Remediation of nitrate pollution of Earth’s rivers and aquifers is hampered by cumulative biogeochemical processes and nitrogen sources. Isotopes (δ¹⁵N, δ¹⁸O) help unravel spatiotemporal nitrogen(N)-cycling of aquatic nitrate (NO₃⁻). We synthesized nitrate isotope data (n = ~5200) for global rivers and shallow aquifers for common patterns and processes. Rivers had lower median NO₃⁻ (0.3 ± 0.2 mg L⁻¹, n = 2902) compared to aquifers (5.5 ± 5.1 mg L⁻¹, n = 2291) and slightly lower δ¹⁵N values (+7.1 ± 3.8‰, n = 2902 vs +7.7 ± 4.5‰, n = 2291), but were indistinguishable in δ¹⁸O (+2.3 ± 6.2‰, n = 2790 vs +2.3 ± 5.4‰, n = 2235). The isotope composition of NO₃⁻ was correlated with water temperature revealing enhanced N-cascading in warmer climates. Seasonal analyses revealed higher δ¹⁵N and δ¹⁸O values in wintertime, suggesting waste-related N-source signals are better preserved in the cold seasons. Isotopic assays of nitrate biogeochemical transformations are key to understanding nitrate pollution and to inform beneficial agricultural and land management strategies.

The processes of microplastic fiber pollution in groundwater are unknown. The recent research on this contaminant threat is generally focused on surface waters (mainly oceans and rivers), while aquifer contamination is only marginally mentioned as an issue needing further investigation. Synthetic microfibers can be introduced into soils in different ways (e.g. wastewater treatment plants or greywater discharge, septic tank outflows, direct injection of contaminated water in cases of managed aquifer recharge, losing streams, etc.), and can thus reach aquifer systems due to leaching or infiltration in soil pores. Microfibers can then adsorb persistent bioaccumulative and toxic chemicals, which include persistent organic pollutants and metals, and become a carrier of harmful substances in the aquifer system, hence contributing to the overall contamination in both urban and rural areas. For this reason, it is of paramount importance, not only to assess the occurrence and fate of microplastic fibers in groundwater, but also to study the role of microplastics as carriers of contaminants within the aquifer and to advance standardization and organization of monitoring campaigns. Only by addressing these key challenges can hydrogeologists contribute to the state of the art on microplastic pollution and ensure that groundwater is not neglected in the environmental assessments tackling this contaminant of emerging concern. Les processus de pollution par les fibres micro-plastiques dans les eaux souterraines sont inconnus. Les recherches récentes sur cette menace de contaminants sont généralement axées sur les eaux de surface (principalement les océans et les rivières), tandis que la contamination des aquifères n’est que marginalement mentionnée comme une question nécessitant des recherches plus approfondies. Les microfibres synthétiques peuvent être introduites dans les sols de différentes manières (par ex. rejets de stations de traitement d’eaux usées ou rejets d’eaux grises, sorties de fosses septiques, injection directe d’eau contaminée dans les cas de gestion de la recharge d’aquifère, perte de cours d’eau, etc.) et peuvent ainsi atteindre les systèmes aquifères en raison de lessivage ou d’infiltration dans les pores du sol. Les microfibres peuvent ensuite adsorber des produits chimiques persistants, bio-accumulatifs et toxiques, qui comprennent les polluants organiques persistants et les métaux, et deviennent porteuses de substances nocives dans les systèmes aquifères, contribuant ainsi à la contamination générale aussi bien dans les zones urbaines que dans les zones rurales. Pour cette raison, il est d’une importance primordiale, non seulement d’évaluer l’occurrence et le devenir des fibres micro-plastiques dans les eaux souterraines, mais aussi d’étudier le rôle des micro-plastiques en tant que porteurs de contaminants dans l’aquifère et de faire progresser la normalisation et l’organisation de campagnes de suivi. Ce n’est qu’en abordant ces principaux défis que les hydrogéologues contribuent à l’état de l’art sur la pollution par les micro-plastiques et veillent à ce que les eaux souterraines ne soient pas négligées dans les évaluations environnementales qui s’attaquent à ce contaminant de préoccupation émergente. Se desconocen los procesos de contaminación por fibras microplásticas en el agua subterránea. La investigación reciente sobre esta amenaza de contaminantes se centra generalmente en las aguas superficiales (principalmente los océanos y los ríos), mientras que la contaminación de los acuíferos se menciona sólo marginalmente como un tema que requiere mayor investigación. Las microfibras sintéticas pueden introducirse en los suelos de diferentes maneras (por ejemplo, en plantas de tratamiento de aguas residuales o descarga de aguas grises, desagües de fosas sépticas, inyección directa de agua contaminada en casos de recarga de acuíferos gestionados, pérdida de corrientes, etc.) y, por lo tanto, pueden llegar a los sistemas acuíferos debido a la lixiviación o infiltración en los poros del suelo. Las microfibras pueden entonces adsorber productos químicos bioacumulativos y tóxicos persistentes, que incluyen contaminantes orgánicos persistentes y metales, y convertirse en portadores de sustancias nocivas en el sistema acuífero, contribuyendo así a la contaminación general tanto en zonas urbanas como rurales. Por esta razón, es de suma importancia, no sólo evaluar la ocurrencia y el destino de las fibras microplásticas en las aguas subterráneas, sino también estudiar el papel de los microplásticos como portadores de contaminantes dentro del acuífero y avanzar en la estandarización y organización de campañas de monitoreo. Sólo abordando estos desafíos clave pueden los hidrogeólogos contribuir al estado del arte de la contaminación microplástica y asegurar que las aguas subterráneas no sean descuidadas en las evaluaciones ambientales que abordan este contaminante de interés emergente....

Despite the European Nitrate Directive (ND) being issued almost 30 years ago, groundwater nitrate contamination is still a serious threat to ecosystems and human health. In one of the areas most affected by nitrates, the Lombardy Plain (Italy), the effectiveness of the ND and the capacity of governance to support its application correctly was assessed using a socio-hydrogeological approach. Nitrate trends over 11 years show that most regions present steady or increasing concentrations, highlighting how contamination can affect previously impaired situations and supposedly resistant and resilient aquifers. Stakeholder network analysis reveals that the governance framework does not support knowledge dissemination and changes in farmers’ attitudes, hindering water quality improvements. Nitrogen input needs to be reduced and manure relocation monitored. The local governance scale has a key role in enhancing ND dissemination. Reports to the EU Commission should integrate multi- or interdisciplinary evaluation of trends, including governance dynamics, alongside hydrochemical information.

Groundwater resources are connected with social, economic, ecological, and Earth systems. We introduce the framing of groundwater‐connected systems to better represent the nature and complexity of these connections in data collection, scientific investigations, governance and management approaches, and groundwater education. Groundwater‐connected systems are social, economic, ecological, and Earth systems that interact with groundwater, such as irrigated agriculture, groundwater‐dependent ecosystems, and cultural relationships to groundwater expressions such as springs and rivers. Groundwater‐connected systems form social‐ecological systems with complex behaviors such as feedbacks, nonlinear processes, multiple stable system states, and path dependency. These complex behaviors are only visible through this integrated system framing and are not endogenous properties of physical groundwater systems. The framing is syncretic as it aims to provide a common conceptual foundation for the growing disciplines of socio‐hydrogeology, eco‐hydrogeology, groundwater governance, and hydro‐social groundwater analysis. The framing also facilitates greater alignment between the groundwater sustainability discourse and emerging sustainability concepts and principles. Aligning with these concepts and principles presents groundwater sustainability as more than a physical state to be reached; and argues that place‐based and multifaceted goals, values, justice, knowledge systems, governance, and management must continually be integrated to maintain groundwater's social, ecological, and Earth system functions. The groundwater‐connected systems framing can underpin a broad, methodologically pluralistic, and community‐driven new wave of data collection and analysis, research, governance, management, and education. These developments, together, can invigorate efforts to foster sustainable groundwater futures in the complex systems groundwater is embedded within.

A replicable multidisciplinary approach is presented for science-based groundwater management practices: Bir Al-Nas (Bottom-up IntegRated Approach for sustainabLe grouNdwater mAnagement in rural areaS). This approach provides a practical example of the concept of “socio-hydrogeology”, a way of incorporating the social dimension into hydrogeological investigations, as reinforced by the translation of the Arabic bir al-nas: “the people’s well”. To achieve this, hydrogeologists act as “social hydrologists” during their monitoring activities, which often bring them into contact with local communities and end users (and polluters) of water. Not only can they retrieve reliable information about traditional know-how and local issues, but they can also change the public perception of science/scientists to create the basis for mutual collaboration and understanding in view of implementing improved integrated groundwater management. The final outcomes are expected to be an increased awareness of communities at the local level and a clear understanding of their water issues and needs from the very early stages of the investigation. Although the importance of using such methods in groundwater analysis and management is widely recognized, hydrogeological investigations are currently dominated by sectorial approaches that are easier to implement but less sustainable. The pressure of population growth, the shift towards more water-dependent economies, climate change and its impact on water availability will require scientists to use a more integrated approach, such as Bir Al-Nas, when dealing with increasing water pollution and water-scarcity issues. Une approche multidisciplinaire reproductible est présentée pour les pratiques scientifiques de gestion des eaux souterraines: Bir Al-Nas (de Bas en haut, IntégRée, Approche pour une gestion durabLe des eaux souterraiNnes en zones rurAleS). Cette approche fournit un exemple pratique du concept de « socio-hydrogéologie », une manière d’incorporer la dimension sociale dans les investigations hydrogéologiques, renforcée par la traduction de l’expression arabe bir al-nas : « puits du peuple ». Pour atteindre cet objectif, les hydrogéologues agissent comme des « hydrologues sociaux » au cours de leurs activités de suivi, qui les amènent souvent au contact avec les communautés locales et avec les utilisateurs finaux (et pollueurs) de l’eau. Non seulement ils peuvent récupérer des informations fiables sur les savoir-faire traditionnels et les enjeux locaux, mais ils peuvent aussi modifier la perception du public envers science/les scientifiques pour créer la base d’une collaboration et compréhension mutuelles en vue de mettre en œuvre une meilleure gestion intégrée des eaux souterraines. Les résultats finaux doivent permettre d’augmenter la prise de conscience des communautés au niveau local et une compréhension claire de leurs questions concernant la ressource en eau et de leurs besoins dès les premiers stades des investigations. Bien que l’importance de l’utilisation de telles méthodes dans l’analyse et la gestion des eaux souterraines soit largement reconnue, les investigations hydrogéologiques et hydrogéochimiques sont actuellement dominées par des approches sectorielles qui sont plus faciles à mettre en œuvre, mais moins durables. La pression de la croissance démographique, la transition vers des économies plus dépendantes de l’eau, et le changement climatique et son impact sur la disponibilité de l’eau exigeront des scientifiques l’utilisation d’une approche plus intégrée, comme celle de Bir Al-Nas, lorsqu’ils seront confrontés à des questions d’augmentation de la pollution et de pénuries d’eau. Se presenta un enfoque multidisciplinario replicable para las prácticas de gestión del agua subterránea basadas en la ciencia: Bir Al-Nas (enfoque integrado de abajo hacia arriba para la gestión sostenible del agua subterránea en las zonas rurales). Este enfoque proporciona un ejemplo práctico del concepto de “socio-hidrogeología”, una manera de incorporar la dimensión social en las investigaciones hidrogeológicas, que es reforzada por la traducción de los árabes de Bir al-nas: “bien para la gente”. Para lograr esto, los hidrogeólogos actúan como “hidrólogos sociales” durante sus actividades de monitoreo, lo cual a menudo los ponen en contacto con las comunidades locales y los usuarios finales (y contaminadores) de agua. No sólo pueden recuperar información fiable sobre conocimientos tradicionales y las cuestiones locales, sino que también pueden cambiar la percepción pública de la ciencia / científicos para crear una base para la colaboración y la comprensión mutua, en vista de la aplicación de una mejor gestión integrada del agua subterránea. Se espera que los resultados finales brinden una mayor conciencia de las comunidades a nivel local y una clara comprensión de sus problemas y necesidades de agua para las primeras etapas de la investigación. Aunque la importancia de la utilización de dichos métodos en el análisis y la gestión del agua subterránea es ampliamente reconocido, las investigaciones hidrogeológicas están dominadas actualmente por los enfoques sectoriales que son más fáciles de aplicar, pero menos sostenibles. La presión del crecimiento demográfico, el cambio hacia economías más dependientes del agua y el cambio climático y su impacto en la disponibilidad de agua requerirán a los científicos a utilizar un enfoque más integrado, como Bir Al-Nas, cuando se trata del aumentos de la contaminación del agua y problemas de escasez de agua. 本文展示了基于科学的地下水管理实践中的可复制的多学科方法:Bir Al-Nas方法(农村地区地下水可持续管理从细节到总体的综合方法)。这个方法提供了“社会-水文地质学”概念的实例,即把社会层面因素融入水文地质调查中,正如阿拉伯语Bir Al-Nas翻译强调的那样:“人民的井”。为了实现这个目标,水文地质学工作者在监测活动中担当着“社会水文地质工作者”,监测活动常常使他们与当地社区和水的终端用户(及污染者)接触。他们不但能获取传统诀窍及当地问题的可靠信息,而且能改变科学/科学家的公共认知,奠定在实施改进的综合地下水管理过程中相互协作和相互理解的基础。预期最终成果就是从调查的最初增强本地级的社区意识及水问题和需求的清晰认识。尽管在地下水分析和管理中使用此方法的重要性被广泛认可,但水文地质和水文地球化学调查目前仍受到部门方法的支配,部门方法较容易实施,但不可持续。人口增长的压力、向更加依赖水的经济上转移,气候变化及其对水资源可利用量的影响将要求科学家在处理日益增加的水污染和缺水问题时采用更加综合的方法,如Bir Al-Nas方法。 Bir Al-Nas (acronimo per “approccio integrato dal basso per una gestione sostenibile delle acque sotterranee in ambienti rurali”) è presentato come approccio multidisciplinare per la gestione delle acque sotterranee su basi scientifiche. Questo approccio fornisce un esempio pratico del concetto di “idrogeologia sociale”, un modo per integrare la dimensione sociale in studi idrogeologici, rafforzato dalla traduzione dell’arabo bir al-nas: “il pozzo della gente”. A tal fine, gli idrogeologi sono chiamati ad agire come “idrologi sociali” durante le loro attività di monitoraggio, che spesso li mettono in contatto con le comunità rurali e gli utenti finali (e inquinatori) delle acque. In questo modo essi possono non soltanto ottenere informazioni affidabili sulle conoscenze tradizionali e le problematiche locali, ma possono anche contribuire a modificare la percezione della scienza e degli scienziati, creando le basi per una comprensione e collaborazione reciproca finalizzata all’implementazione di nuove pratiche di gestione integrata delle risorse idriche. I risultati attesi sono una maggiore consapevolezza da parte delle comunità locali, associata ad una chiara comprensione dei loro problemi idrici e delle loro esigenze sin dalle prime fasi di uno studio. Sebbene l’importanza dell’utilizzo di una simile metodologia nell’analisi e nella gestione delle acque sotterranee sia ampiamente riconosciuta, gli studi idrogeologici e idrogeochimici sono attualmente dominati da approcci settoriali, più facili da realizzare, ma meno sostenibili. La pressione della crescita della popolazione, la transizione verso economie più dipendenti dall'acqua, il cambiamento climatico e il suo impatto sulla disponibilità idrica, richiedono quindi l’utilizzo di un approccio più integrato, quale Bir Al-Nas, per affrontare i problemi legati all’aumento dell’inquinamento ed alla scarsità delle risorse idriche. Uma abordagem multidisciplinar replicável é apresentada para práticas científicas de gestão de águas subterrâneas: Bir Al-Nas (Bottom-up IntegRated Approach for sustainabLe grouNdwater mAnagement in rural areaS - abordagem hierárquica integrada para a gestão sustentável de água subterrâneas em áreas rurais). Esta abordagem fornece um exemplo prático do conceito de “sócio-hidrogeologia”, uma maneira de incorporar a dimensão social em investigações hidrogeológicas, como reforçado pela tradução árabe da frase bir al-nas: “bem do povo”. Para atingir este objetivo, hidrogeólogos agem como “hidrólogos sociais” durante as suas atividades de monitoramento, que muitas vezes levam ao contato com as comunidades locais e com os usuários finais (e poluidores) da água. Eles não só podem recuperar informações confiáveis sobre o conhecimento tradicional e as questões locais, como também podem mudar a percepção pública da ciência/cientistas para criar a base da cooperação e compreensão mútua que visa a melhoria da gestão integrada das águas subterrâneas. Os resultados finais, a partir das fases iniciais de investigações, devem ajudar a aumentar a conscientização das comunidades locais e fornecer uma clara compreensão de seus problemas em relação a recursos hídricos e suas necessidades. Embora a importância do uso de tais métodos na análise e gestão das águas subterrâneas seja amplamente reconhecida, as investigações hidrogeológicas e hidrogeoquímicas estão atualmente dominadas por abordagens setoriais que são mais fáceis de se realizar, mas são menos sustentáveis. A pressão do crescimento populacional, a transição para economias mais dependentes de água e as alterações climáticas, com seus impactos sobre a disponibilidade hídrica, exigirá dos cientistas o uso de uma abordagem mais integrada, como a Bir al-Nas, quando confrontados com questões de aumento da poluição e escassez de água.