Jean Manuel Fonseca Martins

The increasing presence of pharmaceutical compounds in aquatic environments triggers significant environmental challenges. Traditional water treatment systems struggle in fully removing such pollutants, leading to their environmental release and long-term impacts on aquatic ecosystems and public health. This study investigates the effectiveness of biochar derived from coffee grounds (CGB) to remove diclofenac from aqueous solutions. The capacity of diclofenac retention of this biochar was evaluated using a dynamic approach, simulating a 2-D barrier with three-layer columns under controlled conditions. The hydrodynamic properties of these biochar columns were characterized using as a non-reactive tracer. The retention of diclofenac was then characterized along with its mobility at a realistic water flow. The results showed a good reproducibility of the experiments and a low to moderate retention of diclofenac by the tested CGB, with distribution coefficients ranging between 8.30 and 12.97 cm3 g-1. Without process optimization, removal efficiency was calculated to be 40% (± 14%), with a short contact time of around 7h. The breakthrough curves of both the tracer and diclofenac were fitted with the convection-dispersion equation (CDE model) and with its CDE-2SS and CDE-MIM versions. Results were well represented with the convection dispersion approach, giving consistent reactive transport parameters, suggesting that CGB effectively adsorbed diclofenac, with retardation factors eight times larger than on KBr. Altogether, our results suggest that, although not optimized, CGB offers a promising approach for removing pharmaceuticals such as diclofenac from water. Further investigations are needed to improve both biochar reactivity and transfer conditions in columns.

Environmental pollution is one of the main challenges faced by humanity. By their ubiquity and vast range of metabolic capabilities, microorganisms are affected by pollution with consequences on their host organisms and on the functioning of their environment. They also play key roles in the fate of pollutants through the degradation, transformation, and transfer of organic or inorganic compounds. Thus, they are crucial for the development of nature-based solutions to reduce pollution and of bio-based solutions for environmental risk assessment of chemicals. At the intersection between microbial ecology, toxicology, and biogeochemistry, microbial ecotoxicology is a fast-expanding research area aiming to decipher the interactions between pollutants and microorganisms. This perspective paper gives an overview of the main research challenges identified by the Ecotoxicomic network within the emerging One Health framework and in the light of ongoing interest in biological approaches to environmental remediation and of the current state of the art in microbial ecology. We highlight prevailing knowledge gaps and pitfalls in exploring complex interactions among microorganisms and their environment in the context of chemical pollution and pinpoint areas of research where future efforts are needed.

Many contaminants of agricultural origin are released into rural environments, particularly at the soil surface. Their fate has been extensively investigated in repacked soils, but only few studies have addressed their transport in structurally preserved natural soils. Much remains unknown about their fate and transfer within and between environmental compartments, while the susceptibility of these compartments to the contaminants adverse effects can vary considerably. The lack of studies regarding surface and subsurface transfer of contaminants through intact soil compared with studies on repacked soil led us to propose a device and protocol for sampling intact soil monoliths (60 × 30 × 22 cm ³ , length, width, depth [LWD]) without heavy machinery. This is achieved by a modular design with removable top and bottom lid and a protocol of cutting the soil and replacing the affected bottom soil with a drainage layer of glass beads. The device allows the application of artificial rainfall events with simultaneous highly resolved quantification of infiltration excess overland flow and drainage discharge. It is designed to facilitate the collection of samples for physical, biological, and chemical analyses that fulfill cleanliness standards for organic contaminant analysis at trace levels using only poorly reactive stainless steel and glass materials. Testing of the device was performed by measuring the transfer of the antiparasitic drug ivermectin (IVM) through and over a silt‐loam pasture soil. This test case illustrates how the device can be used to gain valuable information on the transfer of trace organic contaminants through topsoils.

The main process that opposes the Greenhouse Effect is called “carbon sequestration”, a phenomenon that essentially seeks to establish a dynamic balance between greenhouse gas (GHG) emissions from the immobilization of its elements, especially C and N. This work evaluated the stocks of carbon and nitrogen in soils of the Brazilian semi-arid submitted to irrigation with treated wastewater from domestic sewage. For this purpose, the carbon and nitrogen stocks in the soil of the semi-arid region of Brazil were compared for four different uses: Open Native Caatinga (ONC); Treated Wastewater Effluent Irrigation (TSEI); Surface Water Irrigation (SWI); and Traditional Rainfed Agriculture (TRA). The hypothesis considered in this research was that the application of treated effluents in agriculture, besides being an alternative that can mitigate the problem of water scarcity of the semiarid region, is also capable of influencing the storage capacity of C and N in the soil, due to its organic load. The results indicate that among the different land uses evaluated, soil C and N stocks were highest in ONC, and decreased with the agricultural land use. The greatest accumulation of C and N in Caatinga is due to the presence of forest litter, and the influence of irrigation with treated sewage effluent was not detected in the present study. It can be concluded that the contribution of vegetation residues to the soil surface is the main factor contributing to C and N storage.

Primary Biogenic Organic Aerosols (PBOA) were recently shown to be produced by only a few types of microorganisms, emitted by the surrounding vegetation in the case of a regionally homogeneous field site. This study presents the first comprehensive description of the structure and main sources of airborne microbial communities associated with temporal trends in Sugar Compounds (SC) concentrations of PM₁₀ in 3 sites under a climatic gradient in France. By combining sugar chemistry and DNA Metabarcoding approaches, we intended to identify PM₁₀-associated microbial communities and their main sources at three sampling-sites in France, under different climates, during the summer of 2018. This study accounted also for the interannual variability in summer airborne microbial community structure (bacteria and fungi only) associated with PM₁₀-SC concentrations during a 2 consecutive years’ survey at one site. Our results showed that temporal changes in PM₁₀-SC in the three sites are associated with the abundance of only a few specific taxa of airborne fungi and bacterial. These taxa differ significantly between the 3 climatic regions studied. The microbial communities structure associated with SC concentrations of PM₁₀ during a consecutive 2-year study remained stable in the rural area. Atmospheric concentration levels of PM₁₀-SC species varied significantly between the 3 study sites, but with no clear difference according to site typology (rural vs. urban), suggesting that SC emissions are related to regional rather than local climatic characteristics. The overall microbial beta diversity in PM₁₀ samples is significantly different from that of the main vegetation around the urban sites studied. This indicates that the airborne microorganisms at these urban sites are not solely from the immediate surrounding vegetation, which contrasts with observations at the scale of a regionally homogeneous rural site in 2017. These results improve our understanding of the spatial behavior of tracers of PBOA emission sources, which need to be better characterized to further implement this important mass fraction of Organic Matter (OM) in Chemical Transport models (CTM).

Primary biogenic organic aerosols (PBOAs) represent a major fraction of coarse organic matter (OM) in air. Despite their implication in many atmospheric processes and human health problems, we surprisingly know little about PBOA characteristics (i.e., composition, dominant sources, and contribution to airborne particles). In addition, specific primary sugar compounds (SCs) are generally used as markers of PBOAs associated with bacteria and fungi, but our knowledge of microbial communities associated with atmospheric particulate matter (PM) remains incomplete. This work aimed at providing a comprehensive understanding of the microbial fingerprints associated with SCs in PM₁₀ (particles smaller than 10 µm) and their main sources in the surrounding environment (soils and vegetation). An intensive study was conducted on PM₁₀ collected at a rural background site located in an agricultural area in France. We combined high-throughput sequencing of bacteria and fungi with detailed physicochemical characterizations of PM₁₀, soil, and plant samples and monitored meteorological and agricultural activities throughout the sampling period. Results show that in summer SCs in PM₁₀ are a major contributor of OM in air, representing 0.8 % to 13.5 % of OM mass. SC concentrations are clearly determined by the abundance of only a few specific airborne fungal and bacterial taxa. The temporal fluctuations in the abundance of only four predominant fungal genera, namely Cladosporium, Alternaria, Sporobolomyces, and Dioszegia, reflect the temporal dynamics in SC concentrations. Among bacterial taxa, the abundance of only Massilia, Pseudomonas, Frigoribacterium, and Sphingomonas is positively correlated with SC species. These microbes are significantly enhanced in leaf over soil samples. Interestingly, the overall community structure of bacteria and fungi are similar within PM₁₀ and leaf samples and significantly distinct between PM₁₀ and soil samples, indicating that surrounding vegetation is the major source of SC-associated microbial taxa in PM₁₀ in this rural area of France.

On the basis of Gram‐negative bacterium Escherichia coli models previously published in the literature, the transmembrane voltage induced by the application of an alternating current (AC) electric field on a bacterial suspension is calculated using COMSOL Multiphysics software, in the range 1–20 MHz, for longitudinal and transverse field orientations. The voltages developed on each of the three layers of the cell wall are then calculated using an electrical equivalent circuit. This study shows that the overall voltage on the cell wall, whose order of magnitude is a few tens of µV, is mainly distributed on inner and outer layers, while a near‐zero voltage is found on the periplasm, due to its much higher electrical conductivity compared with the other layers. Although the outer membrane electrical conductivity taken in the model is a thousand times higher than that of the inner membrane, the voltage there is about half of that on the inner membrane, due to capacitive effects. It follows that the expression of protein complexes anchored in the inner membrane could potentially be disrupted, inducing in particular a possible perturbation of biological processes related to cellular respiration and proton cycle, and leading to growth inhibition as a consequence. Protein complexes anchored in the outer membrane or constituting a bridge between the three layers of the cell wall, such as some porins, may also undergo the same action, which would add another growth inhibition factor, as a result of deficiency in porin filtration function when the external environment contains biocides. Bioelectromagnetics. 2020;41:279–288 © 2020 Bioelectromagnetics Society.