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ZAGREB, 7 September 2026 (Croatia Week) – New expert findings released by Croatia’s anti-corruption office USKOK today have highlighted environmental risks associated with improperly stored and disposed waste at sites in Varaždin and Gospić, including the detection of microplastic particles in groundwater.
USKOK published the findings following significant public interest in an investigation into a suspected criminal group allegedly involved in a number of offences against the environment and economy. The investigation concerns waste management activities at several locations in Croatia.
The latest expert analyses were prepared by the Faculty of Geotechnical Engineering in Zagreb for the Varaždin site and the Josip Juraj Strossmayer Institute for Water Management for groundwater samples from the Gospić area.
More than 1,300 tonnes of waste in Varaždin
At the site of the former Florijan Bobić factory in Varaždin, experts identified two areas where waste had been improperly deposited.
The northern area contains an estimated 1,352 tonnes of mixed waste. Analysis found microplastic, microbiological contamination and elevated levels of dissolved organic carbon (DOC), with some samples exceeding limits applicable to hazardous waste.
A further at least 30 tonnes of sludge-like material containing antimony was identified in the southern area.
The current contamination is described as largely localised, with no evidence found of its spread towards the Bartolovec water supply area or nearby protected areas.
However, experts identified a significant potential risk because the waste is located above an unprotected aquifer without a sealing layer.
In the event of flooding, pollutants and microplastic could potentially be washed from the site and transported towards the Drava River. The expert assessment states that urgent removal of the waste and remediation of the soil would be necessary to prevent longer-term environmental damage.
Microplastic detected in Gospić groundwater
The findings from the Gospić area provide further evidence of concern.
Groundwater samples taken on 8 May 2026 from three piezometric wells at Divоsel, near the waste site known as Silos Velebit, were analysed for microplastic.
Across six samples, researchers identified 610,696 particles, of which 426,500 were confirmed using Raman spectroscopy. Detailed analysis identified 148 particles belonging to priority polymers, classified as microplastic.
The highest concentration was recorded at the Trag K monitoring location, which accounted for 132 of the 148 confirmed priority polymer particles, or 89.2%.
Two samples from Trag K produced particularly different results.
One sample contained just two particles, but both were large polystyrene particles, resulting in a high measured mass concentration of 737.155 micrograms per litre.
Another sample contained 130 smaller particles, including 102 polystyrene particles, 20 polyethylene particles, six PET particles and two polypropylene particles.
Considerably less microplastic was found at the other monitoring points. Six particles were detected in one Trag N sample, while none were found in the other. At Trag O, one sample contained no microplastic and another contained ten polypropylene particles at a very low mass concentration.
The absence of polystyrene at Trag N and Trag O, despite its strong presence at Trag K, was identified as a possible indication of a localised source of contamination near Trag K.
The Institute concluded that there is a spatial connection between the surface area investigated and the presence of polymer material in groundwater, identifying the area as the most likely source of contamination of the groundwater system.
Experts recommended long-term systematic monitoring of groundwater to determine whether microplastic is appearing continuously, at what concentrations, and whether its presence follows patterns associated with rainfall and other hydrological conditions.
The findings form part of a wider USKOK investigation into suspected illegal waste-management activities. USKOK has previously alleged that waste was improperly stored or disposed of at locations in Varaždin, Gospić and Benkovac, with investigators examining suspected environmental and economic offences.
USKOK has made the expert documentation available to the public in response to the level of public interest.