In this research, the capability of vermiculite in arsenic extraction, associated with characterizing its main properties was evaluated. To address this purpose, vermiculite was artificially contaminated with arsenic at 7 and 28-day intervals. Then, arsenic was extracted from contaminated soils by different extractants. Various physical and mechanical tests were performed to investigate the effect of arsenic as an anionic contaminant on the properties of the vermiculite, as well as to evaluate how the properties of the contaminated soil were altered by the extraction process. The carbonate bonding phase was probably mainly responsible for the adsorption and fixation of arsenic with more than 50% portion among measured fractions at different curing times. Based on the vermiculite condition, hydrochloric acid was the best extractant for removing arsenic in all studied samples (around 3 -18 % more than other extractants). The clay soil demonstrated few changes due to arsenic contamination and modification. In general, the most promising characteristics of vermiculite as clay liner are its stability after contamination due to high CEC and SSA; however, its workability and strength (UCS between 110 to 220 kPa at different soil conditions) is a challenge and must be improved by adding coarser fractions like silt particles. In general, the results of this study regarding the effects of arsenic contamination and extraction onto vermiculite’s physical properties can provide appropriate information for researchers and geo-environmental engineers.

Textile effluents are highly colored for synthetic dyes, cause significant water pollution due to high pH, TDS, EC, BOD, and COD content, and are harmful to aquatic species. Among different treatment processes, biological treatment process is considered as a promising approach. In this investigation, a mixed aerobic bacterial consortium was used for the treatment of wastewater. In addition, the fenton process with a normal sand filter was used for treatment and compared with the biological method. The mean values of BOD, COD, TDS, EC, DO, and pH in the raw wastewater indicated that the effluent was highly contaminated according to Bangladesh standard (ECR, 1997). Both the biological treatment process and fenton process separately showed promising removal of pollution load. The aerobic mixed bacterial consortium reduced TDS (66.67%), EC (60%), BOD (91.67%), and COD (85.45%) and fenton process reduced TDS (74.71%), EC (55.11%), BOD (88.33%), and COD (83.63%) compared to the raw effluent bacterial consortium simultaneously degraded dyes and decolorized the wastewater from dark deep green to transparent. Color removal for the mixed aerobic bacterial process after 72 hours of aeration was 58.57% and for the fenton process with a normal sand filter was 80%. BOD and COD removal percentages for aerobic mixed bacterial consortium showed higher removal efficiency than the fenton process with a normal sand filter. Though 92 hours of aeration showed the maximum satisfactory result, aeration time could be reduced to 72 hours which also satisfied the Bangladeshi standard (ECR, 1997).

This research aims at developing a new relation to estimate the urban runoffwater quality through urban land use. According to the first phase of this research, sixurban characteristics and land use indices have been defined concerning all parameterswith either direct or indirect impacts on urban water quality: Population, land use type,meteorological factors, local physiographical parameters, urban patterns etc. have beenconsidered when developing the new indices. Three study areas, including different urbanland uses, have been selected in Tehran Metropolitan and urban drains maps andstructures have gone under study to determine the sampling points. Multi-statisticalanalysis, discriminate analysis, and multi-linear regression analysis have been applied forall water quality results and urban indices in each site, with the results revealing verystrong relations between urban land use and water quality variation. Temporarypopulation especially in downtown site has proved to be an effective temporal factor onhow even public transport could not have any significant effects, in case populationdensity has no significant influence on water quality, as all sanitary waste water inselected sites is collected through urban wastewater systems separately. General slop is asignificant factor in hydrocarbons and heavy metals, once they are not alongside thestreets route. All told, this paper recommends reusing urban drained runoff locally beforejoining other regions’ collectors. Here in urban drainage system, collection andaggregation of water could not be an appropriate factor in water quality managementunlike river systems. The model could be employed in urban local water consumptionmanagement in irrigation and public recovery.

The present study simulates the frontal dust storm by means of WRF-Chem model and AFWA emission scheme between April 23 and 24, 2019. It then applies reanalysis data (ERA5) to analyze this case from a synoptic perspective. The simulation results show that the model have been accurately characterized first by the onset of dust from the south-east of the country in Kerman Province and then via its transmission to large areas of the east and south-east. The model output also fits well with satellite images. A quantitative comparison of PM10 concentration of the model with actual values shows that the PM10 model estimates are larger than actual values, though it predicts the trend of concentration changes well. Examining the synoptic maps, the isobars’ curve, wind direction change, and temperature advection in the area reveals the presence of atmospheric fronts within a strong dynamic low-pressure system. This causes high temperature and pressure gradients, in turn speeding up the wind within the region. Results from the synoptic analysis show that by passing the frontal system and behind the cold front, a dust mass is formed, which gradually spreads in eastern and the southeastern regions of Iran. In this case, extreme pressure gradient, cold front passage, low-level jet, wind gust on dry areas of dry Hamoon wetland, and cold air advection over flat area of the Lut Desert are important factors in storm formation and emission, east of the country.

Because of the pinch of air pollution on human health and its environment, it has become necessary to monitor and map out the peaks and lows threat places of air pollution in different land use across a city. In this regard, air pollution exposure mapping of Kano metropolis based on land use classifications namely industrial, residential, commercial and institutional was carried out for interpretive and assessment of health hazard associated with the selected pollutants. The observations for ambient air quality parameters (CO, SO2, H2S, NO2, and PM10) monitored with portable digital air pollution detecting devices for creation of data. Geographic Information Systems (GIS) technique was applied to create spatial distribution maps of urban air quality of the metropolitan area. The results of pollution index map of ArcGIS extrapolation indicated that neighbourhoods in the vicinity of Bompai and Sabon Gari industrial and commercial zones, respectively were found to be highly exposed and liable to ailments associated with air pollution, while places nearby Dorawa and School of Technology were air pollution-ease zones but could experience bioaccumulation over long exposure time. Therefore, the study reveals that variability of air quality was strongly related to predominant land use in particular areas within the metropolis and could help in estimate and valuation of likely health challenges associated with poor air quality due to air pollution. Besides, the observed spatial variation for air quality could serve as hot spot identifier and as an informant for rational decision on air quality control strategies for environmental management.

Significant attention has been given to nanotechnology as an emerging approach in water/wastewater treatment for heavy metals removal. Numerous research works on synthesizing, fabrication and upgrading nanoparticles have reported as an efficient adsorbent in removal of wide range of heavy metals from wastewater. This review intends to provide researchers with understanding and knowledge regarding the efficient nanoadsorbents, their adsorption mechanism towards selected heavy metals and fundamental principles of nanoadsorbent materials synthesis. In addition, further attention on the modification of nanoadsorbent and development of nanocomposites are highlighted in this paper as value added products to increase the adsorption capacity and enhance the heavy metals removal. Possible challenges and direction on utilization of nanocomposites for heavy metal removal in real wastewater effluent are discussed in view of their removal capability and cost efficiency. Future research works on developing a cost-effective way of nanocomposite production and toxicity testing of nanomaterials in wastewater applications are recommended. Further studies on the efficiency of the nanoadsorbents in pilot or industrial scale are highly needed to test the practicality of the nanoadsorbents for selected heavy metals removal from real wastewater.

This study assesses heavy metal levels in water, soil, and vegetables (swiss chard, lettuce, cabbage, collard green, tomato, green pepper and carrot) irrigated with waste water in Gamo, Ethiopia. The samples of soils, water, and vegetables were randomly collected, processed, and analyzed for heavy metals using atomic absorption spectrophotometry. The results obtained show that the irrigational water is profoundly contaminated with heavy metals Cd, Cr and Ni and Pb, Zn and Cu had the lowest concentration in irrigation water. The levels of Cd in Kulfo river area and Chamo Lake area and Ni in most of the farm soils were also found to be higher than the guideline values. The study also revealed that the mean levels of Cd in most vegetables and Cr and Pb in some vegetables were higher than the maximum recommended limits set by WHO/FAO. In general the results show that the highest concentration of the heavy metals was obtained from Kulfo river area compared to the Arbaminch textile share company area, Abaya Lake area, and Chamo Lake area. Cabbage was maximally contaminated with potential toxic elements followed by Swiss-chard, carrot, tomato, collard green, green pepper and lettuce. Hence, from kulfo river area frequent consumption of cabbage and Swiss chard may cause serious health risks to consumers. The levels of many elements were found to vary with location, suggesting localized inputs of the various contaminants related to industrial and other activities that generate wastewater. This study recommends regular monitoring of heavy metals in soils, waters, and foodstuffs to prevent excessive accrual in food chain.

The present study deals with groundwater pollution in multilayer aquifer. The model is based on decomposition of finite layers in semi-infinite groundwater reservoir. A constant pollutant source is injected at the input boundary of the uppermost layer (UML) of the landfill. At the intermediate inlet boundary, some average value for the longitudinal exchange of the input source concentration in each sub-layer is considered from the previous layer. Initially, the aquifer is not solute free in each sub layer that means some constant background contaminant concentration exists. In each sub layer, concentration gradient is assumed to be zero at the extreme boundary. The linear sorption and first orders decay terms are considered to model the groundwater pollution in multilayer aquifer. The Laplace transform technique is adopted to solve one-dimensional (1D) advection-dispersion equation (ADE). This approach is helpful to understand the solute migration in finite sub layers. The results are elucidated for the different time periods to examine the peak of pollutant concentration level in geological formations.

In this study, efficiency of humic acids (HAs) derived from various sources to reduce CrVI in aqueous solutions was compared. HAs were extracted from leonardite, peat moss, peat, cocopeat, coal, common char, biochar, vermicompost and sewage sludge. Some chemical and spectral characteristics of the extracted HAs were measured. Then, the reducing efficiency of HAs was measured and its relationship with the determined properties was investigated. To measure the reducing efficiency of HAs, a concentration of 0.1 mM CrVI (as potassium dichromate) in a sodium nitrate solution (0.03M) with a pH of 2 and in the presence of 100 mg of HA per liter was used. The experiment was conducted in three ways (symbolized by E1, E2 and E3). They differ from each other with respect to the method of phosphate buffer addition to release CrVI ions adsorbed by HA. This buffer was added to an aliquot of final extract, to the whole volume of final suspension and to initial solution containing CrVI in experiments E1, E2 and E3, respectively. According to the results, the CrVI reducing efficiency depends not only on the nature of HA but on the method of experiment. The minimum reducing efficiency was observed for common char using experiment E2 and the maximum value was for biochar and cocopeat in all three experiments. The results showed that the two factors of ΔlogK and maximum reducing efficiency in the format of a multiple regression had a significant relationship with CrVI reducing efficiency of HAs.

The present study attempts to investigate some blood parameters of Otolithes ruber during different seasons in terms of both temperature and pollution. For so doing it uses 10 specimens, for each station and season, collected from 5 polluted stations, including Petrochemical, Ghanam, Zangi, Douragh, Patil, and Sajafi as the control group, away from pollution in Musa Creek. The fish are anesthetized with 1ml of clove extract per liter. Their blood samples are taken immediately from the caudal vein, using a heparinized syringe. Afterwards, the serum is separated in a centrifuge with a speed of 6000 rpm for 2 minutes. The desired factors are measured by the Mindray BS200 auto-analyzer and the total protein level, by Bradford's usual laboratory methods. Results show that AST, ALT, ALP, Glucose, and Triglycerides have increased in more polluted stations (P≤0.05). In sheer contrast, total protein and Albumin have decreased as pollution grows (P≥0.05). According to this study, environmental water pollution of the fish has a large impact on the concentration of measured blood parameters, whereas the influence of seasonal changes on most of them is low.