Finnish aquatic animals, lake and seabeds, fish and molluscs have been contaminated with microplastics, according to a four-year research project recently decided by the Finnish Environment Institute (SYKE) and the University of Eastern Finland.
“The smaller the microplastic studied, the higher concentrations were observed because the plastics continuously decompose into smaller particles in the environment,” explained Maiju Lehtiniemi, research professor at the institute.
According to the report, most of the microplastics were found in mussels that filter water to get food.
Relatively high concentrations of microplastic particles were observed in local coastal sediments. The amounts correspond to the levels of coastal sediments in Norway and the southern Baltic Sea.
The study was conducted mainly in the Baltic Sea and Kallavesi in Eastern Finland.
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Significant differences in microblast levels found in fish were observed in the results, both regionally and between species.
Herring, Baltic sprat and a three-wire ball found only a small amount of plastic on the high seas. However, there was considerably more abundance of microplastic in European perch, the usual gloomy and three-branched rear on the Finnish coast, and in European perch and vendace in Kallavesi.
About nine percent of the marine fish were contaminated with plastic. In Kallavesi, 17 per cent of perch and one in four vultures had consumed plastic.
However, Lehtiniemi assured that eating fish is still safe.
“Some fish had no plastic at all, others had a lot. You donโt have to think about enjoying this fish. The fish is healthy – the micro-plastics found do not change” he said.
The study also performed laboratory experiments on small planktonic crustaceans. They died or their stress levels rose when they were exposed to car tire rubber and frozen vegetable bags with food scraps.
Rainwater carries plastics
The largest sediment microplastic study was carried out in Porvoo on the outskirts of the Kilpilahti area – 22 microplastic particles per gram of dry sediment. In other coastal areas, researchers recorded less than 10 particles per gram of dry sediment.
An average of 16 particles per seawater were found at coastal sampling stations.
According to SYKE, microplastics end up in water systems from the ground, especially through flowing water from urban environments.
“One of the most important routes is rainwater – rain and meltwater from agglomerations. We need more research, especially into microplastics emissions from transport,” investigator Julia Talvitie said.
Polyethylene most common in waterways
Project researchers developed specific methods for studying the types of plastics found in the samples.
Polyethylene (PE) was often a rich type of plastic in the samples. The various forms of PE are the most widely used plastic raw materials in the world.
The most common types of plastics were found in the samples in both the Baltic Sea and Lake Kallavesi, as well as in fish and benthos,” said Arto Koistinen, SIB Labs and University of Eastern Finland sub-project director.
Source: The Nordic Page