The contents of the potentially harmful elements in the arable soils of southern Poland, with the assessment of ecological and health risks: a case study.

Agricultural soil samples were collected from the areas where edible plants had been cultivated in southern Poland. The PHE content decreased in proportion to the median value specified in brackets (mg/kg d.m.) as follows: Zn (192) > Pb (47.1) > Cr (19.6) > Cu (18.8) > Ni (9.91) > As (5.73) > Co (4.63) > Sb (0.85) > Tl (0.04) > Cd (0.03) > Hg (0.001) > Se (< LOQ). No PHE concentrations exceeded the permissible levels defined in the Polish law. The PHE solubility (extracted with CaCl2) in the total concentration ranged in the following order: Fe (3.3%) > Cd (2.50%) > Ni (0.75%) > Zn (0.48%) > Cu (0.19%) > Pb (0.10%) > Cr (0.03%). The soil contamination indices revealed moderate contamination with Zn, ranging from uncontaminated to moderately contaminated with Pb, and, practically, no contamination with other PHEs was identified. The ecological risk indices revealed that soils ranged from uncontaminated to slightly contaminated with Zn, Pb, As, Cu, and Ni. The PCA indicated natural sources of origin of Co, Cu, Hg, Sb, Zn, Cr, and Pb, as well as anthropogenic sources of origin of Cd, Ni, As, and Tl. The human health risk assessment (HHRA) for adults and children decreased in the following order of exposure pathways: ingestion > dermal contact > inhalation of soil particles. The total carcinogenic risk values for both adults and children were at the acceptable level under residential (1.62E-05 and 6.39E-05) and recreational scenario (5.41E-06 and 2.46E-05), respectively, as well as for adults in agricultural scenario (1.45E-05). The total non-carcinogenic risk values for both adults and children under residential scenario (1.63E-01 and 4.55E-01, respectively), under recreational scenario (2.88E-01 and 6.69E-01, respectively) and for adults (1.03E-01) under agricultural scenario indicated that adverse health effects were not likely to be observed. Investigated soils were fully suitable for edible plant cultivation.

Utilization of sewage sludge in the manufacture of lightweight aggregate.

This paper presents a comprehensive study on the possibility of sewage sludge management in a sintered ceramic material such as a lightweight aggregate. Made from clay and sludge lightweight aggregates were sintered at two temperatures: 1100 °C (name of sample LWA1) and 1150 °C (name of sample LWA2). Physical and mechanical properties indicate that the resulting expanded clay aggregate containing sludge meets the basic requirements for lightweight aggregates. The presence of sludge supports the swelling of the raw material, thereby causing an increase in the porosity of aggregates. The LWA2 has a lower value of bulk particle density (0.414 g/cm(3)), apparent particle density (0.87 g/cm(3)), and dry particle density (2.59 g/cm(3)) than it is in the case of LWA1 where these parameters were as follows: bulk particle density 0.685 g/cm(3), apparent particle density 1.05 g/cm(3), and dry particle density 2.69 g/cm(3). Water absorption and porosity of LWA1 (WA = 14.4 %, P = 60 %) are lower than the LWA2 (WA = 16.2 % and P = 66 %). This is due to the higher heating temperature of granules which make the waste gases, liberating them from the decomposition of organic sewage sludge. The compressive strength of LWA2 aggregate is 4.64 MPa and for LWA1 is 0.79 MPa. Results of leaching tests of heavy metals from examined aggregates have shown that insoluble metal compounds are placed in silicate and aluminosilicate structure of the starting materials (clays and sludges), whereas soluble substances formed crystalline skeleton of the aggregates. The thermal synthesis of lightweight aggregates from clay and sludge mixture is a waste-free method of their development.

Petrophysical examination of CO2-brine-rock interactions-results of the first stage of long-term experiments in the potential Zaosie Anticline reservoir (central Poland) for CO2 storage.

The objective of the study was determination of experiment-induced alterations and changes in the properties of reservoir rocks and sealing rocks sampled from potential reservoir for CO2. In the experiment, rocks submerged in brine in specially constructed reactors were subjected to CO2 pressure of 6 MPa for 20 months at room temperature. Samples of Lower Jurassic reservoir rocks and sealing rocks (sandstones, claystones, and mudstones) from the Zaosie Anticline (central Poland) were analysed for their petrophysical properties (specific surface area, porosity, pore size and distribution) before and after the experiment. Comparison of the ionic composition the brines before and after the experiment demonstrated an increase in total dissolved solids as well as the concentration of sulphates and calcium ions. This indicates partial dissolution of the rock matrix and the cements. As a result of the reaction, the properties of reservoir rocks did not changed significantly and should not affect the process of CO2 storage. In the case of the sealing rocks, however, the porosity, the framework density, as well as the average capillary and threshold diameter increased. Also, the pore distribution in the pore space changed in favour of larger pores. The reasons for these changes could not be explained by petrographic characteristics and should be thoroughly investigated.

Synthesis and characterization of zeolites prepared from industrial fly ash.

In this paper, we present the possibility of using fly ash to produce synthetic zeolites. The synthesis class F fly ash from the Stalowa Wola SA heat and power plant was subjected to 24 h hydrothermal reaction with sodium hydroxide. Depending on the reaction conditions, three types of synthetic zeolites were formed: Na-X (20 g fly ash, 0.5 dm(3) of 3 mol · dm(-3) NaOH, 75 °C), Na-P1 (20 g fly ash, 0.5 dm(3) of 3 mol · dm(-3) NaOH, 95 °C), and sodalite (20 g fly ash, 0.8 dm(3) of 5 mol · dm(-3) NaOH + 0.4 dm(3) of 3 mol · dm(-3) NaCl, 95 °C). As synthesized materials were characterized to obtain mineral composition (X-ray diffractometry, Scanning electron microscopy-energy dispersive spectrometry), adsorption properties (Brunauer-Emmett-Teller surface area, N2 isotherm adsorption/desorption), and ion exchange capacity. The most effective reaction for zeolite preparation was when sodalite was formed and the quantitative content of zeolite from X-ray diffractometry was 90 wt%, compared with 70 wt% for the Na-X and 75 wt% for the Na-P1. Residues from each synthesis reaction were the following: mullite, quartz, and the remains of amorphous aluminosilicate glass. The best zeolitic material as characterized by highest specific surface area was Na-X at almost 166 m(2) · g(-1), while for the Na-P1 and sodalite it was 71 and 33 m(2) · g(-1), respectively. The ion exchange capacity decreased in the following order: Na-X at 1.8 meq · g(-1), Na-P1 at 0.72 meq · g(-1), and sodalite at 0.56 meq · g(-1). The resulting zeolites are competitive for commercially available materials and are used as ion exchangers in industrial wastewater and soil decontamination.

Characteristics and distribution of analyzed metals in soil profiles in the vicinity of a postflotation waste site in the Bukowno region, Poland.

The lead-zinc industry in the Bukowno region of southern Poland has polluted the surface layer of the surrounding soils mainly with lead (Pb), cadmium (Cd), zinc (Zn), arsenic (As), and thallium (Tl). Analysis of six soil profiles, taken on the east side of the postflotation waste site of the Mining and Metallurgical Plants ZGH "Boleslaw" in Bukowno, showed that they were podzol soils, taking form of loose sands with neutral pH and reducing conditions. Concentration of organic matter in the horizons ranged from 2 to 80 %. The main components of the mineral soil were quartz, carbonates, K-feldspars, plagioclases, and micas (sericite). The highest total concentrations of metals were found in the O, A, and B horizons. Over 90 % of the Cd content, 80 % of the Pb content, 60 % of the Zn content, ∼60 % of the Tl content, and 20 % of the As content occurred as mobile forms. The corresponding total concentrations were 10 mg/kg Cd, 922 mg/kg Pb, 694 mg/kg Zn, <1 mg/kg Tl, and <5 mg/kg As. This can potentially be taken up from the soil and transported in the trophic chain. Comparing the total metal content with the legal limits in Poland, it is observed, that the investigated soils exceeded the permissible levels of Cd, Pb, and Zn for agricultural soils. Arsenic and Tl are not reflected in the chemical quality of soil classifications.

Review in Waste Tire Management-Potential Applications in Mitigating Environmental Pollution.

Increasing year-by-year vehicle production is related to the expanding volume of used tires; therefore, exploring waste management strategies is strongly recommended. The global tire market reached 2.27 billion units in 2021 and is expected to reach 2.67 billion units by 2027. Dumping tires in landfills can cause significant environmental impacts, so waste tire utilisation plays an important role. Predominantly, the following three directions are employed for waste tire disposal: retreading, energy recovery and material recovery. The review shows that used tires can remove environmental pollution from both aqueous solutions containing heavy metal ions, dyes, pharmaceutical compounds, and benzene, toluene, ethylbenzene and xylene (BTEX). Particularly high efficiency was achieved in the removal of dyes (72%), taking into account the high initial concentration of impurities. The adsorption process depends on multiple factors, including, in particular, the following: pH, initial concentration of pollution, contact time and the properties of the sorbent used. The optimal pH range was identified to be between 6 and 7. Considering the principles of circular economy as well as based on the current state of knowledge, it can be concluded that the solid fraction obtained from the combustion of waste tires can be practically utilised for various environmental purposes.

Impact of fly ash fractionation on the zeolitization process.

Coal combustion product in the form of fly ash has been sieved and successfully utilised as a main substrate and a carrier of silicon and aluminium in a set of hydrothermal syntheses of zeolites. The final product was abundant in zeolite X phase (Faujasite framework). Raw fly ash as well as its derivatives, after being sieved (fractions: ≤ 63, 63-125, 125-180 and ≥ 180 µm), and the obtained zeolite materials were subjected to mineralogical characterisation using powder X-ray diffraction, energy-dispersive X-ray fluorescence, laser diffraction-based particle size analysis and scanning electron microscopy. The influence of fraction separation on the zeolitization process under hydrothermal synthesis was investigated. Analyses performed on the derived zeolite X samples revealed a meaningful impact of the given fly ash fraction on synthesis efficiency, chemistry, quality as well as physicochemical properties, while favouring a given morphological form of zeolite crystals. The obtained zeolites possess great potential for use in many areas of industry and environmental protection or engineering.

Coal fly ash as a resource for rare earth elements.

Rare earth elements (REE) have been recognised as critical raw materials, crucial for many clean technologies. As the gap between their global demand and supply increases, the search for their alternative resources becomes more and more important, especially for the countries which depend highly on their import. Coal fly ash (CFA), which when not utilised is considered waste, has been regarded as the possible source of many elements, including REE. Due to the increase in the energy demand, CFA production is expected to grow, making research into the use of this material a necessity. As Poland is the second biggest coal consumer in the European Union, the authors have studied different coal fly ashes from ten Polish power plants for their rare earth element content. All the fly ashes have a broadly similar distribution of rear earth elements, with light REE being dominant. Most of the samples have REE content relatively high and according to Seredin and Dai (Int J Coal Geol 94: 67-93, 2012) classification can be considered promising REE raw materials.