Microplastics in the Baltic Sea: A Growing Threat to Health & Environment

The Baltic Sea is facing a growing, and often underestimated, threat from microplastic pollution, compounded by the unique characteristics of the semi-enclosed sea and the increasing presence of nanoplastics. Scientists are raising alarms about the potential impact on marine ecosystems and, human health, as these particles enter the food chain and water supply.

According to researchers at TalTech’s Marine Systems Institute, the problem extends far beyond visible plastic debris. Microplastics – tiny plastic particles invisible to the naked eye – are now found in seawater, sediment, the atmosphere, and even within living organisms. “Everything we introduce into the environment and the sea eventually returns to us through the cycle – via food, water, air, and the entire environment,” explains Natālija Buhalko, a scientist at the institute’s Marine Ecology Laboratory. “Microplastic is not a distant or abstract problem – it directly affects our health, well-being, and future. The sooner we start addressing this issue, the greater our chances of preserving the world’s seas and keeping ourselves healthier.”

The Baltic Sea’s limited water exchange exacerbates the issue. Buhalko notes that the slow rate of water circulation means that pollutants, including microplastics, remain in the environment for exceptionally long periods, potentially indefinitely. “Microplastic isn’t just small pieces of plastic; it contains additives used in plastic production that can affect both marine organisms and terrestrial animals, as well as us,” she states. These additives, along with the microplastics themselves, act as vectors for harmful substances.

Bacteria, fungi, dangerous chemicals, and heavy metals readily attach to the surface of microplastics, effectively turning them into “transport platforms” within the aquatic environment. This facilitates the spread of pathogens and hazardous materials to areas they might not otherwise reach. The impact on marine life is already being observed. Buhalko reports that microplastics affect plankton, fish, birds, and benthic fauna, altering their behavior, energy levels, and even reproductive capabilities.

Evidence of microplastic contamination has been found in Baltic Sea fish, shellfish, and other organisms, as well as in beach sand and even the air. This airborne dispersal means particles are carried by wind, reaching diverse environmental areas far from their original source. A particularly concerning discovery, according to Buhalko, is the presence of microplastics in areas with minimal human activity, highlighting the speed and range of plastic transport and the difficulty in pinpointing its origins.

The situation is expected to worsen with the emergence of nanoplastics – even smaller particles that are more difficult to detect and can penetrate cells and tissues more deeply than microplastics. Research into nanoplastics is ongoing, but requires more sophisticated analytical methods and standardized protocols. Scientists are also calling for more thorough investigation into the actual physiological, metabolic, and behavioral impacts of microplastics on organisms and food chains.

“These research areas already exist, but they are becoming more systematic in order to reach stronger conclusions regarding both environmental and health risks,” Buhalko says. She emphasizes the importance of understanding the socio-economic implications of microplastic pollution, including the economic costs associated with mitigation and the health risks it poses.

Addressing the problem requires international collaboration. “Microplastic transcends borders, so it cannot be studied in just one country or laboratory,” Buhalko asserts. “Collaboration between scientists is crucial: it allows us to share methods, data, and experience, and to create European-scale monitoring networks.”

The need for new scientists specializing in marine research is also paramount. The Baltic Sea, Buhalko describes, is a “living laboratory” – dynamic, scientifically fascinating, yet fragile. Students pursuing marine ecology or marine systems can focus on critical questions of sustainable sea conservation, biodiversity protection, and minimizing human impact.

One example of the next generation of researchers is Ida Virunurm, a student at TalTech’s Geology Institute, who became interested in microplastics during an internship. Her bachelor’s thesis focused on microplastics in the surface layer of the sea. Virunurm highlights the novelty of the field, noting that widespread plastic use only began in the mid-20th century, while the presence of microplastics was only discovered in the early 21st century. This relative newness makes research into the quantity and impact of microplastics both necessary and compelling.

Virunurm’s research includes collecting samples from rainwater runoff in Tallinn. “In one sampling location where rainwater flows directly into the sea, we found a couple of hundred small plastic particles in twenty liters of water,” she reports. “This experience makes you think about how much plastic actually ends up in the sea.”

Globally, plastic production has surged to over 380 million tons per year, with more plastic produced in the last decade than during the entire 20th century. Many plastic products have a short lifespan, while their persistence in the environment is long. According to data from the Organisation for Economic Co-operation and Development (OECD), less than 10% of plastic waste is recycled worldwide, resulting in increasing amounts of waste entering the environment each year.

In Estonia, the volume of plastic packaging waste nearly doubled between 2004 and 2021. While the rate of waste generation has decreased in recent years, falling from 66,000 tons in 2017 to 50,000 tons in 2021, waste generation is still increasing faster than recycling rates. Per capita plastic packaging waste in Estonia rose from 21.2 kg in 2004 to 37.6 kg in 2021, placing the country seventh among European Union member states. Ireland, Portugal, Germany, Denmark, Sweden, and Italy all generate more waste per capita.

Alongside the increase in plastic packaging waste in Estonia, recycling rates have also risen, from 2.6 kg per capita in 2004 to 16 kg in 2021. However, waste generation continues to outpace recycling efforts.