3,500 kilometers, 100 samples and 100 hours ofscience: The outcomes of the SUNDANSE Danube Expedition aboard REXDAN

In June 2026, a team of European experts working under the EU-funded SUNDANSE
project embarked on an international scientific voyage aboard the REXDAN, Europe’s
most advanced freshwater research vessel.

Navigating a 3,500-kilometre round trip along the Danube River from Romania to
Austria and back, an international team of researchers spent 100 operational hours
conducting intensive, real-time scientific analysis directly on the water. The expedition
marked a major step forward in addressing the Danube River-Black Sea system’s
critical environmental challenges, specifically the disruption of its natural sediment
balance. During the mission, scientists successfully collected 100 sediment and water
samples across key demonstration sites and observation points in Romania, Bulgaria,
and Serbia.

While initial toxicity screening and immediate sample preparations were conducted in the
vessel’s specialised onboard laboratories during the voyage, post-mission laboratory
analyses are currently in progress.
Researchers are analysing the samples for a comprehensive range of environmental
parameters, including:

• Microplastics and sediment particle size distribution,
• Heavy metals and chemical pollutants,
• PAHs (Polycyclic Aromatic Hydrocarbons) and PCBs (Polychlorinated Biphenyls),
• Pesticides and emerging contaminants, such as tire additives.

Initial findings are currently undergoing rigorous data evaluation to build a high-resolution
map of the Danube’s environmental health.

Beyond its technical achievements, the voyage served as a platform for regional
engagement, welcoming around 300 diverse stakeholders aboard during dedicated
stops in Novi Sad (Serbia), Budapest (Hungary), Bratislava (Slovakia), and Vienna
(Austria). The vessel’s doors were opened to public authority representatives, local
decision-makers, high school groups, and university students specialising in environmental
protection, biology, and medicine. The mission attracted high-level diplomatic and
political attention, featuring visits from key leaders driving European river policy.

With the physical voyage complete, the SUNDANSE consortium is shifting focus toward
data modeling and regional knowledge sharing. By combining 100 hours of onboard
laboratory research with high-level stakeholder dialogue, this mission demonstrated the
power of transboundary scientific collaboration. The final outcome will represent a
dataset that will directly inform the future management and protection of the Danube
River Basin.

The SUNDANSE mission supports the EU’s “Restore our Ocean and Waters” goal, aiming
to protect freshwater ecosystems and foster a climate-neutral blue economy by 2030.

ADDITIONAL INFORMATION

The SUNDANSE project is a Horizon Europe initiative involving 19 partners from 10
countries. It focuses on innovative sediment management to ensure a sustainable future
for the Danube-Black Sea system.

Website: www.sundanseproject.eu
LinkedIn: www.linkedin.com/company/sundanse/
Facebook: https://www.facebook.com/sundanseproject/
Zenodo: https://zenodo.org/communities/sundanse/records