Ecotoxicology of Microplastics
and Small-boat harbours

Microplastics are an emerging contaminant and environmental stressor. Our understanding of the impacts of different types of microplastics on aquatic life is still limited. Our working group is focusing on experimental work (with Gammarids and Gmelinoides), studying long-term effects in environmentally relevant concentrations. In addition, we have been studying concentrations of microplastics in the coastal areas of the Baltic Sea and small-boat harbours of Estonia. 

In a microplastic (MP) toxicity study involving environmentally relevant concentrations in Amphipods we saw increased mortality at 2 mg/L LDPE MP exposure (in case of Gammarus lacustris also at 2 μg/L). The effect of LDPE on swimming activity was observed in Gmelinoides fasciatus. Oxidative stress marker enzymes SOD, GPx and reduced glutathione GSH varied according to amphipod species and LDPE MP concentration.  

Study focusing on coastal areas revealed a high abundance of microplastics in seagrass beds in the Baltic Sea, Estonia. Sediments had 208 pieces of microplastics per kilogram, which is much higher than previously recorded from adjacent unvegetated and offshore sediments. Blue fibres were the prevalent microplastic in both water and sediments and this was the first microplastic abundance study in seagrass beds in the Baltic Sea.

Currently, a new study focusing on pollution effects (contaminants and microplastics) of a small-boat harbours is beginning, funded by Estonian Environmental Investment Centre. University of Tartu project „Effect of contaminant load from Estonian small harbours and measures to reduce it“ helps to find solutions and alternatives to the toxic pollution originating from the small-boat harbours. During the course of the project soil and water samples are collected from 12 small-boat harbours, and also a laboratory experiment will be conducted:

 – First, pollution effects are in focus. Microplastic pollution is being analysed in the harbour areas (fibres from sails and lines), also contaminants orginating from antifouling paints and fuels (containing copper and zinc and organic tin). The aim is to find out how differences in planning and construction of harbours affect the amount of toxicants reaching the marine environment.

– In the second, experimental part, the effect of antifouling paints on fish olfaction will be tested in Tartu University. The purpose is to see if the ecologically certified antifouling paints indeed work as less harmful alternatives. From the previous studies it is known that heavy metals (especially copper) interfere the olfactory cells to receive important signals (e.g. food, conspecifics). Less is known about the safety of the alternative paints.

As a result of the study the pollution overview of Estonian small-boat harbours will be finalised and suitable measures noted, to reduce the effect to aquatic organisms. These results can be used in planning of the future harbour remediation and reconstruction works.