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Increase in water temperature increases acute toxicity of sumithion causing nuclear and cellular abnormalities in peripheral erythrocytes of zebrafish Danio rerio
2019
Shahjahan, Md | Rahman, Mohammad Shadiqur | Islam, S M Majharul | Uddin, Md Helal | Al-Emran, Md
Global warming and indiscriminate usages of pesticides are notable concern to all. The present study has been conducted to evaluate the effects of high temperature on acute toxicity of sumithion in adult zebrafish. A 2-day renewal bioassay system was used to determine the 96 h LC₅₀ value of sumithion at three temperature regimes, such as 25 °C, 30 °C, and 35 °C. Blood glucose (mg/dL) level was measured in control (0.0 mg/L) and low concentration (1.0 mg/L) of sumithion during the determination of LC₅₀ in three temperature conditions. In addition, micronucleus (MN), erythrocytic nuclear abnormalities (ENA), and erythrocytic cellular abnormalities (ECA) tests were performed in the blood erythrocytes. The 96 h LC₅₀ value of sumithion for zebrafish was significantly lower at 35 °C, which indicates that the toxicity of sumithion increases at higher temperature. Blood glucose level was significantly increased by sumithion in all temperature conditions, while it was significantly higher in the highest (35 °C) temperature compared to the lowest (25 °C) temperature in both control and sumithion-treated fish. Similarly, frequencies of MN, ENA, and ECA were elevated by sumithion in all temperature conditions, whereas it was significantly raised in the highest (35 °C) temperature compared to the lowest (25 °C) temperature in both control and sumithion treated fish. With increasing temperature in exposure to sumithion, dissolved oxygen decreased significantly, whereas free CO₂ increased significantly. On the other hand, no distinct changes were observed in pH and total alkalinity during the experimental period. Therefore, it can be inferred that increasing temperature enhances the toxicity of sumithion in the zebrafish.
显示更多 [+] 显示较少 [-]Nutrient removal from digested swine wastewater by combining ammonia stripping with struvite precipitation
2019
Cao, Leipeng | Wang, Jingjing | Xiang, Shuyu | Huang, Zhenghua | Ruan, Roger | Liu, Yuhuan
Typical biological processing is often challenging for removing ammonia nitrogen and phosphate from swine wastewater due to inhibition of high ammonia on activity of microorganisms, exhaustion of time, and low efficiency. In this study, a physicochemical process by combining ammonia stripping with struvite precipitation has been tested to simultaneously remove ammonia nitrogen, phosphate, and chemical oxygen demand (COD) from digested swine wastewater (DSW) with high efficiency, low cost, and environmental friendliness. The pH, temperature, and magnesium content of DSW are the key factors for ammonia removal and phosphate recovery through combining stripping with struvite precipitation. MgO was used as the struvite precipitant for NH₄⁺ and PO₄³⁻ and as the pH adjusted for air stripping of residual ammonia under the condition of 40 °C and 0.48 m³ h⁻¹ L⁻¹ aeration rate for 3 h. The results showed that the removal efficiency of ammonia, total phosphate, and COD from DSW significantly increased with increase of MgO dosage due to synergistic action of ammonia stripping and struvite precipitation. Considering the processing cost and national discharge standard for DSW, 0.75 g L⁻¹ MgO dosage was recommended using the combining technology for nutrient removal from DSW. In addition, 88.03% NH₄⁺-N and 96.07% TP could be recovered from DSW by adsorption of phosphoric acid and precipitation of magnesium ammonium phosphate (MAP). The combined technology could effectively remove and recover the nutrients from DSW to achieve environmental protection and sustainable and renewable resource of DSW. An economic analysis showed that the combining technology for nutrient removal from DSW was feasible.
显示更多 [+] 显示较少 [-]Understanding the effect of ventilation, intermittent pumping and seasonality in hydrogen sulfide and methane concentrations in a coastal sewerage system
2019
Matos, Rita Ventura | Ferreira, Filipa | Gil, Carla | Matos, José Saldanha
Gas pollutants emitted during wastewater transport contribute to atmospheric pollution, aggravated risks for utility workers, infrastructure corrosion, and odour nuisance. Field studies have shown that is difficult to effectively obtain reliable correlations between in-sewer air movement and gas pollutant concentrations. This study aimed at investigating the influence of different ventilation and operating conditions in H₂S and CH₄ horizontal and vertical movement in a section of a gravity sewer, downstream of a pumping station. Relevant liquid and gas phase quality parameters were monitored, and significant H₂S concentrations were measured (with lower contents of CH₄). Results evidenced that headspace temperature and ventilation played a key effect when analysing H₂S and CH₄ dynamics. Setups with a similar content of sulfide and chemical oxygen demand resulted in different H₂S and CH₄ headspace concentrations. It was also observed that an increase in ventilation resulted in a decrease of average headspace relative humidity of over 70%, with clear implications in corrosion potential estimates. Another interesting observation was that the wastewater drag induced by intermittent pumping, in absence of ingassing, originated pressure differences of up to 0.2 Pa m⁻¹ between studied manholes. This differential originated a wave pattern of gas moving upstream and downstream, thus resulting in several gas peaks per pumping event, at the same sections. In addition, in confined setups, full mixing was not observed along the manholes.
显示更多 [+] 显示较少 [-]Radiofrequency electromagnetic radiation-induced behavioral changes and their possible basis
2019
Narayanan, Sareesh Naduvil | Jetti, Raghu | Kesari, Kavindra Kumar | Kumar, Raju Suresh | Nayak, Satheesha B. | Bhat, P Gopalakrishna
The primary objective of mobile phone technology is to achieve communication with any person at any place and time. In the modern era, it is impossible to ignore the usefulness of mobile phone technology in cases of emergency as many lives have been saved. However, the biological effects they may have on humans and other animals have been largely ignored and not been evaluated comprehensively. One of the reasons for this is the speedy uncontrollable growth of this technology which has surpassed our researching ability. Initiated with the first generation, the mobile telephony currently reaches to its fifth generation without being screened extensively for any biological effects that they may have on humans or on other animals. Mounting evidences suggest possible non-thermal biological effects of radiofrequency electromagnetic radiation (RF-EMR) on brain and behavior. Behavioral studies have particularly concentrated on the effects of RF-EMR on learning, memory, anxiety, and locomotion. The literature analysis on behavioral effects of RF-EMR demonstrates complex picture with conflicting observations. Nonetheless, numerous reports suggest a possible behavioral effect of RF-EMR. The scientific findings about this issue are presented in the current review. The possible neural and molecular mechanisms for the behavioral effects have been proposed in the light of available evidences from the literature.
显示更多 [+] 显示较少 [-]Pollution source localization in an urban water supply network based on dynamic water demand
2019
Yan, Xuesong | Zhu, Zhixin | Li, Tian
Urban water supply networks are susceptible to intentional, accidental chemical, and biological pollution, which pose a threat to the health of consumers. In recent years, drinking-water pollution incidents have occurred frequently, seriously endangering social stability and security. The real-time monitoring for water quality can be effectively implemented by placing sensors in the water supply network. However, locating the source of pollution through the data detection obtained by water quality sensors is a challenging problem. The difficulty lies in the limited number of sensors, large number of water supply network nodes, and dynamic user demand for water, which leads the pollution source localization problem to an uncertainty, large-scale, and dynamic optimization problem. In this paper, we mainly study the dynamics of the pollution source localization problem. Previous studies of pollution source localization assume that hydraulic inputs (e.g., water demand of consumers) are known. However, because of the inherent variability of urban water demand, the problem is essentially a fluctuating dynamic problem of consumer’s water demand. In this paper, the water demand is considered to be stochastic in nature and can be described using Gaussian model or autoregressive model. On this basis, an optimization algorithm is proposed based on these two dynamic water demand change models to locate the pollution source. The objective of the proposed algorithm is to find the locations and concentrations of pollution sources that meet the minimum between the analogue and detection values of the sensor. Simulation experiments were conducted using two different sizes of urban water supply network data, and the experimental results were compared with those of the standard genetic algorithm.
显示更多 [+] 显示较少 [-]Occurrence of persistent organic pollutants in air at different sites in the province of Córdoba, Argentina
2019
Pegoraro, Cesar N. | Wannaz, Eduardo D.
The occurrence of persistent organic pollutants (POPs) and polycyclic aromatic hydrocarbons (PAHs) in the atmosphere of six sites with different emission sources in the province of Córdoba, Argentina, was analyzed. The sites included urban, industrial, agricultural, and mountain areas. Samples were collected using passive air samplers (PAS) consisting of polyurethane foam disks (PUF). Samples were analyzed for 12 PAHs, 31 polychlorinated biphenyls (PCBs), 12 organochlorine pesticides (OCPs), and 11 polybrominated diphenyl ethers (PBDEs). The concentrations of PAHs in the atmosphere were elevated at urban sites and were even higher at the industrial site. With respect to OCPs, it was observed that the concentrations of endosulfan were greater at the agricultural site (AGR) (416 ± 4 pg m⁻³). For hexachlorocyclohexanes (HCHs), only the alpha isomer was detected and there were minimal differences between the different sampling sites (5.9–13.3 pg m⁻³). In the case of dieldrin, the highest concentrations (33.6 pg m⁻³) were found at the mountain site, which may have been due to its use for insect control. Although heptachlor epoxide was not detected, the concentration of heptachlor was significantly higher at the agricultural and downtown sites (∼ 3.6 pg m⁻³). Regarding DDTs, the isomers p,p′-DDT and p,p′-DDE showed the highest concentrations at the mountain site (ΣDDT 120 ± 12 pg m⁻³) and downtown site (ΣDDT 157 ± 62 pg m⁻³). The relationship between the isomers suggested that at the downtown site, the contribution of this pesticide to the environment was recent, probably for the control of diseases vectors. The congener pattern of PBDEs was dominated by BDE-47, and BDE-99 at all sites, with the downtown site having the highest concentrations of compound esters (ΣPBDEs 118 ± 38 pg m⁻³). Finally, high concentrations of PCBs were found at the industrial site (ΣPCBs 1677 ± 134 pg m⁻³), and the predominating homologs were 5-Cl and 6-Cl, in contrast to the other sites where PCBs were dominated by 3-Cl and 4-Cl. This is the first study of POPs carried out in the province of Córdoba.
显示更多 [+] 显示较少 [-]Heavy metal pollution in Nanchang City and its health implication on traffic policemen
2019
Liu, Xiaozhen | Liang, Yue | Guo, Jiangmei
The purpose of this study is to evaluate the health effect of heavy metal pollution in air pollutants on traffic policemen. This study will facilitate the scientific evaluation of health status of traffic policemen. PM₁₀ samples were collected from industrial area, congested traffic area and residential area respectively in Nanchang City, and the concentrations of heavy metals were analyzed. The traffic policemen were examined through chest X-rays. The total of 637 urine samples and 142 blood samples have been collected, and the concentrations of Pb in samples were detected. Vehicle flux data of Nanchang City were collected from the Department of Transport’s Traffic Management. Statistic analyses were carried out by statistics software of Excel 2003 and SPSS20.0, and the health effect of heavy metal pollution of PM₁₀ on the traffic policemen was evaluated. The discharge of pollutants from enterprises is an important reason for the high content of heavy metals in urban air pollution. With the rapid growth of urban traffic flow, Bayi Bridge becomes an important transportation hinge in Nanchang City, and the bidirectional traffic flow rate through the bridge at peak hours reached 99 vehicles per minute. The latent hazard of occupational harm on the traffic policemen caused by automobile exhaust is increasing. The concentration of Pb in the urine and blood samples from traffic policemen working in Nanchang City was 268.310 ± 177.031 and 22.873 ± 21.137 μg/L, respectively. Both results (2.04% of Pb in urine and 18.31% of Pb in blood) exceeded the highest limit of observed occupationally outdoor workers. This study provides an initial contribution for the assessment of city air pollution, esp. the health effect of heavy metal (Pb) pollution on traffic policemen.
显示更多 [+] 显示较少 [-]Assessment of trophic status of the northeastern Mediterranean coastal waters: eutrophication classification tools revisited
2019
Tugrul, Suleyman | Ozhan, Koray | Akcay, Ismail
The Eastern Mediterranean and its Cilician Basin offshore waters have oligotrophic features with low nutrient concentrations, low primary production, and high water transparency. However, the wide shelf area of the Cilician Basin is subject to contaminated river inflows with enhanced nutrient loads and direct discharges of urban wastewaters of southern Turkey, leading to develop local eutrophic/mesotrophic conditions in the inner sites of Mersin and Iskenderun Bays on the Cilician Basin. For the assessment of changing trophic status of the coastal and the bay water bodies under anthropogenic pressures since the 1980s, five extensive field studies were performed in summer and winter periods of 2014, 2015, and 2016. Physical and eutrophication-related biochemical parameters (salinity, temperature, Secchi Disk Depth, nutrients, dissolved oxygen, chlorophyll-a) were measured at 65 stations in different water bodies occupying the Northeastern (NE) Mediterranean coastal, offshore areas and bays. The collected data sets were used in scaling the trophic status of the visited water bodies of NE Mediterranean coastal, offshore areas and semi-enclosed bays, using novel classification tools of Trophic Index (TRIX), Eutrophication Index (E.I.), chl-a, and HELCOM Eutrophication Assessment Tool (HEAT), developed by different experts for highly productive seas. These tools, which can successfully classify highly productive coastal water masses under human pressures, and their sensitivities have been tested for scaling of the current trophic status of the NE Mediterranean coastal water bodies being subject to human pressures. The scaling results of classical TRIX, E.I., and chl-a indices in the NE Mediterranean water masses are not sensitive enough to differentiate mesotrophic and eutrophic water bodies because these indices principally assume to have higher concentrations of eutrophication-related parameters in the least effected (reference) water bodies. The HEAT tool, which uses a site-specific “reference value” for each eutrophication-indicator, has allowed us to produce more reliable and sensitive scaling of the current trophic status of the NE Mediterranean shelf areas, even though we used only the “reference values” derived from the composite data sets. The results of the indices were compared with the HEAT tool and the actual status was assessed from observations, indicating revision requirements of the multi-metric classification tools. For this goal, scales of natural (oligotrophic) and anthropogenic (eutrophic) levels of eutrophication indicators should be determined at a sub-basin scale using long-term site-specific observations in the NE Mediterranean. The revised scale ranges of TRIX for oligotrophic, mesotrophic, and eutrophic water bodies of Mersin Bay are in line with ranges of TRIX classification tool proposed for Aegean Sea waters, which can be used to assess trophic status of the entire Eastern Mediterranean and Aegean coastal seas (surface salinity > 37.5) having oligotrophic properties in the offshore waters.
显示更多 [+] 显示较少 [-]Research on the changing trend of the carbon footprint of residents’ consumption in Beijing
2019
Fan, Zhenting | Lei, Yalin | Wu, Sanmang
Emission of greenhouse gas is a global environmental problem. In recent years, China has been facing growing international pressure because of its large energy consumption and elevated greenhouse gas emissions. As the capital of China, Beijing is central to the study of carbon emission reduction since its carbon emissions have ranked at the forefront nationwide. The existing literature mainly revolves around carbon emissions of a few specific years, and there is a lack of trend study of multiple years in Beijing. This paper, based on the input-output method, calculates carbon emissions in Beijing by carbon footprints; the changing trend analysis was carried out by researching available statistical data of three years, 2002, 2007, and 2012, from the perspective of the entire city of Beijing and from that of urban and rural residents’ consumption. The reasons for the changing trends of total carbon emission in Beijing have also been analysed using the Structural Decomposition Analysis (SDA) model. Results show that the total direct carbon footprint as well as the urban and rural direct carbon footprints of residents’ consumption in Beijing is all increasing gradually. The direct carbon footprint of urban residents’ consumption is mainly produced by electricity, gasoline, and heating power, while that of rural residents’ consumption is mainly produced by raw coal and electricity. The indirect carbon footprint of residents’ consumption in Beijing is increasing gradually, and that of urban areas is higher than that of rural areas. The compositions of indirect carbon footprints of rural and urban residents’ consumption are consistent, and both come mainly from the transportation and communication industry, housing, food, culture, education, entertainment, etc. The SDA results show that the per capita consumption level is the main driving factor for the increase of the indirect carbon footprint of Beijing residents’ consumption, and the intensity of CO₂ emission is the main inhibiting factor. Finally, suggestions for reducing carbon emissions from urban and rural perspectives have been put forward.
显示更多 [+] 显示较少 [-]Mercury species accumulation and distribution in Typha domingensis under real field conditions (Almadén, Spain)
2019
Lominchar, Miguel Ángel | Sierra, María José | Jiménez-Moreno, María | Guirado, María | Martín-Doimeadios, Rosa Carmen Rodríguez | Millán, Rocío
Monomethylmercury (MeHg) is one of the most toxic and the most commonly occurring organomercury compound and the wetlands are one of the main areas of generation of this Hg form. Concretely, it is in the macrophyte root system where better conditions are given for its generation. However, the knowledge of absorption and subsequent distribution of mercury (Hg) and monomethylmercury in aquatic plants is still limited. Mercury mining district such as Almadén (Ciudad Real, Spain) is a natural laboratory where different rivers flow and the species Typha domingensis Pers. is a common macrophyte which grows in their riverbanks. The aim of the present work is to apply a recently developed method specially designed to analyze Hg species in plant tissues to the different fractions of T. domingensis under real field conditions and to study the accumulation and distribution of Hg species (inorganic Hg and MeHg) within the plant. The results proved that whatever Hg species has preference to be accumulated in the belowground fractions and demonstrated a high efficiency in the accumulation of MeHg.
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