Concentrations of five heavy metals (Cr, Cu, Cd, Hg, and Pb) in orchard soils and kiwifruit tissues (root, twig, leave, fruit) collected from Shaanxi province in China were measured, and the potential health risk for human through the fruit consumption was assessed. The orchard soils were in no pollution for Cr, Cu, Hg, and Pb, with their pollution index (PI) ≤1, while 10.0 % of the soil samples were under Cd contamination. Furthermore, kiwifruit tended to have a higher Cd and Hg accumulation (as indicated by Biological Accumulation Coefficient) from soil and have a higher Cu and Hg translocation (as reflected by Biological Transfer Coefficient) to aboveground parts. From the human health point of view, the DIM and HRI values for all the fruit samples were within the safe limits, while for Cr, Cu, Cd, Hg, and Pb, about 22.5, 12.5, 52.5, 15.0, and 47.5 % of the fruit samples exceeded the national maximum permissible levels, respectively. These results showed that, although there was no possible health risk to consumers due to intake of studied kiwifruit fruits under the current consumption rate, the regular survey of heavy metal pollution levels should be performed for the kiwifruit in Shaanxi province and a strict management program should be established to reduce the amount of chemical fertilizers and pesticides used in fruit production in order to prevent the potential health risk.

To estimate the combined effects of elevated CO₂ and temperature on microalgae, three typical and worldwide freshwater species, the green alga Scenedesmus acuminatus, the diatom Cyclotella meneghiniana, and the cyanobacterium Microcystis aeruginosa, as well as mixes of these three species were continuously cultured in controlled environment chambers with CO₂ at 390 and 1000 ppm and temperatures of 20, 25, and 30 °C. CO₂ and temperature significantly affected the production of microalgae. The cell productivity increased under elevated CO₂ and temperature. Although the green alga dominated in the mixed culture within all CO₂ and temperature conditions, rising temperature and CO₂ intensified the competition of the cyanobacterium with other microalgae. CO₂ affected the extracellular polymeric substances (EPS) characteristics of the green alga and the cyanobacterium. Elevated CO₂ induced the generation of humic substances in the EPS fractions of the green alga, the cyanobacterium, and the mixed culture. The extracellular carbohydrates of the diatom and the extracellular proteins of the cyanobacterium increased with elevated CO₂ and temperature, while the extracellular carbohydrates and proteins of the green alga and the mixes increased under elevated CO₂ and temperature. There were synergistic effects of CO₂ and temperature on the productivity and the EPS of microalgae. Climate change related CO₂ and temperature increases will promote autochthonous organic carbon production in aquatic ecosystems and facilitate the proliferation of cyanobacteria, which potentially changes the carbon cycling and undermines the functioning of ecosystems.

Ammonia is a key alkaline species, playing an important role by neutralizing atmospheric acidity and inorganic secondary aerosol production. On the other hand, the NH₃/NH₄ ⁺ increases the acidity and eutrophication in natural ecosystems, being NH₃ classified as toxic atmospheric pollutant. The present study aims to give a better comprehension of the nitrogen content species distribution in fine and coarse particulate matter (PM₂.₅ and PM₂.₅–₁₀) and to quantify ammonia vehicular emissions from an urban vehicular tunnel experiment in the metropolitan area of São Paulo (MASP). MASP is the largest megacity in South America, with over 20 million inhabitants spread over 2000 km² of urbanized area, which faces serious environmental problems. The PM₂.₅ and PM₂.₅–₁₀ median mass concentrations were 44.5 and 66.6 μg m⁻³, respectively, during weekdays. In the PM₂.₅, sulfate showed the highest concentration, 3.27 ± 1.76 μg m⁻³, followed by ammonium, 1.14 ± 0.71 μg m⁻³, and nitrate, 0.80 ± 0.52 μg m⁻³. Likewise, the dominance (30 % of total PM₂.₅) of solid species, mainly the ammonium salts, NH₄HSO₄, (NH₄)₂SO₄, and NH₄NO₃, resulted from simulation of inorganic species. The ISORROPIA simulation was relevant to show the importance of environment conditions for the ammonium phase distribution (solid/aqueous), which was solely aqueous at outside and almost entirely solid at inside tunnel. Regarding gaseous ammonia concentrations, the value measured inside the tunnel (46.5 ± 17.5 μg m⁻³) was 3-fold higher than that outside (15.2 ± 11.3 μg m⁻³). The NH₃ vehicular emission factor (EF) estimated by carbon balance for urban tunnel was 44 ± 22 mg km⁻¹. From this EF value and considering the MASP traffic characteristics, it was possible to estimate more than 7 Gg NH₃ year⁻¹ emissions that along with NOx are likely to cause rather serious problems to natural ecosystems in the region.

Although numerous studies have shown the presence of polybrominated diphenyl ethers (PBDEs) in various environmental media, attention to their distribution in the environmental media surrounding industrial facilities is limited. In this study, eight PBDEs congeners (BDE-28, −47, −99, −100, −153, −154, −183, −209) were investigated in surface soils and water samples collected from commercial PBDE manufacturers, flame-retardant plastic modification plants and waste electrical and electronic equipment recycling facilities in China. Analysis of target compounds was performed using the model NCI GC-MS in SIM mode. The concentrations of ∑₈PBDEs varied from 193.1 to 22,004.3 ng/L in water samples and from 1209.3 to 226,906 ng/g dry wt in surface soils, respectively. More severe PBDE contamination, when compared with previously reported data, was found in industrial areas in this study. This indicates that these industrial areas are highly polluted with PBDEs. BDE-209 was the predominant congener, accounting for more than 94 % in this study, except for a 68.75 % portion at one site. Our results show that PBDE manufacturing and flame-retardant plastic modification plants, easily overlooked by the public, are two primary PBDE pollution sources although they affect surrounding areas. Further research is needed, aimed at managing industrial PBDE emissions and eliminating environmental PBDE pollution, to investigate the material flows and environmental fates of PBDEs in all stages of the life cycle.

Plants used for phytoextraction of heavy metals from contaminated soils with high levels of salinity should be able to accumulate heavy metals and also be tolerant to salinity. Australian native halophyte species Carpobrotus rossii has recently been shown to tolerate and accumulate multiple heavy metals, especially cadmium (Cd). This study examined the effects of salt type and concentration on phytoextraction of Cd in C. rossii. Plants were grown in contaminated soil for 63 days. The addition of salts increased plant growth and enhanced the accumulation of Cd in shoots up to 162 mg kg⁻¹ which almost doubled the Cd concentration (87 mg kg⁻¹) in plants without salt addition. The increased Cd accumulation was ascribed mainly to increased ionic strength in soils due to the addition of salts and resultantly increased the mobility of Cd. In comparison, the addition of Cl⁻ resulted in 8–60 % increase in Cd accumulation in shoots than the addition of SO₄ ²⁻ and NO₃ ⁻. The findings suggest that C. rossii is a promising candidate in phytoextraction of Cd-polluted soils with high salinity levels.

The objective of this paper is to examine the dynamic impact of urbanization, economic growth, energy consumption, and trade openness on CO ₂ emissions in Nigeria based on autoregressive distributed lags (ARDL) approach for the period of 1971–2011. The result shows that variables were cointegrated as null hypothesis was rejected at 1 % level of significance. The coefficients of long-run result reveal that urbanization does not have any significant impact on CO ₂ emissions in Nigeria, economic growth, and energy consumption has a positive and significant impact on CO ₂ emissions. However, trade openness has negative and significant impact on CO ₂ emissions. Consumption of energy is among the main determinant of CO ₂ emissions which is directly linked to the level of income. Despite the high level of urbanization in the country, consumption of energy still remains low due to lower income of the majority populace and this might be among the reasons why urbanization does not influence emissions of CO ₂ in the country. Initiating more open economy policies will be welcoming in the Nigerian economy as the openness leads to the reduction of pollutants from the environment particularly CO ₂ emissions which is the major gases that deteriorate physical environment.

The formation and activity of aniline-degrading biofilms developed by the psychrotrophic Pseudomonas migulae AN-1 were studied for the in situ remediation of contaminated aquifer using in-well bioreactor of groundwater circulating wells (GCWs). Biofilms grown in mineral salt medium with aniline exhibited tolerance to high concentrations of aniline. In aniline degradation rate, AN-1 biofilms exhibited slight differences compared with planktonic cells. The effectiveness and bio-implication of AN-1 biofilms in GCWs were investigated to treat aniline-contaminated aquifer. The results demonstrate that AN-1 biofilms survived the GCWs treatment process with high aniline-degrading efficiency. This system provides a novel environmentally friendly technology for the in situ bioremediation of low-volatile contaminants.

Di (2-ethylhexyl) phthalate (DEHP) is the most detected and concentrated plasticizer in environment and wastewaters, worldwide. In this study, different operating parameters such as current intensity, treatment time, type of anodes, and supporting electrolytes were tested to optimized the electro-oxidation process (EOP) for the removal of DEHP in the presence of methanol as a dissolved organic matter. Among the anodes, the Nb/BDD showed the best degradation rate of DEHP, at low current intensity of 0.2 A after 90 min of treatment time with a percentage of degradation recorded of 81 %, compared to 70 % obtained with the Ti/IrO₂-RuO₂. Furthermore, due to the combination of direct and indirect oxidation, the removal of DEHP in the presence of 1 g/L Na₂SO₄ was higher than NaBr, even though the oxidant production of NaBr was 11.7 mmol/L against 3.5 mmol/L recorded in the presence of sulfate at 0.5 A and after 60 min of electrolysis time. Under optimal condition (current intensity = 0.5 A, time = 120 min, using Nb/BDD anode and Na₂SO₄ as supporting electrolyte), the removal of 87.2 % of DEHP was achieved. The total cost of 0.106 US$/m³ of treated water was achieved based on economical optimization of reactor with current intensity of 0.2 A and 1 g/L Na₂SO₄.

Serpentine and amphibole asbestos occur naturally in certain geologic settings worldwide, most commonly in association with ultramafic rocks, along associated faults. Ultramafic rocks have been used in Piên County, Southern Brazil for decades for the purpose of road paving in rural and urban areas, but without the awareness of their adverse environmental and health impact. The aim of this study was the chemical characterization of aerosols re-suspended in two rural roads of Piên, paved with ultramafic rocks and to estimate the pulmonary deposition of asbestos aerosols. Bulk aerosol samples were analyzed by means of X-ray fluorescence spectrometry and X-ray diffraction analysis, in order to characterize elemental composition and crystallinity. Single-particle compositions of aerosols were analyzed by computer-controlled electron-probe microanalysis, indicating the presence of a few percentages of serpentine and amphibole. Given the chemical composition and size distribution of aerosol particles, the deposition efficiency of chrysotile, a sub-group of serpentine, in two principal segments of the human respiratory system was estimated using a lung deposition model. As an important finding, almost half of the inhaled particles were calculated to be deposited in the respiratory system. Asbestos depositions were significant (∼25 %) in the lower airways, even though the selected breathing conditions (rest situation, nose breathing) implied the lowest rate of respiratory deposition. Considering the fraction of inhalable suspended chrysotile near local roads, and the long-term exposure of humans to these aerosols, chrysotile may represent a hazard, regarding more frequent development of lung cancer in the population of the exposed region.

The aim of this descriptive-analytical study was to measure the concentration of heavy metals (HMs) in the leaf and bark of Ulmus carpinifolia as new biological indicators, and the ecological risk assessment of these metals in the ambient air. To achieve these goals, 48 sampling locations were selected in the city and concentration of four HMs—zinc (Zn), copper (Cu), lead (Pb), and cadmium (Cd)—was measured in the mentioned indicator using atomic absorption spectroscopy method. After this, ecological risk assessment, source appointment, and spatial distribution were conducted. In this regard, the enrichment factor (EF), potential ecological risk factor (E ᵣ), potential ecological risk index (RI), correlation coefficient (r), and other indices were calculated. The results showed that the concentration of HMs in the leaf and bark in ascending order is as Cd<Cu<Pb<Zn and Cd<Pb<Cu<Zn, respectively. The EF results indicated that the main origin of all measured HMs except Zn is anthropogenic sources. Also, the principal component analysis (PCA) and spatial distribution proved that the concentration of HMs is mainly originated from the traffic and other human activities. On the other hand, the results RI presented that the majority of locations sampled in the study area was exposed to serious ecological risk in terms of surveyed HMs. The leaf and bark of U. carpinifolia can be applied as bio-indicators of the presence of heavy metals in the ambient air and ecological risk imposed by them.