Search

The study was conducted with the aim of improving the environmental monitoring of soils in the Rivne urban ecosystem using geo-information technologies, followed by visualization of the results based on indicators of total and accumulated pollution with heavy metals (HM). It was found that for the gross form of HM at 54% of soil sampling points, the soils are classified as "Significantly contaminated", 28% of the soils are "Moderately contaminated", and 18% of the soils belong to the category "No contamination" with HM. According to PLI values of the mobile form of HM, 62% of the soils are of the "No contamination" category. The soils in the "No contamination" category are predominantly of insular localization and are located near water bodies and on the outskirts of the city. The "Moderately contaminated" soils are identified as 26%, "Substantially contaminated" and "Significantly contaminated" - 4% and 8%, respectively. The "Significantly contaminated" category characterizes the soil cover near large enterprises, near main highways and railways. For visualization, interpolated surfaces of the distribution of total and accumulated contamination with HM were constructed. [ABSTRACT FROM AUTHOR]

Air, soil, and water are the major and most important components of the environment and thus should always be protected. The state of these three environmental components directly or indirectly affects life. Pit latrines and septic tanks systems are simple and affordable solutions for onsite sanitation in many underdeveloped and developing parts of the world, especially in peri-urban areas. These have also been identified as culprits for environmental pollution, releasing nitrates, phosphates, ammonia, dissolved solids, and heavy metals into the environment. This paper investigates the negative impacts of pit latrines and septic tanks on soil and water in peri-urban areas of Africa. It highlights that these systems are responsible for soil and water contamination in many areas, leading to the spread of water-borne diseases and other health risks. This paper further highlights the factors that influence the performance of pit latrines and septic tanks on the environment as well as realistic, cost-effective approaches to mitigate the negative environmental effects of septic tanks and pit latrines. The study also serves as a basis for further studies to build on for making pit latrines and septic tanks more environmentally safe. [ABSTRACT FROM AUTHOR]

This article explores the use of lichens in biomonitoring to assess heavy metal concentrations, environmental factors, and lichen diversity in Bengaluru, Karnataka, India. Lichens are cost-effective options for biomonitoring due to their unique characteristics. The study examined heavy metal concentrations, acidity, and electrical conductance in different tree species across six locations. The findings revealed a correlation between acidity levels and lichen species in all tree species studied. Lichen diversity was lower in areas with heavy traffic and industrial activity. The article emphasizes the importance of considering abiotic factors and conducting chemical analysis in environmental pollution studies. The analysis of tree bark acidity, conductivity, and buffering capacity in different locations revealed significant variations. Bark pH values were lower in polluted areas with heavy traffic and higher air pollution levels. Pollution can impact the conductivity and buffering capacity of tree bark through the deposition of contaminants and chemical reactions. Furthermore, the concentration of heavy metals in lichens can indicate pollution levels in the environment, with areas near industrial and heavily trafficked areas showing higher levels. The study concludes that Station 2 and Station 4 are the most polluted locations, while Station 3 and Station 6 have lower pollution levels due to favorable conditions and green spaces. [Extracted from the article]

For effective waste management of mining industries is important to investigate their physical and mineralogical changes. For this purpose, X-ray-diffraction (XRD), thermogravimetry (TG), derivative thermogravimetry (DTG), and differential thermal analysis (DTA) methods were used. Changes in the contents of mobile forms of heavy metals in rocks were investigated using an acetate-ammonium buffer solution with a pH of 4.8 after burning rocks at a temperature of 800-850°C. The obtained data indicated the significant role of the mineral composition in the thermal behavior of the rock samples and the subsequent influence of the thermal processes on the changes in the bioavailability of heavy metals. [ABSTRACT FROM AUTHOR]

Random and unscientific disposal of municipal waste is an important factor affecting the geotechnical characteristics and concentrations of heavy metals in the soil. Unconfined compressive strength, Atterberg limit, and maximum dry density tests were included. These tests were designed to determine the effects of open waste dumps on geotechnical properties and the concentration of heavy metals in the underlying open dump soil. Soil samples collected from the landfill at Al-Sayyahia Village, Babylon Governorate, showed changes in the rates of geotechnical properties evaluation, as the value of the confined compressive strength decreased by high rates from 54 to 22 kN/m². As well, when comparing the maximum values of dry density of samples from the control site, neighboring the landfill, the average value decreased from 1.91 to 1.74 gm/cm³. Chemical tests revealed that the pH and organic matter percentages in the open dump soil samples were significantly higher than in the control site. These percentages ranged from 9.67% and 2.542% to 7.4% and 0.215%, respectively. In addition, the average value of electrical conductivity was 5.6 mS/cm in the open dump soil, whereas in the control site was 3.6 mS/cm. Iron, lead, Copper, Nickel, Chrome, Zinc, Cadmium, and Arsenic have average concentrations of 4.64%, 14.02, 44.86, 236.36, 278.36, 95.26, 2.034, and 13.84 ppm, respectively. They are higher at open landfill sites than in control site samples. [ABSTRACT FROM AUTHOR]

Bioremediation is a branch of biotechnology that employs the use of living organisms, like microalgae and fungi, in the removal of contaminants, pollutants, and toxins from soil, water, and other environments. The experiment was designed to evaluate the efficiency of microorganisms to remove heavy metals by using, two fungi (Aspegillus niger and Candida albicans) with two microalgae (Scenedesmus quadricauda and Tetradesmus nygaardi), in removing heavy metals from liquid media during study period (20 days). For this study, cadmium and lead were selected by different concentrations (5, 15, 35, and 50ppm) of such heavy metals. The results indicate that fungi and microalgae effectively removed a significant amount of heavy metals. With respect to Pb and Cd, the maximum removal of lead for all concentrations (5-50ppm) were, (94, 90, 86.28 and 81.6%) respectively, and maximum cadmium removal were (88, 86.66, 84.57 and 79%) recorded by consortium culture of Scenedesmus quadricauda and Tetradesmus nygaardi on day 20th of the experiment. Statistically there were significant difference (p≤0.05) between control and all treatments for both tested heavy metals. [ABSTRACT FROM AUTHOR]

The paper analyzes the problem of soil cover contamination of the urban ecosystem with heavy metals. The work is based on the authors own long-term monitoring studies. The main sources of soil contamination are identified - industrial enterprises and motor transport. The content of total and mobile forms of Cu, Ni, Pb, Cr, and Zn in the soils of the city territory was found out. The concentration factors (Cf) of heavy metals and their total contamination indexes (TCI) were determined. The highest Cf values for the total form of heavy metals belong to zinc (up to 25.1). At 61.1% of the study sites, the Cf values of zinc are above 9.0. At 83.3% of the sites, the Cf values for the total form of copper content are in the range of 6.0-22.1. The results of the studies indicate high average Cf values for lead and chromium at the majority of the sites. The highest maximum and average Cf values for the mobile form for all heavy metals were found at test-site No. 4. As a result of the studies, it was found that the average values of the total contamination indexes for the total form of heavy metals exceed the permissible level by 1.6-2.7 times. For the mobile form of heavy metals, the average values of the TCI are within the permissible limits, except for test-site No.4, where an excess of 3.7 times is recorded. It is found that the soils of the northern and southern parts of the city are the most contaminated, the least contaminated are soils of the eastern part of the city. [ABSTRACT FROM AUTHOR]

Geochemical study of twenty-seven marine sediments of the Levrier Bay used eleven heavy metals to display descriptive statistics and to assess the environmental impact of this industrial area. The analysis of eleven heavy metals (Pb, Zn, Cu, Ni, V, Cr, Co, Hg, Cd, As and Mo), major and other trace elements, were performed by ICP-MS. Pollution load Index (PLI) show low degree of contamination. Geochemical Index (Igeo) and enrichment Factor (EF) have been used to assess the environment quality at varied sites in sediments. Results display moderate concentrations for the most of elements excepted the As and Hg which often are upon the amount measured in the UCC baseline. The local presence Hg and As, limited to some sites of the area, allow to conclude that the sediments of the Lévrier Bay didn’t suffer from the human activities in the area. [ABSTRACT FROM AUTHOR]

Copyright of Marsh Bulletin is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Lucrari Stiintifice, Universitatea de Stiinte Agricole Si Medicina Veterinara Ion Ionescu de la Brad Iasi, Seria Horticultura is the property of University of Agricultural Sciences and Veterinary Medicine (Editura Ion Ionescu de la Brad) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Soil contamination with heavy metals has increasingly become a serious global environmental issue in recent years. Waste emissions from industrial production, mining activities, waste water irrigation and other activities have increased the number of agricultural soils contaminated with heavy metals in many parts of the world. Soil contamination by heavy metals threatens the quality of agricultural production and human health, so it is necessary to choose certain economic and effective remediation techniques to control the continuous deterioration of land quality. Removal of heavy metals from contaminated soil is expensive and time consuming, so stabilization of heavy metals in situ by adding soil amendments such as lime, compost and biochar is commonly employed to reduce the bioavailability of heavy metals and minimize plant uptake. Biochar can potentially be used to reduce the bioavailability and leachability of heavy metals in soil. It has a large surface area, high capacity to adsorb heavy metals and is typically an alkaline material which can increase soil pH and contributes to stabilization of heavy metals in soil. Application of biochar for remediation of contaminated soils may provide a new solution to the soil pollution problem. In the present review, an attempt is made to summarise the work done on effects of biochar in remediating the heavy metal contaminated soils. [ABSTRACT FROM AUTHOR]

The soil is a living and dynamic ecosystem permanently subject to anthropogenic pollution. Heavy metal pollution is a major factor of microbiota imbalances, and thus of severe soil degradation. The microbiota is represented by a wide range of microbial species that maintain and improve soil fertility by performing biogeochemical cycles in nature. Heavy metals are found naturally in the soil and play a key role in supporting microbial processes, but excess waste stored and neutralized improperly can be harmful, due to bioaccumulation along the trophic chain. Among the heavy metals commonly found in the soil are: lead (Pb), chromium (Cr), zinc (Zn), cadmium (Cd), copper (Cu), mercury (Hg), and nickel (Ni). The mobility of heavy metals in the environment, in general, and in the soil, in particular, is reduced, and therefore their contact with microorganisms is long and influences the structure of the microbial community. Existing studies emphasize the high bioaccumulation capacity of cadmium but also increased mobility affecting an entire trophic chain, and lead exerts an inhibitory effect on telluric microorganisms, even at very low concentrations. The overall activity of the soil, denitrifiers, and enzymes, is deeply affected by the presence of heavy metals. Their effect depends on the concentration and pH of the soil. Pedoclimatic factors can also contribute to these changes. Even in this situation, microorganisms can contribute to bioremediation and rendering the soil in the agricultural circuit. Among the bacterial genera that have developed mechanisms of resistance to certain heavy metals are Bacillus, Arthrobacter, Corynebacterium, Pseudomonas, Alcaligenes [ABSTRACT FROM AUTHOR]

In peri-urban areas of district Vehari, farmers are using untreated city wastewater for crop irrigation owing to the scarcity of good-quality irrigation water. This practice may pose severe environmental and health issues to local inhabitants attributed to the high levels of potentially toxic metals in wastewater. The present study evaluated the potential impacts of wastewater irrigation on metals (Cd, Cr, Cu, Fe, Ni, Mn, Pb and Zn) build-up in the soil–plant continuum and associated health risks. In this study, wastewater (n = 17), soil (n = 108) and plant (n = 65) samples were collected from 15 peri-urban sites of three tehsils of district Vehari. Results showed that the mean concentration (mg/L) of Cd (0.02), Mn (0.25) and Fe (1.57) in wastewater samples was higher than their respective threshold values. Similarly, Cd, Mn and Fe concentration in soil was beyond the permissible limits of agricultural soil receiving wastewater irrigation. However, plants showed high accumulation of Pb, Cr and Fe than their respective limits depending on the vegetable/crop species. The health risk parameters showed that Pb and Cd are the major toxic chemical substances to human health, and the daily intake of crop plants can pose a potential health threat due to wastewater-irrigated crop consumption. Results highlighted the necessity of wastewater pretreatment to avoid the soil and vegetable contamination by wastewater irrigation and to reduce the associated health risks. [ABSTRACT FROM AUTHOR]

Introduction. Urban runoff sediments contain heavy metals that generate risk to the environment. Several risk assessment indexes for heavy metals have been developed, which show the level of contamination of particles in the environment and their origin. Besides, sediment risk is also associated with the particle size distribution and hydrometeorological characteristics. Objective. This work seeks to evaluate the risk of contamination from runoff sediments collected in an experimental catchment, related to their size distribution and hydrological characteristics of the area of influence. Materials and methods. The field and laboratory experiments were carried out on the constructed-wetland/storage-tank structure from Pontificia Universidad Javeriana, Bogotá. The hydrological data were obtained from a nearby El Paraíso rain gauge station. The geoaccumulation (Igeo), pollution index (PI), and enrichment factor (EF) rates were calculated. Furthermore, Principal Component Analysis was used in order to determine the relationships between the risk, hydrological and granulometric variables. Results. There is a low/medium risk for Cu and Cr, in contrast to the high risk for Pb and Zn. According to multivariate statistical analysis, there is a relationship between risk indexes and average particle diameters (D50): these indexes increase for fine particles and periods of high rainfall intensity. Conclusions. The hydrological variables are important to determine the risks of urban runoff sediments. In this study, we found that the variable of dry weather is related to the values of geo-accumulation indexes and contamination. The findings of this work reinforce the possibility of developing early warning systems for sediment risks using key hydrological and sedimentological variables. [ABSTRACT FROM AUTHOR]

Environmental pollution by heavy metals is a contemporary world problem. Developing biotechnological strategies in remediation field has gained great attention in recent years for being more profitable, efficient and friendly to the environment. Heavy metal resistant bacteria are a powerful tool in bioremediation of metal contaminated environments. The aim of this study is to characterize heavy metal resistant bacteria, isolated from lateritic rubble, residual from Moa mining industry. Two bacteria (EL-1 and EL-2) were isolated from the lateritic rubble. The isolated ones were characterized and identified down to gender level. Resistance to nickel, cobalt, chromium and aluminum was evaluated in solid Tri minimal medium. The dose-response curve for nickel, cobalt, chromium and aluminum was determined, as well as the mechanism of bacterial resistance to nickel. In addition, antibiotic susceptibility was assessed. The two isolated were identified as Bacillus sp. The strains were resistant to all the evaluated metals, showing a high resistance to nickel (25 mmol-L-1). The Bacillus sp. EL-1 showed an induced mechanism of nickel resistance, while the Bacillus sp. EL-2 showed a constitutive resistance to this metal. The bacteria showed a predominance of sensitivity to the antibiotics evaluated. All these characteristics make them interesting to be applied in bioremediation strategies for environmental cleanup. [ABSTRACT FROM AUTHOR]

Recent research in Wadi Faynan, a copper mining and smelting region of southern Jordan, indicates that the issues of ancient pollution and contamination are far from straightforward. Whereas previous studies have stated that metal production led to widespread heavy metal contamination of the environment and of humans, this paper argues that lead contamination, a by-product of smelting local ore, is found only in microlocales and affected a small fraction of the local population. Geochemical analysis of agricultural soils revealed an increase of lead in isolated locations due to floodwaters that were contaminated by mining upstream. Distance from copper production areas was not a factor. Analysis of human remains also shows that lead contamination was restricted to a small number of individuals who were directly involved in the copper smelting. These findings suggest that the scale of environmental degradation was not proportional to the scale of economic exploitation. [ABSTRACT FROM AUTHOR]

We present high-level ab initio potential energy curves for barium cations and dications interacting with RG atoms (RG=rare gas). These potentials are employed to derive spectroscopic parameters for the Ba+–RG and Ba2+–RG complexes, and also to derive the transport coefficients for Ba+ and Ba2+ moving through a bath of the rare gas. The results are compared to the limited experimental data, which generally show reasonable agreement. We identify a large change in binding energy going from Ba+–He and Ba+–Ne to Ba+–Ar, which is not present in Ba2+–RG, and show that this is due to significant dispersion interactions in Ba+–RG. [ABSTRACT FROM AUTHOR]

The presence of heavy metals in the environment, resulting from industrial wastewater discharges, causes considerable damage to the natural balance of the aquatic ecosystem when they exceed certain concentrations. During this study, we were able to eliminate the content of Ni2+ ions contained in synthetic wastewater samples by the adsorption technique on a hull substrate taken from the beaches of Mehdia in Morocco. The present study indicates that the envisaged adsorption decreased the efficiency of the retention of Ni2+ ions from 91.03% (6.5 ppm) to 52.36 (250 ppm) and the adsorption capacity of 13.67%. mg / g for 200 ppm. The mass effect of the adsorbent was of the order of 84.8% for a value of 2 g, the temperature was of the order of 95% for 328±2 K. and a yield of 89.15% for a pH of between 6 and 7 and of the order of 93.5% for a contact time of 180 min. [ABSTRACT FROM AUTHOR]

Abstract Multiple heavy metals pollution in environment and food has become an ever-increasing concern and poses a serious threat towards humans and animals. To broad the multiple heavy metals detection, Fe 3 O 4 nanoparticles, Fe 3 O 4 /multi-walled carbon nanotubes (Fe 3 O 4 /MWCNTs) and Fe 3 O 4 /fluorinated multi-walled carbon nanotubes (Fe 3 O 4 /F-MWCNTs) nanocomposites were synthesized by hydrothermal method and constructed as a simultaneous electrochemical sensor, respectively. Compared the catalytic performances of the three electrochemical sensors for the simultaneous detection of Cd2+, Pb2+, Cu2+, and Hg2+, the results showed that the Fe 3 O 4 /F-MWCNTs sensor demonstrated preponderant performance. It showed the sensitivity of 108.79, 125.91, 160.85, and 312.65 μA mM−1 cm−2 toward Cd2+, Pb2+, Cu2+, and Hg2+, respectively, which was obviously higher than that of Fe 3 O 4 /MWCNTs and Fe 3 O 4. Additionally, the Fe 3 O 4 /F-MWCNTs sensor exhibited the wider linear detection ranges of 0.5–30.0, 0.5–30.0, 0.5–30.0, and 0.5–20.0 μM for Cd2+, Pb2+, Cu2+, and Hg2+, respectively. The limit of detections of the Fe 3 O 4 /F-MWCNTs sensor were 0.05, 0.08, 0.02, and 0.05 nM (signal to noise ratio of 3) for Cd2+, Pb2+, Cu2+, and Hg2+, respectively, fulfilling the governmental requests of the World Health Organization, China and Indian. The excellent agreement was recorded between the lowcost Fe 3 O 4 /F-MWCNTs sensor and typical methods (inductively coupled plasma mass spectrometry or atomic fluorescence spectrometry) in river water and soybean samples. Additionally, the sensor also exhibited excellent performances in selectivity, recovery, stability, and reproducibility. This proposal sensor provides a promising strategy to monitor multiple targets in the environment and food. Graphical abstract Image 1 Highlights • A lowcost Fe 3 O 4 /fluorinated multi-walled carbon nanotubes sensor was developed. • Simultaneous sensitive and selective determination of four heavy metal ions. • Fulfilled the governmental requests of the WHO, China and Indian. • Can be applied in multiple heavy metals monitoring in environment and food safety. [ABSTRACT FROM AUTHOR]

The fractionation of humic substances (HS) at the mineral and water interface can change the constituents and reactivity of HS, but there is still a lack of the understanding of the effects of HS fractionation on the binding characteristics of heavy metals to HS. In this study, the binding characteristics of five heavy metals (Cd, Cu, Ni, Pb, and Zn) to humic acid (HA) before and after adsorption by ferrihydrite were investigated by employing two-dimensional correlation spectroscopy (2D COS) integrated with synchronous fluorescence and Fourier transform infrared (FTIR) spectroscopies. 2D COS analyses of the fluorescence results indicated that the susceptibility of the fluorescence of humic-like fraction to heavy metals significantly decreased after the adsorption of HA by ferrihydrite, which may be due to the fact that humic-like components were preferentially adsorbed by ferrihydrite. However, the fractionation processes did not alter the metal binding sequence and affinity to different HA components. 2D COS analyses of the FTIR results suggested that fractionation processes decreased the susceptibility of COO− groups to heavy metals, and changed the metal binding sequence to polysaccharides C-O and aryl groups, with the exception of Pb. Furthermore, model calculations showed that the binding ability of heavy metals to both humic-like and fulvic-like fractions decreased after the adsorption of HA by ferrihydrite. The results of this study contribute to predicting heavy metal behavior in the environment. Image 1 • Mechanisms of heavy metal binding to HA components were investigated with 2D COS. • HA fractionation decreased the binding ability of heavy metals to HA components. • Fractionation decreased the susceptibility of COO− groups to heavy metal binding. • Fractionation changed the relative binding contribution and sequence of HA components. [ABSTRACT FROM AUTHOR]

High contents of azo dyes and heavy metals enter surface waters with the wastewater from dying and dye-manufacturing industries and pose serious threat to fish. In the present study, changes in the ultra-morphological features of the scale have been evaluated as indicators of the stress of lethal and sublethal concentrations of an azo dye Acid Black-1 (AB-1, CI 20470), zinc (Zn), and their mixture AB-1 + Zn to Labeo rohita. Fish were exposed for 96 h to lethal concentration (LC) causing 0–70% mortality, i.e., LC0, LC20, LC50, and LC70 of AB-1 (4, 6, 8, and 10 mg/L respectively) and Zn (25, 50, 55, and 60 mg/L respectively) and LC0, LC50, and LC70 of AB-1 + Zn (2 + 15, 2 + 20, and 2 + 25 mg/L respectively). Subchronic exposures of 150 days were given to 1/12, 1/6, and 1/3 of 96 h LC50 values of AB-1, Zn, and AB-1 + Zn. After each exposure, the fish were kept for a recovery period of 90 days. Breakage of circuli, erosion and breakage of lepidonts, uprooting of tubercles, and disappearance of intercircular teeth were observed in all the fish, after 96 h exposure to AB-1, Zn, and AB-1 + Zn. However, damage to focus and holes were common on the scales of Zn-exposed fish. The mixture AB-1 + Zn was more toxic than either of the two as loss of circuli, lepidonts, and intercircular teeth, and sloughing of surface were observed in the scales after 96 h exposure to 2 + 25 mg/L. Damage at this concentration was more than the damage at 8/10 mg/L AB-1 and 55/60 mg/L Zn. After 150 days of exposure, damage due to sublethal concentrations was more than the damage due to all the concentrations of 96 h exposure. Irregular and sloughed circuli were common at 2 + 1.79 and 2 + 3.59 mg/L AB-1 + Zn. Cracks all over the surface (2 + 7.18 mg/L), calcium projections (2 + 3.59 and 2 + 7.18 mg/L), and holes (2 + 7.18 mg/L) hint towards synergistic toxicity of the mixture. It seems that the present dye and metal formed complexes with collagen and osteoblastic cells of the scale that caused an increase in damage during the post-exposure period. Scales of 2 + 7.18 mg/L AB-1 + Zn exposed fish were completely devoid of the normal architectural pattern on the 90th day of the recovery period. Changes in the ultra-morphology of scales at LC0 (0% mortality) and sublethal concentrations show that these are early indicators of the stress of minute quantities of dyes and metals in water. This is a first report on the cumulative toxicity of the two most abundant components of textile industry effluents. [ABSTRACT FROM AUTHOR]

Heavy metal pollution, in particular with cadmium (Cd), threatens both the environment and human health. The phytoremediation of contaminated soil is one recently developed eco-friendly technique that can be applied to mitigate this issue. Repairing Cd-contaminated paddy soil during the fallow winter period can ensure future rice production while reducing heavy metal pollution. Seven winter crops were planted in this study to investigate the accumulation of this metal in mid-level Cd and low-level lead (Pb) and zinc (Zn)-contaminated paddy soils. Results show that after 4 or 5 months of growth, all crops had become moderately tolerant to toxicity; indeed, shoot Cd bioconcentration factor (BCF) values were 37.4, 17.0, 11.5, 10.5, 5.8, 3.9, and 1.4 for Sedum alfredii (SA), Witloof chicory (WC), edible-leaf beet (EB), Cardamine hupingshanensis (CH), leafy mustard (LM), oil mustard (OM), and perennial ryegrass (PR), respectively, while shoot Pb and Zn BCF values were less than 1 and 5, respectively. And SA, WC, EB, and CH all had higher shoot Cd accumulation capacities, especially SA in which the level reached 53.9 mg kg−1. The calculation results of restoration potential show that it will take at least 5 years for WC, 7 years for SA and EB, and 10 years for CH to reach the repair target. These results show that it is possible to grow winter crops to repair soil Cd pollution, with WC, EB, CH, and SA, the best candidates for making full use of fallow periods while simultaneously achieving soil phytoremediation. The results of this study will prove useful for establishing a new summer production model by ensuring the winter repair of contaminated paddy soil. [ABSTRACT FROM AUTHOR]

Electronic waste (e-waste) is used for all electronic/electrical devices which are no more used. Conventionally, waste management policies are desfig handle the traditional waste. Although e-waste contains toxic materials, however, its management is rarely focused by policy makers; therefore, its negative impact on the global environment, ecosystem, and human health is aggravated. The review outlines the categories of e-waste materials, major pollutants including ferrous/non-ferrous metals, plastics, glass, printed circuit boards, cement, ceramic, and rubber beside, some valuable metals (such as copper, silver, gold, platinum). Toxic elements from e-waste materials, released in the air, water, and soil, include arsenic, cadmium, chromium, mercury, and lead, causing pollution. Although their roles in biological systems are poorly identified, however, they possess significant toxic and carcinogenic potential. It is therefore critical to monitor footprint and device strategies to address e-waste-linked issues from manufacturing, exportation, to ultimate dumping, including technology transmissions for its recycling. This review traces a plausible link among e-waste condition at a worldwide dimension, as far as settlement procedures to keep it secure and carefully monitored when traded. Their fate in the three spheres of the earth, i.e., water, soil, and air, impacts human health. The strategies and regulation to handle e-waste generation at the global level have been discussed. [ABSTRACT FROM AUTHOR]

Endophyte-assisted phytoremediation is considered to be an effective approach for bioremediation of heavy metal–contaminated soil; however, few information is available on Trifolium repens L. and its endophytes to remediate heavy metal–polluted soils. In this study, heavy metal–resistant endophytes were isolated from T. repens growing in mining smelter and identified by BIOLOG system. The isolate was also evaluated for promoting plant growth in heavy metal–contaminated soils in pot experiments. A total of eight Cd2+-resistant endophytes were isolated and these isolates preferred to grow on l-aspartic acid and α-d-glucose. All the isolates had at least two plant growth–promoting properties including siderophore production, phosphate solubilization activity, indole acetic acid (IAA) production, and 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity. Strain RE02, identified as Pseudomonas putida by Biolog system, showed the highest Cd tolerance and could reduce Cd concentration from 20 to 1.84 mg L−1 in about 49 h in liquid medium, amounting to about 90.8%. Among the five endophytes which have positive effect on the growth of T. repens, RE02, whose IAA production ability was 7.06 mg L−1 and phosphate solubilization was 134.76 mg L−1, could improve T. repens root and shoot biomass by 25.9% and 37.7% in cadmium-contained soil, respectively. Our research may provide a new microbial-enhanced phytoremediation of heavy metal–polluted soils and improve the remediation efficiency. [ABSTRACT FROM AUTHOR]

Abstract Unique airborne observations made ≅330 km south of Mt. Everest during the Cloud-Aerosol Interaction Precipitation Enhancement EXperiment (CAIPEEX) 2014 are presented in this case study. These observations provide the vertical profile and elemental composition of aerosols from single particle analysis during the break period. An "aerosol dome" was also documented from the horizontal transect across the Varanasi city. The boundary layer was dominated by light scattering fine mode aerosols mainly a mixture of dust and pollution. The individual particle characterization revealed complex mixing states within the same aerosol aggregate. Externally mixed aerosols were present at the cloud bases. Elemental composition of aerosol particles collected from free atmosphere contained signatures of aged pollution with heavy metals, carbonaceous particles and radioactive elements. Cloud processed aerosols were also noted in the neighborhood of deep convective clouds. Shallow and deep cumulus clouds developing in the haze layer revealed distinct dropsize distributions. Shallow cumulus clouds embedded in the haze layer showed narrow droplet size distribution and were narrower than the ones observed for premonsoon conditions. Deep cumulus tops in the neighborhood of rapidly developing convection showed broad, bimodal droplet size distribution attributing to droplet evaporation and entrainment effects. Aerosol sampling near these cloud tops showed aggregates of particles that are internally mixed. Highlights • Single particle characterization of airborne aerosols from the Indo Gangetic Plains. • Characterization clouds formed in the haze layer. • Possible cloud processing affecting aerosol mixing state [ABSTRACT FROM AUTHOR]

The present paper reports the heavy metal uptake by water lettuce (Pistia stratiotes L.) from paper mill effluent (PME) with its prediction modeling studies. Lab scale phytoremediation experiments were performed in glass aquariums to grow P. stratiotes in 0% (bore well water as a control), 25%, 50%, 75%, and 100% concentrations of PME. The influence of pH and heavy metal concentration in PME for the effective uptake and accumulation of heavy metal contents (∆Y: mg/kg) in plant tissues was modeled using two-factor multiple linear regression. The results showed that the selected input variables were supportive to develop prediction models with higher linear regression (R2 > 0.72), high model efficiency (ME: 0.92–0.99), low mean average normalizing error (MANE < 0.02), and statistically significant F > Prob values. Kruskal-Wallis one-way post hoc test indicated that the contents of Cd, Cu, Fe, Pb, and Zn in the roots, leaves, and whole plant were affected by PME concentration while the contents of Mn did not. The correlation studies showed that the bioaccumulation of heavy metals was found both element and PME concentration specific. This work represents an effective method to model heavy metal uptake by P. stratiotes from PME. Furthermore, this methodology can also be adopted for predicting effective metal uptake by plant species being used for the phytoremediation of heavy metals from industrial effluents. [ABSTRACT FROM AUTHOR]

The aims of this study correspond to (i) determine the feasibility of synthesize geomaterial from two main Pb-contaminated mining sediments (Sed1 and Sed2) without prior activation in substitution to metakaolin (MK), (ii) understand the mechanisms involved toward two types of silicate solution (Na and K one), and (iii) to evaluate the change in the Pb metallic element speciation and leaching after alkali treatment. The raw material as well as consolidated material were characterized by X-ray diffraction, infrared spectroscopy, and electron microscopy. The mechanical properties were evaluated, and the leaching behavior realized according to EN12457-2. The results evidence the limit of mining sediment incorporation by substitution near 50% whatever the sediments and the alkaline solution used. There is no difference in the mechanical properties up to 10% substitution then decrease with the increase of sediment content. The Pb-bearing phases are dissolved during alkaline treatment and redistributed in the geomaterial matrix. Finally, the leaching experiments clearly evidenced the possibility to stabilize Pb into MK-based geomaterial matrix up to 25–30% weight of mine waste. [ABSTRACT FROM AUTHOR]

Abstract Apart from surface complexation, precipitation of minerals also plays an important role in reducing the mobility and transport of heavy metals in the environment. In this study, Cd(II) sorption species on surfaces of γ-Al 2 O 3 at pH 7.5 were characterized using multiple techniques. Results show that in addition to adsorption complexes, Cd hydroxide phases (Cd(OH) 2 precipitates and Cd x (OH) y polynuclear complexes) were formed at the initial stages of Cd(II) sorption and gradually transformed to CdCO 3 with time. In addition, Cd(II) formed Cd Al layered double hydroxide (LDH) on γ-Al 2 O 3 under various conditions, independent of temperature and Cd loadings. The formation of Cd hydroxide phases and Cd Al LDH could be ascribed to surface-induced precipitation because the bulk solution was undersaturated with respect to hydroxides. Cd Al LDH formation on the Al-bearing mineral here is rather surprising because typically this occurs with elements of ionic radii similar to that of Al3+; this formation is unknown for metals such as Cd(II) with a much larger ionic radius. The thermodynamic feasibility of Cd Al LDH formation was further confirmed by laboratory synthesis of Cd Al LDH and density function theory (DFT) calculations. These results suggest that Cd precipitation on Al-bearing minerals can be an important mechanism for Cd immobilization in the natural environment. Additionally, the finding of Cd Al LDH formation on Al-bearing minerals and the thermodynamic stability of Cd Al LDH provides new insights into the remediation of Cd-polluted soils and aquatic systems. Graphical abstract Unlabelled Image Highlights • Cd hydroxide phases were generated at the initial stages of Cd(II) sorption and gradually transformed to CdCO 3. • Cd(II) formed Cd-Al layered double hydroxide (LDH) on γ-Al 2 O 3 despite the much larger ionic radius of Cd(II) than Al(III). • Cd hydroxide phases and Cd-Al LDH were formed via surface-induced process. • The feasibility of Cd-Al LDH formation was verified by laboratory experiments and density function theory calculations. [ABSTRACT FROM AUTHOR]

Titanium dioxide (TiO 2) nanoparticles (NPs) encounter heavy metals in the environment under different scenarios. However, the mechanism of their joint toxicity effects on Daphnia magna remains vague. This study assessed the effects of hydrophobicity of TiO 2 NPs (TDONPs) and exposure scenarios on copper uptake and toxicity in Daphnia magna. In the individual exposure scenario, hydrophilic and hydrophobic TDONPs both showed no acute toxicity to Daphnia magna , whereas individual Cu2+ exposure resulted in a 30% mortality rate. Co-exposure and sequential exposure to the two types of TDONP and Cu2+ resulted in mortality rates of 40%–50%. The mechanisms of the increased Cu2+ toxicity caused by hydrophilic and hydrophobic TDONP were different. In the presence of hydrophobic TDONPs, the Cu toxicity could be attributed to the increased bioaccumulation of Cu and Ti, leading to high oxidative stress injury. The Cu toxicity due to hydrophilic TDONPs could be induced by intensified intestinal membrane damage. The obtained data suggest that the hydrophobicity of the TDONPs plays a critical role in regulating the toxicity of Cu2+. Image 1 • Pre-exposure to the TDONP can significantly reduce Cu bioaccumulation. • Larger hydrodynamic diameter and lower surface charge cause higher TDONPs uptake rate. • Increased Cu2+ toxicities due to hydrophilic and hydrophobic TDONPs were different. • Hydrophobic TDONPs and Cu co-exposure increased bioaccumulation and oxidative stress. • Hydrophilic TDONPs and Cu co-exposure increased intensified intestinal damage. [ABSTRACT FROM AUTHOR]

This review briefly elucidates the research undertaken and benefits of using aromatic plants for remediation of heavy metal polluted sites. A sustainable approach to mitigate heavy metal contamination of environment is need of the hour. Phytoremediation has emerged to be one of the most preferable choices for combating the metal pollution problem. Aromatic plants can be used for remediation of contaminated sites as they are non-food crops thus minimizing the risk of food chain contamination. Most promising aromatic plants for phytoremediation of heavy metal contaminated sites have been identified from families – Poaceae, Lamiaceae, Asteraceae, and Geraniaceae. They act as potential phytostabilisers, hyper accumulators, bio-monitors, and facultative metallophytes. Being high value economic crops, monetary benefits can be obtained by growing them in tainted areas instead of food crops. It has been observed that heavy metal stress enhances the essential oil percentage of certain aromatic crops. Research conducted on some major aromatic plants in this context has been highlighted in the present review which suggests that aromatic plants hold a great potential for phytoremediation. It has been reported that essential oil from aromatic crops is not contaminated by heavy metals significantly. Thus, aromatic plants are emerging as an ideal candidate for phytoremediation. Highlights • Aromatic plants hold a great potential for phytoremediation of heavy metal contaminated sites. • Being high value economic crops, monetary benefits can be obtained by growing them in contaminated areas instead of food crops. • Research done on some major aromatic plants in this context has been highlighted in the present review. [ABSTRACT FROM AUTHOR]

Abstract The problem of heavy metal pollution in farmland has elicited growing concern in the Poyang Lake region, which includes the largest freshwater lake in China and serves as the country's commodity grain base. Here we determined soil As, Cr, and Hg concentrations and characterized their spatiotemporal distributions in the Poyang Lake region using data from 85 and 208 sampling locations that were respectively obtained by the farmland environmental quality surveys conducted in 1983 and 2010. The results showed that the average concentrations of these metals significantly increased from 10.72, 63.25, and 0.10 mg kg−1 in 1983 to 12.14, 84.06, and 0.13 mg kg−1 in 2010, respectively. From 1983 to 2010, the average As and Cr concentrations were higher and the Hg concentration was lower than background values, all of which met China's Soil Environmental Quality Standard (GB 15618-2018). Over the same period, the nugget/sill ratio for soil As and Cr each decreased but it increased for Hg, while for all three metals their ranges of the nugget/sill ratio increased. Spatial variation in soil of As, Cr, and Hg was mainly controlled by geological environment in 1983, whereas it was affected by human activities in 2010. To support the twin goals of sustainable utilization of farmland soils and food security, we should pay more attention to farmland pollution (e.g., heavy metals)—healthy soils for a healthy life. Highlights • Average As, Cr, and Hg levels in farmland topsoils increased from 1983 to 2010. • Spatial variation of these metals was mainly controlled by geological environment in 1983. • Human activities chiefly affected the spatial variation of these metals in 2010. [ABSTRACT FROM AUTHOR]

Abstract The aim of study was to assess the effectiveness of organic and inorganic amendments to immobilize cadmium (Cd), lead (Pb) and zinc (Zn) in soil and reduce their availability in a contaminated soil. We present the results of a field experiment organised in the Copșa Mica area in which different types of amendments were applied: Na-bentonite, dolomite, natural zeolite and manure. The effectiveness of applied amendments was assessed using single extraction of metals from soil (using DTPA-CaCl 2 -TEA at pH 7.3 or NH 4 NO 3) and metal accumulation in plants. All treatments produced significant increases of soil pH, but the best results were observed after applications of dolomite and Na-bentonite. After two years from applications all amendments decreased the metal (Cd, Pb or Zn) availability compared to the control, but the magnitude of effects depends on each metal and amendment. The addition of dolomite and Na-bentonite reduced significantly the concentrations of Pb and Zn in plants, but this reduction is not enough to produce healthy food or fodder. The application of manure led to a significant increasing of biomass yield comparing with control, even if the extractability of metals in manure treated plots was moderate. The results demonstrate the high potential of Na-bentonite and dolomite to reduce the availability and possible toxicity of heavy metals in contaminated soils but more attention should be paid to the transitory liming effect and metal remobilizing over time. Highlights • Copsa Mica is one of the most polluted area from Romania. • Soil amendment addition increased pH and enhances the metal immobilization in soil. • Long-term monitoring of soils and crops quality is compulsory in contaminated area. [ABSTRACT FROM AUTHOR]

The waste generated from antibiotics as influents or effluents in important waters from the rivers over their increased usage is quickly leading to societal health problems. To avoid increased accumulation of these antibiotics and their waste matter, new methods and materials are required to solve the problems before escalation. This paper aimed at evaluating treated wastewater effluent quality of three wastewater treatment plants in South Africa's Vaal Triangle: Sebokeng, Rietspruit, and Leeuwkuil. The influents and effluents were collected and analysed for heavy metals, and eight antibiotic substances for human use (erythromycin, ampicillin, cimethoprim, tetracycline, ciprofloxacin, doxycycline, chloromphemol, and sulfamethoxazol). The physicochemical parameters were also measured and the results showed that Rietspruit influent (Riet IN) had the highest salinity, total dissolved solids (TDS), electrical conductivity (EC), and turbidity. Sebokeng was found to have the lowest values for all the measured parameters except for pH, which was lowest in Leeuwkuil influent (Lee IN). All the antibiotics were below the detection limit in all three wastewater treatment plants (WWTPs), except for sulfamethoxazole. The average concentration of sulfamethoxazole in the influents and effluents for the three investigated WWTPs ranged 39-47.8 ng L-1. The lowest concentrations of magnesium (8.60 mg L-1) and copper (0.054 mg L-1) were found in Rietspruit (Riet MID) and Lee EFF, respectively. Lee IN had the highest concentrations of Na (27.98 mg L-1), K (7.48 mg L-1), Mn (0.249 mg L-1), Cu (0.208 mg L-1), Fe (0.396 mg L-1), Ni (2.271 mg L-1), and Ca (28.60 mg L-1), while Riet IN had the highest Co concentration of 0.324 mg L-1. Sebo EFF and Sebo IN showed 11.82 mg L-1 of Mg and 2.437 mg L-1 of Zn, respectively. The abundance of the metal concentrations follows the order Ca > Na > Mg > K > Zn > Ni > Fe = Pt > Co = Au > Mn > Cu > Cr > As, indicating a higher concentration of Ca as 28.60 mg L-1, while As has the least value, which is 0.053 mg L-1. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The suppression threshold of Zn(II) on reactor performance was 10 mg L−1 for long-term exposure. • Castellaniella mainly was devoted to denitrification under no or low Zn(II) stress conditions. • Klebsiella was the dominant denitrifying bacteria under high Zn(II) stress conditions. Abstract High-rate denitrification is a popular and efficient process for treatment of nitrate-rich wastewater. Knowing the effect of heavy metals on denitrification is essential for industrial development. In the present study, the long-term impacts of Zn(II) on denitrifying granular sludge were investigated. The suppression threshold of Zn(II) on denitrifying bacteria was 10 mg L−1 for long-term exposure. The nitrogen removal rate was decreased by long-term addition of 10 mg L−1 Zn(II). Castellaniella and Klebsiella were the two dominant genera under Zn(II) stress. The relative abundance of Klebsiella sharply decreased to 4.64% after the addition of 10 mg L−1 Zn(II), whereas Castellaniella was susceptible to 2 mg L−1 Zn(II), revealing that Castellaniella mainly was devoted to denitrification under no or low Zn(II) stress conditions, whereas Klebsiella was effective under high Zn(II) stress. [ABSTRACT FROM AUTHOR]

Contamination of soil by heavy metals is among the important environmental problems due to their toxicity and negative impact to human health and the environment. An effective method for cleaning the soil from heavy metals is phytoremediation using the second-generation bioenergy species Miscanthus × giganteus. The purpose of this research is to study the benefits of M. × giganteus cultivation at the soils taken from the mining and former military sites contaminated by As, Pb, Zn, Co, Ni, Cr, Cu, V, Mn, Sr, and U as well as at the soil artificially contaminated by Zn and Pb, to evaluate the physiological parameters of the plant, to establish peculiarities of the phytoremediation process, and to characterize the behavior of the plant in relation to the nature and concentrations of the metals in the soils. Results showed that M. × giganteus was resistant to heavy metals (tolerance index ≥ 1) and that the greatest portion of metals accumulated in the root system. The morphological parameters of the plant while grown on different soils are influenced by soil type and the content of contaminants. The stress effect while growing M. × giganteus on soil artificially contaminated by Zn and Pb was evaluated by measuring the content of pigments (chlorophylls a, b, and carotenoids) in the plant's leaves. The decrease in the total content of chlorophylls, Сa + b/Сcar and transpiration rate of water along with the increase in the water absorbing capacity were observed. The accumulation of heavy metals in different parts of the plant was determined; bioaccumulation coefficient and values of translocation factor were calculated. The obtained results showed that M. × giganteus was an excluder plant for nine highly toxic elements (As, Pb, Zn, Co, Ni, Cr, Cu, V, U) and an accumulator species for the moderately dangerous elements (Mn, Sr). Further research will be focused on the extraction of stable stimulated plant-growth–promoting rhizobacteria from the rhizosphere of M. × giganteus and formulation on that base the plant-bacterial associations as well as on the comparison of the plant physiological parameters, biochemical soil activity, and accumulation of heavy metals in the Miscanthus tissues between first and second vegetations. [ABSTRACT FROM AUTHOR]

Abstract New scientific discoveries for new applications of materials (e.g., metals) lead to extensive industrial use of these materials, which in turn, has significant negative health and environmental impacts. Governments use legislation as a management tool to control the usage of certain materials to lower contamination. This study investigates the level of metal contamination over a period of 12 years to observe the dynamic changes in response to new legislation or industrial improvements. Metals (i.e., Pb, Zn, Co, Cu) associated with urban roadside dust in 21 sites in Riyadh, Saudi Arabia were analyzed during the period of 2001–2013. Three main conclusions were drawn from this study: 1) Phasing out leaded gasoline was an effective tool to control Pb contamination. The average Pb concentration in the city was 37 times higher in 2001 compared to that in 2013. Twenty-nine percent of the investigated sites were at a significant health risk in 2001 compared to none in 2013. 2) The new substitutes of Zn oxides and new limitations of the Zn content in the rubber industry were effective at controlling the Zn contamination in the urban environment. The average Zn concentration of the city was 8 times higher in 2001 compared to that in 2013. Eighty-one percent of the investigated sites in 2001 were considered to be very highly contaminated (CF > 6) compared to none in 2013. 3) The lack of legislation regarding the Co-content in fossil fuels was probably the main reason for the enhancement of the Co contamination in the whole city, with an increase in the average Co concentration >3 times in 2013 compared to that in 2001. Likewise, the health risk index was increased by ∼3 times from 2001 to 2013. For Cu, the average Cu concentration in 2001 was almost twice that in 2003 and 2013. Legislation has been observe to be an effective management tool for controlling metal contamination. Highlights • Phasing out leaded gasoline was an effective tool to control Pb contamination. • Reducing Zn content in the rubber industry justifies the dramatic drop of Zn in the city. • The average Pb concentration in the city was 37 times higher in 2001 compared to 2013. • The average Zn concentration of the city was 8 times higher in 2001 compared to 2013. [ABSTRACT FROM AUTHOR]

Growing requirements of freshwater and unsustainable nature energy sources as gas, fossil fuels, oil and electricity are leading the interest in using renewable energy for water treatment applications. The nature energy processes make carbon footprints, that causing depletion of ozone layer and health and environment hazards. The potential of using solar energy is less energy-intensive nature, high efficient, small footprint and effective in heat to heat conversion. The water distillation is an application processes that used for water purification from multiple kinds of contaminations such as fluoride, heavy metals, coliform, virus and bacteriaby a process of heating and cooling. Heavy metals are a great threat to the human health and environment. This study was carried out to use renewable energy in form of solar radiation to remove heavy metals from water by distillation process. This technique was employed on three contaminated water samples (ground water, drainage water and river water). Suspended and dissolved cadmium (Cd) and lead (Pd) concentrations were measured. The results show that the distillation process by solar radiation succeeded to achieve (76% - 100%) removal efficiency. Influences of initial metal ion concentration and contact time, on removal percentage were investigated. More exposure time to solar radiation were given more quantities of treated water. This study confirms solar distillation as an effective and sustainable option for water treatment. [ABSTRACT FROM AUTHOR]

Abstract The speciation, bioavailability and environmental risk of heavy metals (HMs) in the hydrochar derived from hydrothermal carbonization (HTC) of swine manure were investigated in this study. The results indicated that the majority of HMs originally in swine manure were retained in the hydrochar by HTC, and CaO addition substantially reduced the HMs concentration in the hydrochar. HTC especially CaO assisted HTC significantly promoted the HMs transformation from the bioavailable fraction to the relatively stable fraction, and thus decreased their environmental risk in the hydrochar. Moreover, the Toxicity Characteristic Leaching Procedure and diethylenetriamine pentaacetic acid test revealed that the leachability and plant-bioavailability of HMs in swine manure were greatly declined by HTC especially for HTC with 15% CaO addition. The present study suggested that HTC was an effective disposal approach for swine manure from the perspective of HMs immobilization, especially for CaO assisted HTC. Graphical abstract Image 1017 Highlights • The risk of HMs in the hydrochar from HTC of swine manure were studied. • The majority of HMs were retained in the hydrochar by HTC. • CaO assisted HTC decreased HMs concentration and immobilized HMs in the hydrochar. • HTC especially with CaO addition reduced the leachable and plant-available HMs. [ABSTRACT FROM AUTHOR]

Municipal solid waste incineration (MSWI) fly ash is internationally categorized into a hazardous waste due to its high content of heavy metals (HMs) and dioxins. A traditional electrochemical platform was intrinsically modified by changing stackings of samples in the electrolyzer to solve a near-anode concentration focusing (NA-CF) phenomenon during the electrokinetic remediation (EKR) and to improve electrokinetic performance to the HM removals from MSWI fly ashes. The effect of sample stacking in the electrolyzer on the removal performance of the electrokinetics was comprehensively investigated. Summarily, the stacking styles profoundly affected the electrochemical environment. The excavation of specimen near the anode chamber facilitated the diffusion of Hþ ions in the electrolyte and effectively avoided the generation of NA-CF phenomenon. The best removal efficiencies for all four HM elements were achieved through simultaneously moving the ash samples out near the two electrodes. The influence of voltage gradient (V=cm) on the HM removals was proved to be more significant than the remediation time. The voltage gradient of 1.5-2.0 V=cm and the remediation time of 18-21 days were determined as the optimal ranges for the remediation of MSWI fly ashes. The environmental toxicities of HMs were noticeably decreased using the adjusted EKR system. The average leaching toxicities of Zn, Pb, Cu, and Cd were reduced by approximately 60%, 83%, 58%, and 77%, respectively. The SD-EKR process significantly reduced the environmental activity of MSWI fly ashes. The excavation of samples from subregions of S2 and S5 at the third day of EKR process increased HM dissolution, decreased ion-migration resistances, and facilitated HM removals from fly ashes. [ABSTRACT FROM AUTHOR]

Abstract Terrigenous sediment in estuarine environments serves as a major sink for heavy metals sourced from land, and thus has been widely used for the investigation of anthropogenic pollution and environmental risk. This study presents the concentrations and chemical speciation of eight heavy metals (Zn, Cu, Ni, Pb, Cr, Hg, As, Cd) in 34 surface sediment samples collected from the Changjiang (Yangtze River) estuarine area, which aims to investigate the potential sources and environmental risks of heavy metals. The concentrations of these metals in inner estuary are overall higher than those in coastal and offshore areas, with the highest values occurring in the South Branch, South Channel, and North Hangzhou Bay. Although the Changjiang river input is the dominant source of these heavy metals, the local contamination and variations in sediment characters especially the grain size and particulate organic matter account for the heterogeneous compositions of these heavy metals in these estuarine sediments. The sequential extraction results suggest that most of these heavy metals, except Cd, are bound in the geochemically inert residual fractions, and primarily determined by the Changjiang input from natural weathering sources. The results of geoaccumulation index (Igeo) and enrichment factor (EF) suggest that these heavy metals do not show obvious enrichments and contamination in this region, while the higher bulk concentrations of Cd in the estuarine and offshore sediments are predominantly inherited from the Changjiang sediments, although the residual Cd in the crystal lattice of minerals reflects the average Cd content in the upper continental crust. The extra Cd adsorbed to the river sediments is strongly bound to exchangeable-, carbonate- and Fe-Mn oxides-associated phases, which may be chemically reactive during estuarine processes and thus has high environmental risks under enhancing human activities. Highlights • We report the contents of eight heavy metals in the surface sediments from the Changjiang (Yangtze River) estuarine area. • These heavy metals are mostly bound in the residual fractions and primarily derived from natural weathering sources. • These heavy metals do not show obvious enrichments and contamination in this region. • Higher concentrations of particulate Cd in the estuary are predominantly inherited from the Changjiang river sediments. [ABSTRACT FROM AUTHOR]

Our study focuses on the European perch (Perca fluviatilis) regarding differences in concentrations of the biogenic (P, S, Cl, K, Ca, Mn, Zn) and metallic (Sr, Sb, Rb, Pb, Mo, Cr, Fe) elements relative to perch morphology and environmental factors at the largest dam in Slovakia. The juvenile perch were sampled at four capture sites from June to October. The highest concentration of biogenic elements and metals was found in perch caught in the site disposed to wastewater effluent (WWE). The concentrations of biogenic elements in perch decrease with the size of the fish; at most the perch affected by WWE had the smallest size. The concentration of biogenic elements in perch increased with the date from June to October and with water temperature for all sites. Lead accumulated by the perch in all sites exceeded more than five times the maximum permissible limits provided by international institutions. [ABSTRACT FROM AUTHOR]

TThe contamination of soil and water with heavy metals is one of the major environmental problems in the world. Oil and gas exploration and production activities contaminate the environment with heavy metals. In this study, heavy metal concentration was assessed in drilling waste discharges of different oil and gas wells at Khyber Pakhtunkhwa (KP), Pakistan. Moreover, the concentration of heavy metals in the soil surrounding the drilling waste discharges was determined. The representative samples were collected from seven oil and gas drilling waste discharges and the surrounding soil. The collected samples were analyzed for selected heavy metals (Ba, Pb Cr, Cd, Zn, Mn, and Ni) by atomic absorption spectrometric standard methods. Analysis showed that oil and gas well drilling operation waste is enriched with determined heavy metals. The high concentration of heavy metals, particularly Ba and Pb, was also found in the surrounding soil samples. In particular, Ba concentration varied from 1050 to 4168 mg/kg soil. Statistical correlational analysis depicted a common origin of the heavy metals in the soil of the study area, potentially the drilling waste discharges from oil and gas wells. The concentration of heavy metals in oil and gas well drilling waste discharge high, and also affects surrounding soils. [ABSTRACT FROM AUTHOR]

Abstract Heavy metal pollution is a serious environmental problem. Up to date, research regarding distribution, accumulation and potential risk assessment of metals in aquatic organisms in Laizhou Bay, China is scarce. This study aims to investigate metals in aquatic organisms in this region. The results demonstrated that great variability of metals content occurred among species and sampling locations. Fe was the most abundant metal, followed by Zn, Mn, Cu, Ni, Cr, Cd and Pb. Overall, shellfish and crab displayed high enrichment ability compared with fish and shrimp. There was no significant correlation between metals and samples weight, δ13C and δ15N values. Principal component analysis (PCA) indicated that metals in samples were mainly derived from anthropogenic activities. Health risk of metals was evaluated on the basis of estimated daily intake (EDI) and target hazard quotient (THQ) values. The results indicated that metals in studied seafood had no significant risks for ordinary consumers. Graphical abstract Unlabelled Image Highlights • Shellfish and crab displayed higher enrichment ability than fish and shrimp. • No significant bio-dilution or bio-accumulation of metals happened in this region. • Metals in samples mainly derived from anthropogenic sources. • Organisms in this region cause non-significant health risk for ordinary consumer. [ABSTRACT FROM AUTHOR]

Abstract Sediment samples were collected from twelve selected sites of the Sangu River estuary and seven metals (As, Cr, Cu, Cd, Pb, Ni, Zn) were analyzed with Inductively Coupled Plasma-mass Spectrometry (ICP-MS) to assess the contamination degree of heavy metals in the Sangu River estuary and to represent it as a reference site. This study revealed the descending order of studied metals (mg/kg) observed in sediment as Zn (88.97 ± 58.97) > Ni (32.75 ± 16.09) > Cu (29.2 ± 10.78) > Cr (25.14 ± 5.20) > Pb (19.57 ± 7.01) > As (2.58 ± 2.55). Cadmium was observed below the detection level. Various indices like geo-accumulation index (I geo), contamination factor (CF), pollution load index (PLI) suggested that the Sangu River estuary is not contaminated by studied metals excepting Pb. PCA and correlation matrix analysis indicates that Pb and Zn may have anthropogenic sources and As, Ni, Zn, Cu, Cr may come from natural sources. Highlights • I geo , CF and PLI were used to profile contamination levels of heavy metals in sediments of the Sangu River estuary. • The estuary is not contaminated by studied metals excepting Pb. • PCA and correlation matrix indicates that Pb and Zn may have anthropogenic sources and the rest from natural sources. [ABSTRACT FROM AUTHOR]

Abstract This study provides new insight towards the effects of heavy metal contamination on sulfate-reducing bacteria (SRB) in mangrove ecosystem. We investigated SRB communities in mangrove sediments (0–30 cm depth) from Futian, Xixiang and Shajing mangrove wetlands in Shenzhen, China, with different heavy metal contamination levels. The results showed that SRB community abundance (1.71 × 107–3.04 × 108 dsrB gene copies g−1 wet weight sediment) was depth-related and significantly correlated with Cd and Ni concentrations. The α-diversity indices of SRB community (Chao1 = 21.25–84.50, Shannon = 2.31–2.96) were significantly correlated with Cd level in mangrove sediments. Desulfobacteraceae, Desulfobulbaceae and Syntrophobacteraceae acted as major SRB groups in mangrove sediments, and Syntrophobacteraceae was most sensitive to metal contamination. UniFrace clustering analysis revealed that SRB community structure was influenced by the heavy metal concentrations. Moreover, redundancy analysis indicated that Cd and total phosphorus were the major environmental factors affecting the SRB structure in mangrove sediments. Graphical abstract Unlabelled Image Highlights • Heavy metal pollution and sediment depth influence mangrove SRB communities. • Metal concentrations affected SRB abundance, diversity and community structure. • Syntrophobacteraceae was sensitive to heavy metal pollution. [ABSTRACT FROM AUTHOR]