Polyethylene (PE) plastic waste poses an environmental challenge. To explore degradation processes over an extended period, a 60-year study was conducted at an operational landfill in Poland. This landfill, in use since 1960, offers a unique chronological representation of degradation potential due to distinct layering of waste without mixing. Employing analytical techniques, such as Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimeter (DSC), Scanning Electron Microscopy (SEM), and fluorescence microscopy, plastic waste samples were examined over decades. FTIR identified and characterized the samples, revealing traces of degradation. DSC indicated reduced crystallinity, implying diminished chemical stability. SEM showcased plastic fragment liberation, confirming degradation. Fluorescence microscopy and SEM confirmed microorganisms’ involvement, forming colonies around areas of strong delamination. The study provides insights into plastic waste dynamics, emphasizing microorganisms and hydrolytic processes in landfills. This contributes to understanding over 60 years period and underscores the need for waste management to handle plastic pollution effectively.

Coastal and transitional waters are often used as bathing waters. In many regions, such activities play an important economic role. According to the European Union Bathing Water Directive (2006/7/EC) (BWD) the concentration of Escherichia coli in bathing water exceeding 500 CFU·100 mL⁻¹ poses a high risk for bathers’ health. In order to safeguard public health, microbiological environmental monitoring is carried out, which has recently been supported or replaced by mathematical models detailing the spread of sanitary contamination. This study focuses on the problems and limitations that can be encountered in the process of constructing a mathematical model describing the spread of biological contamination by E. coli bacteria in coastal seawater. This and other studies point to the following problems occurring during the process of building and validating a model: the lack of data on loads of sanitary contamination (often connected with multiple sources of biological contamination inflow) makes the model more complex; E. coli concentrations higher than 250 CFU·100 mL⁻¹ (low hazard for health) are observed very rarely, and are associated with great uncertainty; the impossibility of predicting the time and intensity of precipitation as well as stronger winds and rougher sea, which may be a significant source of E. coli. However, there is universal agreement that such models will be useful in managing bathing water quality and protecting public health, especially during big failures of the wastewater network.

This study investigates the process of long-term (bio)degradation of polyethylene (PE) in an old municipal waste landfill (MWL) and its implications for environmental and human health. Advanced techniques, such as ICP–ES/MS and IC–LC, were used to analyze heavy metals and anions/cations, demonstrating significant concentration deviations from control samples. The soil’s chemical composition revealed numerous hazardous organic compounds, further indicating the migration of additives from PE to the soil. Toxicological assessments, including Phytotoxkit F^TM, Microtox^® bioassay, and Ostracodtoxkit^®, demonstrated phytotoxicity, acute toxicity, and high mortality in living organisms (over 85% for Heterocypris Incongruens). An unusual concentration of contaminants in the MWL’s middle layers, linked to Poland’s economic changes during the 1980s and 1990s, suggests increased risks of pollutant migration, posing additional environmental and health threats. Moreover, the infiltration capability of microorganisms, including pathogens, into PE structures raises concerns about potential groundwater contamination through the landfill bottom. This research underscores the need for vigilant management and updated strategies to protect the environment and public health, particularly in older landfill sites.