NEWS: TETHYS4ADRION: Winter Monitoring Completed on All 5 Pilot Rivers
During January and February 2026 winter monitoring was conducted on five pilot rivers across seven countries in the Adriatic-Ionian region, as part of the TETHYS4ADRION project.
The monitoring was carried out in accordance with agreed protocols, which will be presented in the Toolkit for Monitoring Riverine Litter in a Harmonised Way.
Monitoring on the Alfeios River, Greece
On February 16–19, the first winter monitoring campaign took place along the Alfeios River, in the Peloponnese, Greece. The monitoring was led by project partners from the Mediterranean Information Office for Environment, Culture and Sustainable Development (MIO-ECSDE) and the Hellenic Center for Marine Research (HCMR).
The field mission combined floating macrolitter surveys and floating microlitter sampling with drone surveys to identify areas affected by plastic pollution and to measure surface flow velocity using LSPIV techniques.
- Parts of the Alfeios River experienced extreme flooding during the mission, with water depths reaching up to 4 meters due to recent storms in Western Greece.
- Based on the first-ever floating macrolitter surveys conducted in the Alfeios River, the litter flux was calculated at 96 items per hour.
- The composition of the litter aligned with preliminary results observed last year along the riverbanks and at the outflow, consisting primarily of plastic fragments, drink bottles, cups, and lids.
Data from HCMR’s automatic monitoring stations recorded rapid and pronounced rises in water levels along the river. As a result, some planned macro-, meso-, and microlitter surveys on riverbanks were postponed.
The JRC Floating Litter Monitoring App was used during the monitoring. Photo: Thomais Vlachogianni
Monitoring on the Bojana – Buna River (Montenegro and Albania)
The project partners from the Institute of Marine Biology of the University of Montenegro and the University of Tirana, conducted winter monitoring on the Buna–Bojana pilot river, which forms the natural border between Montenegro and Albania.
The monitoring was carried out separately in the territories of the two countries.
Bojana River, Montenegro
On February 26, winter monitoring was carried out on the Bojana–Buna pilot river in Montenegro. It took place at Ada Bojana Beach, located at the river mouth to the Adriatic Sea, in the Municipality of Ulcinj. The monitoring was led by project partners from the Institute of Marine Biology of the University of Montenegro.
The field mission combined floating macrolitter monitoring using the visual census method, sampling of macro-, meso-, and microplastics along transects, and floating microplastic sampling using a manta plankton net to assess the quantity, composition, and spatial distribution of micro-, meso-, and macrolitter.
- Macroplastics on the beach were sampled along a 100-meter transect extending from the shoreline to the first vegetation line.
- Mesoplastics were sampled within the same transect across five evenly spaced parallel strips, each 0.5 meters wide.
- Microplastics in beach sediment were sampled at three positions: near the shoreline, in the middle section of the beach, and in the backshore area.
A large amount of macrolitter, predominantly plastic, was observed in the backshore area, likely resulting from debris transported and deposited following adverse weather conditions during the previous months.
Mesoplastic sampling on Ada Bojana Beach in Montenegro. Photo: Ana Pešić
Buna River, Albania
On February 20–21, winter monitoring was carried out on the Buna–Bojana pilot river in Pulaj and Velipojë, Albania, led by project partners from the University of Tirana.
The field mission focused on sampling along the riverbanks to assess the quantity and composition of macro-, meso-, and microlitter.
- Plastic was the dominant material, including plastic bottles, shopping bags, styrofoam fragments, and mixed plastic debris.
- Significant amounts of waste were recorded at the Pulaj location.
- Monitoring was completed after multiple postponements due to heavy rain and flooding.
This was the first application of a harmonized, EU-aligned protocol and riverine litter monitoring methodology in Albania.
Litter sampling on the banks of the Buna River. Photo: Elda Marku
Monitoring on the Neretva River, Bosnia and Herzegovina and Croatia
On February 2–4, project partners from the Institute of Oceanography and Fisheries Split (IOR), with assistance from the project partners from the City of Metković and the City of Čapljina, carried out the first winter monitoring on the Neretva River, covering areas in both Bosnia and Herzegovina and Croatia. They were joined by the Professional Firefighting Unit of the City of Čapljina.
The fieldwork combined the assessment of composition and quantities of macrolitter deposited along the shoreline, floating macrolitter, monitoring of mesolitter both along the shoreline and on the water surface, and the monitoring of microplastics in sandy coastal sediment and on the water surface.
- Significant amounts of litter were recorded at most locations, especially floating debris near the Metković bridge.
- Plastic was the dominant material, including shopping bags, agricultural plastic films, styrofoam fragments, and mixed debris.
- Burned plastic fragments were observed, highlighting improper waste management practices.
- High water levels and fast river flow caused by heavy rainfall were recorded on site.
Key areas included the mouth of the Neretva, Krvavac settlement, Metković bridge (Croatia), bridges in Čapljina and Žitomislići, and riverbanks in Ševaš Njive and Čapljina (Bosnia and Herzegovina).
Project partners from the Institute of Oceanography and Fisheries with the Professional Firefighters Unit from the City of Čapljina. Photo: Ana-Marija Prović
Monitoring on the Reno River, Italy
On January 27–28, project partners from the Italian Institute for Environmental Protection and Research (ISPRA) carried out the first winter monitoring on the Reno River, focusing on the areas surrounding the river’s mouth and near Bologna, Italy.
Researchers monitored both floating macrolitter and macrolitter deposited along the riverbanks at five locations characterized by varying levels of human pressure, to assess litter composition.
- Polystyrene fragments were predominantly detected at sampling stations closer to the river mouth.
- Plastic bags and plastic sheet fragments were more frequently observed upstream, particularly near urban areas in the vicinity of Bologna.
The survey took place shortly after a period of heavy rainfall, during which the Reno River experienced elevated water levels and flood-like conditions.
The ISPRA team collected macrolitter along the banks of the Reno River. Photo: Roberto Crosti
Monitoring on the Soča-Isonzo River, Slovenia and Italy
On January 20 and 22, project partners from the Institute for Water of the Republic of Slovenia (IZVRS) conducted winter monitoring of plastic litter on the Soča–Isonzo pilot river, with assistance from project partners at the National Institute of Chemistry (KI) and ISPRA, and ARPA FVG. Monitoring was carried out at two locations in western Slovenia, Deskle and Kamno, and at the Pieris site in northeastern Italy.
The field mission combined sampling of meso- and macrolitter on the riverbanks, floating macrolitter, and microlitter from the water, and visual monitoring of macrolitter from the bridge.
- The water level of the river was low at all locations.
- No floating macrolitter was observed at any of the sites over the course of one hour of visual census.
TETHYS4ADRION Team on the Soča-Isonzo River, at the Pieris Site in Italy. Photo: Andrej Kržan
The collected samples were sent for laboratory analysis.
As part of the project, spring, summer, and autumn monitoring will follow on the five pilot rivers.
This has been produced with the financial assistance of the European Union. The content of the website is the sole responsibility of TETHYS4ADRION project and can under no circumstances be regarded as reflecting the position of the European Union and/or IPA ADRION programme authorities.