Assessing the contribution of wet-weather discharges on micropollutants release by urban catchments

Wet-weather discharges from integrated urban wastewater systems (IUWS) represent a threat for surface waters. When the system capacity is reached during medium/large rain events, a mixture of stormwater and untreated wastewater is discharged to surface water through Combined Sewer Overflows (CSOs) or Bypass (BP) of Wastewater Treatment Plants (WWTP). The loads of contaminants discharged by CSOs and BP are highly variable in time and space (Petrie, 2021), making it difficult to correctly monitor and assess the environmental risk for a specific catchment. The present work aims at assessing the impact of 12 micropollutants present in wet-weather discharges on receiving surface water, by using an archetype IUWS, defined through a stochastic approach. Monitoring data from literature were retrieved and elaborated to characterize the discharges and to predict the risk posed by micropollutants on a yearly horizon. The calculated risk from wet- weather discharges was compared against that posed by WWTP effluent (EFF)

An integrated modelling framework to assess cascade water reuse in urban areas

In the recent years water scarcity has been an increasing problem for many countries worldwide. For this reason, there is currently a strong focus on increasing reclaimed wastewater reuse, especially for agriculture purposes (Fernandes and Cunha Marques, 2023). Besides, the cost of energy from conventional resources is increasing, thus the energy sector is moving towards more distributed and efficient use of heat sources across urban areas. Typical applications are heat pumps using local groundwater reservoirs and subsequently discharging in the nearby surface water bodies/artificial channels (recipients). Furthermore, for a better quality of these recipients and for a better performance of wastewater treatment plants (WWTP), stormwater can be collected in separated sewers discharging only the urban runoff to the recipient. In this context, water is subjected to multiple uses, with potential cross-contaminations across different compartments, posing a risk for the environment. Hence, there is a strong need for tools capable of supporting stakeholders towards a wiser and safer use of water resources, to ensure long-term resilience, stability, sustainability and security of the society with regard to water use. An integrated model was developed to simulate the fate and associated risk of hazardous contaminants in a cascade water reuse system

Bistability in a Metabolic Network Underpins the De Novo Evolution of Colony Switching in Pseudomonas fluorescens

Phenotype switching is commonly observed in nature. This prevalence has allowed the elucidation of a number of underlying molecular mechanisms. However, little is known about how phenotypic switches arise and function in their early evolutionary stages. The first opportunity to provide empirical insight was delivered by an experiment in which populations of the bacterium Pseudomonas fluorescens SBW25 evolved, de novo, the ability to switch between two colony phenotypes. Here we unravel the molecular mechanism behind colony switching, revealing how a single nucleotide change in a gene enmeshed in central metabolism (carB) generates such a striking phenotype. We show that colony switching is underpinned by ON/OFF expression of capsules consisting of a colanic acid-like polymer. We use molecular genetics, biochemical analyses, and experimental evolution to establish that capsule switching results from perturbation of the pyrimidine biosynthetic pathway. Of central importance is a bifurcation point at which uracil triphosphate is partitioned towards either nucleotide metabolism or polymer production. This bifurcation marks a cell-fate decision point whereby cells with relatively high pyrimidine levels favour nucleotide metabolism (capsule OFF), while cells with lower pyrimidine levels divert resources towards polymer biosynthesis (capsule ON). This decision point is present and functional in the wild-type strain. Finally, we present a simple mathematical model demonstrating that the molecular components of the decision point are capable of producing switching. Despite its simple mutational cause, the connection between genotype and phenotype is complex and multidimensional, offering a rare glimpse of how noise in regulatory networks can provide opportunity for evolution

‘Sometimes there’s racism towards the French here’: xenophobic microaggressions in pre-2016 London as articulations of symbolic violence

This article discusses xenophobic microaggressions (Pierce, 1970) experienced by members of the French community in London prior to the EU-Membership Referendum in 2016. Acting at the interface of agency and passivity, implicitness and complicity, they go unseen in the social space despite their omnipresence. Through a close reading of empirical data collected as part of an ethnographic study, the article posits that these microaggressions are articulations of historically embedded anti-French ‘symbolic violence’ (Bourdieu and Wacquant, 1992; Bourdieu, 1993). The three main areas addressed are humour, intersectionality and the reproductive nature of the phenomenon (Bourdieu and Passeron, 1970; Bourdieu, 1972)

Metabolic Adaptation of Ralstonia solanacearum during Plant Infection: A Methionine Biosynthesis Case Study

MetE and MetH are two distinct enzymes that catalyze a similar biochemical reaction during the last step of methionine biosynthesis, MetH being a cobalamin-dependent enzyme whereas MetE activity is cobalamin-independent. In this work, we show that the last step of methionine synthesis in the plant pathogen Ralstonia solanacearum is under the transcriptional control of the master pathogenicity regulator HrpG. This control is exerted essentially on metE expression through the intermediate regulator MetR. Expression of metE is strongly and specifically induced in the presence of plant cells in a hrpG- and metR-dependent manner. metE and metR mutants are not auxotrophic for methionine and not affected for growth inside the plant but produce significantly reduced disease symptoms on tomato whereas disruption of metH has no impact on pathogenicity. The finding that the pathogen preferentially induces metE expression rather than metH in the presence of plant cells is indicative of a probable metabolic adaptation to physiological host conditions since this induction of metE occurs in an environment in which cobalamin, the required co-factor for MetH, is absent. It also shows that MetE and MetH are not functionally redundant and are deployed during specific stages of the bacteria lifecycle, the expression of metE and metH being controlled by multiple and distinct signals

Bacteria-inducing legume nodules involved in the improvement of plant growth, health and nutrition

Bacteria-inducing legume nodules are known as rhizobia and belong to the class Alphaproteobacteria and Betaproteobacteria. They promote the growth and nutrition of their respective legume hosts through atmospheric nitrogen fixation which takes place in the nodules induced in their roots or stems. In addition, rhizobia have other plant growth-promoting mechanisms, mainly solubilization of phosphate and production of indoleacetic acid, ACC deaminase and siderophores. Some of these mechanisms have been reported for strains of rhizobia which are also able to promote the growth of several nonlegumes, such as cereals, oilseeds and vegetables. Less studied are the mechanisms that have the rhizobia to promote the plant health; however, these bacteria are able to exert biocontrol of some phytopathogens and to induce the plant resistance. In this chapter, we revised the available data about the ability of the legume nodule-inducing bacteria for improving the plant growth, health and nutrition of both legumes and nonlegumes. These data showed that rhizobia meet all the requirements of sustainable agriculture to be used as bio-inoculants allowing the total or partial replacement of chemicals used for fertilization or protection of crops

Mobile work, veterinary subjectivity and Brexit: veterinary surgeons' migration to the United Kingdom

paper extends studies of ‘global work’ by considering the mobility of veterinary surgeons in the global countryside. The paper develops the concept of ‘disease ecology’: an assemblage of heterogenous actors and relations that inscribe and normalise mobility within professional subjectivities. Disruptions to these disease ecologies can contribute to new patterns of mobility. Drawing on biographical narrative interviews with 35 vets who have migrated to the United Kingdom to work, the paper shows how veterinary mobility is shaped by and emerges in response to these disease ecologies. Specifically, the paper describes how four narratives – ‘the first job’, ‘escape and adventure’, ‘the lucky break’ and ‘staying mobilities’ – contribute to veterinary migration to the UK, and how the lived experiences of work and inscriptions of mobile veterinary subjectivities within disease ecologies lead vets to stay in the UK. However, the paper also considers the role of Brexit in disrupting established disease ecologies and creating new patterns of veterinary mobilities. In identifying how Brexit challenges vets’ sense of place, the paper concludes by exploring Brexit's potential impact to the future of veterinary services in the UK

Recycled crustal carbon in the depleted mantle source of El Hierro volcano, Canary Islands

The Canary Islands, in the eastern Atlantic, are among the most enigmatic Oceanic Island provinces on Earth, as the mantle source feeding its volcanism exhibits wide spatial heterogeneity and a multiplicity of sources. Multi-isotope whole-rock studies have long revealed the presence of a recycled oceanic crust/lithosphere component in the mantle source. However, noble gas systematics have been more challenging to interpret, and the available carbon isotope data is limited and cannot support/dismiss this interpretation. Here, we present the very first isotopic characterisation of CO2 and noble gases (He-Ne-Ar) in fluid inclusions (FI) in minerals hosted in mantle xenoliths from El Hierro, the youngest and westernmost island of the Canary volcanic archipelago. Six fresh xenoliths from El Julan cliff valley were analysed (3 spinel lherzolites and 3 spinel harzburgites). We find carbon isotopic compositions of CO2 in FI (δ13C) ranging from −2.38 to −1.23‰ in pyroxenes and from −0.19 to +0.96‰ in olivines. These unusually positive δ13C values, well above the typical mantle range (−8‰ < δ13C < −4‰), prove, for the first time, the presence of a recycled crustal carbon component in the local source mantle. We interpret this 13C-rich component as inherited from a mantle metasomatism event driven by fluids carrying carbon from C. In contrast, our El Hierro xenoliths identify a depleted mantle-like He signature, with an average Rc/Ra ratio (3He/4He normalised to air ratio and corrected for atmospheric contamination) of 7.45 ± 0.26 Ra. The involvement of depleted mantle-like fluids, variably admixed with air-derived components (possibly recycled via paleo-subduction event(s)), is corroborated by Ne-Ar isotopic compositions. The depleted mantle-like He signature suggests instead the involvement of a primordial He source in the local lithospheric mantle and indicates a marginal role played by past subduction events in modifying the local mantle He budget. When put in the context of previous 3He/4He measurements in FI and surface gases along the Canary archipelago, our results confirm an overall west-to-east decrease of Rc/Ra ratios, which may be interpreted as due to increasing contributions from the African sub-continental mantle, the addition of radiogenic 4He during magma migration in the oceanic crust (whose thickness increases eastward) and/or magma ageing