Urban soils are an essential element of the city environment. However, studies on urban soils are scattered in terms of geographical distribution, sampling pattern, analytical dataset, etc. One of the major issues arising from the studies on this ecosystem is the diffusion of its contamination. In cities, in fact, the proximity to humans may cause a serious danger for citizens. In the present study, results from the literature about trace elements in urban soils are presented to compare methodologies and results and to offer a basis for the harmonization of investigation approaches and establishment of remediation thresholds. A total of 153 studies on the urban ecosystem published in the last 10 years were collected and data on trace elements in soils of 94 world cities were compared and discussed. Data highlights the discrepancies among different studies (sampling strategies, analytical procedures) and the extreme variability of urban soils. Most cities are contaminated by one or more trace elements, revealing the environmental relevance of the urban soil system. While Pb is still one of the major concerns in many locations, new contaminants are on the rise and would deserve more attention from the researchers. While in fact some contaminants are almost ubiquitous in world cities and could be used as tracers for urban contamination, some traffic-related elements such as platinum, rhodium, and palladium, whose reactivity and toxicity is still unknown, are becoming of concern. Collation of literature data highlights the need for the harmonization of sampling, analytical, and rendering procedures for regulatory purposes and provides a useful dataset for environmental scientists dealing with the urban ecosystem and for city planners. A sampling design adapted to local urban patterns, a prescribed sampling depth, and a minimum set of elements that deserve to be measured could be the core of a common methodology.

Cadmium-contaminated soils can be re-used and also produce biomass energy if we plant soybeans or other biomass crops in the contaminated sites. In this study, two soils with pH values of 5.9 and 6.7 were artificially spiked to make their final total concentration as CK (about 1.0), 3.0, and 5.0 mg Cd kg⁻¹. Different amendments were mixed with these artificially Cd-contaminated soils to study the effect on the growth and Cd uptake of soybean, which include control (without amendment addition), powder-activated carbon (1%), and biosolids (sludge, 5%), respectively. Three kilograms of the treated soils was added into each pot and sowed 10 seeds of soybean (Leichardt species). The experiment was conducted in a 25°C greenhouse and controlled the soil water contents in the levels of 50-70% water holding capacity during the experimental period. Plants were harvested after growing for 90 days, and their fresh weights, dry weights, and plant heights were determined and recorded. Compared with the lower pH soil (5.9), soybeans were higher and have higher fresh weights and dry weights when growing in the higher pH soil (6.7). For most of the treatments, the two amendments had no significant effects on the plant heights of soybeans. For 3.0 or 5.0 mg Cd kg⁻¹ soil, the application of biosolids has significant effect on increasing the fresh weights and dry weights of soybeans (p < 0.05). However, there were no specific effects of applying activated carbons on the fresh weights and dry weights of soybeans.

Diplopods feed organic matter in decomposition; however, some environmental factors can promote changes in tissues of these animals. Sewage sludge has been applied for recuperation of physical structure of degraded soil. This work analyzed the influence of the sludge from a city of São Paulo in the midgut of the diplopod Rhinocricus padbergi. After the exposition to sludge, the midgut was prepared for histological and ultra-structural analyses. After 1 week of exposition, there were various glycoprotein globules in the fat body, which appeared, ultrastructurally, little electron dense. In the animals exposed for 2 weeks, there was an intensive renovation of the epithelium with the invasion of regenerative cells, which was observed in the histological and ultra-structural analyses. These data showed that the sludge present various substances that were very hazardous for these animals; more studies were necessary before the application of this in agriculture.

This study focuses on the distribution of selected trace metals, 137Cs and 210Pb, in floodplain deposits of the lowland Warta River (southern Poland) downstream of Częstochowa, a large city with an iron smelter. The depth profiles of trace metal (Zn, Pb, Cu, Ni, Cd and Mn), 210Pb and 137Cs contents in floodplain sediments were used to derive deposition rates on the floodplain for the twentieth century. The applicability of particular chronometric tools is considered within the context of their mutual relationships and confirmed by the consistency of the results. Deposition rate estimates for the past 50 years based on the vertical patterns of trace metal concentrations, which were correlated with particular events in the development of the smelter, range from 0.4 cm·year−1 in profiles situated in backswamps far from the channel to over 1.1 cm·year−1 in profiles of the natural levee adjacent to the river. Deposition rates based on 210Pb inventories in the profiles range from 0.08 to 0.66 g·cm−2·year−1, which corresponds to linear sedimentation rates of 0.10 to 0.91 cm·year−1, respectively. Dating of characteristic levels associated with peak fallout of 137Cs gives sediment accretion rates resembling those obtained from trace metals and 210Pb. The period of the highest sediment accumulation rate could be related to the highest loads of effluent from the iron smelter and city of Częstochowa, which were substantially reduced after the construction of effluent treatment plant.

Metal pollution is a global problem which represents a growing threat to the environment. Because of bioaccumulation and negative effects of heavy metals, their bioavailability needs to be monitored. Many studies showed accumulation of metals in crayfish tissues as dose- and time-dependent without significant differences in tissue concentration levels comparing males and females. Muscles and exoskeleton were considered as specific for accumulation of mercury and nickel, respectively. Cadmium, zinc, copper, lead, and chromium accumulated mainly in hepatopancreas. By analyzing these specific tissues, it is possible to deduce the bioavailability and, by presumption, the level of environmental pollution by specific metals. However, in the case of zinc and copper, their utility is limited to assessing bioavailability because rapid depuration of these metals renders them less useful for long-term environmental monitoring programs. The literature reporting heavy metal impacts on freshwater crayfish, with reference to accumulation levels, is reviewed and summarized with respect to their suitability as bioindicators. Summarized published data from unpolluted or control localities can be used as referential values in crayfish, and consequently help with evaluation of monitored sites.

Alkanolamines in the wastewater from gas treating plants are not readily biodegradable. In this work, we have investigated the effectiveness of the Fenton's reagent (H₂O₂-Fe²⁺) to treat monoethanolamine (MEA) as a model compound in simulated wastewater. Degradation studies were carried out in a jacketed glass reactor. The effects of concentrations of ferrous sulfate, hydrogen peroxide, and the pH of a solution on the rate of reaction were determined. A pH of 3 was found to be the optimum. The degradation reaction proceeds very fast at the beginning but slows down significantly at a longer time. A larger fractional degradation of the organics in solution was observed if the initial chemical oxygen demand (COD) of the feed solution was high. Gradual addition of H₂O₂ to the reaction mixture increased the COD removal by about 60% compared to one-time addition of the reagent at the beginning of the process. A rate equation for mineralization of the amine was developed on the basis of a simplified mechanistic model, and the lumped value of the rate constant for COD removal was determined. A partially degraded MEA solution as well as “pure” MEA was subjected to biological oxidation by activated sludge. The former substrate degraded much faster. The degradation rate and biomass generation data could be fitted by the Monod kinetic equations.

Oil spill leaves detrimental effects to environment, living organisms, and economy. As such, it is of considerable interest to find an effective, simple, and inexpensive method to treat this calamity. This work reports the use of banana trunk fibers (BTF) modified with oleic acid, stearic acid, castor oil, and palm oil for oil spill recovery. The maximum sorption capacity, effect of oil to water ratio, effect of light oil fractions, and effect of dissolved organic compounds in weathered oil-contaminated seawater were studied. It is found that BTF treated with oleic acid exhibited the best sorption capacity for engine oil, dissolved organic compounds in weathered oil, and light oil fractions. The equilibrium process was described well by the Freundlich isotherm model, and the kinetic studies show good correlation coefficients for a pseudo-second-order kinetic model.

Single-particle analysis of short-term aerosol samplings can provide unique information on the rapid evolution of size distribution and chemical composition of industrial aerosols. In this work, the potential of scanning electron microscopy equipped with energy-dispersive X-ray spectrometry (SEM-EDX) for the time-resolved description of physicochemical properties of individual aerosol particles is investigated. Two sampling campaigns were carried out at a densely populated and industrialised coastal site. The first sampling campaign corresponded to low and stable atmospheric particle loads. Low temporal variations in PM₁₀ and PM₂.₅ mass concentrations during the preceding hours and during samplings were observed. In these conditions suitable to evaluate the accuracy of our sampling and analytical methodologies, very low temporal variation of physicochemical characteristics of atmospheric particles were observed, as expected. During the second sampling campaign, the ability of automated SEM-EDX to describe short temporal variation in PM₁₀ and PM₂.₅ chemical composition was demonstrated. We report the tracking of a steelworks emission plume transported over an urban area by means of short-term aerosol samplings and explore how this transient industrial emission contributed to ambient particulates. Steelworks are important point-source emitters of metallic pollutants such as iron, manganese, and zinc species. Detailed assessment of the microphysical and chemical properties of aerosols collected in the vicinity of steelworks enables to precisely describe how industrial aerosols affect the composition of urban particulate matter. The studied pollution event caused dramatic changes in the composition of urban aerosols by an input of fine metallic particles containing Fe, Mn or Zn oxides and mixed particles (Mn-Fe, Zn-Mn, Zn-Fe oxides). Metal-rich particles were often found internally mixed with marine and/or continental compounds, demonstrating how industrial aerosols efficiently coagulate with particles from other sources, thereby acting as carriers of heavy metals.

Composting municipal wastewater sludge may generate composting wastewater (acid washer water and tunnel wastewater) with high ammonium-nitrogen (NH₄-N) concentration; this kind of wastewater is usually generated in a rather small daily amount. A procedure of air stripping with catalytic oxidation was developed and tested with pilot-scale and full-scale units for synthetic disposal of the high NH₄-N wastewaters from composting facilities. In air stripping, around 90% NH₄-N removal efficiency was reliably achieved with a maximum of 98%. A model to describe the stripping process efficiency was constructed, which can be used for process optimization. After catalytic oxidation, the concentrations in the outlet gas were acceptable for NH₃, NOX, NO₂, and N₂O, but the NH₃ and N₂O concentrations limited the feasible loading range. The treatment costs were estimated in detail. The results indicate that air stripping with the catalytic oxidation process can be applied for wastewater treatment in composting facilities.

We evaluated the applicability of a simple passive sampling method to quantify HNO₃(g) in ambient air. The method has the advantages of not only ease of operation but also low cost. A sampling velocity of 214 m day⁻¹ was determined based on the concentration of HNO₃(g) measured by the four-stage filter-pack method at nine sites located within a 250 × 250-km area in Japan. This sampling velocity was applied at sites located outside of area to verify the applicability and accuracy of the simple passive sampling method. The variation in the results for the application of the sampling velocity ranged from 0.39 to 0.95. The simple passive sampling method should be applied to sites with different meteorological conditions, and the obtained data should be used to obtain more significant information and/or to indicate the need for further developments in the methodology.