Journal of Hazardous, Toxic, and Radioactive Waste

A method to remove oil and grease (O&G) from synthetically produced water using electrocoagulation in a batch process with a mild steel anode is proposed. Preliminary studies were conducted to explore the effects of operating parameters on chemical oxygen demand (COD) and O&G removal. Individual and interactive influences of causal variables were investigated using a response surface methodology. The experimental results indicated that electrocoagulation is very effective in pollutant removal and could successfully reduce COD and O&G to 99.7% and 96.43%, respectively, from an influent oil-in-water (O/W) emulsion concentration of $\mathrm{1,250}\pm 50\mathrm{mg}/\mathrm{L}$ under optimal operating conditions. A notable observation was made on the contribution of the electrooxidative mechanism in COD and O&G removal. It was found that removal due to the oxidative mechanism was increased with increases in current density and salt composition. The methodology is very suitable for the treatment of water produced from offshore basins in particular due to the higher rate of operation and smaller amount of sludge compared with conventional biological treatment and to the presence of supporting electrolyte in situ.

The performance of lateritic soil treated with Bacillus coagulans (B. Coagulans) was assessed for use as hydraulic barrier material in municipal solid waste (MSW) containment use. The soil was classified as A–4(2) and SC using AASHTO (American Association of State Highway and Transportation Officials) and the Unified Soil Classification System, respectively. Index, hydraulic conductivity, calcite content, and microanalysis tests were carried out. Soil specimens were treated with B. coagulans at one-third pore volume (i.e., the numerical difference between the initial degree of saturation before soaking in water and final degree of saturation after full saturation of the soil specimens in water) in stepped suspension densities of 0, $1.5\times {10}^8$, $6.0\times {10}^8$, $1.2\times {10}^9$, $1.8\times {10}^9$, and $2.4\times {10}^9\mathrm{cells}/\mathrm{mL}$, respectively. Cementation reagent was poured on the compacted soil in the mold and allowed to percolate until partial saturation was achieved. Compacted specimens after treatment were placed in water for 24–48 h and then permeated in three sets using water only, water and leachate, and leachate only for a total duration of 90 days. Compatibility test results showed reduction in long-term hydraulic conductivity values for the different permeation regimens considered. Absolute values recorded varied from $7.10\times {10}^{-10}$, $1.04\times {10}^{-9}$, and $7.50\times {10}^{-10}$ to $1.71\times {10}^{-9}\mathrm{m}/\mathrm{s}$, $1.69\times {10}^{-9}$, and $8.28\times {10}^{-10}\mathrm{m}/\mathrm{s}$ when permeated with water only, sequentially with water and leachate, and with leachate only, respectively, at 0 and $2.4\times {10}^9\mathrm{cells}/\mathrm{mL}$, respectively. Calcite content increased for specimens permeated with water only (i.e., from 4.00% to 4.80%) and decreased for specimens sequentially permeated with water and leachate (i.e., from 6.60% to 4.00%) and leachate only (i.e., from 4.80% to 4.00%). Results of chemical compatibility and microanalysis showed that the treated soil is compatible with MSW leachate with the exception of a few cases that did not meet the minimum permisible hydraulic conducutivity value of $1.00\times {10}^{-9}\mathrm{m}/\mathrm{s}$ used for landfill purposes.

The present study investigates the possibility of using ground bottom ash (GBA) as an alternative to cement to produce geopolymer concrete. The process of geopolymerization includes the reaction of a solid precursor and an alkali-activated solution made of diluted sodium silicate (${\mathrm{Na}}_2{\mathrm{SiO}}_3$) and sodium hydroxide (NaOH). Several studies have been reported in the past, which used fly ash as the solid precursor material for producing geopolymer paste and concrete. The main objective of this study was to produce geopolymer paste and conventional ordinary portland cement (OPC) mortar using GBA and demonstrate its effectiveness in comparison to fly ash (FA)-based geopolymer paste. The effect of an increase in the ratio of ${\mathrm{Na}}_2{\mathrm{SiO}}_3:\mathrm{NaOH}$ from $1.5:1$ to $3.0:1$ based on the strength of geopolymer paste was studied. The results showed that the GBA geopolymer paste cube was stronger than the ones made of ground fly ash (GFA) (obtained from the same source), even those of a finer particle size. The results also showed that with the increase in the ratio of ${\mathrm{Na}}_2{\mathrm{SiO}}_3:\mathrm{NaOH}$, the compressive strength of geopolymer paste increased. When different combinations of FA and GBA were used, the results showed that geopolymer paste with higher GBA content produced better results.

This study provides a practical and efficient alternative to neutralize the exorbitant pH of red mud ($>11.5$) followed by long-term sustenance of the neutralization. The usefulness of organic acids (oxalic acid and citric acid) as standalone additives and admixed with lime in mitigating red mud alkalinity was investigated. The efficiency of these acids in terms of posttreatment pH rebound for curing period up to 180 days was monitored. The neutralization treatment produced pH reduction with simultaneous accentuation of coagulation and precipitation of hydrates, which was determined from scanning electron microscope (SEM) analysis. The uniqueness of the study lies in proposing the rebound rate of pH (RRP) and rebound termination period ($t_{rt}$). The observed results offer distinctive insight into the factors affecting red mud chemistry including the role of lime as an additive. It is recommended to use 2.0 M oxalic acid or 2.5 M citric acid for neutralizing red mud. For improved microstructure, it is warranted to resort to a combination of 5% lime and 2.0 M oxalic acid.

In landfills, properties of the liner become affected due to the presence of harmful chemicals that, in turn, reduce its efficiency. In this study, two bentonites having different chemical and mineralogical compositions were tested in the presence of various concentrations of copper. The batch adsorption study, effect of pH (range 2–5), agitation speed (0, 50, 150, and 300 rpm), dose study (0.2–5 g), and kinetic study were conducted on both bentonites. The adsorption study showed that bentonite having higher cation exchange capacity and higher specific surface area showed a 10% higher adsorption capacity. The pH study indicated that a maximum adsorption at pH 5 was observed by both bentonites. Agitation speed also influenced the adsorption of ${\mathrm{Cu}}^{2+}$ on both bentonites. The study indicates that with the increase in bentonite dose, the removal percentage increased and the ${\mathrm{Cu}}^{2+}$ adsorbed per unit mass decreased. The kinetic study revealed that adsorption process was fast for the initial 120 min and reached equilibrium, and the parameters fitted in the kinetic model indicated that the pseudo-second-order kinetic model fit better. The kinetic study also showed that the removal of ${\mathrm{Cu}}^{2+}$ by bentonite with a higher specific surface area and cation exchange capacity (CEC) was higher.

In this research, two industrial by-products produced close to South African mining regions were used to treat acid mine drainage (AMD): steel slag and sugarcane bagasse, i.e., the shredded cane stalk residual after sugar extraction. Basic oxygen furnace (BOF) slag has a high alkalinity that makes it ideal for neutralizing acids. Sugarcane bagasse has a high surface area, and its slow decomposition makes it an ideal host media and long-term carbohydrate source for sulfate reducing bacteria (SRB). Accordingly, this research explored the viability of remediating AMD in a two-step continuous process combining both materials. A design was proposed and tested, in which a mixture of BOF slag eluate (generated from a treated water recycle loop) and raw AMD was used to initially buffer the AMD solution and precipitate heavy metals into a sedimentation tank. This avoided toxic shocking the SRBs in a subsequent sugarcane bagasse bioreactor. Overflow from the sedimentation tank was then passed through a packed bed containing sugarcane bagasse inoculated with SRBs as a polishing step to remove sulfate, precipitate metal sulfides, and elevate pH to near neutral pH conditions. The effluent from this vessel represents the treated water, and a fraction was recycled through a packed bed of BOF slag to create an alkaline eluate for the pretreatment of the raw AMD solution. The effect of AMD composition and slag particle size on the treatment was studied. The operation of the designed process at the laboratory scale, between 1 and $10.4\mathrm{L}/\mathrm{day}$, has confirmed the buffering of the AMD solution to a pH of between 7 and 8 and the removal of heavy metals and sulfate to levels below $10\mathrm{mg}/\mathrm{L}$ for Al, Fe, Mg, and Mn and $<200\mathrm{mg}/\mathrm{L}$ for sulfate. The amount of Ca increased in the system, which was attributed to the dissolution of slag. The SRB functioned well in the system with a maximum sulfate reduction of 35% (accounting for 2% of overall sulfate removal) occurring across the sugarcane bagasse bioreactor. Precipitation and sedimentation accounted for the bulk of sulfate removal with over 90% of sulfate being removed across the sedimentation tank. Residence times of between 44 and 4 days were achieved for different conditions—smaller particle sizes of slag exhibiting better performances in terms of recycle rate and residence times.

Aggregates manufactured from fine-grained thermal waste residues using accelerated carbonation technology (ACT) represent a potential sustainable alternative to natural aggregates. However, for these manufactured products to compete with virgin stone in geotechnical applications, their durability under mechanical and environmental loadings must be assessed. This paper describes the particle breakage that occurs for different grain sizes (entire sample, 5–2.5 mm and 2.5–1.25 mm) of a cement kiln dust accelerated carbonated manufactured aggregate after undergoing triaxial compression, triaxial shear, and freeze/thaw (f/t) testing. The particle breakage of the aggregate was dominated by the larger (5–2.5 mm) size fraction of the sample under all loading conditions. Particle breakage results from f/t testing indicated that the 5–2.5 mm size corresponded to similar or slightly less particle breakage than that under triaxial shear, whereas the particle breakage of the 2.5–1.25 mm aggregate after 20 cycles of freeze–thaw was relatively small. The performance of the carbonated aggregate in terms of relative breakage was similar or slightly better than the results for natural calcareous sand found in the literature.

The treatment of runoff waters from a lignite mine and a power plant generated a sludge heavily polluted with metals. Electromigration laboratory experiments were conducted to evaluate the feasibility of this technology for the removal of metals from the sludge. The experimental results proved that the mobilization of heavy metals could be achieved by the acidification of the sludge. The electro-oxidation of water in the anode can be used as a source of ${\mathrm{H}}^{+}$ to mobilize the metals transported toward the cathode. The suppression of ${\mathrm{OH}}^{-}$ generation at the cathode by the controlled addition of nitric or sulfuric acid increased the electric conductivity of the sludge specimen and the electric current intensity. The increase in the current intensity in the electrokinetic cell resulted in more ${\mathrm{H}}^{+}$ ions electrogenerated at the anode, favoring mobilization of the metals by the direct attack of the ${\mathrm{H}}^{+}$ ions. The electrokinetic tests proved that acid pH in the cathode resulted in higher electric current intensity and faster metal mobilization and removal, but the energy consumption sharply increased. A trade-off occurred among metal removal, energy consumption, and the pH in the catholyte. The best results were achieved by using sulfuric acid to control the pH in the catholyte at 4. The average metal removal was: Fe 27%, Ca 68%, Mg 24%, Na 25%, Mn 68%, Sr 33%, Zn 60%, and Cu 60%. Other elements such as Al, K, Ti, and Zr associated with the crystalline structure of minerals were not affected by the electrokinetic treatment.

The present research work applies ordinary kriging using an R programming script to map the free surface of an unconfined alluvial aquifer, calculating, at the same time, the standard deviation of the estimations. Moreover, indicator kriging is also applied to calculate the probability of the aquifer level to lie below a certain limit that could cause a significant impact on groundwater resources availability. Kriging efficiency depends on the estimation of the optimal spatial dependence of the measurements. Therefore, classical variogram functions and the Matérn model are applied to determine the spatial correlation of the measurements. The power-law variogram application provided the most accurate results. Maps associated with the hydraulic head spatial variability and prediction uncertainty, as well as a probability map were produced. The source R script is available with this work for public use. The concept, tools, and results of this work can be a useful framework for stakeholders and local authorities to design and decide optimal water resources management and governance.

The present study reported on the utilization of pulse processing waste [Bengal gram peel powder (BGPP)] for the removal of lead ions (${\mathrm{Pb}}^{2+}$) and methylene blue (MB) from aqueous solution in single and binary systems. The characterization of BGPP before and after adsorption was done by various advanced techniques. Results depicted that, whereas the maximum removal of ${\mathrm{Pb}}^{2+}$ occurred within 60 min ($\sim 99\%$ removal), MB took 12 h to attain equilibrium ($\sim 95\%$ removal) with the optimum dose of $2.0\mathrm{g}/\mathrm{L}$ in a single system. It is interesting to note that, at the same dose of $2.0\mathrm{g}/\mathrm{L}$, the equilibrium time was increased to 12 and 20 h for ${\mathrm{Pb}}^{2+}$ and MB, respectively, when ${\mathrm{Pb}}^{2+}$ and MB are present in a mixture (binary system). The optimum pH for ${\mathrm{Pb}}^{2+}$ and MB was 4.5 and 7.0, respectively. The equilibrium data fit well with the Freundlich model. Maximum adsorption capacity obtained was $55.58\mathrm{mg}/\mathrm{g}$ for ${\mathrm{Pb}}^{2+}$ and $24.70\mathrm{mg}/\mathrm{g}$ for MB. Kinetic data complied with a pseudo-second-order model. The results suggest that Bengal gram waste can be utilized as an ecologically friendly adsorbent and it can be used as an economical way for the removal of ${\mathrm{Pb}}^{2+}$ and MB in single as well as in binary systems.

Radioactive effluent is generated through a nuclear fuel cycle involving the use of radioactive materials in nuclear power plants. The concentration of the nuclear effluent is of concern if it is discharged into a natural water body and potentially used for human consumption. The present study involves numerical simulation of hydrodynamic parameters for prediction of near-field concentrations of tritium at various sampling points in a natural lake system in India. The modeling software with volume of fluid (VOF) two-phase model, for tracking the fraction of each fluid element, and $k\text{-}\epsilon$ model, as turbulence closure, is used to analyze the dispersion of tritium in the lake domain. The simulated results are validated using data on velocity and tritium (${}^3\mathrm{H}$) concentrations measured at sampling locations in the lake system. The simulated hydrodynamic parameters are reported to be in agreement with their measured values at sampling locations, particularly with a wind effect on the lake surface. The simulated values of hydrodynamic parameters as well as tritium concentrations are found to be within $\pm 10\%$ of their respective measured values in the lake domain. The safe disposal practices of tritium within the lake system are indicated because simulated effluent concentrations are well within the permissible limits of international standards. The numerical model would be useful for real-time operation and management of the chosen lake system in future while simulating the concentration of tritium at different sampling locations, monitoring their concentrations within permissible limits, and ensuring passage of safe water further downstream in the canal system for municipal, industrial, and irrigation usages.

The phenomenon of the abandonment of terraced landscapes compromises environmental well-being and is a preamble to hydrological instability and, consequently, the collapse of terrace retaining walls, soil erosion, and loss of agricultural lands. These problems will escalate in the coming years because of climate change (CC), especially in areas in which a rise in rainfall events is expected, such as the coastline of the Campania region, which is exposed to extreme rainfall events. This study identifies a landscape management guideline for Crapolla Fiord on the Amalfi coast (Campania region), a typical cultural landscape characterized by the presence of archaeological ruins. Potential hazards were evaluated and quantified, taking into account the flow rate and the rain intensity both at the mountainside and microbasin scale. This study shows that potential hazards have increased because of the loss of terraces and may further increase due to the abandonment of agriculture. This paper points out that supporting measures are necessary in areas in which agricultural land use is still present and that the introduction of small interventions designed to raise the infiltration capacity of the soil and/or to regenerate vegetation in areas in which terraces have been lost is a best practice.

This study was conducted at the Singrauli coal mine environment in Singrauli coalfield, India. The activity concentrations of thorium (${}^{232}\mathrm{Th}$), uranium (${}^{238}\mathrm{U}$), and potassium (${}^{40}\mathrm{K}$) in rock samples were analyzed by gamma spectrometry using a $p$-type high-purity germanium (HPGe) detector with a carbon fiber window. From terrestrial radionuclide activity concentration, the ambient radiation gamma dose rate was calculated using UNSCEAR 2000 coefficients. The average activity concentrations ${}^{232}\mathrm{Th}$, ${}^{238}\mathrm{U}$, and ${}^{40}\mathrm{K}$ were $77.6\pm 38.2$, $122.6\pm 46.1$, and $843.5\pm 26.0\mathrm{Bq}·{\mathrm{kg}}^{-1}$, respectively. The average activity ratio of ${}^{232}\mathrm{Th}/{}^{238}\mathrm{U}$ in various types of rocks was $1.8\pm 0.5\mathrm{Bq}·{\mathrm{kg}}^{-1}$. The radium equivalent activity (Raeq) for various types of rock samples varied from $\mathrm{132.8.1}\pm 2.8$ to $382.9\pm 6.2\mathrm{Bq}·{\mathrm{kg}}^{-1}$, with an average value of $317.7\pm 6.53\mathrm{Bq}·{\mathrm{kg}}^{-1}$. The absorbed average gamma dose rate was $145\pm 44\mathrm{nGy}·{\mathrm{h}}^{-1}$. The annual average effective equivalent dose was $0.29\pm 0.09\mathrm{mSv}·{\mathrm{y}}^{-1}$.

Increase in the application of clayey soils in geoenvironmental engineering practice escalated the interest in understanding the compressibility behavior at higher consolidation pressures. Laboratory evaluation of the compressibility data in the higher consolidation pressure range is laborious, time consuming, and expensive. Therefore, theoretical predictions are required to determine the compressibility behavior at high consolidation pressures. Such models for predicting the compressibility curves at high consolidation pressures are limited and applicable either for only low quality clayey soils or very high plasticity bentonites. A general theoretical model, $e_i/e_{P_N}={(P_N/P_i)}^a$ (where, $e_i$ is the void ratio at any given consolidation pressure, $P_i$; $e_{P_N}$ is the void ratio at normalization pressure $P_N$; and $a$ is the intrinsic parameter), for the prediction of compressibility behavior over a wide range of consolidation pressures for clayey soils of different plasticity was proposed in this study. The proposed model was validated over 114 compressibility datasets from 88 clayey soils and bentonites with different inundation fluids and initial states that were obtained from the literature and from the present study. The intrinsic parameter was estimated from the measured void ratio data at low consolidation pressures. The estimated parameter was used to obtain the compressibility data to a very high consolidation pressures ranging between 0.4 and 42 MPa for different clayey soils. The intrinsic parameter in the proposed model varied from 0.714 for lithium bentonite to 0.1 for red soil and was proportional to the plasticity of the clayey soil. The general predictive equation is applicable to all the clayey soils with different plasticity and is suitable for estimating the compressibility data over a wide range of consolidation pressures adequately.

Model footing tests were conducted of a circular footing resting on a randomly distributed fiber-reinforced pond ash (RDFP) layer overlying soft clay. The effect of varying the thickness of the pond ash layer over soft clay was studied. The reinforcement effect also was investigated by adding polypropylene fibers of different lengths with varying content percentages into the pond ash layer overlying soft clay. The results indicated that there is significant improvement in the ultimate bearing capacity with an increase in fiber length, fiber percentage, and RDFP layer thickness. The results also indicated that there is significant improvement of 80% in ultimate bearing pressure when soft clay at the top is replaced by a compacted pond ash layer of $1.5D$ thickness. The ultimate bearing pressure increased 54% with an increase in fiber length from 6 to 18 mm for a $1.5D$ thickness of the RDFP layer at 1% fiber content. The results of the model footing tests were validated with finite-element software PLAXIS 3D. The scale effect also was studied with the help of software by considering footings with diameters of 1, 2, 3, and 4 m.

Iron ore tailings (IOT) are the by-products of iron ore beneficiation, and these tailings are disposed of in several tons annually in quarries, landfills, and tailings dams, causing environmental issues. Various researchers have attempted to study the properties of IOT and the use of them in concrete as a building material. The present research aims to investigate the potential use of alccofine, a microfine particle of slag, as a cement replacement and IOT as fine aggregates in concrete. Experimental results indicated that the concrete workability decreased with an increase in the IOT-alccofine content and the maximum compressive strength (CS) obtained was 70.00, 68.67, and 65 MPa respectively at 40%, 30%, and 20% IOT-alccofine dosage for varying water-to-cement ($\mathrm{w}/\mathrm{c}$) ratios of 0.35, 0.40, and 0.45 respectively. Similarly, the flexural strength (FS) and splitting tensile strength (STS) increased with an increase in IOT-alccofine content. A statistically fitted multiple regression analysis was performed for all the mechanical properties to evaluate the significant level of concrete containing alccofine and IOT in concrete. These prediction models have high accuracy and low bias and the validation process represented that the equations can perform excellently in predicting the IOT-alccofine concrete properties.

Dairy wastewater (DWW) is nutritionally rich and extremely hazardous to the environment if discharged untreated. The conventional treatment is time-, labor-, and energy-intensive. A tailor-made microbial consortium converted DWW into a biofertilizer with the ability to enhance biomass and yield in mung bean (Vigna radiata var. MEHA). The consortium produced ammonia from DWW at a rate of $1.65\times {10}^{-6}\mathrm{mol}{\mathrm{s}}^{-1}100{\mathrm{mL}}^{-1}$ within 16 h of incubation in a biofilm bioreactor at 37°C with highest production of $10.11\mathrm{mg}100{\mathrm{mL}}^{-1}$ demonstrating 41.83% nitrate and 45.83% phosphate removal. The scalability was tested at ambient temperature in a 72-L bioreactor with an ammonia production rate of $3\times {10}^{-8}\mathrm{mol}{\mathrm{s}}^{-1}100{\mathrm{mL}}^{-1}$. Irrigation using the treated effluent resulted in a 1.7-fold increase in biomass, 49-fold decrease in root nodulation, and 2.6-fold increase in seed yield in mung bean while providing protection from aphid (Aphis craccivora Koch) infestation. The total wastewater was converted into biofertilizer for use as a substitute for chemical fertilizer and fresh water for irrigation. This approach makes DWW management not only a zero-discharge process but also a self-sustainable one.

This study describes a laboratory-scale continuous-flow bipolar mode electrocoagulation (CBME) unit that was developed as a downstream process unit for polishing an anaerobically treated palm oil mill effluent (POME). The design of the CBME reactor has the advantage of achieving good treatment efficiency with lesser energy consumption when compared to monopolar electrocoagulation systems. The process optimization was carried out for maximum removal of total organic carbon (TOC) and total phosphorus (TP) using response surface methodology (RSM). The independent process variables selected are initial pH, retention time (RT), reaction area (RA), and current density (CD). The optimum condition was achieved when pH was set at 6.4, retention time at 7.7 min, reaction (electrode) area at 765 cm², and current density at $77.8\mathrm{A}/{\mathrm{m}}^2$. Under this condition, 77% and 73% of TOC and TP removals were observed, respectively. The ratio of the total surface area of electrodes to the volume of the reactor was found to be $76.5{\mathrm{m}}^{-1}$ at the optimum operating condition. The energy consumption at the optimum point was $22.4\mathrm{kW}·\mathrm{h}/{\mathrm{m}}^3$ of wastewater treated. Micropollutants were screened for the organic constituents present before and after the treatment using high-resolution mass spectroscopy (HRMS).

The groundwater of the the Bemetara district of Chhattisgarh in central India over a large area is hard in nature due to its high mineral content. An elevated concentration of ${\mathrm{Na}}^{+}$, ${\mathrm{Mg}}^{2+}$, ${\mathrm{Ca}}^{2+}$, and ${\mathrm{SO}}_4^{2-}$ in the groundwater has been observed, falling within the ranges ($n=16$) 30–437, 43–341, 169–660, and $254–\mathrm{2,330}\mathrm{mg}{\mathrm{L}}^{-1}$ with a mean value of $107\pm 93$, $117\pm 69$, $387\pm 171$, and $\mathrm{1,059}\pm 595\mathrm{mg}{\mathrm{L}}^{-1}$, respectively. The temporal and spatial variations in the groundwater concentration of species, i.e., ${\mathrm{SO}}_4^{2-}$, ${\mathrm{Cl}}^{-}$, ${\mathrm{NO}}_3^{-}$, ${\mathrm{Na}}^{+}$, ${\mathrm{K}}^{+}$, ${\mathrm{Mg}}^{2+}$, ${\mathrm{Ca}}^{2+}$, Al, and Fe, during the period 2010–2016 are described. The sources of the contaminants and quality of the groundwater are discussed. The environmental hazards of the contaminated water, i.e., land degradation, rusting of buildings and pipes, physiological drought, and ill health of aquatics, birds, and animals, in the Bemetara area are discussed.

Rajnandgaon district (Chhattisgarh, India) faces serious arsenic pollution problems. Tree bark could be a valuable indicator of As and heavy metals air contamination. In this study, road dust was sampled in 13 locations, finding As, Cr, Mn, Cu, Zn, and Pb concentrations in the 165–329 , 107–151 , 704–998 , 43–84, 61–117 , and $26–62\mathrm{mg}·{\mathrm{kg}}^{-1}$ range, respectively. The sensitivity of bark from 32 tree species—widespread in the area of study—was assessed with a view to their utilization as bioindicators, and correlations between contaminant contents in the road dust and in the tree barks were calculated. The high accumulation of pollutants and strong correlations attained suggest that M. indica, P. sylvestris, E. globulus, D. sissoo, A. marmelos, and F. benghalensis may be promising choices for As, Cr, Cu, Mn, Zn, and Pb air quality monitoring, respectively.

Macrophytes (aquatic plants or hydrophytes) are sources of food and oxygen for aquatics (e.g., fish, invertebrates) and act as bioindicators for the assessment of environmental conditions in water reservoirs. This articles describes the bioaccumulation pattern of different elements (P, S, Cl, K, Rb, Mg, Ca, Sr, Ba, Ti, Cr, Mn, Fe, Co, Zn, Mo, As, Se, and Pb) and polyphenols in seven plants (Azolla pinnata, Pistia stratiotes, Salvinia molesta, Nelumbo nucifera, Trapa natans, Persicaria punctate, and Persicaria maculosa) grown in the Kharun River (India). Total accumulated concentrations of the aforementioned elements of 55,140, 63,894, 55,706, 67,320, 32,071, 30,282, and $\mathrm{48,077}\mathrm{mg}{\mathrm{kg}}^{-1}$ (dw) were found for the biomass of the aforementioned plants, respectively. Certain elements, Mg, Ca, and Fe, were predominated in bioaccumulation. The concentrations of total polyphenols were 2,870, 12,970, 4,500, 10,720, 3,800, 20,800, and $\mathrm{18,950}\mathrm{mg}{\mathrm{kg}}^{-1}$ of dried weight (dw) for the previously mentioned plants, respectively. The distribution ratio of the elements in macrophytes to water is discussed, and a canonical correlation analysis is used to assess the relationship of water contaminants with macrophytes.

Natural contamination of arsenic (As) and heavy metals (HMs) poses a health threat in many regions. Ambagarh Tehsil, Rajnandgaon, Central India, is a heavily polluted area due to mineralization of geogenic As and HMs in the environment, i.e., water, plants, and soil. In this work, contamination extents and sources of As and HMs (Cr, Mn, Cu, Zn, and Pb) in water, soil, and common plants were investigated to understand the main entry route of these toxic elements in human and domestic animals. The mean concentrations of total As in surface water, groundwater, surface soil, plant leaves, and animal stool samples of $0.031\pm 0.009{\mathrm{mg}\mathrm{mL}}^{-1}$, $0.360\pm 0.114{\mathrm{mg}\mathrm{mL}}^{-1}$, $192\pm 65\mathrm{mg}{\mathrm{kg}}^{-1}$, $5.61\pm 4.78\mathrm{mg}{\mathrm{kg}}^{-1}$, and $51.0\pm 7.6\mathrm{mg}{\mathrm{kg}}^{-1}$, respectively, were found. The speciation, sources, enrichment, and toxicities of the As and other HMs are discussed, together with some associated health hazards, exemplified in domestic animals exposed to the contaminated water and food.