Environmental pollution has become and increasing concern due to growing risk to human health. Soil pollution is an aspect of environmental pollution that has received comparatively less attention than water pollution. However, considering direct effects of contaminants transmission through ingestion to the human body, it can lead to greater risks for human health. Arsenic is a highly prevalent environmental pollutant, and considerable number of people worldwide suffer from constant exposure to it. While there are several ways to manage and remediate contaminated soils, phytoremediation has been paid special attention due to its higher social acceptability and lower cost. Nevertheless, this approach faces challenges, including effectively handling significant quantities of contaminated biomass, managing it appropriately, and selecting suitable plant species for the remediation process. In this regard, numerous endeavors have been undertaken to tackle these obstacles like strategies encompass the utilization of amendments, adept management of biomass, and the implementation of hybrid remediation approaches. This study aims to review prior research on mechanisms, challenges, and enhanced phytoremediation of arsenic-contaminated soils, encompassing reduction of contaminated biomass after phytoremediation.

In the framework of a project aiming to phytoremediate contaminated soils with heavy metal Cr in Long Khanh city, Dongnai province, Southeast of Vietnam, a series of greenhouse experiments followed by field trials were performed in order to evaluate the effect of L. sphaericus on the Cr phytoextraction by S. nigrum. The results showed that L. sphaericus improved the Cr uptake efficiency of S. nigrum through changing growth parameters such as root length, height, biomass and the ability to accumulate Cr in plants. At an application rate corresponding to the T3 treatment in this experiment, L. sphaericus can stimulate the dry biomass of S. nigrum by 143%, increase the Cr concentrations in the aerial part by 70%, the content of Cr extracted in a single plant up to 293% compared to treatment without L. sphaericus.

In order to find an effective decolorization method for dye wastewaters, the present work aims at studying the treatment efficiency of an azo dye Acid Red 14 (AR14) by Electro-Fenton process using an undivided electrochemical cell containing different electrode materials. The optimal removal efficiency was obtained using carbon felt or glassy carbon (cathode) and platinum (anode) electrodes. The method is based on the reaction of electrochemically produced hydroxyl radicals leading to oxidative degradation of the AR14. To find the best conditions for treatment of AR14 dye, the effects of Fe2+ concentration, current density, the effect of pH initial, and the nature of support electrolyte were studied. The results showed 94 % removal efficiency in 30 minutes with 120 mA/cm2 of electrolysis current, 0.2 mM of Fe2+, and pH = 3. However, the decolorization efficiency measurements confirmed that the Electro-Fenton process with the platinum anode and the carbon felt cathode was more efficient.

Noise and toluene are among the numerous physical and chemical pollutants that can induce adverse effects on different body tissues and systems; nevertheless, most studies have only experimented the auditory changes induced by co-exposure to them. The present in-vivo study aimed to examine the endocrine effects of co-exposure to toluene and noise on the testes and adrenal glands. In this experimental study, 24 healthy male New Zealand White rabbits were used. The noise intensity was 100 dB (white noise) and the toluene concentration was 1000 ppm for two consecutive weeks. The luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone, cortisol and adrenocorticotropic hormone (ACTH) were measured using the enzyme-linked immunosorbent assay (ELISA) method. The hematoxylin and eosin stain method (H&E) was performed for the histopathological analysis. Comparing different parameters in different groups on post-exposure days was carried out using GEE (generalized estimating equations) method. The results indicated that noise and toluene increased cortisol, LH and FSH levels during different days after the exposure. Exposure to toluene and noise made vacuolization and reduction of primary spermatogonial cells in the testes. Moreover, lymphocyte infiltration, congestion, swelling and vacuolization were detected in adrenal glands through exposure to toluene and noise. Toluene and noise induced different destructive effects on the endocrine system. More studies are required to elucidate other endocrine changes induced by exposure to toluene and noise.

The main objective of the current study is to determine the distributions of the specific radioactivity concentrations (226Ra, 232Th and 40K) from terrestrial sources using gamma spectroscopy system (HPGe-detector). Forty (40) agricultural soil samples were collected from Wadi Al-Hussini and Tuban in Yemen. The study locations are famous for exporting coffee all over the world. The average of radio-concentrations of 226Ra, 232Th and 40K were 61.95±11.57, 32.33±8.03 and 1045.17±153.47 Bq/kg for Wadi Al-Hussini and 65.20±11.59, 50.95±9.80 and 1078.13±157.57 Bq/kg for Tuban, respectively. The obtained results are higher than the average worldwide values reported by UNSCEAR. So, it is not acceptable with global safe criteria. Also, the radiation hazard parameters such as radium equivalent activity, absorbed gamma dose rate, outdoor and indoor annual effective dose equivalent, external and internal radiation hazard index, gamma index level, annual gonadal dose equivalent and excess lifetime cancer risk. All of these parameters are acceptable and within the worldwide values. The obtained results could be considered as reference data to follow up any changes in the future for natural radionuclides pollutants and their risks in the study area.

This study presents a new approach to solve the one-dimensional solute transport equation with variable coefficients and two input sources in a finite porous media. The medium is divided into m-layers porous media with constant averages coefficients in each transport problem. The transport equations in layer i-1 and i are coupled by imposing the continuity of solute concentration and the dispersive flux at the interfaces of the layers. Unknown functions representing the dispersive flux at the interfaces between adjacent layers are introduced allowing the multilayer problem to be solved separately on each layer in the Laplace domain before being numerical inverted back to the time domain. The obtained solution was compared with the Generalized Integral Transform Technique (GITT) and numerical solutions for some problems of solute transport with variables coefficients in porous medium present in the literature. The results show a good agreement between both solutions for each of the studied problem. An example of application considering an advective-dispersive transport problem with a sinusoidal time-dependent emitting rate at the boundary was study in order to illustrate the effect of sinusoidal frequency on solute concentration.

Nowadays, the pollution of sulfur compounds is gradually increasing due to the growing wastewaters and industrial developments. In this study, 2-mercaptobenzothiazole (MBT) removal from aqueous solution has been investigated using the combination of the ultrasonic and UV waves (ultra/UV). The effective parameters include pH, irradiation time, initial concentration of MBT, and volume of hydrogen peroxide at constant temperature of 25 °C. To exact evaluation of the design of experiments (DOE) and analyze of variance (ANOVA), response surface methodology (RSM) was employed. The results revealed that waves’ energy and subsequently cavitation phenomenon and hydroxyl radicals played significant roles in cracking the studied organosulfur’ bonds. In addition, hydrogen peroxide oxidant promoted the sulfur removal in the process. Maximum sulfur removal was numerically optimized as 99.74 that had an absolute error of 1.47% in comparison with the experimental one (98.29). Finally, COD and DO analyses were studied at optimum conditions. The tests confirmed the experimental results, appropriately. Therefore, the combination of the ultrasonic and UV irradiation can be significantly effective on removing organosulfur’s pollutants in industrial wastewaters and related ones.

Heavy metals contamination of rainwater is a function of the adsorbed metals present in the particulates of the atmosphere in which the rain was formed from and rainwater chemistry is an alternative way of monitoring urban air pollution for predominant metal species. Three distinct sampling sites (residential, industrial and commercial) were investigated in the south western part of Nigeria for one year. After acid digestion, quantification was done using a double-beam Atomic Absorption Spectrophotometer (AAS). The obtained results showed that heavy metals were predominantly present as free metal ion in the commercial and industrial areas but Mn and As mainly occurred in the suspended fraction. Residential area presented major fractions as bound to organic complexes except Cu and Cd which were principally available as suspended fraction. The health risks associated with the intake of the studied rainwaters indicated susceptibility to possible carcinogens upon consumption due to total RI > 10-4. Ecological risk assessment equally shown a very high level of ecological risks related with the metals due to RI ˃ 600. Sequel upon this, there is need for better sensitization of the citizenry to the sources and control of these pollutants.

This study was conducted to assess air quality status in the selected cities of Pakistan through Air Quality Index (AQI) and Multi Pollutant Index (MPI) and their correlation. Secondary data on air pollutants’ concentrations for the year 2021 were used from the literature. For this investigation, major air pollutants including carbon monoxide, nitrogen dioxide, sulfur dioxide, and particulate matter were used and compared with Punjab Environmental Quality Standards. Air quality indices, Multi Pollutant Index (MPI) and the Air Quality Index (AQI) were used in the study. Overall condition of the air pollutants in the particular location was described using the Air Quality Index. For this formula, the average concentration of each pollutant across a range of time periods was first calculated. The concentration of each pollutant was then divided by the relevant standard value, which was then cumulatively averaged and represented as a percentage. Results showed that Lahore and Karachi are two of the cities with unhealthy to hazardous AQI values and poor air quality according to MPI values. Air quality is deteriorating in industrial and traffic-congested cities where pollution levels significantly exceeded the threshold values. Using the linear regression, the results confirmed the strong association between the AQI and MPI. There is a need for immediate action to be taken to lower pollutants’ concentrations and improve air quality in urban areas.

Two fly ashes from municipal solid waste incineration were selected to study their heavy metal leaching behavior. The main purpose of this research is to investigate the characteristics of fly ashes and compare the leaching of heavy metals in different leaching environment. pH and acid neutralization capacity analysis showed that fly ashes were highly alkaline. Fly ashes also contained a variety of heavy metals including Pb, Cu, Cr, Zn, Cd and Ni etc. Leaching studies showed that the alkalinity of fly ashes raised the pH of leaching solution from acidic to basic. Ni, Cu and Zn were strongly bound to ashes and manifested low leaching. In contrast, Cr and Cd had high mobility but their leaching was inhibited by the low solubility of carbonate Cr and Cd. Pb was highly leachable in the alkaline environment with concentration in the leaching solution reached as high as 9.74 mg/L. In addition, the presence of EDTA in the environment also increased leaching. Pb concentration was raised to 16.63 mg/L. This could be attributed to the chelating capacity of EDTA which means that the presence of organics in natural environment should be taken into consideration.