Nuisance dust particles have emerged as a significant environmental concern within the Middle Eastern region. The principal aim of this research was to conduct an extensive investigation into the physical and chemical attributes of dust-fall particles located within the city of Sulaymaniyah, northeastern Iraq. Over a period of six months, a total of 72 dust-fall particle samples were systematically gathered from three distinct stations, with intervals of seven days. In addition to quantitative analysis, this study included detailed morphological examinations and mineralogical composition assessments, facilitated through the application of analytical methodologies, including Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD). The outcomes of these analytical procedures revealed predominantly irregular shapes of the dust particles, characterized by the presence of quartz and calcite minerals, confirming their natural origin due to wind-driven erosion originating from the arid desert landscapes of Iraq and its neighboring southern and western countries. Moreover, this investigation extended to encompass a comprehensive evaluation of both water-soluble and insoluble fractions, in addition to the overall concentration levels of alkali and alkaline earth metals including sodium (Na), potassium (K), calcium (Ca), and magnesium (Mg). Furthermore, the levels of heavy metals of manganese (Mn), iron (Fe), copper (Cu), and arsenic (As) were investigated. The extent of pollution associated with these elements was assessed through the application of the Geo-accumulation index (Igeo) which revealed that, during the study, calcium, magnesium, and copper demonstrated noticeable levels of contamination within the dust-fall particles of Sulaymaniyah city.

Multidisciplinary studies that integrate socioenvironmental aspects into the assessment of water resources contamination significantly enhance the identification of its sources. In the present study, an assessment of heavy metal contamination in sediments of Umayo Lagoon and the behavior of local actors was conducted. The concentrations of As, Cd, Cu, Hg, Pb, and Zn were determined and evaluated using international regulations. These data enabled the creation of distribution maps to pinpoint accumulation zones of different metals and suggest their possible sources of origin. The results were compared with the behavior of local actors, addressing three analytical characteristics: feelings, thoughts, and attitudes. Evidence showed contamination by As (18.11 mg/kg), Hg (0.19 mg/kg), and Cd (0.96 mg/kg), likely originating from mining activities, cheese plants, and agriculture. In terms of social aspects, intense emotions were expressed due to the presence of diseases and livestock mortality associated with metal contamination, causing anxiety and fear in the population. The incorporation of socioenvironmental aspects in the contamination assessment aligned with the physicochemical results, achieving identification of the sources of Umayo Lagoon.

Laboratory wastewater is categorized as hazardous waste that should not be released into the environment since it poses a serious threat to environmental safety. In the present study, the use of Sulphate-Reducing Bacteria (SRB) colonies in an anaerobic reactor to treat heavy metals-containing laboratory wastewater was examined. SRB was initially cultivated with the treatment of fermented compost and Postgate's medium before being attached to the laboratory-size anaerobic reactor to treat laboratory waste containing heavy metal. Within the 15 days of initial incubation under the room temperature of 28 °C, we discovered that SRB optimally grew on the medium with the composition of 5% Postgate B solution, 30% fermented compost liquid, and 5% active suspension liquid, with a total population of cell colonies was 1.2 x 105 CFU/ml. After SRB colonies from the most optimum medium were affixed to the reactor, the reactor attained 89% of lead (Pb) removal, 69.78% of iron (Fe) removal, and 48.93% of copper (Cu) removal for 15 days treatment periods. On the 21st days of treatment time, the removal efficiency increased significantly to 91.57%, 78.09%, and 83.56% of Pb, Fe, and Cu removed, respectively.

In this study, the concentrations of heavy metals were studied using atomic absorption spectroscopy of samples from the sediments of the Tigris River within the boundaries of the city of Mosul, northern Iraq, and the environmental parameters of heavy metals were calculated. The results showed that the average concentrations of Co, Cu, Cd, Pb, Zn, and Ni in (ppm) were (8.78, 30.42, 0.179, 12.04, 75.53, and 144.75), respectively, where these results were higher than the international accepted average. It indicates that the main factor in the high concentrations of heavy metals in the environment of the Tigris River in the city of Mosul is the pollution caused by human activities. The results of the environmental treatments for the studied heavy metals showed that the values of the enrichment factor (EF) were moderately contaminated with Cu, Cd, Ni, and Zn and not contaminated with Co and Pb. The value of the contamination factor (CF) for the sediments of the Tigris River in the studied areas showed that the sediments of those areas are moderately polluted with Co, Ni, and Zn metals. The degree of contamination (Cdeg) for the sediments of the study area in general ranges from low - medium pollution, the pollution load index (PLI) average of (1.03) showed that the sediments of the study area were contaminated with heavy metals. Therefore, we conclude that the environment of the Tigris River is polluted with heavy metals, but it is not at the level that causes concern at present.

Fungi are successful microorganisms in the bioremediation of environmental pollution. So, this study aimed to determine the potential of Trichoderma tomentosum to remediate cadmium, lead, and nickel contaminations from potato dextrose agar (PDA) and potato dextrose broth (PDB) media. Growth rates, toxicity tolerance sporulation, bio-sorption capacity, and bio-sorption efficiency of the fungus were evaluated under different concentrations of CdCl2, Pb(NO3)2, and NiCl2. The findings demonstrated that the growth rate of the fungus differed depending on concentration, metal type, and medium. More metals in PDA medium induced more inhibition on fungus growth rates; however, the rate was independent from the heavy metals concentrations in PDB medium. Cadmium was the most toxic metal tested against T. tomentosum, with a 72h LC50 of 37 ppm. It was about 3.16 and 4.24 times as toxic as nickel and lead, respectively. In the control condition, sporulation of the fungus began at 72 hours, but under the heavy metals, it began at 168, 168, and 192 hours, respectively, for Pb, Ni, and Cd. Both the bio-sorption capacity and efficacy of the fungus were significantly enhanced by an increase in metal content and the highest values were obtained at 200 ppm of the salts. The heavy metals total bio-sorption capacity order was Ni < Cd < Pb in the aqueous medium. The conclusion was that T. tomentosum has a greater potential for the biosorption of heavy metals; hence, the fungus may be employed for the bioremediation of heavy metals from polluted sites, particularly wastewater and industrial influents.

The purpose of this study was to evaluated the origin of the heavy metals amongst nuisance dust particles in Sanandaj, Khorrmabad and Andimeshk cities located in different latitudes in western Iran for the dustiest year during last decade. Samples of dust-fall particles were collected with 10 days intervals from these three cities for the duration of June 2012 to July 2013 using Deposit Gauge Method. Concentration of the heavy metals including iron, manganese, zinc, copper, arsenic, chromium, silver, nickel, lead and cadmium were measured using atomic absorption spectroscopy. The Quantification of Contamination index (QC) was applied to evaluate the origin of heavy metals among dust-fall particles collected in three stations. The results revealed that the annual mean rate of dust-fall was 1.73, 2.66 and 3.37 g/m2 per 10 days for Sanandaj, Khorramabad and Andimeshk, respectively. The highest and the lowest amount of dust-fall were obtained for July and February, respectively, while Fe had the highest concentration among the metals studied. The temperature and wind speed were found to be the most correlated meteorological parameters to dust-fall content throughout the three stations. According to QC index; Ag, Cu, Cd, As, Pb, Mn and Zn (except Pb and Mn for Andimeshk) were derived mainly from similar origins such as anthropogenic activities but the increased values of Fe, Ni, and Cr were ascribed to natural processes. Furthermore, Cu had the highest correlation with other heavy metals measured and was determined the most stable metal amongst dust-fall particles for the three studied stations.

The assessment of human health risk associated with accumulation of lead, copper, zinc, nickel, and Arsenic in the muscle of bartail flathead (Platycephalus indicus) collected from Jofreh pier and Bushehr port, northwest of the Persian Gulf of Iran was examined. A total of 80 P. indicus were collected and analysed using ICP-OES from two seasons (summer and winter) of 2019; estimated daily intake (EDI), estimated weekly intake (EWI), target hazard quotient (THQ), hazard index (HI) and Carcinogenic risk (CR) were determined. The mean concentration (μg/g) range were observed as: zinc (16.37-50.17)> As (5.65-8.83)> Cu (2.19-3.63)> Pb (0.62-6.37)> Ni (0.17-1.08). Hazard index (HI) for adult and children during consumption of P.indicus was <1, the highest HI values were calculated for adults (0.06) in Bushehr and children (0.14) in Jofreh. The CR levels for Ni and Pb were within acceptable limits (10-6 to 10-4) and arsenic was unacceptable (> 10-4) at sampling sites.

Pars special economic energy zone (PSEEZ) in Iran is the second largest energy zone in the world with more than 60,000 operational and non-operational personnel. Considering the nature of the activities being done in PSEEZ, it is rational to expect that a wide range of hazardous materials be present in the air composition of this area. It is shown in this research that Benzene-Toluene-Ethylbenzene-Xylene (BTEX) are the most challenging in PSEEZ and benzene concentration violates the standards in all sampling points. The study area is divided into three subzones of gas refineries, petrochemical complexes and non-operational areas. In the gas refineries, benzene concentration is recorded to be 480 times higher than the standard for exposure limit. The concentration of benzene in petrochemical complexes is also about 160 times higher than the standard limit. Considering the vicinity of the petrochemical complexes the cumulative impacts of BTEX will also worsen the situation regarding BTEX cancer risk. In non-operational areas, benzene concentration reaches 40 times higher than the standard limit which is a serious health challenge. Comparing the data of BTEX distribution with AQI proves that AQI solely is not an appropriate index for assessing the air quality in PSEEZ and defining local indices for air quality assessment with taking hazardous chemicals such as BTEX into account. Moreover, some other pollutants such as heavy metals and H2S are detected in the air quality in significant amounts which raise the need to a reconsideration in location of unprotected non-operational personnel.

The optimization of nickel ion (Ni2+) removal in aqueous solutions with various factors (initial Ni concentration, solution pH, adsorbent dosage, contact time), as affected by raw cow bone (RBO) and its biochar (bone char: BC; produced by pyrolysis processes at 500 °C and a residence time of 4 hours) as adsorbents was investigated by a three-level Box–Behnken model (BBM) under response surface methodology (RSM). A total of 29 experimental runs were set for each adsorbent, and the experimental data were fitted to the empirical model. To understand the Ni2+ adsorption processes better, the properties of RBO and BC were characterized using Fe-SEM, FT-IR, BET, XRD, and CHNS elemental analysis techniques. The BC characteristics showed that pyrolysis increased the specific surface area (by 100 times) and phosphate functional groups, but decreased the carbonate functional groups, and yielded a more irregular and rougher morphological surface compared to RBO. Based on BC's superior ion exchange mechanisms and physical electrostatic adsorption compared to RBO, the removal efficiency of Ni2+ by BC was higher in aqueous solutions. The numerical optimization of BBM revealed that the optimum removal by BC (82.56%) was obtained at an initial Ni2+ concentration of 30.79 mg L−1, pH of 6.99, adsorbent dose of 4.87 g L−1, and contact time of 57.82 min, with the desirability of "1". BC can be effectively used for Ni removal from Ni-contaminated aqueous solutions; still, the application of modification methods (e.g., physical and chemical activation) may be necessary to help remove more Ni2+ by BC.

Severodvinsk city is the largest industrial center for the construction and repair of naval vessels in the NW Russia. The purpose of the presented study was to identify the main sources of pollution of the Severodvinsk industrial region and assess the ecological situation based on analysis of toxic metals in water and snow. Heavy metals content in water, melt snow filtrate and solid residue was measured using ICP-MS. On the urban area, there were high concentrations of Fe (up to 2843 MPC) in soluble form of snow, Al (up to 4680 MPC), Fe (up to 2807 MPC), Ni (up to 66.5 MPC), Pb (up to 44.7 MPC), Cd (up to 43.3 MPC), Cr (up to 43.2 MPC), Mn (up to 13.3 MPC), Co (up to 7.3 MPC), and As (up to 3.4 MPC) in insoluble form of snow, Fe (up to 56213 MPC) in water from wells. There were high values of mineralization (598 mg/L) and low pH values (to 5.21) in sites most susceptible to anthropogenic pollution. Statistical analysis showed that most of the metals in snow cover were linked with each other by strong correlation (r>0.9). Calculation of toxicological indices HMEI, HMPI, HMTL, HI and CR showed extremely high and dangerous for public health level of heavy metal pollution in the Severodvinsk industrial district. Studied radiation parameters of water from wells were within acceptable limits. Results obtained indicate the need to change the type of fuel in thermal power plant and reduce toxic emissions from the shipbuilding enterprises.