The clastogenicity of the water of a lake was investigated using the Tradescantia micronuclei test (Trad-MCN). Genomic damage in the plant’s generative sphere is manifested by a significant increase in micronuclei frequency in all samples. An integrative statistical analysis linked the test endpoints with metals present in low concentration in the lake’s water. Thorough comparisons of the results obtained from Tradescantia stamen hair mutation test (Trad-SHM) were conducted for each of the seven study stations. The performances of both tests used for indicating the genotoxic potential of the lake’s water were compared. Although both tests demonstrated significant genetic disturbances (in pollen mother cells of the plant and during active cell division in the stamen hair), a similar indication of the level of toxicity per site has been produced by the endpoints of Trad-MCN and the non-surviving stamen hair endpoint of Trad-SHM. The integration of the results of both Tradescantia-based assays could be recommended for improving the assessment of the genotoxic potential of natural freshwater.

Clayey soils have been used as liners at the base of waste deposits due to their geotechnical characteristics and capacity to adsorb metallic cations. However, a number of soils may not possess all required properties to ensure contaminant retention and therefore require additives. This study investigated whether the addition of commercial peat to a tropical residual soil (from the Ribeira Valley, Brazil) could improve its lead (Pb) and cadmium (Cd) adsorption capacity for its use as a liner in mining waste disposal. Pure soil and 10 and 20% soil-peat mixtures were compared. The application of peat increased the organic matter (OM) content (from 9 g kg⁻¹ in soil to 58 g kg⁻¹ in the 20% soil-peat mixture) and the cationic exchange capacity (CEC) (from 41.4 mmolc dm⁻³ in soil to 143.1 mmolc dm⁻³ in the 20% soil-peat mixture). Batch equilibrium test results revealed that the maximum Pb adsorption capacity of 623.6 μg g⁻¹ also increased (to 1089.1 and 1270.0 μg g⁻¹ in the 10 and 20% soil-peat mixtures, respectively). The soil Cd adsorption capacity of 261.2 μg g⁻¹ increased to 304.0 and 631.3 μg g⁻¹, respectively, with increasing peat proportions. The results suggest that peat can improve soil liner performance in waste deposits. Soil-peat mixtures are alternatives for minimizing potentially toxic metal contamination with available and low-cost materials.

Three different synthesis methods were applied to obtain TiO₂ nanoparticles: microwave-assisted hydrothermal (TiO₂-MW), sonochemical (TiO₂-US), and polymeric precursor (TiO₂-PP). The nanoparticles thus obtained presented 93% (TiO₂-MW) and 92% (TiO₂-US) anatase phase, and TiO₂-PP 93% rutile phase. The TiO₂-US sample performed best during the Prozac® photodegradation assays because of its lipophilic surface, attributable to the C-H groups therein. Additionally, adsorption rate and photodegradation were optimized by adjusting Prozac® solution to pH ~ 8. Following Prozac® photodegradation, quantitative monitoring of its by-products (PPMA, MAEB, and TFMP) was done using HPLC. This quantitative approach led us to conclude that semiconductor photoactivity cannot be discussed solely in terms of the main compound. Lastly, it was seen that these by-products compete with each other in the degradation mechanisms and are influenced by different materials. Graphical abstract

A BiVO₄-WO₃ nano-composite (NC) was hydrothermally prepared and characterized by different techniques including X-ray diffraction (XRD), scanning electron microscope equipped with an energy-dispersive X-ray (EDX) analyzer, X-ray mapping, UV-Vis reflectance spectroscopy (DRS), and photoluminescence spectroscopy (PL). The average crystallite size of 8.5 nm was estimated for the composite by the Williamson–Hall equation. The band gap energies of 2.46, 3.02, and 2.95 eV were obtained for the direct electronic transitions of BiVO₄, WO₃, and the composite, respectively. The point of zero charges (pHpzc) of the composite was also estimated at 5. The composite was then used in the photodegradation of sulfasalazine (SSZ). When the moles of WO₃ was four times greater than BiVO₄, the best photocatalytic activity and the lowest PL intensity were obtained. The simultaneous effects of the experimental variables on the boosted photocatalytic activity of the composite (to the single semiconductors) were studied by the response surface methodology (RSM). A significant quadratic model was confirmed for processing the data based on the F value of a model F value of 63.55 > F₀.₀₅, ₁₄, ₁₃ = 2.55. This was also confirmed by LOF F value of 2.56 < F₀.₀₅, ₁₀, ₃ = 8.79. Besides, the multiple correlation coefficients R² (R² = 0.9856), adjusted R² (adj-R² = 0.9701), and predicted R² (pred-R² = 0.9098) confirm the goodness of the model. The optimal run included CSSZ 9 mg/L, pH 4, 40 min irradiation time, and 0.8 g/L of the composite under the visible light irradiation.

Immobilization using biochar is a cost-effective and environmentally friendly remediation method to inhibit the transfer of soil contaminants to the food chain. This study evaluated the effects of coconut shell–derived biochar (CSB) and sewage sludge–derived biochar (SSB) on reducing the accumulation of cesium (Cs) by plant from contaminated soil. Pot experiment was conducted by cultivating Napier grass on the soil added with different Cs concentrations (0, 25, and 50 mg kg⁻¹) and biochar ratios (0: control, 5% and 10%). It was observed that both biochars significantly restricted the transfer of Cs to the root, leaf sheath, and leaf blade of Napier grass (p < 0.01). The possible mechanisms of Cs immobilization by biochar could be the sorption of Cs on the surface of biochar as well as the restriction of the uptake of Cs by plant due to the increased K concentration of biochar-amended soil. CSB application was more effective than SSB on reducing the transfer of Cs to plant. Compared to control, the CSB application reduced the concentration of Cs in the plant by 80.2–98.2%. Moreover, obtained results in terms of pH, organic matter content, cation exchange capacity, specific surface area, and K concentration of biochar-amended soil highlighted the remarkable efficiency of CSB to adsorb Cs and restrict Cs transfer to plant providing the key evidences for Cs immobilization. Considering these results, CSB could be a potential amendment for the immobilization of Cs-contaminated soil.

The effects of pyrolysis temperature (350, 450, and 550 °C) on the properties of biochar prepared from chicken manure (CM), dairy manure (DM), and their digestates (CMD and DMD) were investigated in this study. The physicochemical properties and the transformation of phosphorous and heavy metal forms in various types of biochar were analyzed, and the bioavailability was assessed to optimize the pyrolysis condition towards biochar land application. The larger specific surface area was found in CM and CMD derived biochars (14.90–22.45 m²/g), as compared to DM and DMD derived biochars (1.17–7.36 m²/g). The highest contents of total phosphorous (TP) and bioavailable non-apatite inorganic phosphorus (NAIP) were obtained in DMD biochar, i.e., 49.31 and 27.03 mg/g TS, respectively. Cu and Zn are identified as the harmful heavy metal elements in manure derived biochars due to its high level of total concentration. When increasing pyrolysis temperature, the fractions of Zn and Cu in exchangeable-, carbonate-, and the organic-bonded state decreased and the fractions of manganese oxidized and residual state increased. Finally, the citric acid leaching treatment was proposed to decrease the Zn and Cu contents in biochar before land application. The overall leaching rates for Cu and Zn were 37–45% and 27–32%, respectively.

This study investigated the removal of heavy metal ions from industrial wastewater by using rice and corn husk biochar. The choice of the materials was influenced by their large surface area, abundance of functional groups as well as their availability in the local environment. Rice and corn husks were pyrolyzed at 500, 600, and 700 °C to make biochars that were used to treat low-quality industrial wastewater. Initial metal ion levels in wastewater and residual levels after the application of biochars were measured using an atomic adsorption spectrophotometer. Carbonization of rice husks at 600 °C produced the best removal efficiencies for Cr (65%), Fe (90%), and Pb (> 90%). The carbonization of corn husks at 600 °C produced the worst removal efficiencies for Cr (only 20%) and Pb (slightly > 35%). Regardless of the carbonization temperature, rice husk biochars performed better than corn husk biochars. Experimental data fitted well the Langmuir and Freundlich isotherm models (R² values ranging between 0.82 and 0.99). The Langmuir separation factor, RL, had negative values, probably due to the low initial concentration of the adsorbates in the raw wastewater. All the biochars showed a relatively short contact time (20 to 30 min) to attain maximum adsorption efficiencies and are a promising feature for future industrial applications. The studied biochar materials from rice and corn husk have the potential to remove heavy metal ions from industrial wastewater; rice husk biochar showed higher removal capacity than corn husk biochars.

Degradation-resistant chemical contaminants of health concern such as dichlorodiphenyltrichloroethane (DDT) pesticides and polychlorinated biphenyls (PCBs) in the environment are redistributed between different environmental compartments, where they partition between biotic heterotrophic routes and abiotic features (water and immobile soil components). Their fate and the potential risk they pose is a function of translocation, interaction, environmental behavior, and bio-translation/activities. In this study, the partitioning, translocation, bio-translation pathways of 3-DDT and 6-PCB congeners in dosed soils cultured root and leaf vegetables were investigated to predict their soil–vegetable mobility, depuration, and exposure risk. Results showed that PCB_110 and PCB_180 were the least and highest PCBs concentrated in both the leaf and root vegetables. The variations in the 3-DDT and 6-PCB concentrations in the leaf and root vegetables may be attributed to differences in their solubility and partitioning. Total residual mass fraction 3-DDT taken up by the leaf and root vegetables indicated time-dependent preferentiality in pesticide-type vascular tissue translocation to the vegetables. Mann–Whitney non-parametric test showed evidence of spatial variations in levels of the 3-DDT and 6-PCBs across the farmland; however, the variations in the distribution were not significant (PFML₁–FML₆ <<Pₛₜₐₜ). Risk factors for 3-PCBs and 3-DDT tend to 1(f < 1.0), while that for PCBs_149, 153, and _180 were far less than 0.4 (<1.0). It is therefore uncertain that any immediate health risks could arise from exposure to vegetables containing such congener levels. Continuous exposure to an extrapolated estimate of 25% vegetable population has a 20 ± 10% probability of leading to undesirable chronic effects.

Air pollution has an important impact on both human health and sustainable economic development. The relationship of the current account, which is an important carrier of international economic activity, with air pollution has rarely been discussed by scholars. This paper aims to investigate how air pollution affects the current account and the mechanism of this effect. We conducted a theoretical analysis of the relationship between air pollution and the current account by adopting an extended form of the life-cycle model. Then, we used panel data (2000–2017) from 159 countries and the panel double fixed-effect method to empirically test the theoretical outcomes. We found that an increase in the degree of air pollution in a country leads to the deterioration of the domestic current account. In addition, air pollution changes the current account by affecting the demographic structure, following the “air pollution→demographic structure→current account” mechanism. The study also tested the robustness of the benchmark results by solving endogeneity problems, subsample regression and controlling measurement errors. Our findings are an important expansion and innovation for the research about the current account and have important implications for external economic equilibrium and sustainable economic development.

To assess the ecological risk resulting from an accidental gasoline spill upstream from a wetland, groundwater and sediment sampling was carried out during two campaigns at the 48th and 52nd months after the spill had occurred. In total, 21 groundwater monitoring wells in the affected area were sampled plus an additional reference well located upstream from the accident location. Seven sediment sampling points were selected inside the wetland, plus a reference point upstream from the accident. Physicochemical parameters, BTEX (benzene, toluene, ethylbenzene, m-xylene, p-xylene and o-xylene) and metal concentrations were analysed to estimate the chemical risk. Acute (Allivibrio fischeri, Daphnia similis, Hyalella azteca) and chronic (Artemia salina and Desmodesmus subspicatus) toxicity assays were performed with groundwater and sediments elutriate to determine the ecotoxicological risk. Results from groundwater indicated an extreme chemical level of risk in14 out of 21 monitoring wells. These 14 wells also exhibited free-phase gasoline and lead (Pb) concentrations above the threshold values adopted by this study. The presence of Pb, however, could not be associated with the gasoline accident. High acute and chronic toxicities were reported for the majority of wells. Conversely, the risks associated with the sediments were considered low in most sampling points, and the ecotoxicity found could not be related to the presence of gasoline. Groundwater flow modelling results have evidenced the migration of the contamination plume towards the wetland. Thus, to prevent contamination from reaching the protected area, more effective groundwater clean-up techniques are still required.