The new report from the collection ‘Science for Public Policies’ gathers existing scientific evidence about the increasing salt concentration in freshwater ecosystems. It explains the main causes and impacts of this issue while proposing measures to mitigate this growing global problem.
The salinization of inland water ecosystems is one of the most widespread and overlooked environmental and social threats of this century. It is a global problem, although its impact is uneven: it occurs mainly in arid areas and in regions with less control over human activities that cause or exacerbate it.
Human activities contributing to salinization include overexploitation of water resources, mining, intensive agriculture (particularly irrigation) and farming, and industrial processes that generate saline waste (e.g., desalination plants, which produce large amounts of brine that end up in ecosystems). The report also highlights other salinization causes directly linked to human activities, such as wastewater discharge from treatment plants into rivers. Adding to these is climate change, another human-induced factor: intensified droughts, other extreme weather events, and rising sea levels exacerbate salinization.
In Spain, an estimated 28% of the hydrographic network has concerning levels of salinity. As in the rest of the world, the impact is uneven, with some areas severely affected and others less so (or not yet). In regions with higher salt concentrations, there has been a drastic decline in biodiversity, with the loss of species unable to survive in saline environments. This severely impacts ecosystem functioning and the benefits they provide, known as “ecosystem services,” such as water purification and climate regulation (higher greenhouse gas emissions have been observed in highly saline areas).
Increased salt concentration in rivers, lakes, wetlands, and aquifers also poses direct negative consequences for humans. Excessive salinity in drinking water leads to health problems such as kidney dysfunction, preeclampsia, hypertension, and other cardiovascular diseases. There are also socioeconomic repercussions, as many activities are affected.
The anthropogenic salt cycle | Author: CEAB-CSIC
This information is detailed in the report “When Freshwater Becomes Salty: Scientific and Management Challenges for Aquatic Ecosystems” from the CSIC’s Science for Public Policies series. The report highlights the causes and consequences of freshwater salinization, a problem that continues to worsen globally. Editor for, among others, CEAB-CSIC researcher Eugènia Martí, the document also proposes strategies to combat this issue, providing crucial information to guide public policies and private actions to mitigate it.
Recommendations for action
The report emphasizes the need for further research to better understand the mechanisms and impacts of salinization while urging the application of existing scientific knowledge to design and implement solutions.
It calls for regulatory changes, such as lowering the permissible water conductivity levels, which are currently above those deemed safe for biodiversity. It also suggests numerous specific measures to reduce salt emissions, targeting both public and private sectors. For example, it recommends sustainable methods for agriculture and for industry, using “backfilling” techniques in mining or, to mention one of the simplest recommendations, replacing road salt with biodegradable alternatives during icy conditions.
In short, the document offers tangible solutions to address freshwater salinization. It advocates for protecting vulnerable ecosystems and adopting a new model based on the rational and sustainable use of natural resources, recognizing the inseparable link between human and ecosystem health.
“Salinization affects not only nature but also human communities that depend on these resources and the environment,” states one of the researchers who wrote the report. “It is urgent to integrate this issue into climate and environmental agendas,” stresses Eugènia Martí (CEAB-CSIC).
The report contains solid scientific evidence generated in CSIC centers and institutes, compiled, prioritized, and analyzed by a team of experts. Scientific knowledge has been transformed into accessible insights for a non-specialized audience, guiding public policies, private-sector actions, and citizen initiatives. Thus, it serves as a tool for administrations, companies, organizations, and individuals interested in addressing this environmental and social challenge.
The document has been prepared by the researchers: Miguel Cañedo-Argüelles (IDAEA-CSIC), Eugènia Martí Roca (CEAB-CSIC), Miguel G. Matias (MNCN-CSIC) and Marta I. Sánchez (EBD-CSIC).
Download Full Report here:
Original article published in CEAB-CSIC
