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Source identification of chromium in the sediments of the Xiaoqing River and Laizhou Bay: A chromium stable isotope perspective Texte intégral
2020
He, Xiaoqing | Chen, Guojun | Fang, Ziyao | Liang, Wenjian | Li, Boda | Tang, Jianhui | Sun, Yongge | Qin, Liping
Hexavalent chromium, Cr(VI), is a heavy metal contaminant and the reduction of Cr(VI) is accompanied by large isotopic fractionation. In this study, the sources of Cr were explored using the Cr isotopic composition of sediments from the Xiaoqing River, a heavily polluted river located in the Shandong Province of China, which flows into Laizhou Bay. The results show that δ⁵³Cr values of the sediments are the highest upstream near the pollution source, and gradually decrease along the river toward the range for igneous reservoirs observed near the estuary. Based on the calculation of authigenic Cr isotopic composition (δ⁵³Crₐᵤₜₕ) using the detrital index and leaching experiments, we suggest that the authigenic Cr in the sample near the pollution source with the highest δ⁵³Crₐᵤₜₕ value mainly comes from the reduction of Cr(VI) discharged by anthropogenic activity, and authigenic Cr in other samples in the midstream with δ⁵³Crₐᵤₜₕ values slightly higher than the range of igneous reservoirs may come from natural oxidative Cr weathering products. By introducing a Rayleigh model, we calculate that at least 31%–55% of Cr(VI) in the river water had been reduced to Cr(III) near the pollution source. Due to the self-purification ability of the river, Cr(VI) was reduced; thus, there is no record of high δ⁵³Crₐᵤₜₕ values in the downstream of the Xiaoqing River and Laizhou Bay, indicating no obvious Cr pollution in these locations. The limited variation of δ⁵³Cr values for samples from a sediment core in Laizhou Bay is also indicative of no obvious Cr pollution in the history. The Cr isotopic compositions of the river sediments are useful for the identification of Cr sources and can be used to advise environmental remediation on Cr pollution.
Afficher plus [+] Moins [-]Stochastic determination of the spatial variation of potentially pathogenic bacteria communities in a large subtropical river Texte intégral
2020
Zhou, Lei | Liu, Li | Chen, Wei-Yuan | Sun, Ji-Jia | Hou, Shi-Wei | Kuang, Tian-Xu | Wang, Wen-Xiong | Huang, Xian-De
Understanding the composition and assembly mechanism of waterborne pathogen is essential for preventing the pathogenic infection and protecting the human health. Here, based on 16S rRNA sequencing, we investigated the composition and spatial variation of potentially pathogenic bacteria from different sections of the Pearl River, the most important source of water for human in Southern China. The results showed that the potential pathogen communities consisted of 6 phyla and 64 genera, covering 11 categories of potential pathogens mainly involving animal parasites or symbionts (AniP), human pathogens all (HumPA), and intracellular parasites (IntCelP). Proteobacteria (75.87%) and Chlamydiae (20.56%) were dominant at the phylum level, and Acinetobacter (35.01%) and Roseomonas (8.24%) were dominant at the genus level. Multivariate analysis showed that the potential pathogenic bacterial community was significantly different among the four sections in the Pearl River. Both physicochemical factors (e.g., NO₃–N, and suspended solids) and land use (e.g., urban land and forest) significantly shaped the pathogen community structure. However, spatial effects contributed more to the variation of pathogen community based on variation partitioning and path analysis. Null model based normalized stochasticity ratio analysis further indicated that the stochastic process rather than deterministic process dominated the assembly mechanisms by controlling the spatial patterns of potential pathogens. In conclusion, high-throughput sequencing shows great potential for monitoring the potential pathogens, and provided more comprehensive information on the potentially pathogenic community. Our study highlighted the importance of considering the influences of dispersal-related processes in future risk assessments for the prevention and control of pathogenic bacteria.
Afficher plus [+] Moins [-]Fate and risk assessment of sulfonamides and metabolites in urban groundwater Texte intégral
2020
Jurado, Anna | Margareto, Alejandro | Pujades, Estanislao | Vázquez-Suñé, Enric | Díaz-Cruz, M. Silvia
Fate and risk assessment of sulfonamides and metabolites in urban groundwater Texte intégral
2020
Jurado, Anna | Margareto, Alejandro | Pujades, Estanislao | Vázquez-Suñé, Enric | Díaz-Cruz, M. Silvia
Antibiotics, such as sulfonamides (SAs), have recently raised concern as wastewater treatment plants (WWTPs) partly remove them, and thus, SAs continuously enter the aquifers. In this context, the aims of this work are to (1) investigate the temporal evolution of SAs and metabolites in an urban aquifer recharged by a polluted river; (2) identify the potential geochemical processes that might affect SAs in the river-groundwater interface and (3) evaluate the ecological and human health risk assessment of SAs. To this end, 14 SAs and 4 metabolites were analyzed in river and urban groundwater from the metropolitan area of Barcelona (NE, Spain) in three different sampling campaigns. These substances had a distinct behavior when river water, which is the main recharge source, infiltrates the aquifer. Mixing of the river water recharge into the aquifer drives several redox reactions such as aerobic respiration and denitrification. This reducing character of the aquifer seemed to favor the natural attenuation of some SAs as sulfamethoxazole, sulfapyridine, and sulfamethizole. However, most of the SAs detected were not likely to undergo degradation and adsorption because their concentrations were constant along groundwater flow path. In fact, the intensity of SAs adsorption is low as the retardation factors are close to 1 at average groundwater pH of 7.2 for most SAs.Finally, risk quotients (RQs) are used to evaluate the ecological and human health risks posed by single and mixture of SAs in river water and groundwater, respectively. Life-stage RQs of the SAs detected in groundwater for the 8 age intervals were low, indicating that SAs and their mixture do not pose any risk to human beings. Concerning the environmental risk assessment, SAs do not pose any risk for algae, fish and crustaceans as the RQs evaluated are further lower than 0.1.
Afficher plus [+] Moins [-]Fate and risk assessment of sulfonamides and metabolites in urban groundwater Texte intégral
2020
Jurado, Anna | Margareto, Alejandro | Pujades, Estanislao | Vázquez-Suñé, Enric | Diaz-Cruz, Silvia | European Commission | Ministerio de Ciencia e Innovación (España) | Vázquez-Suñé, Enric [0000-0001-7022-2192] | Diaz-Cruz, M. Silvia [0000-0003-3331-4076] | Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]
Antibiotics, such as sulfonamides (SAs), have recently raised concern as wastewater treatment plants (WWTPs) partly remove them, and thus, SAs continuously enter the aquifers. In this context, the aims of this work are to (1) investigate the temporal evolution of SAs and metabolites in an urban aquifer recharged by a polluted river; (2) identify the potential geochemical processes that might affect SAs in the river-groundwater interface and (3) evaluate the ecological and human health risk assessment of SAs. To this end, 14 SAs and 4 metabolites were analyzed in river and urban groundwater from the metropolitan area of Barcelona (NE, Spain) in three different sampling campaigns. These substances had a distinct behavior when river water, which is the main recharge source, infiltrates the aquifer. Mixing of the river water recharge into the aquifer drives several redox reactions such as aerobic respiration and denitrification. This reducing character of the aquifer seemed to favor the natural attenuation of some SAs as sulfamethoxazole, sulfapyridine, and sulfamethizole. However, most of the SAs detected were not likely to undergo degradation and adsorption because their concentrations were constant along groundwater flow path. In fact, the intensity of SAs adsorption is low as the retardation factors are close to 1 at average groundwater pH of 7.2 for most SAs. Finally, risk quotients (RQs) are used to evaluate the ecological and human health risks posed by single and mixture of SAs in river water and groundwater, respectively. Life-stage RQs of the SAs detected in groundwater for the 8 age intervals were low, indicating that SAs and their mixture do not pose any risk to human beings. Concerning the environmental risk assessment, SAs do not pose any risk for algae, fish and crustaceans as the RQs evaluated are further lower than 0.1. | A.J acknowledges the support from the Secretary for Universities and Research of the Ministry of Economy and Knowledge of the Government of Catalonia and the Marie Sklodowska-Curie COFUND of the programme H2020 (BP3, contract number 801370). M.S.D.C acknowledges the Generalitat de Catalunya (Water and Soil Quality Unit, 2017-SGR-1404) and the Spanish Ministry of Science and Innovation (Project CEX 2018-000794-S). E.V.S would like to thank the European Commission, the Spanish Foundation for Science & Technology (FECYT) and State Research Agency (AEI)) for funding in the frame of the collaborative international consortium (URBANWAT) financed under the 2018 Joint call of the WaterWorks2017 ERA-NET Cofund. This ERA-NET is an integral part of the activities developed by the Water JPI. Additionally E.V.S also thank the Ministry of Science, Innovation and Universities, for funding the project UNBIASED (Ref: RTI 2018-097346-B-I00) under the 2018 call of the “Proyectos de I + D Retos Investigación. | Peer reviewed
Afficher plus [+] Moins [-]Optimized parameters of the electrocoagulation process using a novel reactor with rotating anode for saline water treatment Texte intégral
2020
Al-Raad, Abbas A. | Hanafiah, Marlia M. | Naje, Ahmed Samir | Ajeel, Mohammed A.
In this study, a novel rotating anode-based reactor (RAR) was designed to investigate its effectiveness in removing dissolved salts (i.e., Br⁻, Cl⁻, TDS, and SO₄²⁻) from saline water samples. Two configurations of an impeller’s rotating anode with various operation factors, such as operating time (min), rotating speed (rpm), current density (mA/cm²), temperature (°C), pH, and inter-electrode space (cm), were used in the desalination process. The total cost consumed was calculated on the basis of the energy consumption and aluminum (Al) used in the desalination. In this respect, operating costs were calculated using optimal operating conditions. Salinity was removed electrochemically from saline water through electrocoagulation (EC). Results showed that the optimal adjustments for treating saline water were carried out at the following conditions: 150 and 75 rpm rotating speeds for the impeller’s rod anode and plate anode designs, respectively; 2 mA/cm² current density (I), 1 cm² inter-electrode space, 25 °C temperature, 10 min operation time, and pH 8. The results indicated that EC technology with impeller plates of rotating anode can be considered a very cost-effective technique for treating saline water.
Afficher plus [+] Moins [-]Spatial-temporal variations and trends predication of trace metals in oysters from the Pearl River Estuary of China during 2011–2018 Texte intégral
2020
Lu, Guangyuan | Pan, Ke | Zhu, Aijia | Dong, Yanhong | Wang, Wen-Xiong
Estuaries are often considered to be the filters of pollutants from the land-derived outflows of freshwater to open seawater. Oysters are efficient bioaccumulators of metals in the estuarine environment, however, little information is available on the long-term tissue variability of metals in a large dynamic estuary under complex urbanized and anthropogenic impacts. Thus, an eight-year biomonitoring study of metals (Ag, Cd, Cr, Cu, Ni, Pb, and Zn) in the oysters from 10 sites were carried out to reveal the highly spatial-temporal variations in the Pearl River Estuary (PRE) of China during 2011–2018. Cd, Cu, and Zn in oysters were significantly correlated with the dissolved metals in seawater. Geographically, Ag, Cd, and Cr were higher in the western sites, and Cu, Ni, and Zn were higher in the eastern sites. High seasonal variations of Ag, Cu, and Zn were found in the wet season. The calculated annual change rates (vc) of Cd, Cu, Zn, Ag, Pb, Ni, and Cr in the oysters were −1.1, −45, −48, 0.338, −0.216, −2.2, and −2.8 μg/g/y, respectively. If such decreasing rates of vc (or natural logarithm rates v) were maintained, Cd, Cu, Zn, Pb, and Ni in oysters from PRE would be expected to recover to the national 50% concentrations in years 2022 (2024), 2045 (2079), 2073 (2110), 2021 (2023), and 2019 (2020), respectively. Long-term series observations of metals in organisms reflected the real bioavailability of metals, pollution status, and trends for environmental management and control in a large dynamic and contaminated estuary.
Afficher plus [+] Moins [-]Risk assessment of cardiotoxicity to zebrafish (Danio rerio) by environmental exposure to triclosan and its derivatives Texte intégral
2020
Wang, Danting | Zhang, Yuhuan | Li, Jieyi | Dahlgren, Randy A. | Wang, Xuedong | Huang, Haishan | Wang, Huili
Triclosan (TCS) and its two derivatives (2,4-dichlorophenol and 2,4,6-trichlorophenol) are priority pollutants that coexist in aquatic environments. Joint exposure of TCS, 2,4-dichlorophenol and 2,4,6-trichlorophenol, hereafter referred to as TCS-DT, contributes severe toxicity to aquatic organisms. There is currently a paucity of data regarding TCS-DT molecular toxicity, especially on cardiac diseases. We used zebrafish (Danio rerio) as a model organism, and evaluated the molecular-level cardiotoxicity induced by TCS-DT from embryonic to adult stages. TCS-DT exposure prominently led to phenotypic malformations, such as pericardial cysts, cardiac bleeding, increased SV-BA distance, decreased heart rate and reduced ejection fraction, as well as abnormal swimming behavior. Analyses of the GO and KEGG pathways revealed enrichment pathways related to cardiac development and screened for significantly down-regulated adrenaline signaling in cardiomyocytes. The cardiac marker genes (amhc, cmlc2, vmhc, and nkx2.5) were obtained through protein-protein interaction (PPI) networks, and expressed as down-regulation by WISH. After chronic exposure to TCS-DT from 30 to 90-dpf, both body mass and heart indexes prominently increased, showing myocardial hypertrophy, abnormal heart rate and histopathological injury. Heart tissue damage included disordered and ruptured myocardial fibers, broken and dissolved myofilaments, nuclear pyknosis, mitochondrial injury and inflammatory cell infiltration. Further, abnormal changes in a series of cardiac functions-related biomarkers, including superoxide dismutase, triglyceride, lactate dehydrogenase and creatinine kinase MB, provided evidence for cardiac pathological responses. These results highlight the molecular mechanisms involving TCS-DT induced cardiac toxicity, and provide theoretical data to guide prevention and treatment of pollutant-induced cardiac diseases.
Afficher plus [+] Moins [-]Determination of dry deposition velocity of polycyclic aromatic hydrocarbons under the sub-tropical climate and its implication for regional cycling Texte intégral
2020
Dotel, Jagdish | Gong, Ping | Wang, Xiaoping | Pokhrel, Balram | Wang, Chuanfei | Nawab, Javed
Atmospheric dry deposition is a major pathway for removal of polycyclic aromatic hydrocarbons (PAHs) from the atmosphere. Despite its significance in the atmospheric environment, measurements of the dry deposition velocity (VDD) and deposition fluxes (FDD) of PAHs are relatively limited. In this study, a passive dry deposition (PAS-DD) collector was co-deployed with passive air sampler polyurethane foam (PAS-PUF) from November 2015 to November 2016 in two major cities (Kathmandu and Pokhara), Nepal, to investigate the VDD and FDD of PAHs. The VDD of PAHs ranged from 0.25 to 0.5 cm s⁻¹ and the annual average was recorded as 0.37 ± 0.08 cm s⁻¹. On the basis of measured VDD, the FDD of ∑15PAHs in Kathmandu and Pokhara were estimated as 66 and 5 kg yr⁻¹ respectively. According to the measured VDD of Kathmandu and Pokhara in this study, and the previously published VDD data of Toronto, Canada, where the same PAS-DD collector was used, a significant multi-linear correlation (r² = 0.79, p < 0.05) was found between VDD of higher molecular weight (HMW with MW ≥ 228.3 and ≥ 4 rings) PAHs and meteorological parameters (precipitation and wind speed) and vapor pressure of PAHs. To the best of our knowledge, this enabled the development of an empirical model that can exhibit the combined effects of meteorological conditions on the VDD of HMW PAHs. The model was used to estimate the VDD values for major cities in the Indo-Gangetic Plain (IGP) region and the maximum estimated proportion of HMW PAHs deposited by dry deposition reached up to 60% of total emissions. Although PAH emissions in the IGP region pose global risks, the results of this study highlight the considerable risk for local IGP residents, due to the large dry deposition proportion of HMW PAHs.
Afficher plus [+] Moins [-]Sorption of fluoroquinolones to nanoplastics as affected by surface functionalization and solution chemistry Texte intégral
2020
Zhang, Huan | Liu, Feifei | Wang, Su-chun | Huang, Tian-yuan | Li, Meng-ru | Zhu, Zhi-lin | Liu, Guang-zhou
Microplastics have attracted much attention in recent years as they can interact with pollutants in water environment. However, nanoplastics (NPs) with or without the surface functionalization modification have not been thoroughly explored. Here, the sorption behaviors of two fluoroquinolones (FQs), including norfloxacin (NOR) and levofloxacin (LEV) on polystyrene NPs (nano-PS) and carboxyl-functionalized polystyrene NPs (nano-PS-COOH) were investigated. The results showed that sorption isotherms were nonlinear and well fitted by Langmuir model. The sorption capacities of NOR and LEV on nano-PS-COOH were higher than those on nano-PS, and their physical interactions, including polar interaction, electrostatic interaction and hydrogen bonding may be the dominant mechanisms. Moreover, the increase of pH firstly increased the sorption of two FQs on NPs and then decreased because NOR and LEV had a reverse charge at different pH values. Salinity and dissolved organic matter both inhibited the sorption process. These findings show that NPs with or without the surface functionalization modification have different sorption behaviors for environmental pollutants, which deserve our further concern.
Afficher plus [+] Moins [-]microRNA expression profiles and personal monitoring of exposure to particulate matter Texte intégral
2020
Mancini, Francesca Romana | Laine, Jessica E. | Tarallo, Sonia | Vlaanderen, Jelle | Vermeulen, Roel | van Nunen, Erik | Hoek, Gerard | Probst-Hensch, Nicole | Imboden, Medea | Jeong, Ayoung | Gulliver, John | Chadeau-Hyam, Marc | Nieuwenhuijsen, Mark | de Kok, Theo M. | Piepers, Jolanda | Krauskopf, Julian | Kleinjans, Jos C.S. | Vineis, Paolo | Naccarati, Alessio
An increasing number of findings from epidemiological studies support associations between exposure to air pollution and the onset of several diseases, including pulmonary, cardiovascular and neurodegenerative diseases, and malignancies. However, intermediate, and potentially mediating, biological mechanisms associated with exposure to air pollutants are largely unknown. Previous studies on the human exposome have shown that the expression of certain circulating microRNAs (miRNAs), regulators of gene expression, are altered upon exposure to traffic-related air pollutants. In the present study, we investigated the relationship between particulate matter (PM) smaller than 2.5 μm (PM₂.₅), PM₂.₅ absorbance (as a proxy of black carbon and soot), and ultrafine-particles (UFP, smaller than 0.1 μm), measured in healthy volunteers by 24 h personal monitoring (PEM) sessions and global expression levels of peripheral blood miRNAs. The PEM sessions were conducted in four European countries, namely Switzerland (Basel), United Kingdom (Norwich), Italy (Turin), and The Netherlands (Utrecht). miRNAs expression levels were analysed using microarray technology on blood samples from 143 participants. Seven miRNAs, hsa-miR-24-3p, hsa-miR-4454, hsa-miR-4763-3p, hsa-miR-425-5p, hsa-let-7d-5p, hsa-miR-502-5p, and hsa-miR-505-3p were significantly (FDR corrected) expressed in association with PM₂.₅ personal exposure, while no significant association was found between miRNA expression and the other pollutants. The results obtained from this investigation suggest that personal exposure to PM₂.₅ is associated with miRNA expression levels, showing the potential for these circulating miRNAs as novel biomarkers for air pollution health risk assessment.
Afficher plus [+] Moins [-]Estimating regional N application rates for rice in China based on target yield, indigenous N supply, and N loss Texte intégral
2020
Ding, Wencheng | Xu, Xinpeng | He, Ping | Zhang, Jiajia | Cui, Zhenling | Zhou, Wei
Decision-making related to nitrogen (N) applications based solely on historic experience is still widespread in China, the country with the largest rice production and N fertilizer use. By connecting N application rates with target N uptake, indigenous N supply, and N loss estimates collected from 1078 on-farm experiments, we determined regional N application rates for five rice-based agroecosystems, including a quantification of the reduction potential of application rates when using low-loss N sources, such as organic N and slow-release N. Based on our results, the moderate regional N application rates were 165, 180, 160, 153, and 173 kg N ha⁻¹ for single, middle-CE (Central and Eastern China), middle-SW (Southwestern China), early, and late rice, respectively; lower (99–148 kg N ha⁻¹) and upper (195–217 kg N ha⁻¹) limits of N application rates were developed for situations with sufficient and insufficient indigenous N supplies, respectively. The depletion of soil N mineralization was quantified as 46.8–67.3 kg ha⁻¹, and straw return is determined to be a robust measure to maintain soil N balance. Substituting manure or slow-release N for conventional N fertilizer significantly decreased N losses via NH₃ volatilization, leaching, runoff, and N₂O emissions. Overall, we observed 7.2–11.3 percent point reductions of N loss rate for low-loss N sources when compared to conventional N applications. On average, total N application rates could be theoretically reduced by 27 kg N ha⁻¹ by using a slow-release N fertilizer, or by 30 kg N ha⁻¹ when using manure due to their effectiveness at decreasing system N losses. Greater productivity, sustainable soil fertility, and a lower risk of N pollution would result from the ideal N application rate coupled with appropriate management practices. Widespread adoption of using low-loss N sources could become a key solution for future reduction in environmental N pollution and agricultural N inputs.
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