heavy metals

Unlike the more dynamic air basin and surface waters, where active self-purification processes occur, soil virtually lacks this capacity. The cleansing processes in soil are very slow, only through leaching, plant uptake, and water erosion, which poses an environmental hazard in urbanized areas over long periods. In the process of intensive urbanization, the soil cover has been influenced by many anthropogenic factors, resulting in changes to its physical and chemical properties and an increase in heavy metal concentrations.

Pollution of the aquatic environment with heavy metals, particularly lead (Pb²⁺) and zinc (Zn²⁺) ions, is one of our most pressing environmental problems. Even insignificant concentrations of Pb²⁺ and Zn²⁺ ions in the water pose a serious threat to human health, biodiversity, and the functioning of aquatic ecosystems. The work aims to assess the effectiveness of zeolite as a low-cost natural sorbent for purifying the aquatic environment from toxic metals.

This study assesses heavy metal polyelement distribution in the urbanized hydroecosystem of the Kamyanka River within Zhytomyr city, Ukraine. Concentrations of Fe, Cu, Cr, Mn, Zn, Ni, Pb, and Co were analyzed in water, bottom sediments, and the aquatic macrophyte Vallisneria spiralis L. using atomic emission spectrometry. The spatial entropy analysis, employing Shannon-Wiener diversity index (H′ = 0.75-1.55), evenness index (E = 0.47-0.98), and relative organization index (R = 0.17-0.64), revealed metal-specific distribution patterns across ecosystem compartments.

The methods of wastewater treatment from heavy metal ions and dyes are analyzed, and the key advantages of powdered magnetically sensitive carbon nanocomposites as adsorbents are shown. Methods for selecting and preparing raw materials and activators for the synthesis of such nanocomposites are considered, and methods for synthesizing nanocomposites are analyzed. The properties, modeling of adsorption kinetics and isotherms, and efficiency of magnetic carbon nanocomposites for wastewater treatment from dyes and heavy metals are described.

The use of anaerobic digestate as a biofertilizer is quite promising in terms of soil protection technologies in view of the reduction of environmental risks from the use of mineral fertilizers and the positive impact on soil productivity, improvement of their quality and restoration of the humus layer. However, anaerobic digestion does not ensure the complete absence of environmental hazards due to a certain probability of heavy metals, pharmaceutical substances, and pathogenic microorganisms entering the soil with biofertilizer.

 magnetical nanocomposite based on sawdust, magnetic nanoparticles, and polyethylenimine was prepared to remove Pb(II), Cd(II) and Cu(II) ions from an aqueous solution. Adsorption on nanocomposite exhibited a maximum removal of 97% for Pb(II)‏. The adsorption capacity in the pseudo-second-order model for Pb(II) was studied and the value of 1.48 mg/g was obtained.

Electrocoagulation process is widely used for the removal of pollutants from the industrial wastewater. In the present study, an attempt was made to investigate the performance of electrocoagulation process using alu-minum and iron electrodes to treat the metal ions present in the synthetic galvanic wastewater. The electrodes used are with and without perforations and it was observed that the efficiency of electrodes with perforation (80 %) was higher than without perforations (50 %). The removal efficiency of heavy metal ions increased with retention time and direct current.

Batch experiments are applied to determine the effectiveness of zeolite addition on the characteristics of wastewater of the oil industry and operational factors. The concentrations of heavy metals were measured using an atomic absorption spectrophotometry. Results have shown that 2.5 g/L of zeolite at a speed of 270 rpm, 6.5 pH would result in about 99% removal efficiency.

Municipal Solid Waste Management (MSWM) is a new and fast-growing business area that is becoming widespread in Ukraine. The fire accident at Lviv city landfill "Hrybovychi" forced the local governments to initiate work on its closure and reclamation. The Environmental Impact Assessment (EIA) of the planned activity is the first mandatory step in this direction. The complex nature of EIA procedures requires a similarly integrated approach to identify hazards and develop a shared vision of existing risks.

The possibilities of using enterosorbents as mineral additives for bioprophylaxis and prevention of heavy metal retention in the body due to possible food contamination as a result of ecosystem biobalance and their accumulation in livestock bioproducts are analyzed. The dynamics of changes in physiological parameters of the body of experimental animals under the influence of heavy metals depending on the used enterosorbents as effective preventive measures that can reduce the level of lead in the blood and liver of animals in intoxication to control levels.