dissolved one, also promotes their occurrence in retention areas, where particles transported by streams settle. The study focuses on understanding how different constituents of pond sediment are distributed within a suburban pond, revealing patterns or hotspots of PPs accumulation. Results confirmed the heterogeneous spatial distributions of the granulometric fractions, total organic carbon, quantitative palynofacies, crystalline phase distributions and PPs contents. The delta preferentially concentrates total organic carbon (14.5 +/- 2.2 %), and particularly terrigenous organic matter and neutral PPs, while the main decantation area accumulates mostly fine particles (58.2 +/- 7.7 %), kaolinite, algal organic matter and cationic PPs. The potential role played by OM and kaolinite in PPs adsorption is supported by their respective spatial trends at the pond scale. Further attention should be paid to surface sediments components and PPs sensitivity to seasonal variations, especially in terms of flow, pH and oxygenation of the water-column. This spatial approach allowed to identify preferential accumulation and concentration areas within the pond, where the following extensive characterization of interface sediments highlighted the factor likely to influence PPs trapping within the pond.

With the aim of developing a new biodegradable pesticide, batch and transport experiments of a 4-hydroxy-2-pyridone core molecule (4H2P), were carried out through agricultural soil and limestone columns. 4H2P cores are natural biodegradable compounds with diverse biological activities, including fungicidal and bactericidal properties. The results of the transport experiments indicated that the 4H2P molecule is adsorbed in agricultural soil (with a retention rate of 35 %), but not on limestone (with a zero-retention rate). Modeling of the transport data also revealed a higher retardation coefficient in soil (R = 6.04) than in limestone (R = 1.00). Isotherms experiments modeling revealed that the constants "n" of the Freundlich model are < 1 and the free adsorption energy parameters "E" of the Dubinin Radushkevich model are about 4 kJ.mol(-1) < < 8 kJ.mol(-1) which indicates that the adsorption of the 4H2P molecule by the solid phases (Calcite, kaolinite and montmorillonite) is of physisorption type with montmorillonite exhibiting significant adsorption capacity (with Q(m) = 12.10(-3) mol.g(-1)). X-ray diffraction analysis of montmorillonite before and after adsorption showed that the molecule is inserted between the intermediate layers from a concentration of 0.5 gL(-1), with a disorganization in the stacking of the layers involved from 1.5 g.L-1.

This study assesses the occurrence of various types of drugs in a sedimentary archive cored in a sewer settling basin with a depth of 14 m. The coring operations were conducted before the basin was drained. A 2.2-m long sedimentary core was recovered. The sediments consisted of successions of coarse minerals and coarse or fine organic layers. One of the main challenges is to be able to date such a very recent archive. This was realized by using an event-based approach with 19 14C Carbon dating out of the rising and decay phase of atmospheric 14C content linked to the aerial explosion of thermonuclear bombs (bomb peak). The first results revealed the potential of these sediments to record diverse contaminants. Eighteen of the 20 molecules targeted were quantified at least once. The potential of such archives to record the first use of each drug in the city is questioned, as well as the potential of back-calculated drug consumption on the basis of sedimentary occurrences. The estimated wastewater concentrations fit quite well for some molecules, whereas further work remains necessary for other drug values, especially concerning the back-calculation parameters.

Peat-forming wetlands (PFW) are crucial in the global C-cycle, yet they are increasingly threatened by various anthropogenic pressures, including microplastic (MP) pollution. We investigate the impacts of polyvinyl chloride (PVC) and its additive, calcium carbonate (CaCO3) on organic matter (OM) degradation in PFW. We conducted two experiments: first, by mixing peat soil with increasing concentrations of crushed sanitary PVC-MP (0.3 %, 3 %, and 30 %) and second, by assessing the role of CaCO₃ in modulating these impacts. Our findings revealed significant alterations in peat chemical properties largely mediated by CaCO3 (i.e. increased pH, and Ca2+, Mg2+, K+ concentrations). PVC-MP increased carbon dioxide (CO2) and methane (CH4) production, as well as dissolved organic carbon release. CaCO3 may have enhanced CO2 release through its dissolution and contributed to CH4 production as a C source for a more diverse and active methanogenic community (higher mcrA gene abundance). Shifts in microbial community composition (e.g. reduction of Acidobacteriae and increase in active fermenters, such as Clostridia) and metabolism (higher lignin-like compounds degradation and P-uptake activity but lower activity of labile-C degrading enzymes) also contributed in the C-cycle alterations. PVC-MP enhanced denitrification (narG gene abundance) but reduced relative proportion of the ammonia-oxidizing archaea Nitrososphaeria, leading to inhibition of nitrification. The effects of PVC-MP were concentration-dependent, with CaCO₃ strongly influencing on the C cycle, while its impact on the N cycle was only partial, suggesting potential effect of other additives, such as plasticisers. Overall, our results highlight a significant disruption of microbial processes due to MP pollution, leading to increased greenhouse gas emissions and significant implications on the role of PFW as global C-sinks.

A buried layer rich in organic matter (OM) has been identified in the mangrove soils along the West coast of New Caledonia (South Pacific), resulting from a long period of stable sea levels during the Holocene. This study aims to characterize this OM-enriched layer isotopically, molecularly (lignin and neutral carbohydrates), and using Rock-Eval pyrolysis, while identifying the decomposition and preservation processes in these anoxic and sulfidic conditions. The study site is a mangrove forest of the West coast of New Caledonia, with a vegetation typical of this semi-arid area. The species Rhizophora stylosa develops in monospecific stand seaward and the species Avicennia marina landward. Multiple parameters such as the high total organic carbon content (10%) indicate the presence of this enriched layer below 30 cm depth beneath the A. marina stand. Stable isotopic ratios indicate that the roots of R. stylosa are the primary source of OM in this layer. Degradation mechanisms include dehydrogenation and the loss of major neutral sugars (glucose, xylose, galactose), while preservation processes involving arabinose, vanillin, and p-hydroxyacetophenone contribute to the stabilization of OM. The presence of well-preserved root material associated with pyrite observed using a scanning electron microscope, along with high Sorg/C ratio provide tangible evidence of interactions between OM and minerals and OM sulfurization, reinforcing preservation in anoxic and sulfidic environments. Through radiocarbon dating, the OM-enriched layer is placed in the historical context of a period characterized by stable sea levels approximately 4,000 years ago, emphasizing the profound impact of prolonged stability on OM accumulation and preservation in mangrove soils.

Understanding the diagenetic processes of organic matter (OM) within mangrove forests is essential to grasp ecosystem dynamics and exchanges with adjacent ecosystems. This study investigated the influence of urban runoff on leaf litter degradation in a New Caledonian mangrove forest, subjected to urban rainwater for over 50 years. Focusing on Avicennia marina and Rhizophora stylosa, our objectives were to determine factors affecting leaf litter degradation, assess urban runoff effects on decay rates and element concentrations, and understand OM changes at the molecular level. Litterbags containing senescent leaves placed on the mangrove floor were collected after 7, 14, 28, 56, and 72 days. C and N along with their stable isotopes were evaluated during degradation as well as lignin and neutral carbohydrates contents. Despite lower initial N content, R. stylosa exhibited faster degradation (t1/2 of 36 +/- 3 and 28 +/- 2 days) than A. marina (t1/2 of 43 +/- 9 and 33 +/- 4 days), emphasizing the critical role of species position within the mangrove forest regarding tidal immersion. Urban runoff, submerging the urban site, intensified leaf litter degradation, influencing both mass loss and molecular changes in OM. After 72 days of leaf litter degradation, the loss of rhamnose and glucose was more pronounced at the control site (13 % and 75 % for rhamnose and 46 % and 53 % for glucose for A. marina and R. stylosa, respectively) compared to the urban site. The study also exposed molecular tendencies during mangrove leaf litter degradation. The content of ferulic acid in the leaf litter decreased at all stands after 72 days of degradation (between -25 % and -58 %), while total syringyl phenols increased (between + 64 % and + 232 %). This research exposed the global implications of urban runoff, indicating accelerated leaf litter degradation in mangrove forests, potentially disrupting C sequestration dynamics and threatening ecosystem services.

Natural organic matter (OM) has a complex structure whose complete structural and chemical description remains a challenge. Rock-Eval® device constitutes a rapid and affordable method for obtaining key quantitative and qualitative parameters on OM. Previous studies on soil samples proposed to deconvolute or to split into temperature slices Rock-Eval® S2 pyrograms in order to distinguish and quantify chemical fractions of increasing thermal lability. In order to provide support for such an assumption, this work proposes a methodological approach based on coupling a temperature-programmed pyrolyser to a standard mass spectrometer (Py-MS). In this manuscript, we compare results acquired by Rock-Eval® pyrolysis with those from Total Ion Current (TIC) traces obtained by Py-MS on a set of reference soil samples, completed by dissolved OM, source rock and coal samples, in order to test the extent to which this approach can be generalized. Our results show good quantitative and qualitative agreements between the two methods. This comparison is a prerequisite before going further and addressing the molecular significance of S2 pyrograms deconvolution through the examination of m/z fragments abundance curves.

Summary We analysed biomarkers enclosed in carbonate crusts deposited in urban surrounding as tracers of pollution

Summary Storage in a deep geological layer is the final destination for radioactive waste (ILW). In these conditions, the organic waste can be in contact with the infiltrated water and can release new hydrophilic oragnic products, which can complex and remobilize radionuclides. In this work, we are looking for investigate the release of organic ligand from plastics (PVC and PE) at 2 temperatures.