Long-Term Polyethylene (Bio)Degradation in Landfill: Environmental and Human Health Implications from Comprehensive Analysis.

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 FTM, 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.

Difficulties in the Modeling of E. coli Spreading from Various Sources in a Coastal Marine Area.

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.

Polypropylene structure alterations after 5 years of natural degradation in a waste landfill.

Up to 25% of plastic waste in Europe is still disposed of in landfills, despite recycling efforts. The plastic waste in the landfill plot may be exposed both to abiotic and biotic degradation processes, although it is thought that most of the plastic materials tend to be resistant to biodegradation or biodeterioration even after a long time. To verify if polypropylene (PP) can undergo the process of short-term biodegradation and how this process is manifested in a municipal waste landfill, we collected a plastic sample from an already closed landfill plot estimating its age at approximately 5 years. Fourier-Transform Infrared Spectroscopy led to sample identification as PP as well as showed additional bands which are not specific to polymer structure but rather result from microbial metabolism. Differential Scanning Calorimetry was performed to examine the influence of the environmental degradation process on the degree of crystallisation of the tested PP. Moreover, significant changes on the surface of an old PP packaging were observed with Scanning Electron Microscopy (SEM) showing clear signs of PP delamination which resulted in microplastic particles formation (smaller than 5 µm in diameter). Additionally, several round and oval shaped structures were observed with SEM leading to the suspicion of biofilm formation on the PP surface. Indeed, the microorganisms were present in a vast amount on the old PP surface and possibly formed a viable biofilm as it was confirmed with fluorescence microscopy. These data show that plastic waste can be inhabited by microorganisms from the ambient environment which may probably lead to its faster degradation. However, this process should be investigated in more detail in order to shed light upon the possible risk factors of plastic biodegradation in waste landfills to the environment and human health. Even after five years, polypropylene can undergo deterioration/biodegradation in a waste landfill with viable microbial cells on its surface, possibly involved in its degradation.