The present work solves two-dimensional Advection-Dispersion Equation (ADE) in a semi-infinite domain. A variable source concentration is regarded as the monotonic decreasing function at the source boundary (x=0). Depth-dependent variables are considered to incorporate real life situations in this modeling study, with zero flux condition assumed to occur at the exit boundary of the domain, i.e. its semi-infinite part. Without losing any generality, one can consider that the aquifer is initially contamination-free. Thus, the current study explores variations of two-dimensional contaminant concentration with depth throughout the domain, showing them graphically. Non-point source problem, i.e. the line source problem, can be discussed by solving two-dimensional depth-dependent variable source problem, as x=0 is a 2D line. A new transformation has been used to transform the time-dependent ADE to one with constant coefficients, with Matlab (pdetool) being employed in order to solve the problem, numerically, using finite element method.

The present study is the first attempt to examine temporal and spatial characteristics of aerosol properties and classify their modes over Iran. The data used in this study include the records of Aerosol Optical Depth (AOD) and Angstrom Exponent (AE) from MODerate Resolution Imaging Spectroradiometer (MODIS) and Aerosol Index (AI) from the Ozone Monitoring Instrument (OMI), obtained from 2005 to 2015. The high concentration of AOD and AI values (representing high-high cluster) have been observed in the southwest and east regions, while their low concentrations (representing low-low cluster) have been found in the high mountainous areas. Based on AE values, Iran has been divided into three distinct regions, including fine, mixture, and coarse aerosol modes in each season. Results show that the maximum/minimum area under fine aerosols mode has occurred in the autumn, covering an area of 84.15% and in the spring, covering an area of 40.5%. In the case of coarse mode, the maximum/minimum area has been found in the spring, covered area=53.5% / in the Autumn covered area=12. 5%. The different aerosol modes regions strongly coincide with the topographical structure. To analyze the relation between aerosol properties and topography, Aerosol Properties Index (API) has been developed by combining OMI and MODIS datasets. API is a simple indicator, capable of showing the degree of aerosol coarseness in each pixel. There is a negative correlation between API and topography over the studied region, meaning that aerosol concentrations are high in the lowlands, but low in the highlands. However, this relation differs in various geographic regions, as Geographically Weighted Regression (GWR) model shows a higher determination coefficient in all seasons, in comparison to Ordinary Least Squares (OLS).

The present work investigates nitrate and phosphate removal from synthetic treated slaughterhouse wastewater in a novel open raceway pond with sedimentation zone. For this purpose, microalgae Chlorella salina has been cultivated in synthetic wastewater and sedimentation zone has been added to enhance both algae separation in the system and nutrient removal. The effectiveness of Chlorella salina to treat nitrate and phosphate has been tested in open raceway ponds with harvest system. It has been found that Biomass concentration of the Chlorella salina is 1.35 g/L during 11 days of experiment. Also, maximum specific growth rate of the species in the pond has been 0.74 day-1. Throughout the cultivation period, nitrate and phosphate have been analyzed to show that their average removal efficiencies were 100% and 45%, respectively. It can be concluded that the growth of Chlorella salina in novel open pond system is an effective way to reduce nitrate and phosphate levels in slaughterhouse synthetic wastewater. Also, wastewater is suitable for algal growth.

Lipases have many applications in biotechnology, thanks to their ability of acylglycerides hydrolysis. They alsp possess the unique feature of acting at the lipid-water interface, which distinguishes them from esterases. Commercially useful lipases are produced by microorganisms with the extracellular lipase being produced by many bacteria including Pseudomonas. The greatest production of lipase takes place under optimum conditions such as appropriate temperature, suitable carbon, nitrogen sources, etc. This study tries to collect lipase-producing bacteria from the soil of oil-extraction factories and identify isolated bacteria, while creating optimum conditions for lipase production by bacteria. Having collected three soil samples from an oil extraction factory, lipase-producing bacteria have been identified, based on biochemical and morphological tests. Finally the optimal conditions for lipase production as well as molecular analysis has been evaluated. During the study, among the different bacteria, the strain to produce highest lipase has been selected. It has been found out that the optimal conditions for lipase production by this strain is as follows: 48 hours of incubation; incubation temperature of 37 °C; pH of 7; agitation speed of 150 rpm; peptone extract as the nitrogen source; and olive oil as a carbon source. A lipase-producing bacterium has been identified based on morphological, physiological, and biochemical characteristics as well as 16S rRNA analysis, identified as Pseudomonas spp.

Heavy metals that enter marine environment and remain in the water as well as the sediments are accumulated by aquatic organisms, thus becoming highly good indicators to monitor metal accumulation in the long run. Metals are potentially harmful to humans and most organisms at varied levels of exposure and absorption. Northern East Mediterranean Sea is a crucial region as it is an area, shared by numerous aquatic species with pollutant factors such as heavy marine traffic, transportation ports, industry plants, iron and steel works, oil pipeline installation, and other small factories. While the previous part of this review (Review of heavy metal accumulation on aquatic environment in Northern East Mediterranean Sea part I: some essential metals) evaluated the data from previous studies concerning toxic effects of selected essential metals on seawater, sediment, and different tissues of aquatic animals, collected from different areas in Northern East Mediterrenean Sea since the 1990s, the present part intends to evaluate the data from previous studies on toxic effects of selected non-essential metals. For this purpose, 94 articles and 6 theses have been examined and a good deal of information has been gathered to open a forward-looking view of the studied area’s pollution. Althought there has not been any harmonization, when comparing heavy metals investigations in the bay, all studies have shown that consumption of aquatic species from the region causes no problem to human health.

The aim of this study is to assess the risk factors of pipelines and prioritize their severity in order to prevent their effects in Shadegan International wetland, Iran. Due to the participatory nature of the managerial affairs, the study employs an integrated approach that combines Analytic Hierarchy Process (AHP) and Delphi Method. Also, Likret Scale has been applied to quantify the qualitative (verbal) data, thus reducing the uncertainty of oil pipelines' risk evaluation. In order to evaluate potential risk factors, Failure Mode Effects Analysis (FMEA) method has been applied. According to the study results, in terms of the likelihood of environmental impacts on the main considered criteria of natural and man-made environments, the former's effect is a priority risk, weighing 0.670 and primarily important. On the other hand, environmental hazards caused by oil pipes of water quality in Shadegan wetland has been ranked first, with a relative weight of 0.389 to contain the highest level of risk. The risk degree for diversity and density of benthos is 12.6 and 6.3for fish, both higher than other parameters of water systems in Shadegan wetland. Considering the recognized factors that lead to probable risks of pipelines along with their most notable outcomes, the paper suggests environmental management plans on how to control and reduce the potential impacts, with an emphasis on elimination of the most likely causes.

Agricultural intensification is associated with the use of great amounts of agrochemicals that may result in the accumulation of metals in soils, and –subsequently—agricultural products and food chain. Nowadays, this is a major concern for many Iranian agricultural products, necessitating scientific researches on the issue. Therefore, the present study has been conducted to evaluate the level of metal contamination in some agricultural products of Torbat-e Jam, Iran, with the following purposes: (i) to determine concentrations of cadmium (Cd), nickel (Ni), and lead (Pb) in melon (Cucumis melo var. inodorus), sugar beet (Beta vulgaris), and maize (Zea mays) as well as water and soils of some farms in Torbat-e Jam, Iran; and (ii) to examine chemical fertilizers as a possible source of heavy metals' contamination. To do so it has taken some samples from soils, irrigation waters, chemical fertilizers, and crops, measuring their heavy metals contents by means of atomic absorption spectrometry. Results show that heavy metals' concentrations in groundwater and soil were lower than the adopted global standards. Among fertilizers, only Cd content of triple-superphosphate was higher than the standards, leading to a substantial buildup of Cd in the soil, compared to Pb. The greater use of potassium fertilizer has increased Pb concentration in the soil samples of maize farms during the growing season. Among all elements, Pb had the greatest transfer coefficient. It seems that current farm management practices as well as excessive use of chemical fertilizers may further the contamination and loss of soil quality in agricultural systems of the region.

River Ganga is one of the prime sacred National Rivers of India, closely associated with economic, social, and cultural heritage of Indian people. Recently, it has been subjected to immense degradation and pollution as a result of receiving huge amounts of domestic and industrial wastewater as well as religious ritual activities and surface runoff. The present study attempts to study spatial and temporal changes in water quality of River Ganga while calculating its Water Quality Index (WQI) by analyzing 9 physico-chemical, 7 trace metal, and 4 microbiological parameters at eleven sampling stations, on the basis of River Ganga index of Ved Prakash. Thus it can assess water’s suitability for drinking and irrigation purposes along with other human uses. The study is directed towards the use of WQI to describe pollution level in the river for a period of 1 year (from January to December 2014). It has been shown that index values as per CPCB class range between medium to good, while the ones as per NSF Index range from bad to good water quality. The study also identifies critical pollutants, affecting the river water quality within its course through the city. Finally, pH, DO, BOD, DO, EC, and FC have been found to be critical parameters for the stretch in each season of this research.

Even though solid waste management has become a major public health and environmental concern in urban areas of Ethiopia, only 2% of the population receive solid waste management services. The primary objective of this study is to assess solid waste management practices of Bahir Dar City. The technique of multistage random sampling has been employed to draw 350 households for this study, with both quantitative and qualitative primary data put into good use. Finally, the quantitative data has been analyzed by means of descriptive statistics with the results indicating that 78% of the respondents feel that the current solid waste management service is far below the required level; whereas, 22% of the respondents show satisfaction with the existing waste management service. The municipality has planned to provide solid waste management service for the residents once a week, but the survey results demonstrate that only 29% of the sample households received solid waste management services weekly, indicating that the performance of solid waste management service is low. Among 350 households, a sum of 66.6% practice illegal solid waste disposal with the remaining 33.4% waiting until solid waste collectors come to the area to take the waste away. Therefore, participation of urban households, micro and small enterprises, and governmental and non-governmental organizations plays a great role to upgrade the existing low status of solid waste management services.

The present study has used soil samples from Nigeria, contaminated with Brass crude-oil, to determine its biodegradation through enhanced biostimulation with cow dung and periodic aeration. Over a period of twenty-eight days, the hydrocarbon-utilizing bacteria (HUB) and hydrocarbon-utilizing fungi (HUF) have been counted and identified. Results from biodegradation of the brass crude-oil over the aforementioned period show that amended crude-oil-spiked soil has had 54.82% degradation while for amendment and periodic turning this has been 55.90%, not significantly higher than the former at p≤0.05. Also degradation of spiked soil without cow dung amendment has been 16.13%. The identified HUB are Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, and Streptococcus thermophillus, with individual occurrence of 18.52% as well as Proteus vulgaris and Micrococcus luteus with 11.11% and 14.81% occurrence, respectively. Also, the occurrence rate of HUF like Aspergillus flavus, A. niger, Penicillium chrysogenum, Trichothecium roseum, and Penicillium citrinum have been 15.63% each;whilefor Alternaria alternata and Neurospora crazza it has been 6.25% and for Saccharomyces cerevisae and A. fumigatus, 9.38%and3.13%, respectively. The study concludes that amendment with cow dung and periodic turning of the soil enhance degradation of Brass crude-oil significantly. What is more, aeration by periodic turning slightly improves degradation only with cow dung treatment on Days 21 and 28.