Phthalate acid esters (PAEs) are widely used as raw materials for industries that are well known for their environmental contamination and toxicological effects as “endocrine disruptors”. The determining of PAE contamination was based on analysis of dimethyl phthalate (DMP), diethyl phthalate (DEP), dipropyl phthalate (DPP), dibutyl phthalate (DBP), diisobutyl phthalate (DiBP), dicyclohexyl phthalate (DCHP) and di(2-ethylhexyl) phthalate (DEHP) in wastewater and sediment samples collected from city sewer systems of Lithuania and Poland, and Denmark for comparison. The potential PAE sources as well as their concentrations in the wastewater were analyzed and discussed. The intention of the study was to determine the level and key sources of pollution by phthalates in some Eastern European countries and to reveal the successful managerial actions to minimize PAEs taken by Denmark. Water and sludge samples were collected in 2019–2020 and analyzed by gas chromatography-mass spectrometry. The highest contamination with phthalates in Lithuania can be attributed to DEHP: up to 63% of total PAEs in water samples and up to 94% of total PAEs in sludge samples, which are primarily used as additive compounds to plastics but do not react with them and are gradually released into the environment. However, in water samples in Poland, the highest concentration belonged to DMP—up to 210 μg/L, while the share of DEHP reached 15 μg/L. The concentrations of priority phthalate esters in the water samples reached up to 159 μg/L (DEHP) in Lithuania and up to 1.2 μg/L (DEHP) in Denmark. The biggest DEHP concentrations obtained in the sediment samples were 95 mg/kg in Lithuania and up to 6.6 mg/kg in Denmark. The dominant compounds of PAEs in water samples of Lithuania were DEHP > DEP > DiBP > DBP > DMP. DPP and DCHP concentrations were less than 0.05 μg/L. However, the distribution of PAEs in the water samples from Poland was as follows: DMP > DEHP > DEP > DBP, and DiBP, as well as DPP and DCHP, concentrations were less than 0.05 μg/L. Further studies are recommended for adequate monitoring of phthalates in wastewater and sludge in order to reduce or/and predict phthalates’ potential risk to hydrobiots and human health.

Industrial and strategic significance of platinum group elements (PGEs)—Os, Ir, Ru, Rh, Pd, Pt—makes them irreplaceable; furthermore, some PGEs are used by investors as “safe heaven” assets traded in the commodity markets. This review analyzes PGEs from various aspects: their place in the geosphere, destiny in the anthroposphere, and opportunity in the economy considering interactions among the exploration, recycling of urban ores, trade markets, speculative rhetoric, and changes required for successful technological progress towards the implementation of sustainability. The global market of PGEs is driven by several concerns: costs for extraction/recycling; logistics; the demand of industries; policies of waste management. Diversity of application and specific chemical properties, as well as improper waste management, make the recycling of PGEs complicated. The processing approach depends on composition and the amount of available waste material, and so therefore urban ores are a significant source of PGEs, especially when the supply of elements is limited by geopolitical or market tensions. Recycling potential of urban ores is particularly important in a long-term view disregarding short-term economic fluctuations, and it should influence investment flows in the advancement of innovation.

Biochar is a promising tool to immobilize heavy metals (HMs) in the soil. Biochar’s effect on HMs immobilization into acidic soil (pH < 5) and the interaction of plants have been investigated. Three types of feedstocks were used for biochar development via pyrolysis at two temperatures and then applied as soil amendments. A vegetative experiment has been carried out with buckwheat and white mustard to determine the effect of biochar as an HMs immobilizing agent in the presence of sewage sludge. The results show promising biochar properties to immobilize heavy metals and reduce their availability for plants. Biochar incorporation increased soil pH and reduced heavy metal forms available to plants. A sequential extraction procedure was applied to investigate five different forms of six heavy metals (Cd, Cr, Cu, Ni, Pb, Zn) and evaluate their distribution after plants’ cultivation. The proportion of the residual fraction (RES) of HMs varied widely and differed from metal to metal and from plant species. RES in the soil after treatment with biochar and buckwheat harvest varied between 68.14 and 96.40% for Zn, 42.39 and 59.48% (Cu), 75.89 and 93.11% (Cr), 81.85 and 92.83% (Ni), and 98.94 and 99.20% (Pb). In comparison, a slightly opposite trend was found in the soil after white mustard cultivation. The proportion of RES was: 0.82–53.44% for Zn, 0.99–52.93% (Cu), 48.87–76.41% (Cr), 10.22–72.63% (Ni), and 98.31–99.32% (Pb). HMs immobilization efficiency in the soil after biochar treatment followed the order Ni > Cr > Pb > Cu > Zn and Ni > Pb > Zn > Cr > Cu after buckwheat and white mustard cultivation, respectively.

Soil pH influences the composition and activities of microbial communities, which are driving the transformations of soil organic carbon (SOC). However, the effect of liming on SOC sequestration remains controversial. Evaluation of the effect of liming on SOC and humified carbon fractions was one of the most important tasks of this work. Studies were carried out in the long-term field experiment using slaked-lime rates of 0.5 or 2.0, depending on the soil hydrolytic acidity. It was determined that liming did not increase SOC content, but led to redistribution of SOC. The amount of mobile humic acids in the soil decreased while the intensity of liming increased. When liming at the 2.0 rate, the lowest HA1 level (0.251 g kg⁻¹ C) and highest amount of HA2 (0.21 g kg⁻¹ C) were found. It could be stated that soil liming, as a measure, allows the stabilization of HA and FA by the cation bridging mechanism. Liming resulted in slower mineralization of SOC and at the same time it also resulted in carbon sequestration in the form of valuable humic acids. An important consistent pattern of carbon transformation was identified in this study and can be applied in selecting of the most suitable combination of agricultural practices, promoting carbon sequestration and soil fertility.

Environmental pollution caused by increasing levels of heavy metals (HM) is a pressing problem throughout the world. Phytoremediation is considered a prospective remediation approach for HM-contaminated soil, but more research is required to enhance remediation efficiency. Biochar is a promising bio-residue material that can be used for the sustainable remediation of heavy metal-contaminated soil. In this study, a pot experiment was conducted to investigate the effects of biochar from different bio-substrates (digestate, waste of biodiesel production from rapeseed, corn stalk) on HM (Cr, Cd, Cu, Ni, Pb, and Zn) accumulation in buckwheat and white mustard cultivated in sewage sludge-contaminated soil. The total amount of HM in soil, plant above- and below-ground biomass, leachate, and bioconcentration and translocation factors were studied to explore the mechanism of how the different bio-substrates’ biochar affects HM accumulation in selected plants. It was observed that rapeseed biochar showed the greatest significant effect in reducing the HM content in soil, plant biomass, and lysimetric water. Meanwhile, the incorporation of digestate biochar significantly increased the HM content in all the soil-plant systems and affected the HM leaching from the soil. The concentration of HM in the leachate decreased from 2.5 to 10 times. It was determined that phytostabilization is the core process of HM accumulation in buckwheat, in contrast to mustard, where the mechanism is phytoextraction. This study confirmed that biochar addition enhances the phytoremediation efficiency in soil, which can potentially improve the development of ecofriendly in-situ bioremediation technology for HM-contaminated sites.

Global resource limits and increasing demand for non-fossil energy sources have expanded the research on alternative fuels. Among them, algal biomass is designated as a third-generation feedstock with promising opportunities and the capability to be utilized for energy production in the long term. The paper presents the potential for converting beach wrack containing macroalgal biomass into gaseous fuel as a sustainable option for energy production, simultaneously improving the organic waste management that the coastline is facing. Beach wrack collected in the northern Baltic Sea region was converted by gasification technology applicable for carbon-based feedstock thermal recovery, resulting in syngas production as the main product and by-product biochar. Proximate and ultimate analysis, trace and major element quantification, detection of calorific values for macroalgal biomass, and derived biochar and syngas analysis were carried out. A higher heating value for beach wrack was estimated to be relatively low, 5.38 MJ/kg as received (or 14.70 MJ/kg on dry basis), but produced syngas that contained enough high content of CH₄ (42%). Due to macroalgal biomass specifics (e.g., high moisture content and sand admixture), an adjusted gasification process, i.e., the combination of thermochemical procedures, such as mild combustion and pyrolytic biomass conversion, might be a better choice for the greater economic value of biowaste valorization.