خيارات البحث
النتائج 3981 - 3990 من 4,924
Toxicological effects benzotriazole to the marine scallop Chlamys nobilis: a 2-month exposure study
2019
He, Tang-tian | Zhang, Tao | Liu, Shi-bo | Shi, Jing-chun | Huang, Yi-sheng | Zheng, Huai-ping | Liu, Wenhua
Benzotriazole and its associated derivatives (BTs) are widely used as ultraviolet stabilizers and corrosion inhibitors. They have been extensively found in marine environments and are bioaccumulative through the food chain. However, the toxicities of BTs to marine organisms are seldom identified and no assessment has been conducted for filter-feeding bivalves. In this study, a marine scallop Chlamys nobilis was exposed to 0, 0.01, 0.1, and 1.0 mg/L of BT for 60 days. Effects of BT on endocrine system, cytochrome P450 activity, antioxidant activity, and neural activity of C. nobilis were examined. The results showed that BT exerted significant estrogenic effects on both male and female scallops and inhibited EROD activities of C. nobilis even at 0.01 mg/L level. BT at ≥ 0.01 mg/L levels also caused significant oxidative stress on C. nobilis. Moreover, most of the adverse effects of BT to C. nobilis were found from day 35 and 0.01 mg/L was the lowest concentration with observed effects, showing the long-term toxic effects of BT to C. nobilis. Thus, the adverse effects of BT and its derivatives to marine benthic communities deserve more attention in future research.
اظهر المزيد [+] اقل [-]Combined effects of carbonaceous-immobilizing agents and subsequent sulphur application on maize phytoextraction efficiency in highly contaminated soil
2019
Kroulíková, Stanislava | Mohnke, Sascha | Wenzel, Walter W. | Tejnecký, Václav | Száková, Jiřina | Mercl, Filip | Tlustoš, Pavel
The establishment of phytoextraction crops on highly contaminated soils can be limited by metal toxicity. A recent proposal has suggested establishing support crops during the critical initial phase by metal immobilization through soil amendments followed by subsequent mobilization using elemental sulphur to enhance phytoextraction efficiency. This ‘combined phytoremediation’ approach is tested for the first time in a pot experiment with a highly contaminated soil. During a 14-week period, relatively metal-tolerant maize was grown in a greenhouse under immobilization (before sulphur (S) application) and mobilization (after S application) conditions with soil containing Cd, Pb and Zn contaminants. Apart from the control (C) sample, the soil was amended with activated carbon (AC), lignite (Lig) or vermicompost (VC) all in two different doses (dose 1~45 g additive kg⁻¹ soil and dose 2~90 g additive kg⁻¹ soil). Elemental S was added as a mobilization agent in these samples after 9 weeks. Biomass production, nutrient and metal bioavailability in the soil were determined, along with their uptake by plants and the resulting remediation factors. Before S application, Cd and Zn mobility was reduced in all the AC, Lig and VC treatments, while Pb mobility was increased only in the Lig1 and VC1 treatments. Upon sulphur application, Fe, Mn, Cd, Pb and Zn mobility was not significantly affected in the C, AC and VC treatments, nor total Cd, Pb and Zn contents in maize shoots. Increased sulphate, Mn, Cd, Pb and Zn mobilities in soil together with related higher total S, Mn, Pb and Zn contents in shoots were observed in investigated treatments in the last sampling period. The highest biomass production and the lowest metal toxicity were seen in the VC treatments. These results were associated with effective metal immobilization and showed the trend of steady release of some nutrients. The highest remediation factors and total elemental content in maize shoots were recorded in the VC treatments. This increased phytoremediation efficiency by 400% for Cd and by 100% for Zn compared to the control. Considering the extreme metal load of the soil, it might be interesting to use highly metal-tolerant plants in future research. Future investigations could also explore the effect of carbonaceous additives on S oxidation, focusing on the specific microorganisms and redox reactions in the soil. In addition, the homogeneous distribution of the S rate in the soil should be considered, as well as longer observation times.
اظهر المزيد [+] اقل [-]Intradiurnal variation of predominant airborne fungal spore biopollutants in the Central European urban environment
2019
Ščevková, Jana | Hrabovský, Michal | Kováč, Jozef | Rosa, Samuel
Fungal spores are an important cause of allergic respiratory diseases worldwide. However, little is known about the intradiurnal pattern of spore concentrations of different fungal spore types in the air of the urban area. In this study, we evaluated bihourly variation in spore concentration of eight predominant fungal spore types in the atmosphere of Bratislava city (Agrocybe, Alternaria, Cladosporium, Coprinus, Exosporium, Epicoccum, Ganoderma, Leptosphaeria) with the aim to understand the relationships between the spore concentrations against associated environmental variables. Spore samples were collected using a Hirst-type volumetric aerospore trap from January to December 2016. Alternaria, Cladosporium, Epicoccum and Exosporium peaked during the daytime period between 10:00 and 16:00, while for Agrocybe, Ganoderma, Coprinus and Leptosphaeria, the nighttime peaks (20:00 and 04:00) were observed. Effect of a complex of environmental variables on bihourly concentrations of selected airborne fungal spore taxa was evaluated through multiple regression analysis. Air temperature, wind speed, sunshine duration and precipitation were positively associated with daytime spore types, while the association with nighttime spores was negative. In contrast, relative air humidity influenced negatively Exosporium daytime spore type but positively the Leptosphaeria nighttime spore type. Moreover, a circadian cycle of light and darkness was considered as an important predictor of nighttime spore levels. Among the atmospheric pollutants, PM₁₀ was positively associated with all analysed daytime spores, while except for Leptosphaeria, O₃ was negatively associated with nighttime spore types. NO₂ and PM₁₀ had mixed effects on nighttime spore levels. In general, air temperature, PM₁₀ and wind speed were environmental parameters with great influence on airborne fungal spore concentration, being present in eight, seven and four regression models, respectively. Constructed regression models which the best explained variation in fungal spore concentrations were those for Ganoderma (R² = 0.38) and Alternaria (R² = 0.31).
اظهر المزيد [+] اقل [-]Characteristics of vegetable crop cultivation and nutrient releasing with struvite as a slow-release fertilizer
2019
Min, Kyung-Jin | Kim, Daegi | Lee, Jongkeun | Lee, Kwanyong | Park, Ki Young
Struvite precipitation is an effective method to remove and recover ammonia and phosphate from livestock wastewater. Struvite has properties similar to those of the traditional ammonium-phosphate fertilizer, which does not burn the roots owing to its slow-release characteristics. Struvite is an effective fertilizer as its nutrient-releasing rate is very slow. But the release rate of ammonia and phosphate in soil depends on the size of crystals. In this study, the nutrient-releasing pattern of three types of struvite crystals and liquid fertilizer was compared using soil column. X-Ray fluorescence spectrometry was conducted to investigate the potential use of struvite as a fertilizer. Various struvite crystalline fertilizers were evaluated for their fertilizer performance by cultivating potted vegetable crops. The nitrogen removal efficiency of zeolite-seeded struvite was higher than that of no seed struvite. The ammonia nitrogen removal efficiency was more than 99% irrespective of the kind of zeolite. The soil column test revealed that nutrient releasing from liquid fertilizer and zeolite-seeded struvite recovered from livestock wastewater was 11 and 63 days, respectively. Struvite recovered from livestock wastewater contained more than 20% (w/w) potassium oxide; however, the concentration of heavy metals, such as copper and zinc, was very low. Therefore, we considered that the synthesized struvite using livestock wastewater has high value as fertilizer. The recovered struvite was effective under appropriate concentrations to cultivate all the applied vegetable crops in this study.
اظهر المزيد [+] اقل [-]Effect of O3, PM10 and PM2.5 on cardiovascular and respiratory diseases in cities of France, Iran and Italy
2019
Sicard, Pierre | Khaniabadi, Yusef Omidi | Perez, Sandra | Gualtieri, M. (Maurizio) | De Marco, Alessandra
At present, both tropospheric ozone (O₃) and particulate matters (PM) are among the most threatening air pollutants for human health in cities. The air pollution effects over public health include increased risk of hospital admissions and mortality for respiratory and cardiovascular diseases even when air pollutant concentrations are below European and international standards. The aim of this study was to (i) estimate the burden of mortality and morbidity for cardiovascular and respiratory diseases attributed to PM₂.₅, PM₁₀ and O₃ in nine selected cities in France, Iran and Italy in 2015 and 2016 and to (ii) compare estimated burdens at current O₃ and PM levels with pre-industrial levels. The selected Mediterranean cities are among the most affected by the air pollution in Europe, in particular by rising O₃ while the selected Iranian cities rank as the most polluted by PM in the world. The software AirQ+ was used to estimate the short-term health effects, in terms of mortality and morbidity by using in situ air quality data, city-specific relative risk values and baseline incidence. Compared to pre-industrial levels, long-term exposures to ambient PM₂.₅, PM₁₀ and O₃ have substantially contributed to mortality and hospital admissions in selected cities: about 8200 deaths for non-accidental causes, 2400 deaths for cardiovascular diseases, 540 deaths for respiratory diseases, 220 deaths for chronic obstructive pulmonary diseases as well as 18,800 hospital admissions for cardiovascular diseases and 3400 for respiratory diseases were reported in 2015. The study supports the need of city-specific epidemiological data and urgent strategies to mitigate the health burden of air pollution.
اظهر المزيد [+] اقل [-]Assessment of source and health risk of metal(loid)s in indoor/outdoor dust of university dormitory in Lanzhou City, China
2019
Bao, Lili | Wang, Shengli | Sun, Huiling | Huang, Wen | Wang, Guanxin | Nan, Zhongren
The pollution of metal(loid)s from indoor and outdoor dust is of great concern because of its impact on human health. The concentrations of nine metal(loid)s (Mn, Cu, Zn, Cd, Cr, Ni, Pb, Hg, and As) were investigated in indoor and outdoor dust samples of university dormitories in winter and summer seasons in Lanzhou City, China. This study revealed the variations of metal(loid) concentrations in dust samples with the seasonal scale and floor heights. The results showed that the concentrations of some metal(loid)s (Cu, Cd, Ni, Pb, and As) in dust samples collected in winter were higher than those of the dust samples collected in summer. The Hg in indoor dust was mainly derived from building materials and indoor human activities. Additionally, the concentrations of some metal(loid)s (Hg, Mn, As, Cu, Cd) in dust samples varied with the height of the floors from ground level. The concentrations of Hg in dust samples collected on upper floors (9–16th floors) were higher than those collected on down floors (1–8th floors), while Mn and As were the opposite of that. Cu and Cd concentrations increased as the floor height increased. Our results demonstrated that the adults and the children (particularly the children) endured potential health risks due to exposure to metal(loid)s from both indoor and outdoor dust in the studied area.
اظهر المزيد [+] اقل [-]Adsorption of ciprofloxacin and Cu2+ onto biochars in the presence of dissolved organic matter derived from animal manure
2019
Yang, Zhenyu | Xing, Rong | Zhou, Wenjun
Biochar are widely used as adsorbents/amendments for immobilizing pollutants in contaminated soils. In this study, the effects of dissolved organic matter derived from chicken manure (CMDOM) on the adsorption of ciprofloxacin (CIP) and Cu²⁺ onto biochars were investigated. The FTIR spectra indicated that π-π donor-acceptor interactions between the hydroxyl groups on the biochar surface and the fluorine group connected to the benzene ring of CIP molecule was the main adsorption mechanism for CIP. CMDOM molecules interacted with the aromatic components in biochars and thus modified the surface chemical properties of biochar. The effect of CMDOM on the adsorption of CIP onto biochars showed great dependence on the distribution of solid adsorbed CMDOM and CMDOM in aqueous solutions. The solid adsorbed CMDOM facilitated CIP adsorption owing to increase the content of –OH on biochar surface, which could provide more π-electron donors and thus strengthened π-π EDA interactions between CIP and biochars. The EDS spectra showed that the ion exchange with K⁺ was the main adsorption mechanism for Cu²⁺ onto biochars, and the presence of CMDOM enhanced complexation of Cu²⁺ with adsorbed CMDOM, thus increasing Cu²⁺ adsorption onto biochars. These results are useful for the application of biochars to immobilize antibiotic and heavy metals in contaminated farmland soils when animal manure fertilizers is presented in soil environment.
اظهر المزيد [+] اقل [-]Levels and temporal variations of urinary lead, cadmium, cobalt, and copper exposure in the general population of Taiwan
2019
Liao, Kai-Wei | Pan, Wen-Harn | Liou, Saou-Hsing | Sun, Chien-Wen | Huang, Po-Chin | Wang, Shuli
Toxic metal contamination in food products and the environment is a public health concern. Therefore, understanding human exposure to cadmium (Cd), lead (Pb), cobalt (Co), and copper (Cu) levels in the general population of Taiwan is necessary and urgent. We aimed to establish the human biomonitoring data of urine toxic metals, exposure profile changes, and factors associated with metal levels in the general population of Taiwan. We randomly selected 1601 participants older than 7 years of age (36.9 ± 18.7 years (7–84 years)) from the Nutrition and Health Survey in Taiwan (NAHSIT) conducted during 1993–1996 (93–96) and 2005–2008 (05–08) periods and measured the levels of four metals in the participants’ urine samples using inductively coupled plasma-mass spectrometry. The median (range) levels of urinary Cd, Pb, Co, and Cu in participants from the NAHSIT 93–96 (N = 821)/05–08 (N = 780) were 0.60 (ND–13.90)/0.72 (ND–7.44), 2.28 (ND–63.60)/1.09 (0.04–48.88), 0.91 (0.08–17.30)/1.05 (0.05–22.43), and 16.87 (2.62–158.28)/13.66 (1.67–189.70) μg/L, respectively. We found that the urinary median levels of Pb and Cu in our participants were significantly lower in the NAHSIT 05–08 (Pb 1.09 μg/L, Cu 13.66 μg/L) than in the NAHSIT 93–96 (Pb 2.28 μg/L, Cu 16.87 μg/L; P < 0.01), whereas those of Cd and Co were significantly higher in the NAHSIT 05–08 (Cd 0.72 μg/L, Co 1.05 μg/L; P < 0.01). Youths had higher exposure levels of Pb, Co, and Cu than adults. Participants with alcohol consumption, betel quid chewing, or cigarette smoking had significantly higher median levels of urinary Pb or Cu (P < 0.01) than those without. Principal components and cluster analysis revealed that sex had different exposure profiles of metals. We concluded that levels of urinary Cd, Pb, Co, and Cu exposure in the general Taiwanese varied by age, sex, and lifestyles.
اظهر المزيد [+] اقل [-]Revisiting the social cost of carbon after INDC implementation in Malaysia: 2050
2019
Sarkar, Md Sujahangir Kabir | Al-Amin, Abul Quasem | Leal Filho, Walter
This article projects the social cost of carbon (SCC) and other related consequences of climate change by using Malaysia’s intended nationally determined contribution (INDC) and climate vision 2040 (CV2040) by 2050. It compares the projections derived from the Dynamic Integrated Model of the Climate and Economy (DICME) based on the respective INDC and CV2040 scenario. The results reveal that industrial emissions would incur a substantial increase every 5 years under the scenario CV2040, while Malaysia would experience lower industrial emissions in the coming years under the scenario INDC. Emission intensity in Malaysia will be 0.61 and 0.59 tons/capita in 2030 for scenario CV2040 and scenario INDC respectively. Malaysia would face climate damage of MYR456 billion and MYR 49 billion by 2050 under CV2040 and INDC scenario respectively. However, climate damage could be much lower if the INDC regime were adopted, as this scenario would decrease climatic impacts over time. The estimated SSC per ton of CO2 varies between MYR74 and MYR97 for scenario CV2040 and MYR44 and MYR62 for scenario INDC in 2030 and 2050 respectively. Considering different aspects, including industrial emissions, damage cost, and social cost of carbon, INDC is the best policy compared to CV2040. Thus, Malaysia could achieve its emissions reduction target by implementing INDC by 2050.
اظهر المزيد [+] اقل [-]Synthesis of heterojunction photocatalysts composed of Ag 2 S quantum dots combined with Bi 4 Ti 3 O 12 nanosheets for the degradation of dyes
2019
Zhao, Xinxin | Yang, Hua | Li, Ruishan | Cui, Ziming | Liu, Xueqin
Facilitating the separation of photogenerated electron/hole pairs and widening the light-responsive region are crucial to enhance the overall photocatalytic performance of photocatalysts. To achieve this aim, here we have prepared Ag₂S/Bi₄Ti₃O₁₂ heterojunction composite photocatalysts by assembling Ag₂S quantum dots onto the surface of Bi₄Ti₃O₁₂ nanosheets. Transmission electron microscopy observation demonstrates that two types of Ag₂S quantum dots separately with size of 40–70 and 7–17 nm are uniformly assembled onto the surface of large-sized Bi₄Ti₃O₁₂ thin nanosheets. The as-prepared Ag₂S/Bi₄Ti₃O₁₂ heterojunction composites exhibit much enhanced light absorption (particularly in the visible and near-infrared region) and highly efficient separation of electrons and holes photogenerated in Bi₄Ti₃O₁₂. Rhodamine B (RhB) aqueous solution was chosen as the target organic pollutant to evaluate the photocatalytic performance of the samples under simulated sunlight irradiation. It is found that the Ag₂S/Bi₄Ti₃O₁₂ heterojunction composites manifest significantly enhanced photocatalytic activity toward the RhB degradaton. In particular, the 15wt% Ag₂S/Bi₄Ti₃O₁₂ composite exhibits the highest photocatalytic activity, which is ca. 2.8 and 4.0 times higher than bare Bi₄Ti₃O₁₂ and Ag₂S, respectively. The enhanced photocatalytic activity of the composites can be explained as a result of the Z-scheme electron transfer from the conduction band of Bi₄Ti₃O₁₂ to the valence band of Ag₂S, and thus more photogenerated holes in the valence band of Bi₄Ti₃O₁₂ and electrons in the conduction band of Ag₂S are able to participate in the photocatalytic reactions. Active species trapping experiments were carried out, from which it is concluded that photogenerated holes and •O₂⁻ radicals play the dominant and secondary role in the photocatalysis, respectively.
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