Refine search
Results 2591-2600 of 4,937
Tracing the trade–pollution nexus in global value chains: evidence from air pollution indicators Full text
2019
Yasmeen, Rizwana | Li, Yunong | Hafeez, Muhammad
Global trade plays an imperative role in the world economy that yields environmental degradation. Therefore, the current paper’s ambitions are to explore the trade–air pollution nexuses by introducing the value-added trade (VT) concept from a global value chain stance. The value-added trade (VT) indicator is constructed by the World Input-Output (WIOD) classifications database. Owing to scanty data accessibility, the sample set is reduced to 39 countries covering the period from 1995 to 2009. Furthermore, this paper is also contributing by including the eight different pathways of per capita air pollution in terms of ammonia (NH3), carbon monoxide (CO), carbon dioxide (CO₂), methane (CH₄), nitrogen oxides (NOₓ), nitrous oxide (N₂O), sulphur oxides (SOₓ) and non-methane volatile organic compounds (NMVOC) respectively. The valuable outcomes from empirical analysis have been found; Firstly, it explores that the preliminary stage of the development of value-added trade (VT) has a positive impact on air-bonds pollution. However, in the later stage of the economic development, trade improves the environmental quality as the square of value-added trade (VT²) has a negative impact on air pollution. Moreover, it also elaborates that the magnitude impact of trade on carbon monoxide (CO) air pollution is more than the other seven air pollutants. Thirdly, the inverted U-shape in the trade–air pollution Environmental Kuznets Curve (EKC) hypothesis, the non-linear relationship between trade and pollution is also validated in all eight air pollutants indicators. Policy proposals for green economy that underlines the global value chain stance and environmental factors in the growing economy are proposed.
Show more [+] Less [-]Zinc Pyrithione (ZnPT) as an Antifouling Biocide in the Marine Environment—a Literature Review of Its Toxicity, Environmental Fates, and Analytical Methods Full text
2019
Soon, Zhi Yang | Jung, Jee-Hyun | Jang, Mi | Kang, Jung-Hoon | Jang, Min-Chul | Lee, Jae-seong | Kim, Moonkoo
Since the ban of tributyltin in antifouling paints, many alternative biocides have been introduced to prevent settlement and growth of marine organisms on ship hulls. Zinc pyrithione (ZnPT) is one of the most frequently used alternative biocides in antifouling paints. This paper reviewed the overall chemical properties, toxicological characteristics, and environmental fates of ZnPT, as well as the analytical challenges of studying pertinent processes. ZnPT is generally toxic to a wide range of marine organisms, including algae, bivalves, sea urchins, polychaetes, crustaceans, and fish, typically at μg/L levels. ZnPT can be transchelated into other compounds in the presence of metal ions, and photodegrades when exposed to UV light. ZnPT is also reported to be biodegraded or hydrolyzed forming several metabolites of their own toxicity and stability. However, ZnPT accumulates in the water column or sediment, if it does not degrade at certain environmental conditions. To determine potential risks caused by ZnPT in the marine environment, studies have evaluated the environmental distribution of ZnPT with various chromatographic or voltammetry methods. Unfortunately, rapid transchelation and degradation of ZnPT in both the marine environment and laboratory interfered with most of the methods employed, making it difficult to evaluate its environmental distribution. More robust and sensitive analytical methods need to be developed to reliably describe the environmental release and distribution of ZnPT. To comprehensively understand the risk posed by the input of ZnPT into the marine environment, total degradation processes and its potential products also need to be adequately addressed.
Show more [+] Less [-]Enhanced Removal of Phosphorus from Wastewater Using Sequential Electrocoagulation and Chemical Coagulation Full text
2019
Arambarri, James | Abbassi, Bassim | Zytner, Peter
An electrokinetic batch treatment scheme was investigated combining sequential electrocoagulation (EC) and chemical coagulation treatment (CC) processes. Synthetic and microbrewery wastewaters were tested in this investigation. The generated results demonstrated the capacity for the integration of EC-CC to effectively remove phosphorus contamination from wastewater under varying operating conditions. The effect of several operational parameters such as current density, conductivity, nutrient loading, and electrolysis time were investigated. The results showed that increased salinity can significantly accelerate the removal of phosphorous during EC treatment with 84.2% and 92.4% removal found for the applied power of 5 and 10 W, respectively. The addition of a sequential chemical coagulant stage following treatment by EC demonstrated the potential for an integrated EC-CC system to lower energy consumption while maintaining effective nutrient removal capabilities. Removal of phosphorous at 95% and 98% was achieved in just 10 min of EC treatment coupled with the addition of 15 mg/L aluminum sulfate. The estimated power consumption over a 10-min period was found to be 0.28 Kwh/m³ with a dissolution rate of 0.28 g/cm² min held at a constant current density. The experimental anode dissolution rate for the synthetic wastewater ranged between 0.13 and 0.24 g/cm² min encompassing all salinity levels. The anode dissolution rate increased during treatment of microbrewery wastewater with 0.67 g/cm² min for 10 W EC treatment. This was attributed to the increase in current density and nutrient loading resulting in increased energy consumption and electrode passivation.
Show more [+] Less [-]Aqueous Film-Forming Foams (AFFFs) Are Very Toxic to Aquatic Microcrustaceans Full text
2019
da Silva, Silvana Carmo | Pusceddu, Fabio Hermes | dos Santos Barbosa Ortega, Andressa | de Souza Abessa, Denis Moledo | Pereira, Camilo Dias Seabra | Maranho, Luciane Alves
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.
Show more [+] Less [-]Changes in the Physico-Chemical Parameters of Water as a Result of Long-Term Contact with Biomass, on the Example of Pine Bark (Pinus sylvestris) Full text
2019
Garbowski, Tomasz
Water encountering biomass can affect the change in its chemical composition and properties through the leaching process. In the leaching process, leachates are formed, and their composition depends on the type of biomass and the time of exposure to the solvent (water). The aim of the study was to analyze the influence of time of contact of water with biomass on changing the chemical composition of the leachates formed during long-term (counted in days) leaching of pine bark (Pinus sylvestris). Long-term leaching contributes to a loss of organic and inorganic compounds, and in this study, an intensive extraction of biomass components was noted from the first day of leaching. Along with the extension of the leaching time, values for electrical conductivity, concentration of mineral fraction (ashes), concentration of volatile matter, and concentration of total organic carbon significantly increased in the leachates. However, no linear relationship between the extension of the leaching time and the increase in the concentration of chlorides, sulfates, nitrogen, phosphorus, and other elements in the leachates was observed. This study will allow to better understand the impact of vegetation communities on the aquatic and terrestrial ecosystems, as well as help to provide adequate conditions of storage of biomass for technological purposes. Graphical Abstract
Show more [+] Less [-]Correction to: Adsorption, Kinetics and Equilibrium Studies on Removal of Catechol and Resorcinol from Aqueous Solution Using Low-Cost Activated Carbon Prepared from Sunflower (Helianthus annuus) Seed Hull Residues Full text
2019
Vunain, Ephraim | Houndedjihou, Dégninou | Monjerezi, Maurice | Muleja, Adolph Anga | Kodom, BarthélémyTomkouani
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.
Show more [+] Less [-]Effect of Copper Oxide Nanoparticles on the Physiology, Bioactive Molecules, and Transcriptional Changes in Brassica rapa ssp. rapa Seedlings Full text
2019
Chung, Ill-Min | Rekha, Kaliyaperumal | Venkidasamy, Baskar | Thiruvengadam, Muthu
Global deterioration of water, air, and soil quality by the release of toxic chemicals from anthropogenic pollutants is becoming a serious global problem. The extensive use of copper oxide nanoparticles (CuO NPs) can be environmentally hazardous when these NPs enter the atmosphere. The present study aimed to evaluate the role of CuO NPs on plant growth, photosynthetic capacity, and bioactive compounds, as well as their transcriptional level changes in Brassica rapa seedlings. Chlorophyll, carotenoid, and sugar content decreased, while proline and anthocyanins were significantly enhanced in the CuO NP-treated seedlings compared with the untreated controls. Reactive oxygen species (ROS), malondialdehyde (MDA), and hydrogen peroxide (H₂O₂) production were also enhanced in the seedlings exposed to CuO NPs, which could have caused DNA damage that was detected by a DNA laddering assay. The glucosinolate (GSL) and phenolic compound content were significantly increased in CuO NP-treated seedlings compared with that in control seedlings. Transcriptional variation of genes associated with oxidative stress (CAT, POD, and GST), R2R3-type MYB involved in GSL (BrMYB28, BrMYB29, BrMYB34, and BrMYB51), and phenolic compounds (ANS, PAP1, PAL, and FLS) biosynthesis was analyzed using real-time polymerase chain reaction. Significant upregulation of CAT, POD, GST, BrMYB28, BrMYB29, BrMYB34, BrMYB51, ANS, PAP1, PAL, and FLS genes was observed in seedlings exposed to different concentrations of CuO NPs relative to the untreated seedlings. Therefore, we suggest that the use of CuO NPs could stimulate the toxic effects and enhance phytochemicals (i.e., glucosinolates and phenolic compounds) in B. rapa.
Show more [+] Less [-]Life Cycle Comparison of Membrane Capacitive Deionization and Reverse Osmosis Membrane for Textile Wastewater Treatment Full text
2019
Cetinkaya, Afsin Y. | Bilgili, Levent
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.
Show more [+] Less [-]Effect of Residual NAPLs on the Transport of Bisphenol A and Bisphenol S in Saturated Porous Media Full text
2019
Shi, Yanfeng | Gao, Bin | Sun, Yuanyuan | Sun, Kaixuan | Xu, Hongxia | Wu, Jichun
Endocrine disrupter, like bisphenol A (BPA) and bisphenol S (BPS), is frequently detected in the subsurface environment, imposing threats to the groundwater quality and public health. However, current understanding of environmental fate and transport of BPA/BPS is still not clear, especially with respect to those in the subsurface media with trapped non-aqueous phase liquids (NAPLs). In this study, the effect of residual NAPLs on the retention and transport of BPA/BPS in the saturated sand and soil media was investigated using column experiments. The results showed that residual NAPLs (i.e., xylene and perchloroethylene (PCE)) inhibited the transport of BPA in the sand columns, and the inhibit effect of xylene was greater than that of PCE. While the presence of NAPLs showed little influence on the transport of BPS in the sand columns, in soil A (sandy soil), the residual NAPLs had similar effect on the retention and transport of BPA and BPS. Both BPA and BPS showed higher retention in the soil B columns than in the sand and soil A columns due to soil B’s higher organic matter contents, which can strongly sorb BPA/BPS. The presence of residual NAPLs reduced the retention of BPA/BPS in the soil B columns because the NAPLs blocked the sorption sites of the soil organic matter for BPA/BPS. This study demonstrates the importance of residual NAPLs, types of media, properties of contaminants, and their interactions to the fate and transport of BPA/BPS in saturated porous media.
Show more [+] Less [-]How autochthonous microorganisms influence physiological status of Zea mays L. cultivated on heavy metal contaminated soils? Full text
2019
Rusinowski, Szymon | Szada-Borzyszkowska, Alicja | Zieleźnik-Rusinowska, Paulina | Małkowski, Eugeniusz | Krzyżak, Jacek | Woźniak, Gabriela | Sitko, Krzysztof | Szopiński, Michał | McCalmont, Jon Paul | Kalaji, Hazem M. | Pogrzeba, Marta
The aim of this study was to investigate the effect of autochthonous microorganisms present in soil collected from heavy metal (HM) uncontaminated (Pb ≈ 59 mg kg⁻¹, Cd ≈ 0.4 mg kg⁻¹, Zn ≈ 191 mg kg⁻¹), moderately (Pb ≈ 343 mg kg⁻¹, Cd ≈ 12 mg kg⁻¹, Zn ≈ 1876 mg kg⁻¹), and highly (Pb ≈ 1586 mg kg⁻¹, Cd ≈ 57 mg kg⁻¹, Zn ≈ 3280 mg kg⁻¹) contaminated sites on Zea mays elemental composition, physiological status, and growth parameters. For this purpose, half of the collected soil was sterilized and soil characterization was performed. After 45 days of cultivation, the presence of HM in the soil negatively affected photosynthesis and transpiration rates, relative chlorophyll content, anthocyanins index, chlorophyll fluorescence parameters, and content of oxidative stress products (H₂O₂ and Malondialdehyde) of Zea mays, while soil sterilization had a positive effect on those parameters. Average percentage of colonization of root segments by arbuscular mycorrhiza fungi decreased with an increase of HM contamination in the soil. The increase in shoot concentration of HMs, particularly Cd and Zn, was a result of contaminated soils sterilization. Aboveground biomass of maize cultivated on sterilized soil was 3-fold, 1.5-fold, and 1.5-fold higher for uncontaminated, moderately contaminated and highly contaminated soils respectively when compared to nonsterilized soils. Contrary to our expectation, autochthonous microflora did not improve plant growth and photosynthetic performance; in fact, they had a negative effect on those processes although they did reduce concentration of HMs in the shoots grown on contaminated soils.
Show more [+] Less [-]