Heavy metal contamination poses grave risks to all kinds of life. The fastest growing automotive, electroplating, and battery industries release the most common heavy metal, Nickel, into the environment, which has lethal impacts on human health. Our research aims to find Ni-resistant bacteria in the metal-contaminated soil that have a great potential for removing Ni from the environment. Attempts have been made to extract and characterize Ni-resistant bacteria from automobile and electroplating industry waste-contaminated soil using serial dilution, streak plating, and various morphological, biochemical, and genetic techniques. The maximum tolerable concentration of Ni and other heavy elements, such as cadmium, lead, and aluminium for the selected isolate, was investigated using the UV-Vis spectrophotometric method. Additionally, the bacterial strain's ability to remove Ni was assessed using an atomic absorption spectrophotometer.  The current research reveals a novel strain of Kluyvera cryocrescens that could withstand Ni, Cd, Pb, Al, and combinations of these heavy metals. The maximum tolerance concentration of K. cryocrescens M7 for Ni, Cd, Pb, and Al was found to be 150 ppm, 200 ppm, 1000 ppm, and 150 ppm, respectively. Additionally, it was also observed that the bacterial strain could remove Ni by 29.57%, 35.36%, 48.41%, 46.91%, and 44.88% after 12, 24, 48, 72, and 96 hours, respectively. The strain has also exhibited resistance to vancomycin, ampicillin, carbenicillin, and streptomycin. This research discovered a novel bacterial strain, K. cryocrescens M7 that may be beneficial for removing heavy metals, particularly Ni, from metal-contaminated soil.

Radiology and photography films are mainly made of silver halides, which are very sensitive to light. The developer-fixing solution reduces silver salt crystals and turns them into black metallic silver on film and a stable and clear image appears on the film. After several uses of the fixing solution, its efficiency is reduced due to the decrease in the concentration of sodium thiosulfate and finally, it cannot be used since there is not enough awareness regarding its harm, so it enters the environment through wastewater. In this study, the recovery of fixing solution waste has been investigated. The recovery of the solution waste, silver extraction, and direct synthesis of nanoparticles have been performed by chemical reduction method from the waste. The obtained samples were analyzed and studied by EDX, XRD, and SEM techniques. The results showed that the fixing solution waste and silver metal were recovered properly with a purity of 99.81%. Also, AgNPs were synthesized by chemical reduction. Recovery of the fixing solution waste -for the first time- and metallic silver, as well as the synthesis of AgNPs by chemical reduction method, is an economical method and free of any contamination.

Real-time monitoring of Black Carbon and Particulate Matter was done by Aerosol Black Carbon Detector (ABCD) and GRIMM portable aerosol Spectrometer in Agra at five different locations (R1, R2 traffic and R3, R4, R5 residential road sites). Major portion of PM mass was contributed by PM10 followed by PM2.5 and PM1.0. Major portion of PM in number mode is contributed by PM10=PM0.25 followed by PM5.0 =PM0.5, PM1.0, and PM2.5. All the PMs mass and number concentration was highly associated with the R1 site due to the vehicular and other anthropogenic activities and was least at R5 except for PM10. The highest concentration of BC was found at R2 site followed by R1 while During the sampling events NO2 and O3 was found highest at R2 site followed by R1. The source of BC, PMs, NO2, O3 at R1& R2 may be vehicular activities, population activities, crowded area, and industrial activities. BC contribution in PM1.0 was highest followed by PM2.5. The children category in the traffic site has high PM deposition mass visualization as compared to the residential road site so they are highly affected by lung diseases instead of the residential road site children category. From health risk assessment results, it was found that no population was at non-carcinogenic risk from chronic exposure to PM10 while children may be at possible risk from acute exposure. However, cancerous risk assessment showed that both children and adult were at risk from exposure of PM2.5 and may develop cancerous diseases.

Most tilapias are microphytes, but some prefer higher plants. Ammonia is one of the most important toxic compounds of nitrogen, which is a serious problem in the environment and aquaculture industry. In the present study, juvenile Oreochromis niloticus were exposed to 10, 20, and 30% (96h LC50) of ammonia for two weeks, which are equivalent to 0.9, 1.8, and 2.7 mg / l, respectively. After this period, the fish were anesthetized and blood samples were taken from the caudal stalk with a heparin syringe for evaluating blood indicators. The tissue samples were taken 0.5 cm from the liver, fixed in 10% formalin buffer, and after dehydration with alcohol, clarification with xylol, blocking with paraffin, and cutting 4-6 microns thick with microtome were done. Finally, the stained slides were studied with a light microscope. The results showed phenomena such as hyperemia, nuclear hypertrophy, sinusoidal dilatation, increased melanomacrophage centers, nucleus margination, hepatocyte vacuolation, and cell necrosis in the liver. In the studies of blood serum factors with the increase of ammonia, it has been increased in  AST, ALT, and ALP compared to the control and other groups. Also, as the ammonia concentration increased, the severity of the lesions also increased. Therefore, ammonia causes changes in the structure and activity of metabolic enzymes of the liver, which must be controlled by creating the appropriate ammonia and management conditions in the aquatic environment.

Effective denitrification of water using photocatalytic reaction of active TiO2 particles doped with different oxides and metals has been the subject of numerous studies. For a particular research area, the potential of silica bond and its silicate based matrices with titanium dioxide and improving the photocatalytic performance using more economic methods is still challenging, and research in this field is attractive and ongoing. In this study, the effect of cement matrix and its complex bonds with industrial grade TiO2 particles was evaluated on the rate of water denitrification in a fixed bed circulating flow photoreactor. For this purpose, silica fume was substituted for cement in constant percent of 10 as a rich source of amorphous silica. Industrial grade TiO2 was added to the mix as5, 10 and 15 percent weight of cementitious materials (CM). Nano TiO2 was considered as a supplementary photocatalytic material with a constant 1% weight of CM in two mix designs. The results implied that the addition of 5% TiO2 increased the rate of nitrate concentration reduction by up to 10 times. Also, the specimen including 10% TiO2 increased denitrification rate by 107% compared to the previous content, which had much less impact. Also, the addition of nanoTiO2 increased denitrification rate up 113%.

A potential hazard is anything that could potentially cause damage, accident, injury, loss, or even death due to the system or work processes. Hazards in the work environment are due to physical, biological, chemical, and psychosocial factors. One of the chemical factors hazards in the work environment that require control is the level of dust in the air environment at work. High levels of dust can cause health problems for workers. These health problems can cause dust allergies, impaired lung function, and other lung function disorders due to the dust that can eventually reduce worker productivity. Out of all industries, the manufacturing industries are usually high in dust content. During the manufacturing process, it is crucial to maintain efforts in controlling risk factors. This research aims to develop a tool that can reduce the air dust level in the industrial environment. Therefore, this study tries to apply an electrostatic precipitator with electrode distance variations to reduce dust levels in the manufacturing industry. The results of this study are the dust content reduction percentage, an electrode distance of 4 cm resulted in 52.3% to 64.9%, electrode distance of 6 cm is 35.5% to 46.7%, while an electrode distance of 8 cm is 16.6% to 26.7%. There is a difference in the electrodes effect of 4 cm, 6 cm, and 8 cm with a decrease in dust levels in the air. The most effective electrode distance in decreasing the air dust level is a 4 cm distance.

A geochemical evaluation was performed to determine the occurrences of many heavy metals as well as their natural activities, in the southeast-Baghdad.  For this purpose, seventeen subsurface soil samples from the cited location were collected at a depth of 50-100 cm. Samples collection included many types of land uses such as open space, roadside, green land, industrial and commercial samples. The samples were characterized systematically using XRF and gamma-ray spectrometry with NaI (Tl) scintillation detector. The total average concentrations of heavy metals Ag, Sn, Sb, I, Hf, W, Th and U in the soil were 1.94, 3.13, 3.01, 2.82, 1.70, 72,5.66 and 0.85 ppm respectively. Heavy metals Sn, I and W appeared with high concentrations among the others as shown in total average, compared with the standard. The enrichment with Sn elements strictly appeared in green and commercial lands with an average 3.63 ppm, whereas I and W concentrated in industrial land 3.0 and 0.95 ppm respectively, indicating anthropogenic rather than autogenic. It was asserted that the observed elements can be used as pollution indicators to discover the state of the contamination. The EF values of the soils in some sites displayed enrichment with Sb and moderate with Ag reflected mild enrichment (EF > 2), confirming their level of pollution by the hazardous heavy metals. The contents of 238U, 232Th and 40K in the samples varied from 34.64-48.54, 47.22-67.73, and 323.27-585.11 Bq/kg, respectively. The mean activities of 238U, 232Th and 40K in the dry weight samples were correspondingly 41.25, 56.89, and 424.12 Bq/kg, which were higher than the global averages of 35, 30 and 400 Bq/kg, respectively. The radium equivalent levels in all samples were much lower than the global average (370 Bq/kg). In addition, all external and internal hazard indices were within the recommended limit. The average dose rate and gamma index levels were greater than the global average value.

Substrates play a major role to filter, adsorb, sediment, flocculate, precipitate, and exchange ions. In CW (Constructed wetland), selecting substrate or bed materials is not difficult, as locally accessible, cost-effective, and environment-friendly materials can be used based on size, hydraulic conductivity, texture, porosity, etc. CW substrates undergo a multitude of purification processes, including physical filtration and sedimentation, sorption, ion exchange and microbial degradation, precipitation, and bio-immobilization in the substrate, in addition to uptake and metabolism by macrophytes. With constructed wetlands, treatment facilities with well-defined substrates, vegetation species, and flow patterns can be built with greater control than with natural systems. This report details investigations of some of the locally available substrates that all fit the requirements. Based on analysis of parameters which are pH, water absorption capacity, hydraulic conductivity, porosity, surface area, bulk density, particle size distribution, D10 particle diameter, D60 uniformity coefficient, permeability and specific gravity, a comparison of four materials is presented in this paper. The study found that the construction waste materials evaluated showed satisfactory physical properties for use as filler media in constructed wetlands for wastewater treatment.

Improper management of wet waste in cities located in temperate, humid regions with abundant rainfall leads to the production and spread of leachate across ecosystems. This not only pollutes soil and surface water but also contributes to the emission of greenhouse gases, negatively impacting both ecosystem and human health. Effective waste management can transform these wastes into valuable products, such as fertilizer and biogas, while also preventing environmental damage. In this study, we focus on a region with moderate weather conditions, which offers the potential for efficient waste management at a reasonable cost. By evaluating various technologies and methods, as well as considering global implementation approaches, anaerobic digestion emerges as a more suitable solution for waste management compared to conventional methods like burying and burning. Apart from waste reduction, anaerobic digestion offers several advantages, including reduced greenhouse gas emissions, prevention of soil, air, and water pollution, decreased toxicity and heavy metal contamination, and eradication of pathogenic organisms. Numerous types of digesters have been developed to date, and factors such as geographical location, substrate availability, construction materials, climatic conditions, cost and capital requirements, and energy consumption influence the design of these digesters. In this study, we estimate the design, construction, and management of a small-scale digester for a town with a population of 2000 people. By providing reliable information, this research aims to assist executive officials of towns and villages in establishing such units within their communities, promoting sustainable rural development.

Acid-activated corn husk waste (CHW) was used to investigate the adsorption mechanism of Indigo Carmine (IC) dye from an aqueous solution. The effect of different operating parameters such as pH (1-7), initial IC dye concentration (40-400 mg/L), contact time (5-75 min), and heating temperature (25–200 °C) was measured on the removal of IC dye by the CHW. The maximum uptake of IC dye was observed at an initial pH of 2. The maximum capacity of 13.57 mg/g and the maximum dye removal of 89.01 % in wastewater. The adsorbents were characterized using Fourier Transforms Infrared Spectrophotometry (FTIR), Scanning Electron Microscopy (SEM), Brunauer-Emmett-Teller (BET) surface area analysis, X-ray Fluorescence (XRF), and Thermogravimetry Analysis. The characterization process reveals the differences in adsorbent characteristics before and after the adsorption processes. The Langmuir showed the best fitting (R2 = 0.977) and described multilayer adsorption on diverse surfaces. The pseudo-second-order kinetic model best correlated with the experimental data (R2 = 0.981). Thermodynamics revealed that adsorption was favorable spontaneous and exotherm. The study's results indicated that using CHW as a low-cost adsorbent to treat IC dye was efficient and beneficial to the environment.