This paper presents the results of testing the content of 5-hydroxymethylfurfural (HMF) in honey from Greater Poland. The production of honey from this area of Poland, its processing, and its consumption are closely related to the sustainable development of this region. It is created in the process of the production, storage, and transport of honey, especially during its thermal processing. Therefore, it can be an indicator in the analysis of sustainable development throughout the life cycle of honey and its products. The aim of this research was to determine the HMF content in Greater Poland’s honey available on the Polish market using three different methods and to compare the obtained results. The methodology used was as follows: two spectrophotometric methods (White and Winkler) and an HMF determination method based on the LC-MS/MS technique developed especially for this study. The determined HMF content in all tested honey samples did not exceed the applicable standard. The determined HMF values in all honey samples ranged from 0 to 28.5 mg HMF/kg honey. All results fell within the scope of European Council Directive 2001/110/EC of 20 December 2001, i.e., they did not exceed the HMF content in honey, which is 40 mg/kg. The results will encourage modifications to the universal honey testing procedures to be developed for the agri-food sector. In the study, seven honeys of different origins and types were selected; three HMF detection methods were selected; a comparative procedure was developed; and the content of the reference ingredient in honey was determined.

This work presents coal analyses for heavy metal content (Tl, Cu, Zn, Cd, Fe). The tested coal samples came from a Russian deposit in the Kuzbass Basin (Novosibirsk and Kemerovo Oblasts, near Kazakhstan) and from Poland. The concentration of thallium in coal was determined using DPASV—differential pulse anodic stripping voltammetry—and other metals were examined with FAAS, i.e., flame atomic absorption spectrometry. The study confirmed the presence of thallium in the tested coal sample. The coal samples from outside the European Union contained four times more thallium (the maximum content of thallium in coal has been determined to be 0.636 mg·kg⁻¹) than the samples of Polish coal (where the maximum content of thallium was 0.055 mg·kg⁻¹). Cadmium concentration was on average 1.99 mg·kg⁻¹ in the samples from outside the European Union, and 1.2 mg·kg⁻¹ in the samples of Polish coal. Zinc concentration in the samples from outside the European Union was on average 11.27 mg·kg⁻¹, and in the samples of Polish coal approx. 7 mg·kg⁻¹. In addition, iron concentration in all coal samples was determined as 14.96 mg·kg⁻¹, whereas copper concentration in the samples from outside the European Union averaged as 3.96 mg·kg⁻¹. The obtained results do not show any correlation between the presence of thallium and the presence of other metals. It is worth noting that heavy metals pose a threat to living organisms due to their persistence and bioaccumulation, particularly in the context of dust emissions to the atmosphere.

The article presents the safety issue bonded to the Polish Air Force F-16 multirole aircraft. The authors pointed out the issue of fuel used for emergency supply system of these aircrafts. The paper emphasized the fact that these aircrafts require special fuel with designation H-70, which is 70% aqueous solution of toxic hydrazine. For this reason, the rescue services of Polish Air Force bases where Polish F-16 are stationed had to be adjusted accordingly. Just as importantly authors noticed that in the event of an emergency landing of this aircraft at different airports can receive difficulties associated with the possible leakage of hydrazine, or its neutralization in the absence of specialized Hydrazine Response Team, which are part of the Airport Rescue Group.

The type of plant substance from which brown coal is formed and the conditions in which it forms largely influence its characteristics and properties. On account of a lower degree of coalification and calorific value compared to hard coal and a high content of humic substances, brown coal is becoming a valuable fertiliser component. Humic acids contained in brown coal are also found in the soil’s humus substances, and their beneficial sorptive and complexing properties are a factor speaking in favour of their use both in agriculture and in other branches of the economy. The article presents the manner of preparing a sample of brown coal in order to determine the content of humic acid intended in particular for use in making chemical fertilisers and for other applications, particularly in agriculture. The optimum conditions in which the amount of humic acid in the sample is the highest were determined. The influence of the proportions of water, KOH, and brown coal, temperature, and mixing time on the solubility of the sample of brown coal was analysed. The solutions were mixed in mixers built especially for this purpose. The solubility of brown coal in the prepared solutions was controlled UV-ViS spectrophotometrically.