In this paper, we present a characterization of the optical properties of the aerosols emitted during biomass burning (BB) season in the period 2005–2009. Trends of aerosol optical depth (AOD), Angstrom exponent (α), and precipitable water (PW) were analyzed using a 5-year dataset from AErosol RObotic NETwork (AERONET) observations over Tuxtla Gutierrez (TG), Chiapas. The overall mean AOD (500 nm) during the 2005–2009 period was 0.26 ± 0.18. However, monthly mean values of AOD > 0.5 during the spring months (April and May) would indicate the high load of particles emitted by fires. The overall mean of α (440–870 nm) was 1.40 ± 0.21, which confirms the presence of fine aerosols. Additionally, the combined analysis of the α with its spectral curvature δα, and the results from the spectral de-convolution algorithm (SDA) shows that fine-mode aerosols dominated AOD variability in TG. In this paper, the trajectories of air masses (400 and 1500 m, a.s.l.) arriving at the TG site were classified by using backward trajectory cluster analysis. Trajectory clustering results indicate a BB regional transport from Central America that affects the atmosphere in southeastern Mexico. We use observations of fire radiative power (FRP) from the Moderate Resolution Imaging Spectroradiometer (MODIS) to study the incidence of wildfires and to estimate the BB emissions from 2005 to 2009 in southeastern Mexico. The results indicated a gradual decrease in fires throughout the years. Campeche and Yucatan are the states in southeastern Mexico where BB produces the highest emissions of carbon dioxide (CO₂), carbon monoxide (CO), black carbon (BC), and particulate material PM₂.₅. However, the largest emissions come from wildfires in Guatemala. Finally, to put in context the aerosol optical properties over southeastern Mexico, the sun photometric measurements in TG are compared with those retrieved from AERONET stations located in other tropical biomass burning regions (Brazil and Zambia).

In this paper, nanosized titanium dioxide as catalysts for degrading dye wastewater was in situ synthesized on the surface of cotton fabrics used tetrabutyl titanate as precursor. The morphology and structure of prepared catalysts were characterized by scanning electron microscopy, energy-dispersive spectrometer, and X-ray diffraction. The characterization results showed that anatase nanosized titanium dioxide was successfully synthesized in situ on cotton fabrics and had excellent dispersibility. Subsequently, the effects of irradiation time, catalyst dosage, dye concentration, initial pH value of dye, hydrogen peroxide dosage, and dye type on dye degradation rate were investigated one by one by a photocatalytic performance test. The test results indicated that the degradation rates of methylene blue, methyl orange, and rhodamine B were 90.4%, 81.4%, and 58.3%, separately, at catalyst dosage of 4.8 g/L, initial dye concentration of 10 mg/L, pH of 7, and hydrogen peroxide dosage of 0.24 mol/L, after 4 h of UV irradiation.

The presence of toxic metals in soil enables them to be absorbed by plants. The RDC 42/2013 published by Brazilian Health Regulatory Agency (ANVISA) defines the maximum values of cadmium (0.4 mg kg⁻¹) and lead (0.6 mg kg⁻¹) in yerba mate commercialized in Common Market of the South (Mercosul). This work is a retrospective study that aimed to evaluate cadmium and lead levels in processed yerba mate and in natura leaves in Southern Brazil. The cadmium and lead concentrations in 370 processed yerba mate and 122 in natura leave samples obtained in Southern Brazil were analyzed. In 47.56% of the processed samples, the levels of cadmium and/or lead were found to be above the authorized levels. The cadmium levels found in the processed yerba mate were 0.37 ± 0.19 mg kg⁻¹, and the corresponding values for lead were 0.34 ± 0.21 mg kg⁻¹. Values above the authorized levels were also found in the non-processed leaves. Studies are required to determine whether these levels are natural or represent contamination.

Mobile sources are considered to be one of the most important sources of air pollution among which are motor vehicles, recognized as the major contributor of air pollutants in urban areas. To determine the emissions for CO, SO₂, and NO₂ from motor vehicles as part of the attempt to realize the extent of traffic air pollution, measurements were carried out in two heavily traversed traffic tunnels in Tehran metropolitan area. The concentrations of pollutants and metrological and traffic data were collected through intensive measurements from September 27 to October 17, 2016. Resalat Tunnel fleet was composed of about 10% diesel-fueled vehicles and 90% non-diesel-fueled vehicles while throughout the entire duration of our campaign, only non-diesel-fueled vehicles traversed Niayesh Tunnel. Under an average traffic speed of 43 km h⁻¹, emission factors from Resalat Tunnel campaign were measured to be (6.59 ± 2.69)E+3, (1.42 ± 0.84)E+2, and 6.80 ± 4.99 mg km⁻¹ for CO, SO₂, and NO₂, respectively. These values were respectively 11% higher, 22% lower, and 40% higher than those from Niayesh Tunnel measurements which were recorded at a traffic speed of 30 km h⁻¹. Current results indicate that the vehicular emissions in certain countries, especially the developing ones and in this case, Iran, are quite different from those measured in developed countries and that the high emission levels of SO₂ in Iran are associated with the high sulfur content of the gasoline.

Alkali-leaching residual wire sludge (AWRS) is an abundant by-product in the harmless disposal process of wire rope sludge. In this study, we modified AWRS through thermal treatment to produce a low-cost and highly efficient adsorbent for the removal of Cu²⁺ and Ni²⁺ from wastewater. The results indicated that AWRS calcinated at 700 °C exhibited maximum Cu²⁺ and Ni²⁺ removal capacities (36.48 mg/g and 46.58 mg/g, respectively). The adsorption process was observed to follow the Elovich kinetic model and the Langmuir–Freundlich isotherm model. The sorption of Cu²⁺ and Ni²⁺ on AWRS700 was highly pH dependent and behaved optimally at the solution pH values of 6 and 5, respectively. Column studies and physicochemical analyses (XRD, SEM-EDS, and XPS) indicated that the sorption of Cu²⁺ and Ni²⁺ on AWRS700 was mainly governed by the chemisorption mechanism, and this was attributed to active metal oxides (Fe₂O₃, CaO, and Al₂O₃) in AWRS700. Specifically, Cu²⁺ is mainly adsorbed on AWRS700 in the form of Cu(OH)₂, CuO₂, and CuFeO₂, and Ni²⁺ is mainly adsorbed in the form of NiAlO₄, Ni₂O₃, and Ni(OH)₂. Given the low-cost and high adsorption efficiency of AWRS700, the developed AWRS700 is a promising adsorbent for Cu²⁺ and Ni²⁺ removal from wastewater.

The reduced natural water sources on the one hand and the large amount of wastewater produced by the textile industry on the other hand lead to the requirement of an effective reuse of textile wastewater. In this study, the treatment of textile wastewater by the reverse osmosis membrane system and membrane capacitive deionization (MCDI) system has been investigated to improve the quality and the recovery rate of the effluent for reclamation. The maximum chemical oxygen demand (COD) removal efficiency obtained at 10 bar was 96.3% for BW30 reverse osmosis membrane. Diversified operating conditions, including working voltage and flow rate, were investigated systematically in the MCDI system which is an effective water purification technology. According to the obtained experimental results, the COD removal efficiency was thoroughly increased by rising the working voltage (from 0.2 to 1.2 V) and the flow rate (from 5 to 17.5 ml/min). The flow rate and the working voltage at which the COD from textile wastewater removal ratio was the highest were 10 ml/min and 1.2 V, respectively. A life cycle approach has also been implemented for the comparison of environmental impact assessment of the two desalination systems. In this study, a life cycle approach has been implemented for the comparison of environmental friendly impact assessment of the two desalination systems. It is concluded that MCDI system is much more environmental friendlier with 5641 times less values for damage assessment categories, on average.

In the original publication, the given name of the fourth author was mispelled as Adolp instead of Adolph. The correct name of the fourth author is Adolph Anga Muleja.

Ammonia-oxidixing bacteria (AOB) and archaea (AOA) mediate the first and rate-limiting step of nitrification and are responsive to agricultural management practices. These two attributes make them ideal indicators of biological soil health. We conducted a laboratory incubation study to determine their response to elevated levels of zinc (Zn) and copper (Cu) in poultry litter treated soil at three substrate concentrations: 0 (low), 50 (medium) and 100 (high) mg ammonium ([Formula: see text]-N) kg⁻¹ soil. Nitrification potential (NP) was measured to characterize changes in their function in which 1-octyne was used to separate their contributions. Quantitative polymerase chain reaction was used to measure their abundance by targeting amoA. Increasing Zn from 21 to 250 mg kg⁻¹ resulted in large reductions in AOB (78%) and AOA (85%) abundance at the high [Formula: see text] level over 28 days. Likewise, increasing Cu from 20 to 120 mg kg⁻¹ significantly reduced AOB (92%) and AOA (63%) abundance at the high [Formula: see text] level over 28 days. The relative contribution of AOB to NP was significantly higher than that of AOA in both Zn (~60%) and Cu (~70%) treated soils despite the numerical dominance of AOA over AOB. Overall, results indicate that elevated levels of Zn and Cu depressed AOB and AOA abundance and function and that their effect was dependent on availability of [Formula: see text]. The results also indicated that AOB are functionally more important than AOA under elevated Zn and Cu concentrations and that management practices to improve N use efficiency should focus on AOB under this condition.

The use of aqueous film-forming foams (AFFFs) have been related to environmental contamination due to handling, storage, and use in the firefighting against class B fire. Studies have associated the use of AFFFs with toxic effects from its perfluorinated compounds (PFCs) to the aquatic ecosystem, which led the Stockholm Convention to restrict their use. In Brazil, despite the large-scale use, there is no data on employment or annual commercialization of these products. This study evaluated the toxicity of seven brands of AFFFs used in the firefighting of the petrochemical’s terminal of fuel storage in Port of Santos (Santos, São Paulo, Brazil) which occurred in 2015, in which more than 61,000 L of AFFFs drained into the adjacent aquatic ecosystems. The toxicity evaluation was performed by means of the acute bioassay using the freshwater microcrustacean Daphnia similis. The AFFF brands tested were considered toxic to D. similis, including at much lower dilutions than those recommended by the manufacturers. The brand that showed the lowest toxicity was Kidde Sintex® 3% × 6%, followed by Kidde Sintex® 1% × 3%, Argus Prime®, Cold Fire®, Ageofoam®, and Liovac®, and the one with the highest toxicity was F-500 fire®. These results provide valuable information for the development of public policies aimed at managing the AFFF discharge in freshwater ecosystems.

Plitvice Lakes National Park presents one of the most beautiful karst complexes in the world. Its waters are supersaturated with dissolved calcium carbonate (calcite) which is released and deposited in the form of tiny crystals as a result of water splashing at tufa barriers. Sulphates, present in the particulate matter (PM), can be deposited on the surface of the calcite. In the air, sulphate particles are formed by the oxidation of SO₂ in a series of chemical reactions as reported by Li et al. (Atmospheric Chemistry and Physics 6:2453–2464, 2006). Fast oxidation of SO₂ in nature can also take place on the surface of the calcite in the presence of ozone and is significantly enhanced by high humidity as reported by Li et al. (Atmospheric Chemistry and Physics 6:2453–2464, 2006) and Massey (Science of the Total Environment 227(2–3), 109–121, 1999). The resulting sulphates can destroy the surface of the calcite and indirectly influence the composition and quality of water. Hourly concentrations of ozone, PM₁₀ and PM₂.₅ at the monitoring station Plitvice Lakes in the period from 2012 to 2014 are presented. After assessing the observed values of both PM and ozone, presently there are no significant danger for Plitvice Lakes. However, this can change in the future so continuous monitoring will be necessary in the future.