Chemical precipitation is a useful conventional process to remove heavy metals from aqueous solutions. In this work, a waste sludge from the Solway process was used as a precipitation agent for the precipitation of Cu (II), Ni (II), Pb (II) and Zn (II) ions with an initial concentration of 50 mg/L. The results of the research showed that the waste sludge from the Solway process completely removed Pb (II) ions from the solution in the pH range of 8.39 -11.74, also good efficiency was shown in other cations. The maximum precipitation efficiency for Cu (II) is 99.890% at pH 10.98, Ni (II) 99.940% at pH 11.81, Zn (II) 99.616% at 10.1. Waste sludge is proved to be a good precipitate for cation separation.

The natural plant Cornus mas, sometimes called Cornelian cherry, has been known since ancient times and the fruit is used for various purposes. Cornus mas gives healthy fruits without the use of chemical protection, which are used as healthy, tasty and medicinal food. Cornus mas fruits can be used for eating fresh or in the form of numerous processed products: marmalade, jam, sweet, compote, syrup, juice, fruit yogurt, liqueur, wine and brandy. Due to its antioxidant, antiallergic, antimicrobial and antihistamine properties, it is increasingly used as a dietary supplement, as well as for medical purposes. Taking into account all the above, the aim of this paper is to examine samples of a mixture of honey and fresh wild Cornelian cherry, as well as a sample of honey and Cornelian cherry and determine the physical - chemical parameters: electrical conductivity, pH value, vitamin C content, HMF (hydroxy methyl furfural), as well as individual heavy metals such as iron, cadmium, lead, zinc, copper. Based on the obtained results, appropriate conclusions will be given and the possibility of registering these products as food supplements will be determined.  Based on the performed analyzes, it was shown that the sample of honey and Cornelian cherry mixture had the highest pH value and electrical conductivity, and that the honey sample had the lowest value. Also, the highest value of water activity had the sample of a mixture of honey and Cornelian cherry, while the highest content of hydroxymethylfurfural had the content of Cornelian cherry. The analysis showed the absence of manganese (Mn), cadmium (Cd) and lead (Pb) in all samples, while it was shown that the highest content of Cu and Zn has the sample of Cornelian cherry 2.665 mg/kg Cu ​​and 14.41 mg/kg Zn, followed by a mixture of Cornelian cherry and honey Cu 2.778 mg/kg, Zn 14.670 mg/kg, while the honey sample has the highest Fe content of 16.72 mg/kg. This shows that the samples are rich in zinc, iron and copper, and that they are a good source for those minerals that could meet daily needs.

In addition to soda, the Solway production process yields large amounts of waste sludge that contains a high percentage of CaCO3 and Ca(OH)2. In this paper, solid waste sludge from a soda factory in Bosnia and Herzegovina of a certain granulation was used to remove metal ions from the binary system initial concentrations of 500 mg/L. The research results showed that the precipitation efficiency for the binary system Cu - Ni was 99.810% at a pH of 11.42 for Cu2+ and 99.896% for Ni2+ at a pH of 10.86, while for the binary system Pb - Zn it was 99.84% at the same pH value of 10.64. This research has shown that it is very difficult to separate and remove metal precipitation from binary systems because the optimal pH for one metal does not correspond to another metal.

In this paper, the influence of biological acid dough with a strain of lactic acid bacteria (Lactobacillus plantarum) on the properties of the dough and the addition of sourdough on the quality of crackers was investigated. Changes in total titratable acidity and pH were monitored during the fermentation of the sourdough (24 hours). In the dough for the production of gluten-free crackers, the influence of the addition of sourdough on the total titratable acidity and pH value was examined. The content of water, protein, fat, starch, crude fiber, pH value and total titratable acidity was determined by flour samples for the production of gluten-free crackers and gluten-free crackers. The influence of sourdough on the sensory properties of crackers was examined. The mineral composition of zinc was determined and the contribution of the daily recommended intake was assessed. In samples of crackers subjected to storage for 5, 10, 20 and 30 days, a change in water content was monitored. The length of fermentation had a significant impact on the dynamics of pH change and on the total titratable acidity during the fermentation of sourdough. The results of the study showed that the control sample has a higher pH value than the samples with sourdough. The reason for that is the development of acetic acid during fermentation. The change in water content in the crackers over 30 days was significantly higher in the control sample compared to the samples with sourdough. Crackers with sourdough contain a significantly higher percentage of protein, ash, fiber, zinc at the expense of reducing carbohydrates.

During the last few years, we have witnessed more frequent floods affecting the northeastern part of Bosnia and Herzegovina, the valley of the Spreca River. Flooded soil has undergone various changes, in terms of numerous deficiencies and heavy metal contamination, where such soil represents a great danger both for people and animals. Therefore, in this paper the physicochemical analysis of soil and degree of pollution is determined. The aim of soil sampling and analysis is to determine its status after water withdrawal, in terms of nutrient supply, and to determine possible chemical pollution. Based on the results obtained, agricultural producers will receive recommendations regarding restoration of production on these areas, the choice of cultivated culture, corrective measures or remediation of these areas. As part of the analysis, hygroscopic moisture, acid-base soil status, oxidoreduction potential, organic matter content, carbonate content and heavy metals content were determined. Based on the performed analyzes, the soil was shown to be of neutral character (determined in 1M KCl), and weakly alkaline (determined in distilled H2O) with predominantly reducing condition prevailing in the soil. The conducted analyzes have shown that the soil is very poor in humus, and that the heavy metals content is within the limit values determined by the Rulebook on Determination of Allowed Quantities of Harmful and Dangerous Substances in Soil and Method of Testing there of (“Official Gazette of Federation of Bosnia and Herzegovina”, number 52/09). Therefore, from the aspect of the pollution degree, the soil from this plot belongs to the first class when it comes to iron, manganese, cadmium and lead, to the second class when it comes to zinc, and the third class when it comes to copper.

During the last few years, we have witnessed more frequent floods affecting the northeastern part of Bosnia and Herzegovina, the valley of the Spreca River. Flooded soil has undergone various changes, in terms of numerous deficiencies and heavy metal contamination, where such soil represents a great danger both for people and animals. Therefore, in this paper the physicochemical analysis of soil and degree of pollution is determined. The aim of soil sampling and analysis is to determine its status after water withdrawal, in terms of nutrient supply, and to determine possible chemical pollution. Based on the results obtained, agricultural producers will receive recommendations regarding restoration of production on these areas, the choice of cultivated culture, corrective measures or remediation of these areas. As part of the analysis, hygroscopic moisture, acid-base soil status, oxidoreduction potential, organic matter content, carbonate content and heavy metals content were determined. Based on the performed analyzes, the soil was shown to be of neutral character (determined in 1M KCl), and weakly alkaline (determined in distilled H2O) with predominantly reducing condition prevailing in the soil. The conducted analyzes have shown that the soil is very poor in humus, and that the heavy metals content is within the limit values determined by the Rulebook on Determination of Allowed Quantities of Harmful and Dangerous Substances in Soil and Method of Testing there of (“Official Gazette of Federation of Bosnia and Herzegovina”, number 52/09). Therefore, from the aspect of the pollution degree, the soil from this plot belongs to the first class when it comes to iron, manganese, cadmium and lead, to the second class when it comes to zinc, and the third class when it comes to copper.

The effect of pH and initial concentration on the removal of Cu(II) and Ni(II) ions from their monocomponent and two-component aqueous solutions using Na2CO3 as a chemical precipitation agent was investigated in this paper. Monocomponent aqueous solutions  of Cu(II) and Ni(II)  ions with their initial concentrations of 50 and 500 mg/L and two-component aqueous solution with initial concentration of 500 mg/L were prepared. The precipitation was carried out by batch method at room temperature by stirring the solution at 300 rpm for 5 minutes, resulting in the formation of precipitates. The resulting precipitate was separated by filtration from the solution. The experiment proved that Na2CO3 is a good agent for removing Cu(II) and Ni(II) ions from their monocomponent water solutions of 50 and 500 mg/L concentration and two-component water solution with initial concentration of each metal 500 mg/L. The percentage of Cu(II) removal was higher at lower pH values compared to Ni(II) removal.

Summary Heavy metals are natural ingredients of many plant cultures, and they are increasingly found in the soil as the main group of inorganic contaminants. The consumption of food products, either fresh or processed, with an increased concentration of heavy metals leads to the deposition of these metals in the body, which further leads to a series of consequences in the form of cardiovascular, respiratory, and neurological problems. The behavior of heavy metals in soil and their accumulation by plants depends on many factors, such as soil structure, soil pH value, organic matter content, adsorption complex and other factors. Therefore, the aim of this work is to present the influence of physical and chemical soil parameters on the distribution of heavy metals (Pb(II) and Cd(II)) in plant cultures and to assess the health risk pollution of the mentioned metals in plant cultures (cucumber, pepper, tomato, eggplant).