Viviana Re

Nitrogen inputs to a river course in a heavily impacted watershed: A combined hydrochemical and isotopic evaluation (Oglio River Basin, N Italy)

This study aims at evaluating sources and processes affecting NO₃(-) concentrations in the Oglio River. Five sampling campaigns considered the main watercourse, tributaries, point pollution sources, springs, and groundwater. Physico-chemical parameters, N forms, B, Sr(2+), stable isotopes (δ(2)HH₂O, δ(18)OH₂O, δ(15)NNO₃, δ(18)ONO₃, δ(11)B) and discharge were measured. Hydrological modelling was performed using mass balance and End Member Mixing Analysis equations. During the irrigation period, in the upstream reach, up to 90% of the natural river flow is diverted for irrigation and industrial purposes; excess water drained from agricultural fields is returned to river in the downstream reach. Results evidenced, in the middle reach, a large input of NO₃(-)-rich groundwater which could be quantified using hydrological modelling. Groundwater inputs are responsible for the sharp, tenfold increase in NO₃(-) in the river water, from 2.2-4.4 up to 33.5 mgL(-1), and are more evident in summer, when discharge is lower. Nevertheless, river water preserves its natural B isotopic composition, indicating that the two tracers do not have a common origin and are not co-migrant. In the lower plain, surface-groundwater interconnections and human disturbances in the water cycle favour the recycling of the compounds in the environment, and lead to a similarity in composition of the different water bodies (Oglio River, tributaries and groundwater). The long lasting agronomical practices have profoundly modified the surface-groundwater equilibrium and chemical characteristics, resulting in a highly buffered system. Infiltrating irrigation water leaches down NO₃(-) which is subsequently denitrified; when returned to the Oglio River, groundwater modifies the river water composition by dilution, in the case of NO₃(-), or by addition, for other constituents (e.g. Cl(-), B). The results of this study indicate that, in order to reduce the NO3(-) transport towards the Adriatic Sea, groundwater contamination should be addressed first, with expected long recovery times.

Integrated socio-hydrogeological approach to tackle nitrate contamination in groundwater resources. The case of Grombalia Basin (Tunisia)

Nitrate contamination still remains one of the main groundwater quality issues in several aquifers worldwide, despite the perduring efforts of the international scientific community to effectively tackle this problem. The classical hydrogeological and isotopic investigations are obviously of paramount importance for the characterization of contaminant sources, but are clearly not sufficient for the correct and long-term protection of groundwater resources. This paper aims at demonstrating the effectiveness of the socio-hydrogeological approach as the best tool to tackle groundwater quality issues, while contributing bridging the gap between science and society. An integrated survey, including land use, hydrochemical (physicochemical parameters and major ions) and isotopic (δ15NNO3 and δ18ONO3) analyses, coupled to capacity building and participatory activities was carried out to correctly attribute the nitrate origin in groundwater from the Grombalia Basin (North Tunisia), a region where only synthetic fertilizers have been generally identified as the main source of such pollution. Results demonstrates that the basin is characterized by high nitrate concentrations, often exceeding the statutory limits for drinking water, in both the shallow and deep aquifers, whereas sources are associated to both agricultural and urban activities. The public participation of local actors proved to be a fundamental element for the development of the hydrogeological investigation, as it permitted to obtain relevant information to support data interpretation, and eventually guaranteed the correct assessment of contaminant sources in the studied area. In addition, such activity, if adequately transferred to regulators, will ensure the effective adoption of management practices based on the research outcomes and tailored on the real needs of the local population, proving the added value to include it in any integrated investigation.

Topical Collection: Climate-change research by early-career hydrogeologists

Scientific outreach, international networking, collaboration and adequate courses are needed in both developed and developing countries to enable early-career hydrogeologists to promote long-term multidisciplinary approaches to cope with climate-change issues and emphasize the importance of groundwater in a global strategy for adaptation. One such collaboration has involved the Early Career Hydrogeologists’ Network of the International Association of Hydrogeologists (ECHN-IAH) and the UNESCO International Hydrological Programme’s (IHP) Groundwater Resources Assessment under the Pressures of Humanity and Climate Changes (GRAPHIC) project. This collaboration seeks to foster the education and involvement of the future generation of water leaders in the debate over groundwater and climate change.RésuméLe rayonnement scientifique, le réseautage international, la collaboration et des cursus de formation adéquats sont nécessaires dans les pays développés et en développement permettre aux hydrogéologues en début de carrière de promouvoir des approches multidisciplinaires à long terme pour faire face aux questions de changement climatique et insister sur l’importance des eaux souterraines dans une stratégie globale d’adaptation. L’une de ces collaborations a impliqué le réseau des hydrogéologues en début de carrière de l’association internationale des hydrogéologues (RHDC-AIH) et le projet d’évaluation des ressources en eau souterraine sous contraintes de l’humanité et des changements climatiques (GRAPHIC) du programme hydrologique international de l’UNESCO (PHI). Cette collaboration vise à favoriser l’éducation et la participation de la génération future des leaders du domaine de l’eau dans le débat concernant les eaux souterraines et le changement climatique.ResumenLa divulgación científica, la creación de redes internacionales, la colaboración y cursos adecuados son necesarios tanto en países desarrollados como en desarrollo para permitir a los hidrogeólogos jóvenes a promover enfoques multidisciplinarios a largo plazo para hacer frente a los problemas del cambio climático y enfatizar la importancia del agua subterránea en una estrategia global de adaptación. Una de estas colaboraciones ha sido la Early Career Hydrogeologists’ Network de la Asociación Internacional de Hidrogeólogos (ECHN-IAH) y el proyecto Pressures of Humanity and Climate Changes (GRAPHIC) de la UNESCO International Hydrological Programme’s (IHP) Groundwater Resources Assessment. Esta colaboración busca fomentar la educación y la participación de la futura generación de líderes del agua en el debate sobre las aguas subterráneas y el cambio climático.摘要发达国家和发展中国家需要科学上的延伸、国际网络化、合作及充足的课程,使青年水文地质学家能够促进长期多学科方法应对气候变化问题,在全球适应战略中强调地下水的重要性。一项这样的合作涉及国际水文地质学家协会青年水文地质学家网络及联合国教科文组织的人类和气候变化压力下水文计划地下水资源评价项目。这项合作寻求地下水和气候变化争论中有关未来一代水领导的教育和参与问题。RiassuntoDivulgazione scientifica, networking internazionale, collaborazione e corsi di formazione sono elementi necessari, sia nei paesi avanzati che in quelli in via di sviluppo, per premettere ai giovani idrogeologi di promuovere ricerche multidisciplinari volte ad affrontare le emergenze associate ai cambiamenti climatici e ad enfatizzare l’importanza delle acque sotterranee nelle strategie di adattamento globale. Una collaborazione di questo tipo ha coinvolto l’Early Career Hydrogeologists’ Network della Associazione Internazionale di Idrogeologia (ECHN-IAH) e il gruppo “Valutazione delle risorse idriche sotterranee sotto le pressioni dell’umanità e cambiamenti climatici” (Groundwater Resources Assessment under the Pressures of Humanity and Climate Changes - GRAPHIC) del Programma Idrogeologico Internazionale (IHP) dell’UNESCO (UNESCO-IHP). Questa collaborazione mira a promuovere l’educazione e il coinvolgimento della futura generazione di leader dell’acqua nel dibattito sulle acque sotterranee e sui cambiamenti climatici.ResumoDivulgação científica, trabalhos em redes internacionais, colaboração e cursos adequados são necessários tanto nos países desenvolvidos como nos países em desenvolvimento para permitir que os hidrogeólogos em início de carreira promovam abordagens multidisciplinares de longo prazo para lidar com questões de mudança climática e enfatizem a importância das águas subterrâneas em uma estratégia global de adaptação. Uma dessas colaborações envolveu a Rede de Hidrogeólogos em início de carreira da Associação Internacional de Hidrogeólogos (ECHN-IAH) e o Programa Hidrológico Internacional da UNESCO (IHP) com o projeto sobre Avaliação dos Recursos Hídricos Subterrâneos sob Pressões da Humanidade e Mudanças Climáticas (GRAPHIC). Esta colaboração busca promover a educação e o envolvimento da geração futura de líderes da água no debate sobre as águas subterrâneas e as mudanças climáticas.