Contamination of soil by heavy metals is among the important environmental problems due to their toxicity and negative impact to human health and the environment. An effective method for cleaning the soil from heavy metals is phytoremediation using the second-generation bioenergy species Miscanthus × giganteus. The purpose of this research is to study the benefits of M. × giganteus cultivation at the soils taken from the mining and former military sites contaminated by As, Pb, Zn, Co, Ni, Cr, Cu, V, Mn, Sr, and U as well as at the soil artificially contaminated by Zn and Pb, to evaluate the physiological parameters of the plant, to establish peculiarities of the phytoremediation process, and to characterize the behavior of the plant in relation to the nature and concentrations of the metals in the soils. Results showed that M. × giganteus was resistant to heavy metals (tolerance index ≥ 1) and that the greatest portion of metals accumulated in the root system. The morphological parameters of the plant while grown on different soils are influenced by soil type and the content of contaminants. The stress effect while growing M. × giganteus on soil artificially contaminated by Zn and Pb was evaluated by measuring the content of pigments (chlorophylls a, b, and carotenoids) in the plant’s leaves. The decrease in the total content of chlorophylls, Сₐ ₊ b/Сcₐᵣ and transpiration rate of water along with the increase in the water absorbing capacity were observed. The accumulation of heavy metals in different parts of the plant was determined; bioaccumulation coefficient and values of translocation factor were calculated. The obtained results showed that M. × giganteus was an excluder plant for nine highly toxic elements (As, Pb, Zn, Co, Ni, Cr, Cu, V, U) and an accumulator species for the moderately dangerous elements (Mn, Sr). Further research will be focused on the extraction of stable stimulated plant-growth–promoting rhizobacteria from the rhizosphere of M. × giganteus and formulation on that base the plant-bacterial associations as well as on the comparison of the plant physiological parameters, biochemical soil activity, and accumulation of heavy metals in the Miscanthus tissues between first and second vegetations.

It was the aim of this work to evaluate the adsorptive performance of the biochar obtained from the gasification of wood residues onto a solution of Indosol Black NF1200 dye. The study was performed by means of factorial design 2², having as control variables: pH and adsorbent’s granulometry. Batch tests were carried out at 200 rpm for 3 h (T = 28 °C). As output variable, the percentage removal of dye was determined. The best operating conditions were pH = 2 and 100 mesh granulometry. Also, adsorbent dosage studies were carried out, as well as equilibrium and adsorption kinetics. Both kinetics and equilibrium of adsorption tests were proceeded in basic and acid medium. For a basic pH value (pH = 12), it was concluded the equilibrium was reached in about 3 h of experiment, the experimental qₘₐₓ value was near 12 mg g⁻¹, and the equilibrium data fitted the Langmuir model. On the other hand, for tests with pH = 2, the equilibrium was reached after 5 min of experiment, the experimental qₘₐₓ value was over 185 mg g⁻¹, and the equilibrium data fitted both the Langmuir and Freundlich models. Thus, the biochar produced via gasification of wood wastes appears to be a promising adsorbent for the removal of azo dyes from textile wastewater, especially when working at lower pH values. Also, for a 10-kg/h consumption of wood residue, approximately 10 kW of energy is generated and 1 kg of biochar is produced, which represents another advantage from the environmentally friendly point of view. Graphical abstract

Leakage of hydrocarbon fuel (light nonaqueous-phase liquid, LNAPL) from petroleum processing facilities and storage tanks may result in significant subsurface contamination. Remediating the contaminated areas represent considerable challenges, especially when remediation resources are limited and site data are incomplete. A reasonable management strategy under this scenario may be to identify sites where LNAPL recovery operations should be located that would provide the largest LNAPL recovery initially while minimizing the LNAPL remaining in the subsurface (entrapped and residual LNAPL), which may serve as future sources for groundwater contamination. To accomplish this objective, we use estimates of subsurface recoverable and total LNAPL specific volumes and LNAPL transmissivities to generate GIS maps that can be combined to highlight locations where to develop LNAPL recovery operations. When the approach is applied to a LNAPL-contaminated area in Iran, we were able to narrow the locations for potential LNAPL recovery operations. Specifically, we combine maps of the LNAPL specific yield, an introduced term, and the LNAPL transmissivity where the LNAPL specific yield is the ratio of the recoverable to total LNAPL specific volumes. The LNAPL specific yield is a relative measure of the amount of LNAPL that potentially can be recovered while minimizing residual LNAPL in soils. The approach can be applied to sites where the recoverable and total LNAPL specific volumes and LNAPL transmissivities can be estimated using data from boreholes in the contaminated area.

Polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) are ubiquitous and toxic contaminants. Their atmospheric deposition fluxes on the regional scale were quantified based on simultaneous sampling during 1 to 5 years at 1 to 6 background/rural sites in the Czech Republic and Austria. The samples were extracted and analysed by means of gas chromatography coupled to mass spectrometry. For all seasons and sites, total deposition fluxes for Σ₁₅PAHs ranged 23–1100 ng m⁻² d⁻¹, while those for Σ6PCBs and Σ12OCPs ranged 64–4400 and 410–7800 pg m⁻² d⁻¹, respectively. Fluoranthene and pyrene were the main contributors to the PAH deposition fluxes, accounting on average for 19% each, while deposition fluxes of PCBs and OCPs were dominated by PCB153 (26%) and γ-hexachlorobenzene (30%), respectively. The highest deposition flux of Σ₁₅PAHs was generally found in spring, while no seasonality was found for PCB deposition. For deposition fluxes for Σ₁₂OCPs, no clear spatial trend was found, confirming the perception of long-lived regional pollutants. Although most OCPs and PCBs hardly partition to the particulate phase in ambient air, on average, 42% of their deposition fluxes were found on filters, confirming the perception that particle deposition is more efficient than dry gaseous deposition. Due to methodological constraints, fluxes derived from bulk deposition samplers should be understood as lower estimates, in particular with regard to those substances which in ambient aerosols mostly partition to the particulate phase.

The objective of this research is to examine the effects of stock market on air pollution in Malaysia during the period 1980–2017. To realize this aim, a nonlinear autoregressive distributed lag (ARDL) model is constructed. The short results in general revealed that the increase in stock markets will increase CO₂ emissions and its significance increases in the long run. Moreover, the decline in stock market will reduce Malaysia’s CO₂ emissions but only in the long run. From the outcomes obtained, a number of policy recommendations were provided for the investigated country.

Although the role that renewable energy consumption plays on economic growth and emissions has been widely studied, there are relatively few papers focusing on the determinants of renewable energy consumption, and only one study focuses on the factors related to the share of renewables in the energy consumption in Africa. This paper contributes to the literature by filling the gap in knowledge by exploring the nexus between the share of renewables in energy consumption and social and economic variables, for a panel consisting of 21 African countries for the period between 1990 and 2013, extending the set of variables and the time span used by a previous study. Estimating a random-effects generalized least squares regression, we find that countries with a higher Human Development Index and a higher gross domestic product per capita have a lower share of renewable energy in the national grid. On the other hand, an increase in foreign direct investment has been found to be related to higher renewable energy integration. The level of democracy, measured by the Freedom House political rights and civil liberties ratings, does not directly affect the integration level of renewable energy sources. The negative relationship between gross domestic product per capita and the share of renewables contradicts previous findings for developed countries. This contradiction and policy implications are discussed in the light of the review of the energy mix of the selected countries.

The authors investigated the arsenic (As) accumulation in different tissues (muscle, gill, liver, stomach, and intestine) and the possible correlation between tissue concentration and hematological parameters in mullet (Mugil cephalus Linnaeus, 1758) caught in Faro Lake (Messina, Sicily, Italy). On all fish, hematological analyses of blood samples, measurement of biometric indices, and the removal of the muscles, gills, liver, stomach, and intestine for the determination of arsenic concentration were performed. A hemogram was performed to find effects of arsenic concentration in tissues on hematological variables. One-way analysis of variance showed significant differences of arsenic concentration in different tissues, with higher values in the gill. The correlation between hematological parameters and tissue arsenic concentration showed a statistical significance for red blood cell (RBC), hemoglobin concentration (Hb), and hematocrit (Hct) with the liver As concentration. Biometric indices (weight, length, and fork length) showed a significant correlation with As concentration of the muscle and liver also. Our results indicate the role of some hematological parameters as biomarkers useful to monitoring anthropogenic load of arsenic in water and sediment, because variations of these parameters represent one of the effects that arsenic exposure can have on fish.

The disposal of food waste has attracted worldwide attention. Each year, the amount of wasted food accounts for an estimated one third of annual food production globally. This large amount of food waste has caused serious land, water, and air pollution. In the past, most research on food waste was focused solely on food waste disposal processing. Only a few studies analysed the flow of materials in food waste treatment processes. Therefore, this paper focused on the process of food waste anaerobic treatment in Beijing and investigated the treatment. According to a life cycle theory, the food waste treatment process is divided into three processes: “collection and transportation, disposal, and resource utilization.” This paper analysed the input and output of food waste treatment in different processes and evaluated the economic and environmental costs and benefits of food waste treatment. The study found that 200 t of food waste anaerobic treatment can obtain benefits 66,888 Chinese yuan, generate electricity energy 43,350 kW⋅h, and reduce carbon dioxide emissions 16,087 kg. Generally, the economic and environmental benefits of the food waste anaerobic treatment project are considerable. However, the economic benefits are mainly from government subsidies. There are many impurities in food waste, which indicates some problems in food waste treatment. Thus, the proposals to strengthen waste classification, optimize the layout of garbage collection and transportation, and accelerate the development of waste treatment plants have been put forward.

In this study, the levels of 11 heavy metal(loid)s (HMs) were determined in ten different fish species (wild, farmed, freshwater, and marine) frequently consumed in Turkey and compared with the maximum permissible limits (MPLs) established by international standards. Also, human health risks for the consumers were assessed. Among 11 HMs, only Al and Cr levels did not show significant differences among fish species. The highest concentrations of As were found in red mullet, which is a demersal fish. The average concentrations of Cd, Cr, Cu, and Pb in all fish species were below the MPLs, whereas those of Zn in European anchovy and Mediterranean horse mackerel, and that of inorganic As in red mullet exceeded the MPLs. The highest and lowest toxic metal contents (Al, As, Cd, and Pb) were recorded in red mullet and farmed rainbow trout, respectively. The estimated daily intakes of HMs in each fish species were very lower than their corresponding tolerable daily intakes, suggesting the daily intake of HMs through fish consumption would not pose health risks for the consumers. The target hazard quotient for individual HMs and hazard index for combined HMs in fish species were below 1, which indicated that non-carcinogenic health effects are not expected. The carcinogenic risk results revealed that there was a carcinogenic risk from exposure to inorganic As via the consumption of red mullet. Among all investigated fish species, rainbow trout and common carp were safer in terms of both non-carcinogenic and carcinogenic risks from exposure to HMs.

Mining is known as one of the primary economic activities where exploitation of minerals and other materials have become essential for human development. However, this activity may represent a risk to the environment, starting from deforestation and ending with production of residues that might contain potentially toxic elements. Tailing deposits from historical mining are an example of waste that may represent an environmental concern when abandoned and exposed to environmental conditions. The town of Nacozari de Garcia, in northwestern Mexico, has three abandoned mine tailings (locally known as tailings I, II, and III) located around the urban area that represent important sources of dust and pollution. Images obtained using unmanned aerial vehicles (UAV) in conjunction with geochemical data are used to assess historic erosion calculation and pollution considering contamination and hazard indexes in tailings II and III. Digital elevation models of abandoned tailings were obtained using photogrammetry with UAV. A total of 37 surficial samples were collected from mine tailings to determine elemental concentrations (As, Cu, Pb, W, Zn) using portable X-ray fluorescence. Higher concentrations were found on samples from mine tailing II. Average concentrations followed the decreasing order of Cu > Zn > W > Pb > As for tailing II, whereas decreasing order of Cu > Zn > W > As > Pb was found for tailing III. Contamination Index (CI) values obtained from tailings II and III represent a low potential of pollution, whereas efflorescent crusts from these tailings represent a high potential of polluting soils and sediments by dust generation. Hazard Average Quotient (HAQ) values on both tailings suggest a very high potential of contamination if fluids infiltrate tailings and interact with surficial water and/or groundwater. Obtained surfaces of mine tailings II and III are 146,216 and 216,689 m², respectively, which represent around 11% of the urbanized area. A loss mass of 321,675 tons was determined for mine tailing II, whereas 634,062 tons for tailing III, accounting for 0.96 million tons of total eroded mass. Since abandonment, calculated erosion rates of 493 t ha⁻¹ year⁻¹ (tailing II) and 232 t ha⁻¹ year⁻¹ (tailing III) are in agreement with those determined in other mining areas. CI and HAQ indexes provide good estimates of pollution associated with abandoned mine tailings from Nacozari de García. Historic erosion determined in these tailings is an environmental concern since eroded material and polluted water have been incorporated into the Moctezuma River, which feeds several villages, whose major activities include agriculture and livestock raising.