Search

The flow of graphene oxide (GO) into natural water systems can adversely affect water environments and ecosystems. In this study, the adsorption effect of calcite on GO under different conditions was studied using calcite as adsorbent. Meanwhile, characterized by a combination of microscopic experiments, including SEM, TEM, XRD, FTIR, Raman, XPS, and AFM, additional research on the performance and the mechanism of GO sorption by calcite was conducted. The findings indicated that the highest adsorption efficiency was observed at a temperature of 303 K, pH 3, a mass of 90 mg of calcite, with an initial concentration of 60 mg L−1 GO, resulting in a 95% adsorption rate. The adsorption isotherm conformed to the model of Langmuir and Temkin, and it is a heat absorption process dominated by monolayer adsorption. The thermodynamic analysis showed that the adsorption was spontaneous and heat-absorbing. The adsorption kinetics conformed to the pseudo-second-order kinetic model, and the sorption procedure is chemisorption. In conclusion, calcite has a good sorption capacity for GO, which can provide a reference for the removal of GO in the aqueous environment. [ABSTRACT FROM AUTHOR]

The novel photocatalyst of Fe3O4@SiO2/PAEDTC@MIL-101(Fe) was prepared based on the sol–gel method, and its structure and morphology were determined by SEM mapping, TEM, XRD, FTIR, and N2 adsorption–desorption analyses. The photocatalytic activity of nanocomposite was evaluated in comparison with other particles as well as adsorption and photolysis processes. The effect of operating parameters showed that the complete degradation of penicillin G (PNG) can be provided at a photocatalyst dosage of 0.6 g/L, radiation intensity of 36 W, pH of 5, and time of 60 min. In the optimum condition, 84% TOC removal was attained and the BOD5/COD rate for the treated effluent was above 0.4, which was representative of the high biodegradability of the treated effluent compared to the raw sample. The findings of energy consumption showed that PNG can be easily and effectively treated by the photocatalytic process based on magnetic MIL-101(Fe) with electrical energy per order between 10 and 20.87 kWh/m3. Due to the excellent interaction between the MIL-101(Fe) and Fe3O4@SiO2/PAEDTC, the photocatalyst stability test showed a recyclability of the particles for 5 consecutive reaction cycles with a minimum reduction of 7%. Solution treated with photocatalyst under UV and visible light sources explained that the toxicity of the effluent after treatment is significantly reduced with the growth of Escherichia coli. Scavenging experiments showed that •OH radical and hole (h+) are the main agents in degrading PNG to CO2, H2O, and biodegradable and low-toxicity products. Finally, the findings of the diagnostic analysis and comparative experiments proved that with the interaction of Fe3O4@SiO2, NH2, and MIL-101(Fe), a lower band gap can be prepared for more absorption of photons and pollutant and also more and faster production of active radicals. [ABSTRACT FROM AUTHOR]

Photovoltaic power generation is developing rapidly with the approval of The Paris Agreement in 2015. However, there are many dust deposition problems that occur in desert and plateau areas. Traditional cleaning methods such as manual cleaning and mechanical cleaning are unstable and produce a large economic burden. Therefore, self-cleaning coatings, which have unique mechanisms and high adaptability, have attracted wide attention in the photovoltaic industry and scientific community, especially the super-hydrophobic and super-hydrophilic coatings. The paper systematically reviewed the theory, materials, preparation, and applications of the super-hydrophobic and super-hydrophilic coatings on the photovoltaic modules. Super-hydrophobic materials such as organosilicon compounds, fluorinated polymers, and some inorganic materials are popular. TiO2 is widely used to prepare super-hydrophilic coatings on glass covers of photovoltaic panels due to its good photocatalytic activity. CVD-based surface treatment is suitable for preparing photovoltaic self-cleaning surfaces. These methods prepare self-cleaning surfaces by reacting gaseous substances with hot surfaces and depositing them on the surface. They are efficient but difficult to control accuracy. When applied to photovoltaic modules, it is crucial to consider the factors such as self-cleaning, transparency, anti-reflection, anti-icing, and durability. In future research, it is significant to improve the transparency, durability, and self-cleaning properties of coatings. [ABSTRACT FROM AUTHOR]

Cigarette butt–littering behavior is common among most smokers. The present study aimed to determine the predictors of butt-littering behavior in a sample of Iranian male current smokers based on the Bandura's social cognitive theory variables. In this cross-sectional study, 291 smokers who throw their cigarette butts in public parks in Tehran city, Iran were selected and completed the study instrument. Finally, the data were analyzed. The average number of butts littered daily by the participants was 8.59 (± 8.661). The results of multiple Poisson regression showed that knowledge, perceived self-efficacy, positive and negative outcome expectations, self-regulation, and observational learning variables were statistically significant predictors of butt-littering behavior among the participants. It is concluded that Bandura's social cognitive theory is a suitable theoretical framework for predicting butt-littering behavior and might be used to develop theory-based environmental education efforts in this field. [ABSTRACT FROM AUTHOR]

Globally, treating and disposing of industrial pollutants is a techno-economic challenge. Industries' large production of harmful heavy metal ions (HMIs) and dyes and inappropriate disposal worsen water contamination. Much attention is required on the development of efficient and cost-effective technologies and approaches for removing toxic HMIs and dyes from wastewater as they pose a severe threat to public health and aquatic ecosystems. Due to the proven superiority of adsorption over other alternative methods, various nanosorbents have been developed for the efficient removal of HMIs and dyes from wastewater and aqueous solutions. Being a good adsorbent, conducting polymer-based magnetic nanocomposites (CP-MNCPs) has drawn more attention for HMIs and dye removal. Conductive polymers' pH-responsiveness makes CP-MNCP ideal for wastewater treatment. The composite material absorbed dyes and/or HMIs from contaminated water could be removed by changing the pH. Here, we review the production strategies and applications of CP-MNCPs for HMIs and dye removal. The review also sheds light on the adsorption mechanism, adsorption efficiency, kinetic and adsorption models, and regeneration capacity of the various CP-MNCPs. To date, various modifications to conducting polymers (CPs) have been explored to improve the adsorption properties. It is evident from the literature survey that the combination of SiO2, graphene oxide (GO), and multi-walled carbon nanotubes (MWCNTs) with CPs-MNCPs enhances the adsorption capacity of nanocomposites to a large extent, so future research should lean toward the development of cost-effective hybrid CPs-nanocomposites. [ABSTRACT FROM AUTHOR]

Pollution of water sources by pathogens is a significant concern worldwide. In the present study, a pilot-scale once-through reactor was fabricated to investigate bacteria's inactivation and the degradation of organic matter present in municipal wastewater using an iron-mediated TiO2 catalyst in fixed mode. The catalyst was fabricated (in a spherical shape) using waste material such as foundry sand and fly ash and coated with TiO2 for a combined hybrid effect. The influence of H2O2 concentration and the flow rate of the reactor were examined. 4.1 log reductions of bacteria with 52% and 39% of BOD and COD reductions in 45 min of treatment were observed. The catalyst was also found to be highly durable, with only a 12.5% of reduction in catalyst activity observed after 200 recycles. Therefore, this pilot-scale research indicates the ability of waste materials to be employed as a practical approach for water disinfection applications. [ABSTRACT FROM AUTHOR]

A precise nano-scale biosensor was developed here to detect Hg2+ in aqueous media. Nitrogen-doped carbon nanospheres (NCS) created from the pyrolysis of melamine–formaldehyde resin were characterized by FESEM, XRD, Raman spectra, EDS, PL, UV–vis spectra, and N2 adsorption–desorption, and were used as a highly selective and sensitive probe for detecting Hg2+ in aqueous media. The sensitivity of NCS to Hg2+ was evaluated by photoluminescence intensity fluctuations under fluorescence emission in the vicinity of 390 nm with a λexc of 350 nm. The fluorescence intensity of the NCS probe weakened in the presence of Hg2+ owing to the effective fluorescence quenching by that, which is not corresponding to the special covalent liking between the ligand and the metal. The effects of the fluorescence nanoprobe concentration, pH, and sensing time were monitored to acquire the best conditions for determining Hg2+. Surprisingly, NCS revealed excellent selectivity and sensitivity towards Hg2+ in the samples containing Co2+, Na+, K+, Fe2+, Mn2+, Al3+, Pb2+, Ni2+, Ca2+, Cu2+, Mg2+, Cd2+, Cr3+, Li+, Cs+, and Ba2+. The fluorescence response was linearly proportional to Hg2+ concentration in 0.013–0.046 µM with a limit of detection of 9.58 nM. The in vitro and in vivo toxicological analyses confirmed the completely safe and biocompatible features of NCS, which provides promise for use for water, fruit, vegetable, and/or other forms of natural-connected materials exposed to Hg2+, with no significant toxicity noticed toward different cells/organs/tissues. [ABSTRACT FROM AUTHOR]

In recent years, special attention has been given to emission research that led to the deposition of toxicants from road traffic. Thus, it is imperative to focus on heavy metal (HM) stressors in food items, their source contribution, and health risk assessment providing insight into their spatial role at the population level. In this study, heavy metal in the street vended noodles was studied while correlating the quality of noodle with different environmental origins. The samples were prepared using acid digestion and analysed by flame atomic absorption spectrophotometer, except Hg which was analysed by direct mercury analyser. The results showed that some heavy metals like Cr, Pb, Mn, Cd, and Hg exceed their permissible limits established by the international legislation for food products. In the noodle samples, the concentration of heavy metal ranged from < 0.1 to 0.904 mg/kg for Pb, < 0.09 to 0.843 mg/kg for Ni, < 0.004 to 0.201 mg/kg for Cd, < 0.0001 to 0.004 mg/kg for Hg, < 0.01 to 1.388 mg/kg for Cu, < 0.015 to 8.049 mg/kg for Mn, and < 0.02 to 16.514 mg/kg for Cr. Noodle samples vended on high traffic density streets are directly associated with increased HM content due to atmospheric deposition from the surrounding. Source apportionment study determines that HM contamination belongs to the same source of origin, except Cr. Based on the cluster analysis, these samples fall into three major groups that were further validated by the canonical discriminant function. Health risk prediction by Monte Carlo simulation revealed an elevated non-carcinogenic health hazard risk to consumers with a hazard index (HI) shift from 71 to 75%. Health hazard analysis showed that consumers of high traffic density street vended food are at higher risk of developing health-related issues. This study is important to evaluate the health risk of the population exposed to heavy metals due to ingestion of street vended food. [ABSTRACT FROM AUTHOR]

Sewage irrigation has solved the shortage of agricultural water and increased the content of heavy metal(loid)s (HMs) in soil-crop systems, which harms human health via the food chain. In this study, 43 pairs of soil and corn samples (leaf, stem1, stem2, stem3, root, husk, grain, and corncob) were collected in the Dongdagou (DDG) and Xidagou (XDG) streams of Baiyin City. Fraction and transfer of As and Hg were investigated, and toxicological effects and contamination were assessed in soil-corn systems. The results showed that the mean values of As and Hg in soil were 33.79 mg/kg and 0.96 mg/kg, respectively, which exceeded the soil background values in Gansu Province. As and Hg are mainly dominated by the residual fraction. Total and bioavailability contributed significantly to As and Hg accumulation in corn, with root, stem3, and leaf accumulating more strongly. The results based on the bioavailability concentration soil-corn transfer factor indicated that As and Hg tended to accumulate more in the root, stem3, and leaf and less in grain, and further assessment of the human health effects of consuming contaminated cron is needed. Scanning electron microscope (SEM) and Fourier transform infrared (FTIR) results showed that As and Hg were not significantly toxic to corn parts, indicating morphology. As and Hg were bound to hydroxyl groups in the outer epidermal cell wall of the roots, thereby reducing upward translocation. The trinity assessment (TA) model results indicated that the most severe contamination was found in root and stem1. The TA provides a practical tool for soil-cron systems and helps develop management strategies to prevent ecological hazards. [ABSTRACT FROM AUTHOR]

The present study aimed to evaluate the potential toxic heavy metal (PTHM) concentrations and associated ecological and health risk of nearby inhabitants (child and adult populations) of the Bokaro thermal power station (BTPS), Jharkhand, India. The fly ash containing PTHMs is released from the thermal power plant and contaminates the soil of the nearby agricultural area, roadside area and residential area. Furthermore, PTHMs cause ecological risk as well as carcinogenic health effects in adults. Inhabitants are exposed to PTHMs through exposure pathways (for instance, direct ingestion, dermal contact and air inhalation), and PTHMs were examined in this study by calculating the estimated daily intake (EDI). The contamination factor (Cf) of Cd exceeded the threshold value throughout the study area, whereas the Cf of Hg was observed higher only in roadside soil (RSS). The geoaccumulation index (Igeo) of Cd was higher in the top soil of agricultural soil (AS) (7.39) and RSS (9.38). The level of PTHMs was monitored slightly higher in the topsoil of RSS. The ecological risk index (Eri) was detected to be the highest in RSS (1628.9). The permissible limit of Cd (0.05 mg kg−1) and Pb (0.1 mg kg−1) for all sampled vegetables and grain crops was surpassed. The transfer factor (TF) of the studied vegetables and grain crops was in the order of Cd > Cr > Pb > Hg > As. The results of the present study concluded that the hazard quotient (HQ) values for all PTHMs analysed in soil throughout the study area were < 1, which indicates that the child population was within the safe limit. However, the adult population was at a high risk of non-carcinogenic health effects due to increased permissible limits of Cd, Pb and Cr in vegetables and grain crops whereas the target carcinogenic risk (TCR) of Pb and Cr was higher and indicated that there may be a health risk of cancer in adults. [ABSTRACT FROM AUTHOR]

Cancer is an illness characterized by abnormal cell development and the capability to infiltrate or spread to rest of the body. A tumor is the term for this abnormal growth that develops in solid tissues like an organ, muscle, or bone and can spread to other parts of the body through the blood and lymphatic systems. Nutrition is a critical and immortal environmental component in the development of all living organisms encoding the relationship between a person's nutrition and their genes. Nutrients have the ability to modify gene expression and persuade alterations in DNA and protein molecules which is researched scientifically in nutrigenomics. These interactions have a significant impact on the pharmacokinetic properties of bioactive dietary components as well as their site of action/molecular targets. Nutrigenomics encompasses nutrigenetics, epigenetics, and transcriptomics as well as other "omic" disciplines like proteomics and metabolomics to explain the vast disparities in cancer risk among people with roughly similar life style. Clinical trials and researches have evidenced that alternation of dietary habits is potentially one of the key approaches for reducing cancer risk in an individual. In this article, we will target how nutrigenomics and functional food work as preventive therapy in reducing the risk of cancer. [ABSTRACT FROM AUTHOR]

For the past few years, the environmental safety problems of radioactive nuclides caused wide public concern. In this work, the dodecyl trimethyl ammonium bromide-modified silicon dioxide composite (DTAB/SiO2) was synthesized for the elimination of uranium. The dodecyl trimethyl ammonium bromide can decorate the surface of the silicon dioxide and change its surface topography, which can offer more active sites and functional groups for the combination of U(VI). The removal capacity of U(VI) on DTAB/SiO2 reached 78.1 mg/g, which was greater than that of the silicon dioxide nanopowder. In the adsorption process, the surface oxygen-containing functional groups formed surface complexation with uranium. The results may provide helpful content to eliminate U(VI) and expand the application of surfactant in radioactive nuclide cleanup. [ABSTRACT FROM AUTHOR]

Cigarette butts are hazardous wastes that are not properly discarded by most smokers. They are one of the most abundant litters in the environment and a threat to various organisms because they leak numerous pollutants. This study aimed to assess the distribution of cigarette butts in a coastal city south of the Caspian Sea in Mazandaran Province, Iran. Observations were performed using the visual survey technique based on standardized protocol. The results showed 11,261 littered cigarette butts in 15 studied urban areas (an average of 0.306 units per square meter). Also, the average density of littered cigarette butts on the studied beaches was 0.106 per square meter. The littered cigarette butts had significant spatial variation, and the number of counts was 135 to 2090. The land-use has a significant effect on the density of littered cigarette butts due to its population density. The inquiry's index demonstrated that 33.3% of the studied urban areas are high pollution and severe pollution, while all beaches are high and severe. Therefore, a significant focus must be considered to reduce cigarette butts littering due to the collection problems and challenges of cigarette butt management. Because the pollution on the beaches is higher than in urban areas, improving waste management services and establishing a regular cleaning program are essential. [ABSTRACT FROM AUTHOR]

Zinc (Zn) is a vital nutrient element required for plants normal growth and development. It performs imperative functions in numerous metabolic pathways in the plants. However, potentially noxious levels of Zn in terrestrial environment can lead to inhibited photosynthesis, growth, respiratory rate and imbalanced mineral nutrition. In micronutrient malnutrition, Zn deficiency is a global human health problem owing to the human dependence on cereals grains especially wheat-based diet. Therefore, this study investigated the Zn uptake efficacy in Triticum aestivum that is grown under two different doses (100 g/kg or 200 g/kg) of various soil amendments in both pot and field experimentation. Results of this study revealed that mean Zn concentration in different wheat varieties and treatments were varied from 1.53 to 6.03 mg/kg, 11.27 to 40.65 mg/kg, 11.28 to 39.93 mg/kg, and 11.32 to 37.70 mg/kg in amended soil, root, shoot, and grains, respectively. All observed Zn values in soil and wheat parts were lower than the FAO/WHO standards. Zinc values observed for pollution load index (0.034–0.134 mg/kg), daily intake (0.00492–0.01533 mg/kg), and health risk (0.0164–0.0570 mg/kg) index were lower than 1 except bio-concentration factor. Bio-concentration factor (5.076–10.165 mg/kg) revealed that DHARABI-11 variety showed maximum Zn uptake efficacy in farmyard manure treatment. The daily intake and health risk index values also showed that Zn level in grains is safe for inhabitants consumption. Overall, study recommended that these organic amendments are a good source of fertilizers, essentially required for the sustainable management of soil and increases the Zn accumulation in wheat grains which can ultimately reduce the Zn malnutrition in human food chain. [ABSTRACT FROM AUTHOR]

Fe3+-TiO2 (Fe-TiO2) thin films were successfully prepared using a "sandwich" approach. TiO2 NPs were doped with different Fe3+ content (0.05%, 0.1%, 0.2% molar ratio), and the modified TiO2 NPs were deposited on glass flat support by dip coating. Structural, morphological, optical, and photocatalytic properties of Fe-TiO2 thin films were studied. XPS spectra confirm the presence of Ti, Fe, O, and defective –OH groups at the material surface. The Fe 2p spectrum demonstrates the existence of Fe3+. SEM images indicate that the incorporation of Fe3+ deforms in some degree the homogeneity of the TiO2 system. Additionally, incorporation of Fe3+ ions to the network creates an impurity band near the VB due to the oxygen vacancies, resulting in the reduction of the effective optical band gap. Photocatalytic activity of fabricated thin films in the elimination of sulfamethoxazole (SMT) follows pseudo first-order kinetics. The highest SMT removal yields were achieved using the sample with 0.05%Fe. Additionally, the use of greater thicknesses improves the removal performance. However, material detachment limits the maximum usable value around 6 µm. Finally, stability and reusability of catalysts were confirmed studying the photocatalytic activity over three cycles and evaluating that no Fe3+ leaching occurred. [ABSTRACT FROM AUTHOR]

The bioavailable trace metals are closely related to environmental safety and human health, which might have different source characteristics from the total trace metals in soil. To identify such differences, 31 farmland soil samples were collected from a typical agricultural watershed in East China and analyzed for bioavailable trace metal sources by using chemical fractionation, linear regression, and receptor model. Results showed that the total concentrations of Pb, Cu, Zn, Cr, and Ni in the soils were 1.25–1.59 times higher than watershed background values, but they were all dominated by the residual fraction (63.39–86.36%) according to a modified Community Bureau of Reference (BCR) sequential extraction procedure. Both chemical fractionation and enrichment factors (EFs) indicated a major contribution of the natural source to the total trace metal concentrations in the soils. However, linear regressions revealed that 60.07–89.88% of the bioavailable Pb, Cu, Zn, and Ni concentrations were contributed by anthropogenic sources. Atmospheric deposition and livestock manure were identified as the two major anthropogenic sources, and their contributions were further estimated by using a multiple linear regression of absolute principal component scores (MLR-APCS) model. Together with natural contribution, atmospheric deposition could contribute 74.55–89.86% of bioavailable Pb, Cr, and Ni concentrations. Livestock manure contributed 85.54% of bioavailable Cu and 80.05% of bioavailable Zn concentrations, respectively. These results implied that the bioavailable trace metals were influenced by both anthropogenic and natural sources, but more influenced by anthropogenic sources for bioavailable Pb, Cu, Zn, and Ni in the soils. Special attention should be paid to bioavailable Pb when implementing effective pollution control strategies in this watershed. Moreover, the risk caused by bioavailable trace metal losses from soils to aquatic system should not be ignored. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the element content of wild edible and inedible mushroom species (Agaricus campestris, Armillaria ostoyae, Boletus reticulatus, Bondarzewia mesenterica, Bovistella utriformis, Cantharellus cibarius, Marasmius oreades, Megacollybia platyphylla, Meripilus giganteus, Neoboletus erythropus, Panellus stipticus, Phaeotremella foliacea, Pleurotus ostreatus, Podoscypha multizonata, Russula aurea, R. chloroides, R. virescens, T. versicolor, Trametes gibbose, and Trichaptum biforme) collected from the Belgrad Forests and the Ilgaz Mountain National Park. Based on the results of elemental analyses, daily metal intake (DMI) and health risk index (HRI) values of edible mushrooms collected from both localities were also calculated. As, Cd, Cr, Se, P, Hg, Cu, Mn, Fe, Zn, Al, Ca, Mg, and K contents of mushrooms were in the ranges of 0.16–3.45, 0.09–2.4, 0.15–2.34, 0.3–8.13, 0.28–11.44, 14.03–37.81, 3.87–108.57, 6.18–149.77, 11.9–776.1, 5.4–317.4, 7.4–355.2, 15.4–3517.3, 266.0–2500.0, and 628.0–24083.0 mg/kg dry weight, respectively. As a result of the DMI and HRI analyses, Cu concentration of B. utriformis (DMI: 46.53 μg/kg body weight/serving, HRI: 1.16) and Cd concentrations of A. campestris (DMI: 0.49 μg/kg body weight/serving, HRI: 1.36), A. ostoyae (DMI: 1.03 μg/kg body weight/serving, HRI: 2.86), B. utriformis (DMI: 0.52 μg/kg body weight/serving, HRI: 1.44), and P. ostreatus (DMI: 0.45 μg/kg body weight/serving, HRI: 1.24) were found to exceed the legal limits determined by authorities. It was concluded that the species collected from the regions in question should be consumed in a controlled manner. [ABSTRACT FROM AUTHOR]

The objective of this research is to examine the impact of bioenergy usage on health outcomes, especially adult mortality in both developed and underdeveloped countries in the European Union, where the use of solid biomass is growing to generate bioheat, biocool, and biopower. Over the period studied, findings indicate that increased consumption of bioenergy has increased mortality rates in developed and underdeveloped EU28 countries during the period 1990–2018. This feedback proposes, using generalized least squares (GLS), that the resulting death rate from burning biomass-related cases is higher in the EU15 developed countries compared to EU13 underdeveloped countries. There is a need to lower burning biomass in the entire EU15 countries, more importantly its developed region, by critically evaluating the bioenergy production life cycle before it is available for final consumption. However, there is a continuous need to intensify stringent production procedures in the bioenergy industry in EU15 countries, more importantly the imported biomass crops for energy use. There is also a need to be consistent with the campaign on the usage of bioenergy products, i.e., bioheat, bioelectricity, and biofuels, particularly in the rural areas where the use of wood fuels for cooking, heating, and cooling are significant in EU15 developed countries in comparison to EU13 developing countries. [ABSTRACT FROM AUTHOR]

The husk of brown rice, as a source of silica, was applied to synthesize natural SiO2 nanoparticles via sonochemical method. SiO2/CH/Fe nanocomposite was synthesized from SiO2, chitosan (prepared from shrimp shells via sonochemical method), and iron functional groups and detected using BET, EDX-SEM, and FTIR techniques. These natural-based nanostructures (SiO2 and SiO2/CH/Fe) have been applied for vanadium adsorption. The influences of initial pH, initial concentration, and adsorption time were studied via a batch process. The analysis of the kinetics data indicated that the chemical adsorption is predominant. The analysis of the equilibrium data indicated the single layer and exothermic adsorption process. The mono-layer adsorption capacity of SiO2/CH/Fe was 199.540 mg g−1. The performance of SiO2/CH/Fe in a continuous column system was investigated in four adsorption and desorption cycles. Results showed that SiO2/CH/Fe nanocomposite synthesized with the sonochemical method is a candidate with high adsorption ability for use as an industrial adsorbent. [ABSTRACT FROM AUTHOR]

The aim of this study is to assess the content of heavy metals and their potential health risk in consumed food crops. To this end, the samples from vegetables, rice, potato, onion, and black tea were derived from high sales and commonly consumed types. The noncarcinogenic health risk of heavy metals to the adults, teens, and children was estimated by target hazard quotients (THQs) and hazard index (HI) calculation. Sensitivity and uncertainty analyses were carried out using Monte Carlo simulations. Heavy metal pollution index (HMI) was used for ranking noncarcinogenic heavy metal pollution in sampled food crops. THQs showed that noncarcinogenic health risks to the local population were largely related to As (0.71 for adults, 0.87 for teens, and 2.4 for children), Mn (0.43 for adults, 0.28 for teens, and 0.64 for children), and Mo (0.12 for adults, 0.02 for teens, and 0.4 for children). HI for individual food crops (HIΣfi) in terms of different populations showed that the highest HIΣfi was for children while the highest HIΣTea was for adults. The arrangement of the calculated HIΣfi along with its highest value was in the order of HIΣRice (3.71) > HIΣTea (0.39) > HIΣBeans (0.2) > HIΣVegetables (0.13) > HIΣOnion (0.12) > HIΣPotato (0.11). The value of HI for all sampled food crops based on their daily ingestion rate achieved by deterministic and probabilistic (Monte Carlo simulations) approaches for adults, teens, and children was 1.63, 1.28, and 1.87, 1.67, 4.51, and 2.48 respectively, and revealed that all populations are vulnerable to the significant noncarcinogenic health risks and children are at more risk. The sensitivity analysis revealed that the ingestion rate (IR) is the most influential factor that contributed to the total risk. The determined HMI showed no heavy metal pollution for all food crops, and rice had higher-order in HMI ranking. These results showed that heavy metals exposure due to food ingestion is a threat to human health and needs choosing a proper strategy to reduce heavy metal exposure. [ABSTRACT FROM AUTHOR]

Doping a transition metal into photocatalysts enhances the photocatalytic activity drastically. In the first part of this study, Taguchi design of experiment is applied to evaluate and optimize the efficiency of the Fe2O3/TiO2 photocatalyst synthetized by thermal method assisted by UV radiation. The contribution percentages of Fe:TiO2 mass ratio, Fe2O3/TiO2 dosage, and pH on the total organic carbon (TOC) removal are determined using analysis of variance (ANOVA). In the second part of this study, in order to model the photocatalytic degradation process, the optical properties of the photocatalyst, including the extinction, absorption, and scattering coefficients, are determined. Subsequently, the radiation transfer equation (RTE) is solved numerically based on the surface emission model using the discrete ordinate method. Furthermore, a rigorous model, including chemical reaction rates, radiation transfer, and mass transfer is proposed and validated by a set of experimental data. A satisfactory correlation between the predicted and experimental data with less than 5% error confirms the reliability of the model. The intrinsic kinetic parameters are also determined by comparing predicted values to those of the experimental results by applying non-linear regressions. [ABSTRACT FROM AUTHOR]

Areas contaminated with heavy metals can pose major risks to human health and ecological environments. The aims of this study are to assess human health risk and pollution index for heavy metals in agricultural soils irrigated by effluents of stabilization ponds in Birjand, Iran. The results revealed that the levels of Cr, Mn, Zn, Fe, Cu, Cd, and Pb were in range of 70.3–149.65, 355–570, 31.15–98.45, 23,925–29,140, 22.75–25.95, 0.17–6.51, and 8.5–23.5 mg/kg in topsoils, respectively. Total hazard index values from heavy metals through three exposure routes for adults and children were 9.13E−01 and 1.10, respectively, indicating that there was non-carcinogenic risk for children. The total risk of carcinogenic metals (Cr, Cd, and Pb) through the three exposure routes for adults and children was 1.06E−04 and 9.76E−04, respectively, which indicates that the metals in the soil will not induce carcinogenic risks to these age groups. Pollution levels of heavy metals in soil samples including enrichment factor (EF), contamination factor (CF), pollution load index (PLI), and geo-accumulation index (Igeo) showed heavy metal contamination of agricultural soils. The results of the present study provide basic information about heavy metal contamination control and human health risk assessment management in the study area. [ABSTRACT FROM AUTHOR]

The concentration level related to toxicities of trace elements in drinking water, rice, wheat flour, and their associated negative impacts on human health have become an emergent issue in China. Because Xinjiang is the largest province in China with the majority of arable pasture land available for cultivation, it is important to analyze the concentrations of trace elements in relation to their toxicities in water, rice, and wheat flour and to investigate the health risk differences between agricultural and pastoral areas in Bay County, Xinjiang. The study results showed that (1) metal concentrations from drinking water, rice, and wheat flour were within the permissible limits; (2) concentration levels of trace elements and their total risk from drinking water and rice were higher in the agricultural areas than those in the pastoral areas, whereas concentration levels of trace elements and their total risk from wheat flour were higher in the pastoral areas than those in the agricultural areas; (3) the concentration level of the trace elements in rice were higher than in the wheat flour, but the risk from the wheat flour was higher than the risk from rice; (4) total non-cancer risk from the flour (HIf) in both areas exceeded the respective safe reference doses; (5) total cancer risk from the wheat flour, rice, and water exceeded the safety limit (1 × 10−4); (6) for the exposed population, arsenic was suggested as the most evident pollutant leading to carcinogenic concerns regarding the water, rice, and wheat flour; (7) the risk index from the wheat flour made up the highest percentage both in the total cancer risk and the non-cancer risk, followed by rice and then water; and (8) the human health risk was attributed to influence from the local environment in the agriculture areas, while it was attributed to the external environment in the pastoral areas. [ABSTRACT FROM AUTHOR]

Direct ingestion of soil and/or soil attached to the food items is a potential rout for wildlife exposure to contaminants. In this study, bioaccumulation of five heavy metals (HMs) in internal tissues of an urban bird (Pica pica) collected from Aran-O-Bidgol City, Central Iran and their related soil were investigated. A total of 15 magpie specimens were collected in autumn 2013 and then their internal tissues were digested using a mixture of HNO3 and H2O2, and finally, concentrations of HMs were detected by ICP-OES. In addition, in order to show level of HM exposure risk to magpie, an exposure risk assessment was modeled. Results indicated that HMs were accumulated as follows: liver > kidney > muscle. Zn and Cu were significantly higher in magpie’s tissues collected from agricultural site; on the other hand, Pb and Cd were significantly higher in industrial site (p < 0.05). Level of Cd in male’s livers (2.11 μg/g dw) was significantly higher than in females (1.85 μg/g dw) (p < 0.05). Levels of Cd, Pb, and Ni in liver, muscle, and kidney, respectively, were significantly higher in adults than in subadults (p < 0.05). Soil exposure doses of all HMs were lower than tolerable daily intake (Zn 4.35, Cu 1.34, Ni 5.65, Pb 0.35, and Cd 0.53). The calculated hazard quotations (HQs) for HMs were as follows: Pb > Zn > Cu > Ni > Cd and for all HMs were at no risk level (HQ < 1). The amounts of hazard index for three sites were as follows: urban (1.032) > agriculture (0.943) ≥ industry (0.941) and only for urban area was at low risk (1 < HQ < 2). It seemed that birds living in a safe environment and/or HM contaminations in soil separately had no negative effects on magpies. We can also suggest that low levels of HMs in magpie’s tissues can be due to low levels of HMs in soil. [ABSTRACT FROM AUTHOR]

Soil contamination by heavy metals in coal mine wastelands is a significant environmental issue in most developing countries. The purpose of this study is to evaluate contamination characteristics in the coal mine wastelands of Sanlidong coal mine, Tongchuan, China. To achieve this goal, we conducted field sampling work, followed by further analysis of the properties of soil contamination and accumulation characteristics in woody plants. At this site, the pH value ranged from 4.41 to 7.88, and the nutrient content of the soil rose gradually with the time after deposition due to the weathering effect improving the soil quality. Meanwhile, the levels of Cd, Cr, Cu, Ni, and Zn gradually decreased with the passage time. Generally, heavy metal contamination was found to be more serious in the discharge refuse area, with Cd contamination at moderate or heavy levels; Ni, Zn, and Cu contamination at light levels; and with no Cr contamination. The geoaccumulation index ( I) was highest for Cd (2.38-3.14), followed by Ni, Zn, Cu, and Cr. Heavy metals accumulated on the lower slopes and spread to the surrounding areas via hydrodynamic effects and wind. According to transfer and enrichment coefficient analyses, Robinia pseudoacacia, Ulmus pumila, and Hippophae rhamnoides with considerable biomass could be used as pollution-resistant tree species for vegetation restoration. This study provided a theoretical basis for the restoration of the ecological environment in the mining area. This report described a link between heavy metal contamination of soils and growth dynamics of woody plants in China. [ABSTRACT FROM AUTHOR]