Polycyclic aromatic hydrocarbons (PAHs) were measured in 32 surface sediment samples collected around three cities (Barcarena, Belém, and Santana) located on the coast of the Brazilian Amazon. The concentration of total PAHs ranged from lower than detection limit to 33,101 ng g⁻¹ in a sample from Barcarena and was related to a large aluminum industrial complex and port activities. In Belém, which is the most populated area in the Amazon region, PAHs were probably derived from untreated sewage discharge and inputs from a large municipal landfill. Pyrogenic PAHs were predominant in both cities, with a smaller contribution of petrogenic PAHs. Low alkylated PAH levels may be associated with small boats and ship traffic. Santana had low total PAH concentrations, with a predominance of unusual alkylated PAHs, probably related to diagenetic transformations of organic matter in the sediment. In general, PAH concentrations in the samples were low and may reflect baseline levels for this Amazon estuarine system.

The transformation of poultry litter waste through the pyrolysis process produces a product called biochar which, applied to the soil, improves its characteristics. The objective of this work was to evaluate the effect of biochar produced from poultry litter wastes, submitted to pyrolysis at 350 °C on soil chemical and physical characteristics. For this, an experiment was carried out involving soil incubation treatments during 100 days with six doses of biochar equivalent to 0.0, 2.02, 4.05, 6.07, 8.10, and 10.12 t ha⁻¹, calculated by the base saturation method, with correction levels from 61 to 87%. After the incubation, soil samples were physically and chemically analyzed. Biochar doses promoted significant increase in pH, electrical conductivity, potassium, sodium, carbon, phosphorus, and base saturation, and decrease in potential acidity and in the soil cation exchange capacity contributing to the increase of soil fertility. The application of the biochar to the soil decreased the bulk density and increased porosity, field capacity, wilting point, and available water for plants. In general, the use of the biochar demonstrates great potential of it as a soil amendment.

Ooty lake, in the southern part of India, has raised huge concern about the role of metals in a lake due to increasing anthropogenic activities. Present study is aimed at understanding fate of trace metals in a lake’s sediment. Sixteen sediment samples collected from bottom of the lake at various locations during March 2017 were analysed for trace metals cobalt, chromium, copper, iron, lead, manganese, nickel and zinc. Fe and Mn dominate total metal concentration followed by Ni and Cr. A high concentration of Cr, Cu, Ni and Zn in residual fraction indicates weathering as the source for these metals. A significant concentration of metals in exchangeable, reducible and oxidisable fraction indicates adsorbtion/chelation of these metals with oxides and organic matter due to change in oxic state. Geo-accumulation index for metals show unpolluted to moderate nature of sediments at all sampling locations. Moderate to significant enrichment factor of Cr, Ni and Zn indicates influence of anthropogenic sources. Co, Pb and Zn show a high amount of bioavailability for aquatic life. Other metals (Cr, Ni, Fe and Mn) show scarce to moderate bioavailability. On the other hand, a global contamination factor denotes moderate to high metal contamination of sediments in the entire lake. Statistical analysis of metals shows good inter-element correlation among metals Fe, Cr, Ni, Co, Cu and Zn indicating natural source. Influence of domestic sewage and recreational activities as the main/additional source is revealed by negative loading of Pb and Zn in principal component analysis. The present study, in essence, has identified rock weathering, as a major source of trace meals in the sediments of Ooty lake entering through stream and surface runoff from an adjacent forest area. The study has also identified high bioavailability of Pb and Zn, which is derived through the recreational activities (boating) causing permanent adverse impact.

The biomass control potential of three metabolic uncouplers (carbonyl cyanide-p-trifluoromethoxyphenylhydrazone (FCCP), carbonyl cyanide m-chlorophenylhydrazone (CCCP), and m-chlorophenol (m-CP)) was tested in biotrickling filters (BTFs) degrading toluene. The experiments employed two types of reactors: a traditional column design and a novel differential BTF (DBTF) reactor developed by De Vela and Gostomski (J Environ Eng 147:04020159, 2021). Uncouplers caused the toluene elimination capacity (EC) (~33 g/m³h for column reactors and ~600 g/m³h for DBTF) to decrease by 15–97% in a dose-dependent fashion. The EC completely recovered in the column reactor in 3 to 13 days, while only partial recovery happened in the DBTF. Short-term (1 to 3 days) true uncoupling was indicated by the 20–160% increase in %CO₂ recovery, depending on concentration. FCCP and CCCP increased the pressure drop due to increased extracellular polymeric substances (EPS) production for protection against the uncouplers. The 4.0-mM m-CP weakened the biofilm in the BTF bed, as evidenced by the 130–500% increase in the total organic carbon in the liquid sump of the column and DBTF reactors. Moreover, a microbial shift led to the proliferation of genera that degrade uncouplers, further demonstrating that the uncouplers tested were not a sustainable biomass control strategy in BTFs.

The disparity of tolerance in plants in response to Cd stress is associated with multiple physiological processes. A pot experiment was conducted to investigate the physiological properties involved in Cd tolerance of a high-cadmium (Cd)-accumulating rice line (Lu527-8) in comparison with a normal rice line (Lu527-4) under different levels of Cd exposure. Lu527-8 showed higher biomass and Cd concentrations compared with Lu527-4. The tolerance index (TI), bioconcentration factor (BCF), and translocation factor (TF) of Lu527-8 could be up to 3.08, 1.48, and 4.50 times these of Lu527-4, respectively. The two rice lines owned a uniform strategy to reduce Cd toxicity in root and stem by Cd deposition in cell wall and compartmentalization in vacuoles instead of keeping Cd in organelles. For Lu527-8, the higher distribution proportions of Cd combined with cell wall in leaf was linked to its higher Cd tolerance in comparison with Lu527-4. Lu527-8 showed a lower decline in membrane stability, antioxidation, photosynthetic parameters, and pigments than Lu527-4 when exposed to Cd stress. Taken together, the results demonstrated that higher Cd tolerance in high-Cd-accumulating rice Lu527-8 is closely linked to its greater abilities of cell wall fixation in leaf, oxidation resistance, as well as osmotic regulation and photosynthesis.

The impacts of vegetation cover changes (VCCs) and land use land cover changes (LULCCs) on climate variabilities need to be addressed while maintaining healthy urban development. This study aimed to evaluate LULCCs and VCCs and their impacts on land surface temperature (LST) and rainfall in the Darbhanga district of Bihar, India. Landsat data and climate hazard group infrared precipitation with stations (CHIRPS) were used to assess LST or LULCCs and rainfall, respectively, over the study area. Results showed a decline in vegetation cover to 11.73% (26,857.43 ha) in the year 2019 from 19.12% (43,733.61 ha) in 1999. Also an increase in built-up and cropland by 4.9% (11,224.6 ha) and 4.38% (10,043.2 ha), respectively, was observed in the last 20 years. With decreasing vegetation cover in the study area, the mean LST increased while the mean annual rainfall decreased for the study period. The Mann–Kendall trend (MKT) test exhibited no significant trends for LST and rainfall with p values of 0.43 and 0.69, respectively, although Sen’s slope indicated variability in LST and rainfall even though it was insignificant over the study area. The study would identify areas requiring immediate action for saving its resources and providing insight into upholding its competence. The findings would also lead to proper decision making for the concerned stakeholders, assuring sustainability in appropriate planning of land use and utilisation of resources and maintain the agroclimatic condition.

Water contamination is a common problem, especially considering dyes and drugs disposal. A possible and effective treatment method to remove these organic pollutants from water is photocatalytic reaction. This study aimed to improve the photocatalytic properties of TiO₂ using iron oxides (Ti/Fe composite). Different magnetic photocatalysts based on commercial TiO₂ were obtained with 30, 50, and 80% (wt./wt.) of TiO₂ supported on maghemite. X-ray diffraction with Rietveld refinement confirms the presence of γ-Fe₂O₃, α-Fe₂O₃, anatase, and rutile, as well as the relative percentages of the phases present in each photocatalyst. The magnetic properties were certified by VSM and sedimentation kinetics in the presence of a magnetic field. Besides their magnetic properties, UV-vis DRS shows that the obtained photocatalysts presented lower bandgap values when compared with TiO₂. These factors allowed the materials to absorb radiation in the visible-light region and the separation from the reaction medium by the application of magnetic field. It was observed an enhancement of photodegradation reaction of methylene blue (MB) and paracetamol (PC). For example, when the content of TiO₂ increased from 30 to 80% (wt./wt.), the efficiency increased from 58 to 99% (for MB) and 39 for 80% (for PC) under UV (λ = 254 nm). The reactions carried out with solar radiation showed 56 to 95% efficiency to discolor MB. In addition, the results of sedimentation kinetics and characterization confirmed the goals of the synthesis.

This manuscript deals with the bioremediation of aqueous media containing Cd²⁺ and Pb²⁺ by using dead biomass of the fungus Phialomyces macrosporus. This filamentous fungus with 19.1 m² g⁻¹ of surface area showed promising adsorption results, since more than 80 % of Cd²⁺ and Pb²⁺ were removed from synthetic aqueous media. Adsorption isotherms from this fungal biomass were satisfactorily linearized (R² > 0.95) by the mathematical Langmuir model and maximum adsorption capacities (MAC) were 1.03 × 10⁻⁴ and 6.48 × 10⁻⁵ mol g⁻¹ for Cd²⁺ and Pb²⁺, respectively. In turn, Gibbs free energy variations were about –25 kJ mol⁻¹, thus highlighting predominantly physical adsorptions. Concomitant cations decreased Cd²⁺ and Pb²⁺ MAC values by up to 72.6 % and 70.4 %, respectively, although this limitation has been largely circumvented after increasing the amounts of fungal biomass. As an environmental application of the biosorption of Cd²⁺ and Pb²⁺ on Phialomyces macrosporus, real chemical laboratory wastewaters were successfully treated with this filamentous fungus, thus meeting the Brazilian legal standards for cadmium (≤ 1.8 × 10⁻⁶ mol L⁻¹) and lead (≤ 2.4 × 10⁻⁶ mol L⁻¹). Based on these results and considering that the use of Phialomyces macrosporus to adsorb cadmium and lead is being evaluated for the first time, the original contribution of this study was to broaden the understanding of bioremediation mechanisms.

Green technology innovation is an important way to solve the dilemma of economic growth and environmental protection, while the relevant policies issued by the government have an important impact on the promotion of regional green technology innovation. This paper regards the implementation of the Regional Planning of Yangtze River Delta (RPYRD) as a quasi-natural experiment, using the panel data of 274 cities in China from 2003 to 2016 to explore the green technology innovation effect of regional planning and its transmission mechanisms through the double-fixed effect model and the difference-in-difference (DID) method. The results show that (1) the implementation of the RPYRD promotes regional green technology innovation significantly and the green technology innovation effect of the policy is increasing year by year. (2) There is significant regional heterogeneity in the incentive effect of green technology innovation in regional planning. The policy effect is more obvious in cities with a larger scale, a higher level of human capital and less resource dependence. (3) The regional planning promotes green technological innovation by optimizing industrial structure, reducing FDI and increasing R&D investment.

The development of economies and energy usage can significantly impact the carbon dioxide (CO₂) emissions in the Middle East and North Africa (MENA) countries. Therefore, this study aims to analyze the factors that determine CO₂ emissions in MENA under the environmental Kuznets curve (EKC) framework by applying novel quantile techniques on data for CO₂ emissions, real income, renewable and non-renewable energy consumption, and urbanization over the period from 1990 to 2015. The results from the estimations suggest that renewable energy consumption significantly reduces the level of emissions; furthermore, its impact increases with higher quantiles. In addition, non-renewable energy consumption increases CO₂ emissions, while its magnitude decreases with higher quantiles. The empirical results also confirm the validity of EKC hypothesis for the panel of MENA economies. Policymakers in the region should implement policies and regulations to promote the adoption and use of renewable energy to mitigate carbon emissions.