Humans are generally exposed to a variety of pollutions present in the air they breathe, the food they eat or in the water they drink. Some of the most dangerous pollutions are metals and heavy metals. These are naturally occurring substances which are harmless when present in the environment at low levels. However, due to many pollutants such as industry processes or war activities, the heavy metal concentration can exceed the limit of tolerance and become very toxic for the natural environment and living organisms in it, including humans. Unlike organic pollutants, the heavy metals (as ions and as particulate matter) once introduced into the environment cannot be biodegraded and remain there indefinitely. By rainfall these pollutants can be partially transferred from air or soil into the rivers and drinking water sources, where they accumulate in even higher toxic levels. The high concentrations of heavy metals in contaminated natural water reservoirs have an impact on the microbial community composition which resides there. This type of water pollution can cause the changes in life cycles of natural bacterial populations, influencing their metabolic processes and proliferation. The presence of pathogens in water is normally indirectly determined by the testing for “indicator organism” such as coliform bacteria. Coliforms are usually present in larger numbers in contaminated water and at the same time they are indicators of whether other pathogenic bacteria are present, too. In crisis situations, like war or some natural disasters, where trusted sources of drinking water are not available anymore, the military and residents of affected areas are forced to use some alternative water resources that cannot be tested for their microbial or metal contamination properly. Therefore, the existence of some fast test that would detect not only dangerous bacterial pathogens in water, but also the presence of metals and heavy metals as well, would be of great help and importance for the human health. Even though the number of pathogens can be drastically reduced by the boiling of water, the heavy metals are not destroyed by high temperature. Hence the main objective of our work was to optimize the biosensor chip for microbial detection in contaminated water that would serve at the same time as an indicator for the chemical composition of the water, such as presence of metals and heavy metals, with potential to be used as a novel test tool in public health.

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The results of investigation of  inorganic and organic speciation of copper compounds  in  the lake Modrac, using the geochemical equilibrium model  BLM (Biotic Ligand Model; USEPA 2007) and other geochemical models are presented, as well as toxicity and bioavailability of copper compounds in the lake Modrac for chosen biotic ligand of fish fathead minnow (Pimephales promelas). Speciation and bioavailability of copper complexes was investigated and toxicity levels for chosen biotic ligand determined. The influence of water chemistry on copper toxicity is predominant, and application of sophisticated BLM model enables the prediction of toxicity and bioavailability of copper.

A well-developed immune system of the organism, which, among other things, arises as a result of a healthy lifestyle, is a prerequisite for a healthy and quality life. Natural food products, primarily honey and other bee products, greatly contribute to the proper development of the body's immune response to the harmful effects of foreign substances. Honey and other bee products are a valuable and rich source of biologically active substances. They have been used for centuries in traditional medicine, due to their wide range of antibacterial, antiradical, antioxidant and anticancer effects, as well as their supportive effect in the prevention and treatment of many diseases. Consumption of honey contributes to the improvement of immunity and enriches the human diet with many valuable nutrients and bioactive substances. Bioactive substances, including polyphenols, are organic chemical compounds naturally present in honey. Polyphenols are important secondary metabolites of plants that are transferred to honey along with nectar, pollen or propolis. Several studies have confirmed the immunomodulatory role of the basic phenolic compounds present in honey. For the purpose of our research, a total of 21 samples of honey and 10 samples of alcoholic propolis extract were collected, mostly from the Federation of Bosnia and Herzegovina. Based on the obtained results, it is clear that honey itself is a rich source of antioxidants in the diet, but that the addition of propolis significantly increases its antioxidant power. The addition of propolis to honey significantly increased the antioxidant activity of all analyzed samples. After the addition of propolis, the highest antioxidant activity was again shown by a sample of forest honey from the area of Bihać, Una-Sana Canton (Š5) and its antioxidant activity is 1143.96 µmol Fe (II) / L. The lowest antioxidant activity after the addition of propolis was shown by the meadow sample of honey from Sanski Most, Una-Sana Canton, (L21), 462.71 µmol Fe (II) / L.Based on the presented results, it is clear that after the addition of propolis in the analyzed honey samples there was a significant increase in the concentration of polyphenols by an average of 11.96%.