Geosynthetic materials are applied in measures for coastal protection. Weathering or any damage of constructions, as shown by a field study in Kaliningrad Oblast (Russia), could lead to the littering of the beach or the sea (marine littering) and the discharge of possibly harmful additives into the marine environment. The ageing behavior of a widely used geotextile made of polypropylene was studied by artificial accelerated ageing in water-filled autoclaves at temperatures of 30 to 80 °C and pressures of 10 to 50 bar. Tensile strength tests were used to evaluate the progress of ageing, concluding that temperature rather than pressure was the main factor influencing the ageing of geotextiles. Using a modified Arrhenius equation, it was possible to calculate the half-life for the loss of 50% of the strain, which corresponds to approximately 330 years. Dynamic surface leaching and ecotoxicological tests were performed to determine the possible release of contaminants. No harmful effects on the test organisms were observed.

Microplastic concentrations in surface water and wastewater collected from Daugavpils and Liepaja cities in Latvia, as well as Klaipeda and Siauliai cities in Lithuania, were measured in July and December 2021. Using optical microscopy, polymer composition was characterized using micro-Raman spectroscopy. The average abundance of microplastics in surface water and wastewater samples was 16.63 ± 20.29 particles/L. The dominant shape group of microplastics in water was fiber, with dominant colors found to be blue (61%), black (36%), and red (3%) in Latvia. Similar distribution in Lithuania was found, i.e., fiber (95%) and fragments (5%) with dominant colors, such as blue (53%), black (30%), red (9%), yellow (5%), and transparent (3%). The micro-Raman spectroscopy spectra of visible microplastics were identified to be polyethylene terephthalate (33%) and polyvinyl chloride (33%), nylon (12%), polyester (PS) (11%), and high-density polyethylene (11%). In the study area, municipal and hospital wastewater from catchment areas were the main reasons for the contamination of microplastics in the surface water and wastewater of Latvia and Lithuania. It is possible to reduce pollution loads by implementing measures such as raising awareness, installing more high-tech wastewater treatment plants, and reducing plastic use.

The aim of this study was to assess sediment quality in the ecoregion Engure, western coast of the Gulf of Riga, by using sediment ecotoxicity tests with amphipods Monoporeia affinis and Pontogammarus robustoides and selected biomarkers (AChE, GST, GR, CAT, MT) measured in Macoma balthica, to represent different types of biological responses reacting to different stressors. Ecoregion Engure sediments are characterised by comparatively low concentrations of heavy metals, and the area could be considered as unpolluted. Ecotoxicity tests of ecoregion Engure sediments did not show statistically significant (> 20% mortality) toxic effects. Survival of test organisms ranged from 83 to 100% and revealed “good quality” of tested sediment. There were no established strong differences between the stations and years regarding biomarkers. The integrated biomarker response index indicated more stressful conditions in station Mērsrags, while MT activity revealed heavy metal pollution in station Engure. In general, heavy metal concentrations, ecotoxicity tests and biomarker responses indicate that the ecoregion Engure is not markedly various and anthropogenically affected.