The present study aims at phytoremediation of Lemna gibba L. in aqueous solutions with different concentrations of TC and Degradation Products (DPs). It also tries to determine whether there are differences in TC, ETC, EATC, and ATC levels, accumulated by Lemna gibba L. Exposure concentrations of 50, 100, and 300 ppb have been selected for TC and DPs, showing that the highest TC50, TC100, and TC300 concentrations in the plant have been 23.5+1.1, 80.1+3.9, and 274+13 ppb, respectively, while the highest ETC50, ETC100, and ETC300 have proven to be 39.5+1.9, 47.8+2.4, and 168+8.4 ppb, respectively. The highest EATC50, EATC100, and EATC300 concentrations in the plant have been 45.3+2.3; 65+3.0 and 173+9.0 ppb, respectively, whereas the highest ATC50, ATC100, and ATC300 concentrations in Lemna gibba L. have been 34.7+1.7, 39.6+0.2, and 114+5.6 ppb, respectively. TC, ETC, EATC, and ATC concentrations in Lemna gibba L. have increased with the increase of initial TC, ETC, EATC, and ATC concentration.

One of the most comprehensive tools to show the changing trend in urban ecosystems is by providing periodic State of Environment Report (SoER) for cities in national programs, wherein it is quite essential to have a truthful and realistic view of the current state of the environment as well as significant human impacts. Developing countries like Iran are faced with incoherent and deficient SoER; due to lack of data, which originates from neglecting environmental issues such as poverty, overpopulation, etc. The present study makes a comparative assessment of Tehran and Sydney's SoER in terms of sustainable urban environment indicators with the purpose of recognizing the weaknesses and strengths as well as finding the most important gaps in Tehran's SoER, which can be a useful resource for decision-makers. Results indicate the necessity of establishing integrated urban environmental management. On the whole, this paper recommends programs of environmental development and implementation as suggested strategies to reduce uncertainty and increase the reliability of SoER in the study area.

The extensive use of pesticides leads to accumulation of a huge amount of residues in the environment. As such, the present study investigates the potentiality of Pleurotus pulmonarius to bioremediate dichlorvos pesticides (2,2-dichlorovinyldimethylphosphate) in contaminated soil. DDVP-polluted soils have been contaminated in five concentrations (5% v/w, 10% v/w, 15% v/w, 20% v/w, and 25% v/w), and the soil samples have been inoculated and incubated with pure culture of growing spawns of P. pulmonarius, obtained from commercial mushroom laboratory of Federal Institute of Industrial Research Oshodi, Lagos. The control, however, has not been inoculated. Each treatment has been in triplicates with the soils, analyzed for total amount of DDVP at day 0 and day 60, using gas chromatography and mass spectrometry. Also, pH, moisture content, and total organic matter of the soil have been determined. Results show that the rate of DDVP degradation in the soils with Pleurotus pulmonarius has been higher than the soil samples without mushroom after 60 days. However, for the control without mushroom (loss due to natural attenuation) and those inoculated with P. pulmonarius (bioremediation) the loss percentage of DDVP ascended with the percentage of pesticide from 5% to 25%. The DDVP loss across all different concentrations of mushroom inoculation have been significant (p<0.05); however, for natural attenuation, it has not been significant (p>0.05), except for the lowest pesticide level (5%). Activities of mycelia have decreased soil pH, moisture content, and total organic matter. There has been a very minimal pesticide bioaccumulation in mushroom tissue, which has not been significant (p>0.05), but considerable at p<0.001, indicating that P. pulmonarius has the potential to degrade DDVP pesticides in soil.

Nitrate is a major contributor to water contamination, which can affect humans' and animals' health. Due to increased sewage production, growth of agricultural activities, and development of urbanization, recent years have seen an increase of Nitrate in water resources. Drinking water resources in both rural and urban areas of Jiroft City are supplied by water wells, scattered throughout the region. Thus the present research analyses the Nitrate pollution of 31 drinking water wells in summer and winter of 2016, in the urban area of ​​Jiroft City and by means of GIS as well as statistical analysis, presents the results as zoning and survey maps. It also studies and evaluates the effect of rainfall and soil type on the amount of Nitrate. Results from statistical analyses show that the amount of water pollution to Nitrate is independent from the type of land use as well as the soil type. Furthermore, statistical results show that the amount of Nitrate in the wells under test is affected by precipitation, being higher in the winter. Therefore, considering the agricultural density in this area and the untapped use of nitrogen fertilizers, it is necessary to take into account the use of chemical fertilizers for proper management, scientific and practical control, and maintenance of the wells' health safety.

This study aims at evaluating the improved facultative ponds performance in pilot scale. Wastewater has been collected from primary settling basins of Ahvaz wastewater treatment plant. Treatment efficacy of the four systems (three systems in parallel with a control system) has been evaluated over a period of 12 months at various hydraulic retention times (HRT) and organic loading rates (OLR). There has been no baffle and no attached growth media (AGM) in the control system (S0), while other three systems (S2, S3, and S4) have been equipped with different numbers of baffles and AGM packages, containing the mineral shells. Results show that efficiency of BOD5 removal for S0, S2, S3, and S4 are 53.4%, 60.8%, 64.7%, and 67.6%, respectively, while for COD these rates alter to 28.1%, 37.7%, 45.8%, and 50.1 % and of coliform to 66.7%, 76.6%, 80.7%, and 83.4%. Filtered BOD5 in the effluent of S0, S2, S3, and S4 is 32.5, 27.6, 24.6, and 22.3 mg/l, respectively and 60.2, 52.1, 47, and 44.3 mg/l for TSS. Also the 10-day HRT has been optimum among applied HRTs. As such, attached growth-baffled ponds function better than conventional ones, making the technique, examined in the present paper a low-cost process to establish new wastewater treatment plants or upgrading the existent WSPs, especially in case of warm areas of southwestern Iran.

The aim of this study is to develop analytical solutions for one-dimensional advection-dispersion equation in a semi-infinite heterogeneous porous medium. The geological formation is initially not solute free. The nature of pollutants and porous medium are considered non-reactive. Dispersion coefficient is considered squarely proportional to the seepage velocity where as seepage velocity is considered linearly spatially dependent. Varying type input condition for multiple point sources of arbitrary time-dependent emission rate pattern is considered at origin. Concentration gradient is considered zero at infinity. A new space variable is introduced by a transformation to reduce the variable coefficients of the advection-dispersion equation into constant coefficients. Laplace Transform Technique is applied to obtain the analytical solutions of governing transport equation. Obtain results are shown graphically for various parameter and value on the dispersion coefficient and seepage velocity. The developed analytical solutions may help as a useful tool for evaluating the aquifer concentration at any position and time.

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.

This study has used TOMS AI as well as the reanalysis dataset of thirty-four years (1979-2012) to investigate the influence of atmospheric circulation on dust transport during the Harmattan period in West Africa, using Aerosol Index (AI) data, obtained from various satellite sensors. Changes in Inter-Tropical Discontinuity (ITD), Sea Surface Temperature (SST) over the Gulf of Guinea, and North Atlantic Oscillation (NAO) during Harmattan period (November-March) have been analyzed on daily basis with Harmattan dust mobilization as well as atmospheric circulation pattern being evaluated via a kernel density estimate that shows the relation between the two variables. The study has found out that strong north-easterly (NE) trade winds were over most of the Sahelian region of West Africa during the winter months with the maximum wind speed reaching 8.61 m/s in January. The strength of NE winds determines the extent of dust transport to the coast of Gulf of Guinea during winter. This study has also confirmed that the occurrence of the Harmattan chiefly depends on SST in Atlantic Ocean as well as ITD position, not to mention the strength of low level winds. However, it has been noted that NAO has limited effects on dust mobilization in West Africa, in shear contrast to North Africa where NAO is a strong factor in dust mobilization.

The aquatic fern Azolla, a small-leaf floating plant that lives in symbiosis with a nitrogen fixing cyanobacteria (Anabaena), is an outstanding plant, thanks to its high biomass productivity along with its tremendous rate per unit area for nitrogen-fixation.  The present study investigates the potential growth of Azolla in secondary effluents for removal of COD, phosphorus, and nitrogen. Results have shown that N and P removal at 100 ppm of each component in separate medium turned out to be 36% and 44%, respectively, whereas in case of a mixed solution of these two compounds, N and P removal declined to 33% and 40.5%, respectively. Moreover, results have suggested that in the presence of phosphorus nitrogen absorption decreased. Furthermore, Azolla has revealed a high potential of COD removal by 98.8% in 28 days. Finally, Azolla may be one of the most promising agents to remove COD and treat nitrogen-free and phosphorus-rich wastewaters.

The rising global demand for palm oil and its associated products has led to increased numbers of palm oil refineries with its attendant effluent discharge. Many researches have confirmed the ecological disruptive potentiality of Palm Oil Mill Effluent (POME), still further attention has to be directed at POME’s potential genotoxicity. The present study has made physico-chemical and genotoxicity assessments of POME from a corporate refinery in Nigeria, using the American Public Health Association (APHA) procedures along with Allium cepa root assay. Allium cepa roots were grown in graduated concentrations of POME and the roots were analyzed for chromosomal aberrations. Results suggest that POME caused growth inhibitions and chromosomal aberrations in A. cepa roots. with mitotic index of A. cepa roots dropping as POME concentrations were increased. The chromosomal aberrations induced in A. cepa were vagrant, sticky chromosomes, bi-nucleated cells, and C-mitosis. These results indicate that palm oil mill effluent is not only capable of causing ecological disruptions in the receiving environment, but is also potentially genotoxic to resident organisms. It is recommended that if effluents from palm oil mill refineries cannot be converted to other useful products and ought to be disposed of, it should first be properly treated and tested for genotoxicity.