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Seasonal Loading and Concentration Patterns for Fecal Bacteroidales qPCR Markers and Relationships to Water Quality Parameters at Baseflow
2019
Stallard, M. A. | Winesett, S. | Scopel, M. | Bruce, M. | Bailey, F. C.
Bacteria belonging to the Order Bacteroidales predominate the intestines of warm-blooded animals, and monitoring of these bacteria can indicate fecal pollution impacts to a waterbody. Differences in seasonal concentrations and loadings for Bacteroidales and their relationship with physicochemical water parameters were investigated in temperate, inland streams. Seasonal samples (n = 321) were collected during baseflow in three central Tennessee, USA, watersheds. To estimate total fecal bacteria in receiving streams, general Bacteroidales 16S rRNA gene targets were analyzed by quantitative PCR and reported as concentration and loadings for individual and combined watersheds. In most cases, Bacteroidales marker concentrations were highest during spring/summer and loading values were highest in the spring. Bacteroidales concentrations were positively correlated with temperature and total suspended solids and negatively with dissolved oxygen, while no consistent correlations were found between loadings and abiotic factors. Temperature, total suspended solids, and dissolved oxygen are likely drivers influencing seasonal patterns for Bacteroidales concentrations. Researchers and water quality stakeholders should carefully consider measurement type (concentration versus loading), season, and water quality parameters as elements that could impact results when developing fecal monitoring projects.
Afficher plus [+] Moins [-]Identifying floating plastic marine debris using a deep learning approach
2019
Kylili, Kyriaki | Kyriakides, Ioannis | Artusi, Alessandro | Hadjistassou, Constantinos
Estimating the volume of macro-plastics which dot the world’s oceans is one of the most pressing environmental concerns of our time. Prevailing methods for determining the amount of floating plastic debris, usually conducted manually, are time demanding and rather limited in coverage. With the aid of deep learning, herein, we propose a fast, scalable, and potentially cost-effective method for automatically identifying floating marine plastics. When trained on three categories of plastic marine litter, that is, bottles, buckets, and straws, the classifier was able to successfully recognize the preceding floating objects at a success rate of ≈ 86%. Apparently, the high level of accuracy and efficiency of the developed machine learning tool constitutes a leap towards unraveling the true scale of floating plastics.
Afficher plus [+] Moins [-]Column and batch sorption investigations of nickel(II) on extractant-impregnated resin
2019
Tetgure, Sandesh R. | Choudhary, Bharat C. | Borse, Amulrao U. | Garole, Dipak J.
Macroporous resin-supported reagents have been identified as potential adsorbents for removal of toxic pollutants. This article presents an experimental designed to evaluate the sorption and desorption of nickel(II) with the help of column and batch procedure using simple extractant-impregnated resin (EIR). Isonitroso-4-methyl-2-pentanone (IMP) as an extractant was impregnated on a solid support like Amberlite XAD-4 to prepare the EIR sorbent. Column experimental conditions such as pH, sample flow rate and volume, eluting solution, and interfering ions were studied to optimize the nickel(II) sorption and recovery from aqueous media. The column results suggest that the quantitative nickel(II) sorption was observed at pH 5–6, and the quantitative recovery (≥ 95%) was achieved by using 1.0 M HNO₃. The high concentrations of cations and anions (except EDTA) present in the spiked binary and multi-element mixture solution show no interferences in both quantitative sorption and recovery of nickel(II), whereas the batch experiments were performed to evaluate nickel(II) sorption behavior using the linearized and non-linearized kinetic and isotherm models. By error function analysis, the Freundlich isotherm and the pseudo-first-order kinetic model were found to describe best the experimental data obtained over the studied concentration range and sorption time, respectively. The maximum sorption capacity of nickel(II) onto the EIR sorbent was found to be ~ 81 mg/g. The mean free energy (E = 10.1 kJ/mol) determined using Dubinin-Radushkevich isotherm suggests chemical nature of nickel(II) sorption on EIR. The novelty of the EIR adsorbent lies in its potential for separation and recovery of nickel(II) at trace level in water samples of different origin.
Afficher plus [+] Moins [-]Effects of different potassium fertilizers on cadmium uptake by three crops
2019
Wang, Kang | Fu, Guiping | Yu, Yao | Wan, Yanan | Liu, Zhe | Wang, Qi | Zhang, Jingsuo | Li, Huafen
Cadmium contamination of agricultural soils has aroused worldwide concern because of the threats posed to human health through accumulation in food chains. A greenhouse pot experiment was conducted with in situ Cd-contaminated soil to study the influence of different potassium fertilizers (KCl, K₂SO₄, and KNO₃) on Cd accumulation in rice, wheat, and pak choi as well as the NH₄NO₃-extractable Cd (NEX-Cd) content in soils. In our study, rice and wheat biomass increased in the presence of K fertilizers, whereas pak choi biomass remained stable. Moreover, our experiment demonstrated that Cl⁻ increased Cd uptake by crops more effectively than SO₄²⁻ or NO₃⁻. The KCl treatments increased the Cd content of all three crops; as the KCl dose was increased, the Cd content of rice grains, wheat grains, and pak choi shoots increased by 10.8–192.8%, 17.1–67.7%, and 15.1–40.4%, respectively. The KNO₃ treatment also increased the Cd content of all three crops; however, the K₂SO₄ treatment only slightly increased the Cd content of wheat and pak choi and greatly decreased the Cd content of rice. In addition, both of the NEX-Cd content of wheat soil and pak choi soil were much higher than that of rice paddy soil. The KCl treatment resulted in a significant increase in the NEX-Cd content of rice paddy soil, but there were no significant differences in the NEX-Cd content of wheat soil or pak choi soil, regardless of which types or doses of K fertilizers were supplied. Based on these results, when K fertilizers are applied to Cd-contaminated soils, both types and doses should be carefully considered to mitigate Cd accumulation in crops, especially the edible part.
Afficher plus [+] Moins [-]Effects of environmental regulation on the upgrading of Chinese manufacturing industry
2019
Hu, Wen-Quan | Jin, Tong | Liu, Yong
In recent years, China has constantly strengthened environmental regulation (ER) to force the manufacturing industry to upgrade. This study theoretically analyzes interaction mechanism of ER on the upgrading of manufacturing industry through foreign direct investment (FDI) and technological innovation (TI) and carries out empirical verification by using provincial panel data from 2000 to 2016 in China. The results demonstrate that the current ER intensity in China is unable to directly promote the upgrading of manufacturing industry, while through the interaction effects of FDI and TI do boost the upgrading of the industry. The above mechanisms are also robust even if we take the regional heterogeneity into consideration. Basic education and urbanization are favorable for the upgrading of the manufacturing industry. However, the increase in dependence on foreign trade is not conducive to upgrading manufacturing industry. Chinese government should further strengthen ER and give full play of the interaction mechanism of ER to guide the flow of foreign investment and force enterprises to carry out TI. In the meanwhile, Chinese government also needs to ensure balanced regional development, thus better promoting the upgrading of manufacturing industry.
Afficher plus [+] Moins [-]Chronic exposure to urban air pollution from Buenos Aires: the ocular mucosa as an early biomarker
2019
Maglione, Guillermo A. | Kurtz, Melisa L. | Orona, Nadia S. | Astort, Francisco | Busso, Iván Tavera | Mandalunis, Patricia M. | Berra, Alejandro | Tasat, Deborah R.
Air pollution represents a major health problem in megacities, bringing about 8 million deaths every year. The aim of the study was to evaluate in vivo the ocular and respiratory mucosa biological response after chronic exposure to urban air particles from Buenos Aires (UAP-BA). BALB/c mice were exposed to UAP-BA or filtered air for 1, 6, 9, and 12 months. After exposure, histology, histomorphometry, and IL-6 proinflammatory cytokine level were evaluated in the respiratory and ocular mucosa. Total cell number and differential cell count were determined in the brochoalveolar lavage fluid. In the lung, chronic exposure to UAP-BA induced reduction of the alveolar space, polymorhonuclear cell recruitment, and goblet cell hyperplasia. In the ocular surface, UAP-BA induced an initial mucin positive cells rise followed by a decline through time, while IL-6 level increased at the latest point-time assayed. Our results showed that the respiratory and the ocular mucosas respond differently to UAP-BA. Being that lung and ocular mucosa diseases may be triggered and/or exacerbated by chronic exposure to urban air PM, the inhabitants of Buenos Aires whom are chronically exposed to environmental urban air pollution may be considered a subpopulation at risk. Based on our results, we propose the ocular mucosa as a reliable and more accessible surrogate for pulmonary mucosa environmental toxicity that might also serve as an earlier biomarker for air pollution adverse impact on health.
Afficher plus [+] Moins [-]Influence of Metarhizium anisopliae (IMI330189) and Mad1 protein on enzymatic activities and Toll-related genes of migratory locust
2019
Abro, Nazir Ahmed | Wang, Guangjun | Ullah, Hidayat | Long, Guo Long | Hao, Kun | Nong, Xiangqun | Cai, Ni | Tu, Xiongbing | Zhang, Zehua
Efficacy of Metarhizium anisopliae strain (IMI330189) and Mad1 protein alone or in combination by feeding method to overcome immune-related enzymes and Toll-like pathway genes was investigated in migratory locust. M. anisopliae (IMI330189) is a potent and entomopathogenic fungal strain could be effectively used against insect pests. Similarly, Mad1 protein adheres to insect cuticle, causing virulence to insects. We confirmed maximum 55% of mortality when M. anisopliae (IMI330189) and Mad1 was applied in combination. Similarly, increased PO activity was observed in locust with combined dose of Mad1 + IMI330189 whereas PO, POD, and SOD activities reduced using Mad1 independently. Four Toll-like signaling pathway genes (MyD88, Cactus, Pelle, and CaN) were investigated from midgut and body of the migratory locust after 72 h of treatments. Subsequently, the expression of MyD88 in the midgut and body significantly decreased with the application of Mad1 and Mad1 + IMI330189. Performance of these treatments was absolutely non-consistent in both parts of insects. Meanwhile, IMI330189 significantly raised the expression of Cactus in both midgut and body. However, the combined treatment (Mad1 + IMI330189) significantly reduced the Cactus expression in both body parts. Pelle expression was significantly increased in the midgut with the application of independent treatment of Mad1 and IMI330189 whereas the combined treatment (Mad1 + IMI330189) suppressed the Pelle expression in midgut. Its expression level was absolutely higher in body with the application of IMI330189 and Mad1 + IMI330189 only. On the other hand, Mad1 significantly increased the expression of CaN in midgut. However, all three treatments significantly affected and suppressed the expression of CaN gene in body of locust. This shows that the applications of M. anisopliae and Mad1 protein significantly affected Toll signaling pathway genes, which ultimately increased level of susceptibility of locust. However, their effect was significantly different in both parts of locust which recommends that the Toll-related genes are conserved in midgut instead of locust body.
Afficher plus [+] Moins [-]Performance of Physically and Chemically Activated Biochars in Copper Removal from Contaminated Mine Effluents
2019
The increasing global demand for metals and minerals justifies the intensive study of treatment options for contaminated mine effluents. The present study evaluated the conversion of wood residues into physically and chemically activated biochars and their subsequent use in the treatment of Cu in synthetic and actual contaminated mine drainage. First, wood residues were converted into biochar by fast pyrolysis. Then, physical (using steam or CO₂) or chemical (using KOH) activation was carried out in a homemade pilot-scale furnace. After activation, highly microporous (KOH materials) and micro/mesoporous activated biochars (CO₂ and steam materials) were obtained. Batch adsorption testing was first conducted with synthetic effluents. Results showed that CO₂-activated biochar was the most Cu effective adsorbent (99% removal) at low concentrations (5–20 mg L⁻¹). The mechanisms of Cu²⁺ adsorption involved physical and chemisorption for biochars and CO₂-activated biochar, while chemisorption for KOH-activated biochars was probably due to the high proportion of functional groups connected to their surface. In multi-metal acid mine drainage, metal adsorption capacities deteriorated for most of the materials, probably due to the effects of ion competition. However, KOH-activated biochar decreased Cu²⁺ concentrations to below the authorized monthly mean allowed by Canadian law (0.3 mg L⁻¹) and decreased Co, Pb, and Mn concentrations up to 95%. These findings indicate that high porosity and oxygenated functional groups connected to the surface of activated biochars are important properties for the enhancement of interactions between carbon materials and metals from mine effluents, as well as for their performance improvement in mine drainage treatment.
Afficher plus [+] Moins [-]Effect of Residual NAPLs on the Transport of Bisphenol A and Bisphenol S in Saturated Porous Media
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.
Afficher plus [+] Moins [-]Leaching of ANC and Chromium from Concrete: Effect of Aging Simulated by Sample Carbonation
2019
Demars, S. | Benoit, G.
Chemicals leached from concrete are an important way that urban stormwater can influence water quality. In this study, we evaluated the weathering properties of sidewalk samples and tested how carbonation (exposure to elevated levels of gaseous CO₂) can be used to simulate natural aging of concrete. The experiments focused on acid neutralizing capacity (ANC), which is known to be released by concrete in large amounts, and Cr(VI), because of its established carcinogenicity and prevalence in concrete. Chemical weathering of crushed sidewalk samples was measured with upflow recirculating columns carrying simulated acid rain. The weathering rate of ANC from four different samples was found to decrease after 1 week of exposure to a 5% carbon dioxide atmosphere and to remain constant thereafter through 8 weeks of carbonation treatment. In contrast, weathering of chromium (VI) increased after exposure to a 5% carbon dioxide atmosphere for 1 week, though it also remained stable from then through 8 weeks of carbonation. Almost all ions approached steady state after 2.5 h in the recirculation columns irrespective of carbonation time. The main contributor of ANC was Ca²⁺ ion, though this was partly balanced by an unexpectedly high amount of SO₄²⁻. A notable exception to the temporal leaching pattern was largely un-ionized Si, which continued to increase in concentration for at least 3 days of recirculation. Si levels were also higher than is generally observed for aluminosilicate weathering in small watersheds, a novel finding.
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