Уточнить поиск
Результаты 121-130 из 61,240
Removal of Fe3+ Ions from Wastewater by Activated Borassus flabellifer Male Flower Charcoal
2021
Kumar, Goutam | Tonu, Nusrat Tazeen | Dhar, Palash Kumar | Mahiuddin, Md.
Safe and clean water is essential for all living beings. Consumption of polluted water which is contaminated with iron may cause serious health implications. Therefore, removal of Fe3+ from wastewater is prerequisite for further uses. The present study intended to prepare activated charcoal (AC) from Borassus flabellifer male flower (BF) for the removal of Fe3+ ions from wastewater in a cost effective way. BFAC was produced based on carbonization method. Surface morphology and elemental composition were investigated by Scanning Electron Microscopy and Energy Dispersive X-Ray Spectroscopy. Additionally surface charge was determined by iodine number and zero point charge calculation. Batch adsorption studies were monitored using UV-visible spectroscopy. The obtain results showed a maximum adsorption at pH 8 with 0.3g adsorbent dosage at 50ppm initial Fe3+ ion concentration for 130 min contact time. The analysis of adsorption isotherm was in good agreement with both Langmuir and Freundlich adsorption isotherms. The Fe3+ removal method was found to be controlled by 1st order kinetics mechanism. However, the production cost was much cheaper and the removal performance was comparatively better than other commercial charcoals. Hence, BFAC could be used as a commercial charcoal in rural area of Bangladesh for purification of waste water.
Показать больше [+] Меньше [-]CO Emissions Modeling and Prediction using ANN and GIS
2021
Etemadfard, Hossein | Sadeghi, Vahid | Hassan Ali, Faleh | Shad, Rouzbeh
Air pollution is considered a global concern due to its impacts on human life and the urban environment. Therefore, precise modeling techniques are necessary to predict air quality in congested areas such as megacities. Recently, machine learning algorithms such as Neural Networks show significant possibilities in air quality studies. This paper proposes a model to estimate air quality in a congested urban area in Baghdad city using Artificial Neural Network (ANN) algorithm and Geospatial Information System (GIS) techniques. Carbon Monoxide (CO) gas is selected as the main air pollutant. The model parameters involve; CO samples, traffic flow, weather data, and land use information collected in the field. The proposed model is implemented in Matlab environment and the results are processed after entering ArcGIS software. Using its spatial analysis tools, the outputs are presented as a map. The final findings indicate the highest value of CO emissions that reached 34 ppm during the daytime. The most polluted areas are located near congested roads and industrial locations in comparison with residential areas. The proposed model is validated by using actual values that are collected from the field, where the model's accuracy is 79%. The proposed model showed feasibility and applicability in a congested urban area due to the integration between the machine learning algorithm and GIS modeling. Therefore, the proposed model in this research can be used as a supportive model for decision making of city managers.
Показать больше [+] Меньше [-]Particulate Matter and Adverse Respiratory Health Outcome: Exposure of Street Vendors in Kolkata city in India
2021
Ghosh, Nabanita | Das, Biplob | Das, Nandini | Chatterjee, Souran | Debsarkar, Anupam | Dutta, Amit | Chakrabarty, Shibnath | Roy, Joyashree
Exposure to airborne particulates is a major occupational hazard especially for outdoor workers who spending time outdoors at ground level getting exposed to traffic fumes and roadside dust. Aim of this study was to assess respiratory health symptoms and determine the change of lung functions of the roadside vendors and its association with traffic-related exposures and their working experience. A cross-sectional study was conducted in key market places of Kolkata – Gariahat (GH), Esplanade-Park Street (EP), Shyambazar-Hatibagan (SH) and Behala (BE). Particulate (PM10 and PM2.5) levels and meteorological parameters (wind speed, temperature and relative humidity) were monitored in the morning, afternoon and night over the period of October 2019 to February 2020. Lung function status (FEV1, FVC, FEV1/FVC ratio and PEF) was measured for 111 purposively selected participants. PM concentration was observed higher in the morning and night peak hours for all sites. At SH area the average occupational exposure level for PM10 and PM2.5 were observed as 1502.22 μg/m3h and 684.01 μg/m3h. Percentage predicted FEV1 (%FEV1) of street vendors was found decreasing with their work experience and the worst-case scenario was observed in the EP area, with the corresponding value being 70.75%, 49.15% and 47.3% for less than 10 years, 10 to 20 years and more than 20 years participation respectively. The higher particulate burden was observed to have declining lung function status of the street vendors. A strong policy framework should be adopted to improve outdoor working environment for outdoor workers.
Показать больше [+] Меньше [-]Optimisation of Crystal Violet and Methylene Blue Dye Removal from Aqueous Solution onto Water Hyacinth using RSM
2021
Prasad, Rajnikant | Yadav, Kunwar Durg
In this study, the adsorptive removal of two dyes (crystal violet (CV) and methylene blue (MB)) with HNO3 pre-treated water hyacinth powder (WHP) adsorbent was analysed. The experiments were designed using response surface methodology (RSM) with variable input parameter pH (2-12), adsorbent dose (0.5-3 g/L), initial dyes concentration (25-200 mg/L) and time (10-180 min). The optimization condition for dye removal were (pH = 7.22, adsorbent dose = 3.0 g/L, initial dye concentration = 195.28 mg/L and time of contact = 99.29 min) for CV with removal of 98.20% and (pH = 9.82, adsorbent dose = 2.96 g/L, initial dye concentration = 199.36 mg/L and contact time = 111.74 min) for MB with removal of 97.843%. The above findings observed that pre-treated water hyacinth powder can be utilised as a cost-effective and efficient adsorbent for dye effluent wastewater treatment.
Показать больше [+] Меньше [-]Biological and Geochemical Studies of Urinary Tract Stones in Lorestan Province
2021
Aghajari, Saadat | Sabzalipour, Sima | Nazarpour, Ahad | Mohammadiroozbahani, Maryam
Mineralogy studies can help understand the interactions of geographical, environmental, and geological factors. Considering frequent occurrence of urinary tract stones in the south and west of Iran, the present paper examines trace elements, like heavy metals, in 53 urine stone samples collected from patients in Lorestan Province. It investigates the mineralogy of the stones, using X-ray diffraction. The samples are then classified into five mineral groups (calcium oxalate, urate, cysteine, calcium oxalate-urate, and calcium oxalate/phosphate). Results from this analysis are confirmed by SEM images, showing the crystalline form of the mineral phases. The microscopic studies show that only the mineral group of calcium oxalate (whewellite) could be detected in thin sections, prepared from urinary tract stone samples. The main and trace elements in each group are determined through ICP-MS method with the results showing that calcium is the most abundant substance in urinary tract stones, compared to other elements. This is caused by the role of calcium in most basic functions of cell metabolism. The correlation between magnesium and strontium is 0.64, originated from the placement of high amounts of strontium in calcium oxalate minerals. The positive correlation between sodium and calcium also indicates that sodium is replaced by calcium due to the similarity of the ionic radius in the crystal structure. Results from this study can help us find the causes behind the frequent occurrence of urinary tract stones in Lorestan Province.
Показать больше [+] Меньше [-]Seasonal Dynamics of Heavy Metal Concentrations in Water, Fish and Sediments from Haor Region of Bangladesh
2021
Islam, Md. Sirajul | Rahman, Md. Mazedur | Kabir, Md. Humayun | Hoq, Md. Enamul | Meghla, Nowara Tamanna | Suravi, Suravi | Al Mamun, Shamim | Sarker, Md. Eusuf
Heavy metal concentrations in water, fish, and sediments from Bangladesh's haor region were investigated. Fish and sediment samples were taken once a season and evaluated using standard methods, while water samples were collected monthly. Results showed that metals in water (mg/L) were found in order of Mn (0.1694) > Cu (0.0189) > Zn (0.0045) > Pb (0.0040) > Cd (0.0028) within the maximum permissible level of Environment Conservation Rules (ECR). Mean concentrations of metal in fish (mg/kg–dry wt.) found in order of Zn (56.16) > Cu (25.47) > Mn (4.36) > Pb (2.19) > Cd (1.27) that were higher than maximum allowable level of Food and Agricultural Organization (FAO) except Cu. Metal in sediments (mg/kg) found in order of Mn (127.61) > Zn (32.51) > Pb (10.09) > Cu (5.40) > Cd (0.43), and except Cu all metal concentrations were lower than the Environmental Protection Agency's (EPA) probable effect concentrations. In water and sediments, pollution indices revealed a critical pollution threshold for water, and a range of unpolluted to highly polluted for sediments. Sampling sites had low potential ecological risk, despite the fact that metals were showing signs of a negative impact on people' health. Furthermore, bio-concentration factor for fish and water was low to extremely high, but for fish and sediment was low. The level of heavy metal contamination in haor shows the situation is alarming for biota and residents of the region. The relevant authority should control and monitor the aquatic ecology in order to protect it.
Показать больше [+] Меньше [-]Exploring the use of Macrophytes as Biological Indicators for Organic Pollution of Chanchaga River in North Central Nigeria
2021
Ali, Andrew | Obi-Iyeke, Grace | Keke, Unique | Arimoro, Francis
Macrophytes are creatures with low versatility and cannot stay away from any mix of streamflow, nutrient accessibility, and other physical and chemical attributes that impact their survival in the aquatic system. Sampling for macrophytes in Chanchaga River was conducted monthly for a 6-month period (May - October 2019). Sampling stations were selected at approximately equal distance along the streamline, the aquatic vegetation were surveyed, and some environmental variables were analysed using standard methods. Results obtained indicated that temperature ranged from 24.6-28.4°C; pH 6.4 -9.7; Electrical conductivity 28.0-79.0μS cm-1; Total dissolved solids 16-75 mg L-1; Dissolved oxygen(DO) 1.3-5.2 mg L-1; Nitrate 0.217-0.654 mg L-1; Phosphate 0.084-0.211 mg L-1; Biological oxygen demand (BOD) 0.89-5.4 mg L-1 and total alkalinity 8.00-11.00 mgL-1 for the study period. A total of eleven (11) macrophyte species belonging to ten genera and eight families were identified during the entire study. Variations in terms of families showed that Araliaceae was the most abundant followed by Poaceae, while Cyperaceae had more species throughout the study period. The high frequency of Araliaceae, Cyperaceae, and Poaceae families suggests that the environmental characteristics favour these species. We propose the use of Cyperus digitatus, Cyperus papyrus and Mimosa spp. as macrophytes indicators of organic pollution in Chanchaga River.
Показать больше [+] Меньше [-]Biochemical and Physiochemical Assessment of Air Pollution Tolerance Index of Selected Plant Species at Ikpoba Okha Gas Flaring Site, Edo State, Nigeria
2021
Akande, Anthony | Dada, Esther | Olusola, Johnson | Adeyemi, Moyosola
The Air Pollution Tolerance index (APTI) of six plants located within Ikpoba Okha gas flaring site in Oredo Local Government Area of Edo State, Nigeria during wet and dry seasons were assessed. Plant samples for this research work were randomly collected from the vicinity of the flaring site. Six (6) sample of each plant was used for laboratory analysis. The plant parameters assessed include relative water content (RWC), the ascorbic acid content (AAC), total leaf chlorophyll (TLC) and pH extract of the leaves and were used to compute the Air pollution tolerance indices (APTI). Based on the analyzed result, the RWC in Drypetes leonensis, Ficus exasperata Vahl, Chromolaena odorata (Linn) and Gmelina arborea Roxb. ex Smith species in dry season were higher than those in wet season. Icacina tricantha showed a relatively high level of acidity when compared to others. A. boonei De Wild has the highest ascorbic acid content in the leaves in both seasons. The highest level of chlorophyll contents was recorded in the dry season with Drypetes leonensis having the highest, followed by Icacina trichantha. There was no statistically significant difference in pH and total chlorophyll contents between samples collected in wet and dry season; however, there were significant difference observed in ascorbic acid and RWC in both seasons. APTI in wet and dry season showed a statistically significant difference. This study recommends planting of tolerant species that can acts as bio-indicators especially in gas flaring stations in Nigeria.
Показать больше [+] Меньше [-]The Effect of Monsoon on Chemical Composition and Bioaccumulation of Heavy Metals in Scomberomorus commerson, Lacepede 1800, from Oman Sea
2021
Esmaeilzade Ashini, Asma | Sadeghi, Parvin | Tootooni, Mohammad Mansoor
This study was performed to determine the chemical compositions and heavy metals in the muscle of Scomberomorus commerson from the Oman Sea, during the two seasons, pre-monsoon and post-monsoon in 2018. The protein, fat, moisture, and ash contents were determined by AOAC (Association of Official Analytical Chemists) methods. Heavy metal (Zn, Cu, and Pb) analyses were performed by atomic absorption spectrophotometer after acid digestion. There were significant differences between protein, fat, moisture, and ash values in muscle tissue in two seasons (P< 0.05). The highest content of protein (22.53±2.09%) and fat (4.15±1.25%) was recorded in pre-monsoon. The mean concentrations of heavy metals (μg g-1dw) in muscle tissue were 0.08-0.05 for Zn, 0.04-0.02 for Cu, and 0.02-0.01 for Pb in the pre and post-monsoon, respectively. The accumulation of heavy metals in muscle followed the Zn>Cu>Pb. The amounts of Zn, Cu, and Pb were below maximum permissible limits (MPL) recommended by international standards (FAO, FAO/WHO, and MAFF). Results revealed that estimated daily and weekly intakes of Zn, Cu, and Pb were far below the permissible tolerable daily intake (PTWI) recommended by FAO/WHO. Therefore, consumption of S. commerson in the pre and post-monsoon has no risks for human health in the Oman Sea.
Показать больше [+] Меньше [-]Analysis of Water Quality Trends Using the Mann-Kendall Test and Sen’s Estimator of Slope in a Tropical River Basin
2021
Hashim, Mohmadisa | Nayan, Nasir | Setyowati, Dewi Liesnoor | Said, Zahid Mat | Mahat, Hanifah | Saleh, Yazid
Trends in water quality, either increasing or decreasing over the long term, are becoming an essential guide to understanding water quality. This study aims to analyse the trends in water quality in the upstream part of the Bernam River Basin, Malaysia from 1998 to 2018. This study involved the collection of data on water quality from the Department of Environment, Malaysia. Six main parameters of the water quality index (WQI) were chosen, including the dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), ammoniacal nitrogen (NH3-N), total suspended solids (TSS) and pH. The analysis methods applied are the Mann-Kendall test and Sen’s estimator of slope. The results of the WQI value trend analysis revealed that most stations have decreasing trends. A trend analysis of the parameters found that most stations had increasing trends for the DO, BOD, NH3-N and pH parameters, while decreasing trends for the COD and TSS parameters were observed. An increasing trend indicated that the water quality parameters were getting better, and a decreasing trend indicated the opposite. This study will benefit the parties responsible for planning and monitoring developments to reduce water pollution around the upstream Bernam River Basin. In the upstream of Bernam River Basin, land use changes have occurred rapidly, especially forest areas have been explored for human settlements, agricultural and industrial activities. Thus, the sustainability of the river basin can be maintained and valued by the various parties in the future. The river basin is also important as a domestic water supply for the residents of Selangor and Perak.
Показать больше [+] Меньше [-]