The mobilization of hazardous elements after a tropical storm event in a polluted estuary

Life cycle assessment of coal mines of diverse scales over time in China

Coal mining has important detrimental effects on the environment and human health. By the end of 2022, China mined more than 4 billion tons of raw coal, and coal mining contributed to adverse environmental impacts. The objective of this work is to evaluate the environmental impacts emanated from coal mines in different periods (construction period, production period and closing period) and to find the relationship between coal mine scale and ecological impacts. This study uses coal mines that produce 0.45 Mt/a (considered a medium sized mine), 3 Mt/a and 8 Mt/a (both classified as large mines in this study) and a 12 Mt/a extra-large coal mine. Based on the time dimension, the mine life cycle was classified into construction, production and closing period, and the life cycle assessment method was used to conduct environmental assessment. The main influencing substances and key processes were tracked. The results indicated that mining engineering and gangue are the main factors affecting the construction and production periods of coal mines. Freshwater ecotoxicity, marine ecotoxicity, and human toxicity are the main environmental effects of coal produce, and they are mostly brought up by the release of hazardous elements like copper, chromium, zinc, nickel, and copper. Furan, formaldehyde, and chromium emissions during mine closure can be effectively reduced through environmental compensation, however coal mines' environmental compensation during mine closure is minimal. The environmental impact of coal mines producing 3 Mt and 8 Mt annually is minimal. The environmental impact of 0.45 Mt/a and 3 Mt/a coal mines is more prominent in the construction period. The pollutant discharge throughout the production phase, particularly the metal leaching discharge from gangue, needs to receive more attention from the 8 Mt/a and 12 Mt/a coal mines. Additionally, the larger the scale of coal mine production, the greater the proportion of the total environmental impact in the production stage.

Evidence of transboundary movement of chemicals from Mexico to the U.S. in Tijuana River Estuary sediments

The Tijuana River Estuary (TRE) has been a public health hazard and point of contention between the United States and Mexico for decades, with sources of pollution on both sides of the border. The goal of our study is to determine the presence and dynamics of chemical contamination in the TRE. We sampled sediment from four TRE locations in the U.S. during stable dry conditions and immediately after a wet weather period. Organic chemicals were initially screened with non-targeted analysis using gas chromatography high-resolution mass spectrometry (GC/HRMS) that tentatively identified 6978 chemicals in the NIST 20 database. These tentative identifications were filtered using the USEPA CompTox database to guide quantitative targeted analysis at detection limits below 1 ng/g dry weight sediment. Quantitative targeted analysis of 152 organic pollutants and 18 inorganic elements via GC/HRMS revealed generally higher concentrations of contaminants in dry weather sediments compared to wet weather sediments. The highest concentrations of all chemical classes were detected at the site closest to the U.S.-Mexico border, followed by an urban area near Imperial Beach, California, U.S. All sites exhibited a mixture of petrogenic and pyrogenic polycyclic aromatic hydrocarbons (PAHs). Current-use pesticides were dominated by pyrethroid insecticides and the thiocarbamate herbicide s-Ethyl dipropylthiocarbamate (EPTC), while the U.S.-banned organochlorine pesticides were dominated by chlordanes, dieldrin, and dichlorodiphenyltrichloroethane (DDT) and its degradation byproducts. Polychlorinated biphenyl (PCB) concentrations were greatest at the site closest to the U.S.-Mexico border but in the low nanogram-per-gram range. Phthalates were only found at the same site, with relatively high concentrations of bis(2-ethylhexyl) phthalate. This study provides positive identification and quantitative concentrations for organic pollutants in TRE sediments. Our data suggest that there are multiple sources of chemical contamination in the estuary, including possible transboundary movement of pollutants from Mexico.

Environmental impacts of Indian coal thermal power plants and associated human health risk to the nearby residential communities: A potential review

Worldwide, harmful emissions from coal power plants cause many illnesses contribute to premature deaths burden. Despite its high impact on human health and being a major source of toxic pollutants, coal has been considered a component of global energy for decades. Hence, this work was envisaged to understand the rising environmental and multiple health issues from coal power plants. Studies on the adverse impacts of coal power plants on the environment, including soil, surface water, groundwater and air, were critically evaluated. The health risk from exposure to different pollutants and toxic metals released from the power plant was also demonstrated. The study also highlighted the government initiatives and policies regarding coal power operation and generation. Lastly, the study focused on guiding coal power plant owners and policymakers in identifying the essential cues for the risk assessment and management. The current study found an association between environmental and human health risks due to power generation, which needs intervention from the scientific and medical fields to jointly address public concerns. It is also suggested that future research should concentrate on exposure assessment techniques by integrating source-identification and geographic information systems to assess the health effects of different contaminants from power plants and to mitigate their adverse impact.

Hazardous enrichment of toxic elements in soils and olives in the urban zone of Lavrio, Greece, a legacy, millennia-old silver/lead mining area and related health risk assessment

Lavrio is a Greek town with several abandoned Ag/Pb mines. In this study, 19 potentially toxic elements (PTEs) were measured in soil, weeds, and olives. Levels of seven of the studied PTEs in soil were highly elevated: Zn (56.2-58,726 mg kg^-1), Pb (36.2-31,332), As (7.3-10,886), Cu (8.3-1273), Sb (0.99-297.8), Cd (0.17-287.7), and Ag (0.09-38.7). Synchrotron-based X-ray absorption near edge structure analysis of the soils revealed that As was predominantly associated with scorodite, Pb with humic substances, Zn with illite, Zn(OH)₂ and humic substances, and Fe with goethite-like minerals. The transfer of the PTEs to weeds was relatively low, with the transfer coefficient being less than 1.0 for all PTEs. Cadmium in table olives surpassed 0.05 mg kg^-1 fresh weight (the limit in EU), while Pb surpassed its limit in approximately half of the samples. Health risk assessment confirmed soil contamination in the study area where As and Pb hazard quotients were well above 1.0 and the average hazard index equaled 11.40. Additionally, the cancer risk values exceeding the 1 × 10^-4 threshold. The results obtained in the study indicate that Lavrio urgently requires an adequate ecofriendly remediation plan, including revegetation with tolerant species and targeted efforts to chemically stabilize harmful PTEs. The presented approach may serve as a pivotal study for industrial areas with similar contamination levels.

Atomic sheets of silver ferrite with universal microwave catalytic behavior

Prompt degradation of organic pollutants renders microwave (MW) catalysis technology extremely lucrative; ideal microwave catalysts are therefore being hunted with an unprecedented urgency. Ideal functional microwave catalyst should be highly crystalline, room temperature ferromagnetic (for magnetic retrieval), highly dielectric (for sufficient microwave absorption) apart from being structurally stable at high temperature. The potential of silver ferrite 2D sheets (2D AFO) synthesized using a novel microwave technique as a microwave catalyst for the degradation of a variety of organic dyes and antibiotics was investigated in this article. While organic dyes like malachite green (MG), brilliant green (BG) and nile blue A (NB) achieved 99.2%, 98.8% and 95.2%, respectively; antibiotic tetracycline hydrochloride (TCH) molecule resulted in 75.8% degradation efficiency. Total organic carbon (TOC) measurements yielded 76%, 59.1%, 49.1% and 47.6% of carbon content for MG, BG, NB and TCH, respectively. The reaction pathway via intermediates and subsequent degradation to CO₂ and H₂O is revealed by liquid chromatography-mass spectrometry (LCMS). Both superoxide and hydroxyl radicals are participating in the process, according to scavenger tests. The evolution of silver ferrite as a new 2D material and its demonstration as an ideal microwave catalyst will lead to a new beginning in catalysis science and technology.

An Analysis of Nanoparticles Derived from Coal Fly Ash Incorporated into Concrete

The environmental benefits of incorporating coal fly ash (CFA) into the concrete manufacturing process as a partial substitute for Portland cement are well known. What is less studied is the potential release of CFA derived nanomineral and amorphous nanoparticles during this process of incorporation. A thorough understanding of this makes it possible to understand the risks of exposure to particulates that are harmful to human health when CFA is mixed into concrete. The general objective of this study is to analyze airborne particulates released when CFA is mixed into concrete at the point of manufacture, focusing on the levels of nanominerals, amorphous nanoparticles and hazardous elements (HEs) contained within that are considered harmful to human health. These airborne particulates can be easily inhaled by plant workers in the absence of personal protective equipment. The authors analyzed samples of ash itself and collected actual airborne particulates using self-made passive samplers installed at the manufacturing plant. Regarding the ash analyzed, iron (Fe) was found in large amounts in relation to calcium (Ca), magnesium (Mg) and silicon (Si). The transport, disposal and application of CFA in civil construction projects can provide an increased efficiency and reduce overall costs associated with the production of concrete. However, CFA poses a threat to human health due to the significant amount of HEs, nanominerals, and amorphous nanoparticles found to be released into the environment at the manufacturing plant.

Effective adsorptive removal of atrazine herbicide in river waters by a novel hydrochar derived from Prunus serrulata bark

In this work, a novel and effective hydrochar was prepared by hydrothermal treatment of Prunus serrulata bark to remove the pesticide atrazine in river waters. The hydrothermal treatment has generated hydrochar with a rough surface and small cavities, favoring the atrazine adsorption. The adsorption equilibrium time was not influenced by different atrazine concentrations used, being reached after 240 min. The Elovich adsorption kinetic model presented the best adjustment to the kinetic data. The Langmuir model presented the greatest compliance to the isotherm data and indicated a higher affinity between atrazine and hydrochar, reaching a maximum adsorption capacity of 63.35 mg g^-1. Thermodynamic parameters showed that the adsorption process was highly spontaneous, endothermic, and favorable, with a predominance of physical attraction forces. In treating three real river samples containing atrazine, the adsorbent showed high removal efficiency, being above 70 %. The hydrochar from Prunus serrulata bark waste proved highly viable to remove atrazine from river waters due to its high efficiency and low precursor material cost.

Indoor Nanoparticle Characterization in Construction Waste Recycling Companies over Time

Building activity is a significant source of atmospheric contamination by ultrafine dust. Cognizant of this fact, those active in the use and recycling of construction materials must be aware of the risks associated with exposure to nanoparticles (NPs) and ultra-fine particles (UFPs), as well as the associated health impacts. This work analyzed NPs and UFPs generated in a small building-material recycling company using high-resolution electron microscopes and X-ray Diffraction. A self-made passive sampler (LSPS) that can obtain particulate samples without physical and morphological changes, especially where there is a suspension of particulate material, was used in this study. A total of 96 particulate samples, using the LSPS for three months in four seasons, were collected during the study. Thus, the dry deposition of the particles, which are considered highly harmful to human health, was found in each of the four seasons of the year. It is suggested that for future research, the toxicological evaluations of the particulates in the construction industry should be investigated through the consideration of measures to control and mitigate the health risks of workers regarding exposure to NPs and UFPs.

Nanoparticles as vectors of other contaminants in estuarine suspended sediments: Natural and real conditions

Studding the behaviour and danger of nanoparticles (NPs, minerals and amorphous phases) in the estuarine ecosystem is presently incomplete by the lack of measureable description of NPs in the ecological conditions, such as suspended-sediments (SS). In the last years, several works have revealed the toxic consequences of ultra-fine and nanoparticulate compounds on diverse systems, raising apprehensions over the nanocontaminants behaviour and destiny in the numerous ecological partitions. The general objective of the manuscript is to explain the geochemical conditions of the LES (Laguna estuarine system, southern Brazil) suspended sediments covering an area around the main South American coal plant, enhancing the creation of future public policies for environmental recovery projects. Subsequently the discharge of nanoparticles and toxic element (TE) in the ecosystem, NPs react with several constituents of the nature and suffers active alteration progressions. Contamination coming from engineering actions, wastewater, are something identifiable, however when these contaminations are accompanied by other contamination sources (e.g. mining and farming) the work gets defaulted. By combining material about the concentration of TE contaminants and NPs occurrences, this work offers novel visions into contaminant contact and the possible effects of such exposure on estuarine systems in Brazil. The results presented here will be useful for different areas of estuaries around the world.

Numerical and experimental studies on dynamic gas emission characteristics of boreholes

The gas emission rate of boreholes is one of the most important indices for coal and gas outburst prediction. In this work, instantaneous gas emission velocity and environmental effects on borehole gas emission were studied. Through theoretical analysis, the mechanism of crack propagation in the coal borehole was clarified, and the effect of soft and hard coal on gas desorption and gas emission. The results of numerical simulations also indicated that the initial gas emission has a function relationship to the drilling distance and the physical characteristics of the coal seam. A novel dynamic testing technology was proposed to obtain gas emission velocity. Laboratory experiments under adsorption and desorption of CO₂ and N₂ were performed using coal samples from Xuehu, Fenghui, Weishe, and Wuzhong coal mines. The data of initial gas emission under different coal samples were recorded, and the fitting curves were obtained. The results show a positive correlation between initial gas emission and drilling depth. However, abnormal would occur when the drill pipe enters the soft stratification, and the maximum value of the initial gas emission of the abnormal part is 3.8 times the normal value, which indicates a high degree of sensibility to soft stratification. The results were revealed the dynamic gas emission law of boreholes.

How tropical cyclone flooding caused erosion and dispersal of mercury-contaminated sediment in an urban estuary: The impact of Hurricane Harvey on Buffalo Bayou and the San Jacinto Estuary, Galveston Bay, USA

Hurricane Harvey (Harvey), a slow-moving storm, struck the Texas coast as a category 4 hurricane. Over the course of 53 days, the floodwaters of Harvey delivered 14 × 10⁹ m³ of freshwater to Galveston Bay. This resulted in record flooding of Houston bayous and waterways, all of which drained into the San Jacinto Estuary (SJE,) with its main tributaries being Buffalo Bayou and the San Jacinto River. The lower SJE and lower Buffalo Bayou has experienced up to 3 m of land subsidence in the past 100 years and, as a result, prior to Hurricane Harvey, up to 2 m of sediment within the upper seabed contained an archive of high concentrations of Total Hg (HgT) and other particle-bound and porewater contaminants. Within the SJE, Harvey eroded at least 48 cm of the sediment column, resulting in the transport of an estimated 16.4 × 10⁶ tons of sediment and at least 2 tons of Hg into Galveston Bay. This eroded sediment was replaced by a Harvey storm deposit of 7.73 × 10⁶ tons of sediment and 0.96 tons within the SJE, mostly sourced from Buffalo Bayou. Considering that the frequency of slow-moving tropical cyclones capable of delivering devastating rainfall may be increasing, then one can expect that delivery of Hg and other contaminants from the archived sediment within urbanized estuaries will increase and that what happened during Harvey is a harbinger of what is to come.

Assessing Biota Accumulation Due to Contamination of Sediments by Storm Water Heavy Metals

Evaluating sediment recontamination due to storm water discharges is important when evaluating the long-term effectiveness of sediment remediation efforts at reducing biological impacts. The bioaccumulation of the heavy metals zinc, nickel, copper, cadmium, mercury, and lead and the metalloid arsenic in a clam (Macoma nasuta) was studied in surficial sediments before and after storm water inputs from Paleta Creek, California, USA, during wet seasons in 2015 to 2016 and 2016 to 2017. The bioaccumulation was compared with bulk sediment concentrations and porewater concentrations measured by diffusion gradient in thin film devices. Significant reductions in biota accumulation and porewater concentrations were observed in samples collected after storm seasons compared with before storm seasons despite bulk sediment concentrations remaining the same or increasing. This was apparently the result of the deposition of storm water contaminants in low bioavailable forms. The bioaccumulation of all the measured contaminants showed a positive significant correlation with porewater concentrations (p < 0.1, α = 0.1) and weak or no correlations with bulk sediment concentration. In conclusion, observed bulk sediment recontamination due to storm water should not be assumed to lead directly to greater biota accumulation without bioavailability assessment. Environ Toxicol Chem 2020;39:2475-2484. © 2020 SETAC.

Implications of iron nanoparticles in spontaneous coal combustion and the effects on climatic variables

Atmosphere, water, and soil contamination with toxic compounds is a recurrent issue due to environmental disasters, coal burning, urbanization, and industrialization, allf of which have contributed to soil contamination over the decades. Consequently, understanding of the nanomineralogy and potential hazardous elements (PHEs) in coal area soil are always a vital topic since contaminated soil can affect the environment, agricultural safety, and human health. Colombian coal mining in the La Guajira zone has been usually been related with important health and ecological effects. Coalmine rejects from active and/or abandoned operations are causes of high intensities of potential hazardous elements (PHEs) and nanoparticles (NPs, minerals and/or amorphous compounds). Although these pollutants can be reduced by sorption to NPs, in this study was recognized an analytical procedure for understand distribution of PHEs and their relationship to iron NPs(Fe-NPs) was recognized. Non and poorrly crystalline Fe-NPs performances as the major PHEs association. This complex interaction is constant and efficient in resolving PHEs in proportions above monitoring quantities. The indefinite basis of PHEs in Colombian (La Guajira area) coalmine rejects sources results in years-long leaching of PHEs into rivers and drainages. The iron-clays and their great geomobility interfere the mitigating character that Fe hydr/oxides alone show through adsorption of PHEs and their control in spontaneous coal combustion (SCC) zones. This can have significant consequences to the probable availability of several pollutants (e.g. drinking water). The new results presented in this study add novel viewpoints into the description of Fe-NPs and its incidence in SCC areas. The methodology utilized in this work can be applied as a supplementary technique to evaluate the influence of coalmining actions on ecological and human health.

Geochemistry of potentially hazardous elements in loess-amended mining sediment

Contaminated mining sediment may cause environmental and human health risk due to potentially hazardous elements (PHEs) leaching into groundwater, especially under very acid (pH ≤ 3) conditions. The capability of Chinese loess to immobilise and retain copper (Cu), zinc (Zn), cadmium (Cd) and lead (Pb) from element contaminated mining sediment was explored by a column leaching experiment. Results showed that loess could effectively reduce Cu geomobility, and their leachate concentrations were lower than the quality standard (1.0 mg L^-1) for ground water in China. The sierozem showed strong adsorption for Zn, Cd and Pb. The geomobility of Cu, Zn, Cd and Pb were affected by pH, electrical conductivity, organic matter and carbonate content of sediment/loess-amended sediment and sierozem. The long-term leaching of PHEs in loess-amended sediment may pose a potential risk to sierozem and groundwater in the region. This study highlights the need to develop a remediation technique to minimise the concentration level of hazardous elements in the mining sediment.

Identification of mercury and nanoparticles in roots with different oxidation states of an abandoned coal mine

The morphology and composition of roots with different degrees of oxidation as a function of time were evaluated aiming to identify possible hazardous elements and nanoparticles. The roots were obtained from an abandoned coal mine located in the city of Criciúma, Santa Catarina, Brazil. From the roots, analyses were performed to identify nanoparticles (NPs) and ultrafine particles (UFPs), containing possible hazardous elements (PHEs) that cause potential environmental risks and impacts on human health. The identification of nanoscale materials requires greater robustness, so advanced integrated techniques have been used. The characterization of different types of roots was done by using focused ion beam (FIB), to evaluate nano-compound assemblies with high-resolution transmission electron microscopy/energy dispersive spectroscopy (HR-TEM/EDS). The results showed the presence of NPs containing Hg, Co, Cr, Ni, and V. The presence of these elements has increased consistently with the increase of C concentration in the roots, suggesting that the PHEs were gradually released from organic matter and inorganic minerals of coal. However, even with their decrease in roots, it was found that these elements still remained in the soil in significant quantities, even after 15 years of inactivation of the coal mine.

A three-dimensional nanoscale study in selected coal mine drainage

Sediments from coal mine drainages (CMDs) contain large quantities of suspended pollutants (possibly numerous chemical substances) along with sulfates and hazardous elements (e.g., chromium, zinc, copper, lead) that irreversibly accumulate in the water. As this accumulation can continue for decades after discontinuation of coal extraction, it is necessary to employ multidisciplinary approaches to control the threat in such zones. The quantity of amorphous material in some CMDs was evaluated by X-ray powder diffraction (XRD) using the Rietveld-based SIROQUANT software package. Modern Dual Beam Focused Ion Beam (FIB), field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscope (H-TEM), and energy-dispersive X-ray spectrometer (EDS) were used to evaluate the occurrence and transformation of nanophases (NPs). FIB is used to determine the 3D distribution of different species (internal structure) within individual NPs, whereas EDS is used to observe NP features (e.g., shape, constituent, range, assembly, and form of polymerization). The mineralogy of the sediment from the Brazilian CMDs, including the proportions of quartz, clays, Al-Fe-oxides, and amorphous NPs, appears to be related to the nature of the mineral matter in the relevant coal cleaning rejects (CCRs). The sediments of CMDs from the Brazilian coal area derived at a lower-pH range have different amorphous compositions as compared to those derived at a higher pH range. These special amorphous compositions are shown to be related to several other sediment properties such as particle surface area. The information gleaned in this study will be useful for further geochemical evaluation of CMDs in other parts of the world.

Recycling of iron and titanium resources from early tailings: From fundamental work to industrial application

The comprehensive recovery of iron and titanium resources from early tailings were systematically attempted from fundamental work to industrial application. Geochemical characterization of the tailings was first conducted, followed by the iron recovery and titanium recovery. Iron recovery was mainly achieved through a series of magnetic separation, and titanium recovery was on the combination of magnetic pre-concentration and flotation separation. Special for titanium recovery, different pretreatment methods including ultrasonic cleaning and attrition-scrubbing were studied to reduce the influence of serious surface pollution of early tailings on ilmenite floatability, and attrition-scrubbing proved to be the best one. Associated mechanisms of flocculants influence on ilmenite floatability and the attrition-scrubbing effects were explored using micro-flotation and XPS tests. After a series of fundamental studies, the industrial production of iron and ilmenite concentrate went into operation and the industrial debugging results were roughly satisfactory. At last, a brief economic analysis was given for the present work.

Tracing geochemical pollutants in stream water and soil from mining activity in an alpine catchment

This research developed a method of tracing major water chemical parameters (WCP) and soil heavy metals (HM) to identify the processes of mining pollution in topographically complex landscapes. Ninety-nine spatially distributed water samples were collected to characterise the hydrochemical characteristics of an alpine river in north-west China. Sixty river WCP and fifty-six soil HM samples from areas near mining sites were then used to analyse the mining pollution process. Geographical and mining activity characteristics were derived from topographic and mine site information. The occurrence of sulphates (SO₄^2-) and nitrates (NO₃^-) in river water were highly correlated (up to 0.70), providing strong evidence of pollution from nearby mining activities. Levels of arsenic and cadmium were high in first and fifth order streams, where mining activities were most concentrated. The modelling results showed that geographical patterns and mining activity account for predicting HM distribution, and WCP can be reasonable predictors to trace soil mining pollution. This research can help improve the accuracy of predicting the mining pollution process.

A realistic study of 3D composition of carbon nanotubes and carbonaceous nanocompounds from different soils around coal power plant

Information on the effects of multi-walled carbon nanotubes (MWCNTs) on topsoil around coal power plants (CPPs) is still very limited. In the present work, the influences of MWCNTs on potential hazardous elements (PHEs) and environmental carbonaceous compounds in agrarian topsoil around CPPs of Latin America were investigated. The environmentally elevated proportions of MWCNTs and PHEs can cause damage to developing a fetus. The ecological impacts of industrial energy byproducts generated by MWCNTs were also studied. The surface morphologies of MWCNTs and PHEs detected in topsoil samples were analyzed by advanced electron microscopy in a combination of energy dispersive X-ray spectroscopy (EDS). The alterations could be originated due to the different geophysical constituents and superficial structure, which in turn disturbed their geoavailability in studied topsoil. It was found that a large amount of MWCNTs and amorphous carbonaceous matters, which are responsible for adsorbing PHEs, existed in soils around CPPs. Hence, these findings could be used to better understand the geochemical properties of PHEs near CPPs.

Physical, Chemical, and Microbial Quality of Floodwaters in Houston Following Hurricane Harvey

Hurricane Harvey brought more than 50 in. of rainfall to some areas of the Greater Houston Metro area (GHMA) starting on August 25, 2017; the Hurricane was also associated with damage to environmental infrastructure such as wastewater facilities, superfund sites, and leaks and spills from industrial and municipal facilities. This study collected post-Harvey water quality data in multiple streams for several weeks after the Hurricane. In addition to measuring impact, the study compared the observed concentrations of several physical, chemical, and microbial constituents and water properties to their historical counterparts in an effort to understand the water quality impacts of Harvey on the natural water systems within the GHMA. Unusual water quality findings such as low pH were observed that likely had acute and chronic effects on ecosystems including the loss of oyster populations in Galveston Bay. In-stream microbial concentrations, using E. coli as the indicator, were within historical norms typically reported for the GHMA. The observed levels of measured dissolved metals post Harvey, while relatively low, when multiplied by the significant volume of water discharged from bayous to Galveston Bay, meant the delivery of a substantial load of trace metals to the estuary. Specifically, the load in the particulate phase would be expected to accumulate and gradually repartition to the dissolved phase for a long period of time. Total metal concentrations, when elevated relative to their historical counterparts, could be associated with the presence of industrial activities. Overall, anthropogenic activities including the presence of hydraulic flood control structures, local runoff from industrialized areas, and active superfund sites were recognized as key factors affecting short-term acute water quality impacts. Watersheds with very little human alterations experienced minimal water quality changes and had relatively rapid recoveries post-Harvey.

A modelling approach to assess the impact of land mining on marine biodiversity: Assessment in coastal catchments experiencing catastrophic events (SW Brazil)

Analysis that link hydrological processes with oceanographic dispersion offer a promising approach for assessing impacts of land-based activities on marine ecosystems. However, such an analysis has not yet been customised to quantify specific pressures from mining activities on marine biodiversity including those from spillages resulting from tailing dam failure. Here, using a Brazilian catchment in which a tailing dam collapsed (Doce river) as a case study, we provide a modelling approach to assess the impacts on key ecosystems and marine protected areas subjected to two exposure regimes: (i) a pulse disturbance event for the period 2015-2016, following the immediate release of sediments after dam burst, which witnessed an average increase of 88% in sediment exports; and (ii) a press disturbance phase for the period 2017-2029, when impacts are sustained over time by sediments along the river's course. We integrated four components into impact assessments: hydrological modelling, coastal-circulation modelling, ecosystem mapping, and biological sensitivities. The results showed that pulse disturbance causes sharp increases in the amount of sediments entering the coastal area, exposing key sensitive ecosystems to pollution (e.g. rhodolith beds), highlighting an urgent need for developing restoration strategies for these areas. The intensity of impacts will diminish over time but the total area of sensitive ecosystems at risk are predicted to be enlarged. We determined monitoring and restoration priorities by evaluating and comparing the extent to which sensitive ecosystems within marine protected areas were exposed to disturbances. The information obtained in this study will allow the optimization of recovery efforts in the marine area affected, and valuation of ecosystem services lost.

Soil and maize contamination by trace elements and associated health risk assessment in the industrial area of Volos, Greece

Agricultural lands adjacent to industrial activities are vulnerable due to the risk of trace elements (TEs) being accumulated into crops and subsequently humans. One such case concerns the industrial area of Volos, Greece, a suspected contaminated area which has never been studied. We measured Ag, Al, As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sb, Se, Sn, Tl, V, and Zn in soil and maize (leaves and grains) and assessed health risk of human exposure via soil ingestion and grain consumption. We found that the most highly enriched elements in soils were Tl (enrichment factor = 19), Se (17.68), Sb (14.81), As (7.89), Ni (6.91), Mo (5.22) and Cr (4.33); they all likely derived from anthropogenic activities and in particular from a nearby major steel factory, except for Ni which is known to be lithogenically elevated in that area. Synchrotron XANES spectra analysis revealed that As species were associated with ferrihydrite, and predominant species were As(V) (at ca. 85%) and As(III) (at ca. 15%). Although the total content of the studied elements was high, the ammonium bicarbonate-DTPA extractions recovered very low element concentrations, probably due to the fact that soil conditions decelerated solubility (i.e., soils were alkaline, clayey, and with high Fe oxides content). This was confirmed by the soil-to-grain transfer index, which was particularly low for all studied elements. In 5% of sampled grains concerning Cd, and in 40% concerning Pb, the European food-related regulation limits were surpassed. Health risk assessment showed a dramatically elevated risk for Tl via soil ingestion (hazard quotient, HQ = 2.399), a value that contributed 74% of the total risk. Similarly, concerning the grain consumption-related health risk, Tl was the predominant contributor (HQ = 0.128, contributing 40% of the total risk). Such elevated Tl risk which has rarely been reported previously, led to a considerably high hazard index (HI) well above the threshold of HI = 1. Cancer risk was below the 1 × 10^-4 risk threshold for As and Pb. Our findings indicate that this study should be pivotal concerning similar industrially-affected agricultural soils of suspected contamination, since less-expected toxic elements such as Tl here may be primary contributors to health risk.

Quantification of the relationship between multiple metal(loid) distribution and integrated effect of internal-external factors in riverbed sediments across Xijiang River basin, South China

Understanding the integrated effect of external factors (e.g., human activities) and internal factors (e.g., hydrodynamics, sediment properties) on metal(loid) distributions is necessary for relevant decision-makers to develop river basin management strategies. In attempts to understand the possible causes of the distribution of nine target metal(loid)s in riverbed sediments across Xijiang River basin in China, we grouped and portrayed the multiple metal(loid) distributions by calculating metal(loid)'s normalised-and-weighted average concentrations, and then canonical correlation analysis combined with a series of statistical operations, collectively called optimized CCA analysis, was applied to quantify the strength of relationship between multiple metal(loid) distribution and integrated effect of internal-external factors. Results showed that the target metal(loid)s can be divided into three groups according to their distribution patterns: Group A (including Zn, As, Cd, Sb and Pb), Group B (including Cr, Ni and Cu) and Group C (including Tl). Among them, metal(loid)s in Group A was significantly enriched in comparison with the reference values of Chinese sediments, and the wide-ranging accumulation of Cd and Sb in the whole study area needs paying great attention to. For those metals in natural states (e.g., metals in Group B), the affinity of sediment (e.g., Fe and Mn oxides) is responsible for their distributions. By contrast, when metal(loid)s (e.g., metal(loid)s in Group A and Group C) had obvious anthropogenic sources, the interferences of anthropogenic inputs (e.g., non-ferrous metal enterprises' waste-discharging activities) and the specific sedimentary characteristics (e.g. karst topography and low-energy hydrodynamic depositional conditions) in study area can weaken the correlation between the binding affinity of sediment and the contents of metal(loid)s. The optimized CCA analysis can be an alternative and advantageous statistical operation for determining the main types of causes of multiple metal(loid) distribution in the case of observations with relatively low case-per-variable ratios.

Alteration behavior of mineral structure and hazardous elements during combustion of coal from a power plant at Huainan, Anhui, China

The alteration behavior of minerals and hazardous elements during simulated combustion (100-1200 °C) of a raw coal collected from a power plant were studied. Thermogravimetric analysis indicated that there were mainly four alteration stages during coal combustion. The transformation behavior of mineral phases of raw coal, which were detected by X-ray polycrystalline diffraction (XRD) technique, mainly relied on the combustion temperature. A series of changes were derived from the intensities of mineral (e.g. clays) diffraction peaks when temperature surpassed 600 °C. Mineral phases tended to be simple and collapsed to amorphous glass when temperature reached up to 1200 °C. The characteristics of functional groups for raw coal and high-temperature (1200 °C) ash studied by Fourier transform infrared spectroscopy (FTIR) were in accordance with the result obtained from XRD analysis. The volatilization ratios of Co, Cr, Ni and V increased consistently with the increase of combustion temperature, suggesting these elements were gradually released from the organic matter and inorganic minerals of coal.

Risk assessment and driving factors for artificial topography on element heterogeneity: Case study at Jiangsu, China

The rapid expansion of construction related to coastal development evokes great concern about environmental risks. Recent attention has been focused mainly on factors related to the effects of waterlogging, but there is urgent need to address the potential hazard caused by artificial topography: derived changes in the elemental composition of the sediments. To reveal possible mechanisms and to assess the environmental risks of artificial topography on transition of elemental composition in the sediment at adjoining zones, a nest-random effects-combined investigation was carried out around a semi-open seawall. The results implied great changes induced by artificial topography. Not only did artificial topography alter the sediment elemental composition at sites under the effect of artificial topography, but also caused a coupling pattern transition of elements S and Cd. The biogeochemical processes associated with S were also important, as suggested by cluster analysis. The geo-accumulation index shows that artificial topography triggered the accumulation of C, N, S, Cu, Fe, Mn, Zn, Ni, Cr, Pb, As and Cd, and increased the pollution risk of C, N, S, Cu, As and Cd. Enrichment factors reveal that artificial topography is a new type of human-activity-derived Cu contamination. The heavy metal Cu was notably promoted on both the geo-accumulation index and the enrichment factor under the influence of artificial topography. Further analysis showed that the Cu content in the sediment could be fitted using equations for Al and organic carbon, which represented clay mineral sedimentation and organic matter accumulation, respectively. Copper could be a reliable indicator of environmental degradation caused by artificial topography.

Coal-water slurries containing petrochemicals to solve problems of air pollution by coal thermal power stations and boiler plants: An introductory review

This introductory study presents the analysis of the environmental, economic and energy performance indicators of burning high-potential coal water slurries containing petrochemicals (CWSP) instead of coal, fuel oil, and natural gas at typical thermal power stations (TPS) and a boiler plant. We focus on the most hazardous anthropogenic emissions of coal power industry: sulfur and nitrogen oxides. The research findings show that these emissions may be several times lower if coal and oil processing wastes are mixed with water as compared to the combustion of traditional pulverized coal, even of high grades. The study focuses on wastes, such as filter cakes, oil sludge, waste industrial oils, heavy coal-tar products, resins, etc., that are produced and stored in abundance. Their deep conversion is very rare due to low economic benefit. Effective ways are necessary to recover such industrial wastes. We present the cost assessment of the changes to the heat and power generation technologies that are required from typical power plants for switching from coal, fuel oil and natural gas to CWSPs based on coal and oil processing wastes. The corresponding technological changes pay off after a short time, ranging from several months to several years. The most promising components for CWSP production have been identified, which provide payback within a year. Among these are filter cakes (coal processing wastes), which are produced as a ready-made coal-water slurry fuel (a mixture of flocculants, water, and fine coal dust). These fuels have the least impact on the environment in terms of the emissions of sulfur and nitrogen oxides as well as fly ash. An important conclusion of the study is that using CWSPs based on filter cakes is worthwhile both as the main fuel for thermal power stations and boiler plants and as starting fuel.