Refine search
Results 3381-3390 of 7,290
Lead, zinc tolerance mechanism and phytoremediation potential of Alcea rosea (Linn.) Cavan. and Hydrangea macrophylla (Thunb.) Ser. and ethylenediaminetetraacetic acid effect Full text
2022
Duan, Yaping | Zhang, Ying | Zhao, Bing
In this study, we aimed to elucidate the defense mechanism of Alcea rosea (Linn.) Cavan. and Hydrangea macrophylla (Thunb.) Ser. against the single and compound toxicity of lead (Pb) and zinc (Zn) along with the synergistic effect of ethylenediaminetetraacetic acid (EDTA) in accumulation of metals in these two species. The two plant species were subjected to single metal treatment (Pb 1000 mg kg⁻¹, Zn 600 mg kg⁻¹) and compound metal treatment (Pb 1000 mg kg⁻¹ + Zn 600 mg kg⁻¹) in a greenhouse. Besides, different levels of EDTA were applied (2.5, 5.0, and 10.0 mmol kg⁻¹) with compound metal treatment. Several physiological and biochemical parameters, including plant photosynthetic parameters, enzymatic antioxidant system, accumulation concentration of metals, and subcellular distribution were estimated. The results showed that the antioxidative enzymes, proline, root morphological changes, and metal localization all played important roles in resisting Pb and Zn toxicity. A notable difference was that Zn was concentrated in the roots (58.5%) of H. macrophylla to reduce the damage but in the leaves (38.5%) of A. rosea to promote photosynthesis and resist the toxicity of metals. In addition, Zn reduced the toxicity of Pb to plants by regulating photosynthesis, Pb absorption and Pb distribution in subcells. The biological concentration factors (BCF) and translocation factors (TF) for Pb in two plants were less than 1, indicating that they could be considered as phytostabilizators in Pb-contaminated soils. Moreover, EDTA could enhance the enrichment and transport capacity of Pb and Zn to promote the phytoremediation effect. In summary, both plants have a certain application potential for repairing Pb–Zn-contaminated soil.
Show more [+] Less [-]Prenatal air pollution exposure increases the risk of macrosomia: evidence from a prospective cohort study in the coastal area of China Full text
2022
Li, Changlian | Ju, Liangliang | Yang, Mei | Zhang, Qi | Sun, Shu | Cao, Jiyu | Ding, Rui
Effects of prenatal ambient air pollution exposure could increase the risk of adverse pregnancy outcomes, which have been well documented by various studies. However, only very few studies investigated the effects on macrosomia. This study investigated the effects of prenatal air pollution exposure on the risk of macrosomia in a coastal city of China. Data of birth outcomes and air pollution in a coastal city in China between November 1, 2013, and December 31, 2017, were collected. Finally, 58,713 eligible births, including 8159 (13.9%) macrosomia and 50554 (86.1%) normal birth weight (NBW) infants, were included in the analysis. Logistic regression analyses were used to evaluate the effects of prenatal air pollution exposure on macrosomia. In the single-pollutant models, each 10 μg/m³ increase of PM₂.₅, PM₁₀, and SO₂ exposures, during the entire pregnancy or three trimesters, were related to elevated risk of macrosomia (adjusted RR, 95% CI) ranging from 1.018 (1.001, 1.035) to 1.314 (1.188, 1.454). In addition, O₃ exposure in the first trimester (adjusted RR =1.034, 95% CI 1.009, 1.059) also increased the macrosomia risk. Prenatal PM₂.₅, PM₁₀, and SO₂ exposure could significantly increase the risk of macrosomia. These findings need to be further verified in more studies with multiple coastal cities included.
Show more [+] Less [-]Climate change and major crop production: evidence from Pakistan Full text
2022
Abbas, Shujaat
Climatic changes are posing serious threats to crop production and food insecurity across the globe. This study explores the dynamic relationship between changing annual temperature and production of major crops such as wheat, rice, bajra, jowar, maize, barley, gram, sugar cane, mastered oil, and cotton in Pakistan from 2000 to 2019 through an eclectic production model. The estimated result of panel econometric analysis revealed a significant negative effect of rising temperature on selected crop production in the long run with an insignificant impact in the short run. Among other explanatory variables, the area under cultivation and fertilizer input have significant positive effects in both the long run and the short run. Improved quality seeds revealed insignificant effects and urging authorities to enhance quality research to develop climate change resilient crops. This study urges Pakistan to improve agriculture technology along with adopting other greenhouse gas mitigation, such as forestation and clean energy, and water conservation policies.
Show more [+] Less [-]Hydrochemical characteristics, trace element sources, and health risk assessment of surface waters in the Amu Darya Basin of Uzbekistan, arid Central Asia Full text
2022
Zhan, Shuie | Wu, Jinglu | Jin, Miao
Thorough knowledge of hydrochemical characteristics and trace element concentrations in surface waters is crucial for protection of this resource, especially in arid regions. Uzbekistan lies in central, arid Central Asia, and is experiencing severe water scarcity as a consequence of warming climate and accelerated human impacts. Fifty-five surface water samples were collected from the Amu Darya Basin of Uzbekistan (ADBU) and measured for relevant variables, to determine hydrochemical characteristics and evaluate water quality. River water samples from the middle reach and Amu Darya Delta (ADD) were dominantly HCO₃–Ca and SO₄–Ca·Mg types, respectively, whereas water samples collected near the former shoreline and sewage outlets in the ADD were predominantly Cl–Ca·Mg and Cl–Na types, consistent with the distribution of sites that display high concentrations of trace elements and are seriously affected by human activities. Principal component analysis indicated that Pb and Cd in surface waters of the ADBU had industrial origins. Local agricultural activities are thought to have contributed to the concentrations of NO₃, Zn, Ni, Hg, and Mn, through pesticide and fertilizer applications, and concentrations of Cu, Cr, As, and Co are controlled by mixed natural and anthropogenic sources. Water quality and health risk assessments indicated that unsuitable drinking waters are distributed mainly near the former shoreline and sewage outlets in the ADD, making human health risks in these areas high.
Show more [+] Less [-]Removal of Nitrogenous Compounds from Municipal Wastewater Using a Bacterial Consortium: an Opportunity for More Sustainable Water Treatments Full text
2022
Fontalvo, Nubia Patricia Marquez | Gamero, Wendy Beatriz Morgado | Ardila, Henry Alfonso Maury | Gonzalez, Andres Felipe Pulgar | Ramos, Claudete Gindri | Muñoz, Alexander Elias Parody
The integrated management of water resources is a requirement for environmental preservation and economic development, with the removal of nutrients being one of the main drawbacks. In this work, the efficiency of a bacterial consortium (Ecobacter WP) made up of eight bacterial strains of the genus Bacillus subtilis, Bacillus licheniformis, Bacillus megaterium, Bacillus cereus, Arthrobacter sp., Acinetobacter paraffineus, Corynebacterium sp., and Streptomyces globisporus was evaluated in the removal of nitrogen compounds in domestic wastewater in a plug flow system, in the extended aeration and bioaugmentation (FLAEBI). To promote the nitrification and denitrification processes, three doses were tested to establish the optimal concentration of the bacterial consortium on a laboratory scale and its subsequent application in an outdoor wastewater treatment plant (WWTP). The evaluation period was 15 days for each treatment in the laboratory and WWTP. The parameters monitored both at laboratory and outdoor were pH, temperature, dissolved oxygen, chemical oxygen demand (COD), biochemical oxygen demand (BOD₅), ammonium, nitrites, and nitrates. The results indicated that the optimal concentration of the consortium was 30 mg L⁻¹, with a removal of 92% of nitrate at the laboratory and 62% outdoor. Such a difference is attributed to the different operation residence times and the volume that caused different concentration gradients. The consortium studied can be used to promote nitrification and denitrification processes that intervene in the removal of nitrogenous compounds in plants with similar operating conditions, without investment in restructuring or design modification of the WWTP.
Show more [+] Less [-]Allocation of carbon emission quotas based on global equality perspective Full text
2022
Zhang, Fan | Wang, Xiaoyu | Liu, Gang
In a context of global climate change and issues relating to national carbon neutrality, carbon emissions (CE), which are linked with sustainable national development, have become the focus of worldwide competition. We performed geographic information system (GIS) spatial analysis using historical CE data for major countries and world regions for the period 1970–2018 to identify their cumulative and per capita CE. The analysis revealed the characteristics of large cumulative CE in countries that underwent early industrialization, notably the USA, Russia, and Germany and of low per capita emissions in developing countries, notably China and India. We identified 10 mainstream international emission reduction scenarios and compared and analyzed the advantages and disadvantages of different models for measuring CE allowances. We further summarized the characteristics of IPCC scenarios, shared socioeconomic pathway scenarios, and temperature-controlled threshold scenarios along with the CE allowances of China and other major countries under different scenarios. The intended nationally determined contributions (INDCs) commitment mechanism may have an impact on promoting the construction of a new global climate governance order. Considering multiple scenarios and the uncertainty of carbon emissions, choosing a certain carbon budget plan is an important future research direction. Last, we reviewed the current methods of allocating CE rights globally and among major countries and the development trend of CE to provide scientific evidence for the formulation and implementation of future international climate change agreements. In conclusion, we offer solutions for enhancing participation in the global governance of climate change.
Show more [+] Less [-]Sewerage infrastructure asset management based on a consumer-centric approach Full text
2022
Jo, Hanseul | Ryu, Jaena | Shin, Jungwoo
In most developed countries, such as the USA, the E.U., and East Asia, the importance of public infrastructure asset management has been stressed for a long time. Among the various types of public infrastructure, sewerage systems are one of the most cost-intensive facilities to manage. Sewerage systems are considered highly difficult to manage due to the undetermined level of service needed, different standards of user satisfaction, and the large gap of service understanding between experts and users. To address these issues, this study aims to define the appropriate target level of service improvement by combining consumers’ expected level of service and complaint data. In this study, the case of the inland flood management project in South Korea is investigated because of the global trend of increasing flood damage. The complaint data represent the frequency of flood damage in the area. Using the contingent valuation method, we found that people want to use 25% of their current monthly sewage bill on the management project. In addition, the results of this study demonstrate that people prefer to deal with the problems caused by old service infrastructure when it can be handled at a lower cost during early stages.
Show more [+] Less [-]Mesenchymal stem cells derived from the kidney can ameliorate diabetic nephropathy through the TGF-β/Smad signaling pathway Full text
2022
Rafiee, Zeinab | Orazizadeh, Mahmoud | Nejad Dehbashi, Fereshteh | Neisi, Niloofar | Babaahmadi-Rezaei, Hossein | Mansouri, Esrafil
Diabetic nephropathy (DN) has been introduced as one of the main microvascular complications in diabetic patients, the most common cause of end-stage renal disease (ESRD). Based on the therapeutic potential of mesenchymal stem cells in tissue repair, we aimed to test the hypothesis that kidney stem cells (KSCs) might be effective in the kidney regeneration process. Stem cells from rat kidney were separated, and the surface stem cell markers were determined by flow cytometry analysis. Thirty-two Sprague Dawley rats were divided into four groups (control, control that received kidney stem cells, diabetic, diabetic treated with stem cells). To establish diabetic, model STZ (streptozotocin) (60 mg/kg) was used. The KSCs were injected into experimental groups via tail vein (2 × 10⁶ cells/rat). In order to determine the impact of stem cells on the function and structure of the kidney, biochemical and histological parameters were measured. Further, the expression of miRNA-29a, miR-192, IL-1β, and TGF-β was determined through the real-time PCR technique. Phosphorylation of Smad2/3 was evaluated by using the standard western blotting. The KSCs significantly reduced blood nitrogen (BUN), serum creatinine (Scr), and 24-h urinary proteins in DN (P < 0.05). IL-1β and TGF-β significantly increased in the kidney of diabetic rats. In addition, the expression of miR-29a is significantly increased, whereas miR-192 decreased after treatment with KSCs (P < 0.05). Diabetic rats showed an increased level of phosphorylation of both Smad2 and Smad3 (P < 0.05). Periodic acid-Schiff (PAS) staining showed improved histopathological changes in the presence of KSCs. Stem cells derived from adult rat kidney may be an option for treating the early DN to improve the functions and structure of kidneys in rats with DN.
Show more [+] Less [-]Bioaccumulation of pesticides and genotoxicity in anurans from southern Brazil Full text
2022
Ascoli-Morrete, Thaís | Bandeira, Nelson M. G. | Signor, Elias | Gazola, Humberto A. | Homrich, Isis S. | Biondo, Rhaíssa | Rossato-Grando, Luciana G. | Zanella, Noeli
The expansion of agricultural activities causes habitat loss and fragmentation and the pollution of natural ecosystems through the intense use of pesticides, which may affect the populations of amphibian anurans that inhabit agricultural areas. The present study evaluated the in situ bioaccumulation of pesticides in a population of Leptodactylus luctator that occupies farmland in southern Brazil. We also compared the genotoxicity of L. luctator populations from farmland and forested areas in the same region. We analyzed the micronuclei and nuclear abnormalities of 34 adult anurans, 19 from farmland, and 15 from the forested area. We also assessed the presence of 32 pesticides in liver samples obtained from 18 farmland-dwelling anurans, using chromatographic analysis. We recorded significantly higher rates of nuclear abnormalities in the individuals from the farmland, in comparison with the forest. We detected nine pesticides in the liver samples, of which, deltamethrin was the most common and carbosulfan was recorded at the highest concentrations. The bioaccumulation of pesticides and the higher levels of genotoxic damage found in the anurans from agricultural areas, as observed in the present study, represent a major potential problem for the conservation of these vertebrates, including the decline of their populations and the extinction of species.
Show more [+] Less [-]Using QMRA to understand possible exposure risks of SARS-CoV-2 from the water environment Full text
2022
Tyagi, Neha | Gurian, Patrick L. | Kumar, Arun
This study investigated the human risk of infection due to inadvertent ingestion of water during swimming in a river that receives SARS-CoV-2-containing effluent from a wastewater treatment plant (WWTP). A quantitative microbial risk assessment (QMRA) approach was applied for risk estimation using dose-response models (DRM) of different surrogate coronaviruses (SARS-CoV-1, MERS-CoV) and the virus responsible for most infectious respiratory illnesses (i.e., influenza A H5N1) due to the unavailability of DRM for SARS-CoV-2. The ratio of infectious concentration to genomic copies of SARS-CoV-2 is unknown and also unavailable for other coronaviruses. Therefore, literature-based information on enteric viruses was used for formulating the ratio used for QMRA, although it is acknowledged that identifying this information for SARS-CoV-2 is a priority, and in the absence of information specific to SARS-CoV-2, another coronavirus would be a preferable surrogate to the enteric viruses used here. The calculated concentration of ingested SARS-CoV-2 ranged between 4.6 × 10⁻⁷ and 80.5 genomic copies/dip (one swim = 32 mL). The risk of infection (> 9 × 10⁻¹² to 5.8 × 10⁻¹) was found to be > 1/10,000 annual risk of infection. Moreover, the study revealed that the risk estimation was largely dependent on the value of the molecular concentration of SARS-CoV-2 (gc/mL). Overall immediate attention is required for obtaining information on the (i) ratio of infectious virus to genomic copies, (ii) DRM for SARS-CoV-2, and (iii) virus reduction rate after treatment in the WWTPs. The QMRA structure used in present findings is helpful in analyzing and prioritizing upcoming health risks due to swimming performed in contaminated rivers during the COVID-19 outbreak.
Show more [+] Less [-]