Most studies on the effects of organisms on microplastic characteristics have focused on microorganisms, while the impact of animal feeding behavior, particularly in aquatic species like fish and decapod crustaceans, has been less explored. This study examines how polyethylene spherical microplastics (275 μm in diameter) passing through the digestive tracts of crucian carp (Carassius carassius) and Australian crayfish (Cherax quadricarinatus) affect surface properties, particle size, and bacterial colonization. The species were fed diets with or without microplastics. The particles underwent two rounds of passage through the digestive tracts and were then exposed to known bacterial densities. Surface damage, size, and biofilm coverage were analyzed using scanning electron microscopy, while alterations in surface chemical composition were assessed through Fourier transform infrared spectroscopy with attenuated total reflectance, and the formation and penetration of nanoplastics in gut tissues and glands were determined using Py-GC/MS. Results show that the passage significantly altered surface properties and reduced microplastic size, without affecting chemical composition or nanoplastic penetration into tissues. These changes promoted bacterial colonization compared to controls. The findings suggest that animal feeding activity may play an important role in the mechanical fragmentation of microplastics in aquatic environments, potentially leading to their faster degradation.

Twenty-seven gases and sixteen rock wastes from the thermal active Rymer coal waste dump were collected. The composition and origin of gaseous, liquid, and solid pollutants emitted during the self-heating process and the development of these processes with time were established. Gases were subjected to determination of molecular and stable isotope (δ¹³C and δ²H) composition. Rock-Eval pyrolysis and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) were applied for evaluation of the quantity and molecular composition of pyrolysates released during the heating of rocks in temperatures from 100 to 650 °C. The main products of Py-GC-MS are released between 350 and 650 °C, namely alkanes, aromatic hydrocarbons, and aromatic alcohols. These components were also recorded in Py-GC-MS products of samples collected from the dump surface. Besides the high-molecular-weight organic compounds, in emitted gases CO₂, CO, gaseous hydrocarbons, and S-compounds were recorded. The stable isotope data indicated that methane was generated mainly during the low-temperature thermogenic process, but a share of the microbial-originated gas was visible. The source of the CO₂ was the oxidation of organic matter. The gaseous S-compounds were products of high-temperature decomposition of sulphides and organic S-compounds. The hydrocarbon and CO contents of the emitted gases proved to be good indicators for tracking of the self-heating processes.

Soil contamination with petroleum-derived compounds is one of the most serious ecological problems. Their main source in urbanized areas is public transport. According to the Regulation of the Polish Minister of Environment about the assessment of earth’s surface contamination, hydrocarbon compounds are divided into: gasolines and oils, aromatic hydrocarbons and polycyclic aromatic hydrocarbons (PAHs). The subject of the research is the use of a gas chromatography coupled with mass spectrometry (GC-MS) method to assess the degree of soil contamination in the vicinity of the main communication routes of the Kielce agglomeration. This method is useful for the detection and identification of many organic compounds occurring in samples in very small quantities, which cannot be determined by common methods. For the purpose of this study, 14 soil samples were collected. After carrying out extraction with various methods, the ultrasonic solvent extraction method was chosen as the most effective way of extracting hydrocarbon impurities for the GC-MS studies. During single analysis, both oil fraction and PAHs quantities were determined.

Coal wastes deposited in heaps may undergo self-heating and spontaneous combustion processes. Under oxygen-limited conditions in the dump, besides burning, pyrolysis processes occur. Both processes (pyrolysis and oxidation) result in emissions of volatile pollutants and have been developed in several heaps in the Upper Silesian Coal Basin (USCB), where coal exploitation has lasted for over a century. To examine the molecular composition and yields of volatile compounds produced during self-heating, in relation to organic matter (OM) content and its maturity, mineral matter composition, temperature, water presence and oxidation conditions, four coal waste samples were collected from the Polish part of the USCB: two from the Janina Mine (JAN-1, JAN-2) (Rr ca. 0.5%) and two from the Marcel Mine (MAC-1, MAC-2) (Rr ca. 0.9%). JAN-1 and MAC-1 are siltstones containing more quartz and less OM than JAN-2 and MAC-2 claystones. Results of the Rock-Eval analysis evidenced 1.8, 27.3, 1.9, and 21.4 wt. % TOC, respectively and the presence of the Type-III kerogen in all samples. Simulations of the self-heating were conducted in 1-L closed reactors in conditions: dry pyrolysis (DP), hydrous pyrolysis (HP) in 250, 360, and 400oC for 72 h, and oxidation with air (OXI) in 250 and 400oC for 72 h.The molecular composition of generated gases (i.e., HCs (C1-C8), CO, CO2, H2, H2S, organic S-compounds) was determined and then re-calculated as yields, taking into account the amount of gas generated (pVT) and the mass and TOC of the rock used for each experiment.The concentration of HCs in HP and DP runs increases with temperature increase up to 58.4 mol %. The concentrations of other generated gases in these experiments strongly relate to the temperature increase of the process as well: the concentration of CO decreased, and the concentration of CO2, H2, H2S and organic S-compounds increased. The presence of water and elevated TOC amounts boost the generation of S-compounds (dominated by H2S). During all OXI experiments, only traces of HCs, H2 and S-compounds were produced; the concentration of CO2 increased and CO decreased with experiment temperature increase. Gases generated from TOC-rich rocks are richer in HCs, and organic S-compounds, resulting in yields of these gases, up to 4.3 kg/Mg rock and 1.4 g/Mg rock, respectively. The highest CO2 and CO yields were recorded in OXI experiments, reaching approximately 390 and 20 kg/Mg rock, respectively; in pyrolytic experiments, these yields did not exceed 8.4 and 0.15 kg/Mg rock, respectively. After recalculating the gas yields per TOC mass in waste, it appeared that the highest HCs yields, exceeding 20 kg/Mg TOC, were recorded during HP and DP pyrolysis at 400°C of samples poor in organic carbon. CO2 and CO yields are highest in OXI experiments of the above-mentioned samples, reaching 850-2000 and 10-50 kg/Mg TOC, respectively. The yields of these gases in pyrolysis experiments for these samples reach 24-310 kg/Mg TOC and 0.0-1.3 kg/Mg TOC, respectively. This study was financed from the AGH University of Krakow research subsidy (16.16.140.315) and the National Science Centre, Poland, grant No 2017/27/B/ST10/00680.