Toxicity of Metal Ions Released from a Fixed Orthodontic Appliance to Gastrointestinal Tract Cell Lines.

The mechanism of toxicity and cellular response to metal ions present in the environment is still a very current area of research. In this work, which is a continuation of the study of the toxicity of metal ions released by fixed orthodontic appliances, eluates of archwires, brackets, ligatures, and bands are used to test the prooxidant effect, cytotoxicity, and genotoxicity on cell lines of the gastrointestinal tract. Eluates obtained after three immersion periods (3, 7, and 14 days) and with known amounts and types of metal ions were used. Four cell lines-CAL 27 (human tongue), Hep-G2 (liver), AGS (stomach) and CaCo-2 (colon)-were treated with each type of eluate at four concentrations (0.1×, 0.5×, 1.0×, and 2.0×) for 24 h. Most eluates had toxic effects on CAL 27 cells over the entire concentration range regardless of exposure time, while CaCo-2 proved to be the most resistant. In AGS and Hep-G2 cells, all samples tested induced free radical formation, with the highest concentration (2×) causing a decrease in free radicals formed compared to the lowest concentrations. Eluates containing Cr, Mn, and Al showed a slight pro-oxidant effect on DNA (on plasmid φX-174 RF I) and slight genotoxicity (comet assay), but these effects are not so great that the human body could not "resist" them. Statistical analysis of data on chemical composition, cytotoxicity, ROS, genotoxicity, and prooxidative DNA damage shows the influence of metal ions present in some eluates on the toxicity obtained. Fe and Ni are responsible for the production of ROS, while Mn and Cr have a great influence on hydroxyl radicals, which cause single-strand breaks in supercoiled plasmid DNA in addition to the production of ROS. On the other hand, Fe, Cr, Mn, and Al are responsible for the cytotoxic effect of the studied eluates. The obtained results confirm that this type of research is useful and brings us closer to more accurate in vivo conditions.

Disturbance in invasion? Idiopathic necrotizing hepatopancreatitis in the signal crayfish Pacifastacus leniusculus (Dana, 1852) in Croatia.

As the most successful crayfish invader and possible vector for infectious agents, signal crayfish Pacifastacus leniusculus is among the major drivers of the native crayfish species decline in Europe. We describe histopathological manifestation and frequency of newly detected idiopathic necrotizing hepatopancreatitis along the invasion range of the signal crayfish in the Korana River in Croatia. Our results show extremely high prevalence of necrotizing hepatopancreatitis (97.3%), with 58.9% of individuals displaying mild and 31.5% moderate histopathological changes in the hepatopancreas, also reflected in the lower hepatosomatic index of analysed animals. Recorded histopathological changes were more frequent in the invasion core where population density is higher. Our preliminary screening of co-occurring native narrow-clawed crayfish Pontastacus leptodactylus showed lower incidence (33.3%) and only mild hepatopancreatic lesions, but potentially highlighted the susceptibility of native crayfish populations to this disease. Pilot analyses of dissolved trace and macro elements in water, sediment fractions and crayfish hepatopancreas do not highlight alarming or unusually high concentrations of analysed elements. Hepatopancreas microbiome analysis, using 16S rRNA gene amplicon sequencing, identified taxonomic groups that should be further investigated, along with impacts of the disease on health and viability of both invasive and native crayfish populations.

Can Urban Grassland Plants Contribute to the Phytoremediation of Soils Contaminated with Heavy Metals.

The main objective of this study was to investigate whether the most common wild plant species of urban grassland can be used for phytoremediation of soils polluted with heavy metals. The study was conducted in the city of Varazdin, in northern Croatia. The content of heavy metals (Cd, Cu, Fe, Mn, Ni, Pb, Zn) was determined in soil samples as well as in unwashed and washed plant samples (Taraxacum officinale, Plantago lanceolata, Trifolium repens). The results show that the most polluted site is the railway station, while most sites are polluted by road traffic. The soils are most enriched with Pb, Cu, Zn and Cd. The bioconcentration factors for all three plant species are <1, indicating the relatively low capacity of phytoextraction. A considerable amount of heavy metals is found in the dust deposited on the plant surface, which is confirmed by a statistically significant difference between washed and unwashed plant samples. In addition, the biomass of each plant species that can be removed (in t/ha year), the mass of specific heavy metal that can be removed (in kg/ha), and the years required for phytoremediation are reported. In conclusion, phytoremediation with only common plant species of urban grassland is not possible within a reasonable period of time.

Soils and spoils: mineralogy and geochemistry of mining and processing wastes from lead and zinc mining at the Gratz Mine, Owen County, Kentucky.

Purpose: Mineralogical and geochemical features of mining and processing wastes collected in Owen County, part of the Central Kentucky Lead-Zinc district, were investigated. The Gratz mine, abandoned in the 1940s, is on a dairy farm. Aside from discerning the nature of mining refuse at the site, the investigation was part of the University of Kentucky College of Pharmacy's mission to explore unusual environments in the search for unique microbiological communities. Materials and methods: Four samples of a soil-plus-spoils mix were collected from spoil piles and two samples, the sluice and coarse samples, were closely associated with the site of the ore processing. Optical petrology (polarized reflected-light, oil-immersion optics at a final magnification of 500 ×), X-ray diffraction, X-ray fluorescence, inductively coupled plasma mass spectrometry, field emission scanning electron microscopy (FE-SEM), and high-resolution transmission electron microscope (HR-TEM) with selected area electron diffraction (SAED) and/or microbeam diffraction (MBD), scanning transmission electron microscopy (STEM), and energy-dispersive X-ray spectrometer (EDS) analyses were employed to characterize the samples. Results and discussion: Calcite is the main mineral in most samples, followed by near equal amounts of quartz and dolomite. Sphalerite and galena are the principal sulfides and barite is the dominant sulfate. Geochemistry of major elements reflected the mineralogy, whereas trace elements showed different groupings between the minerals. Scandium, Cu, Ga, Ge, Cd, and Sb were found predominantly associated with Zn and Pb and sulfide minerals; Bi, Hf, In, Sn, and Zr with heavy mineral fraction; while the remaining trace elements, including the rare earths, were mostly distributed among other present phases, i.e., oxyhalides, oxides, silicates, and carbonaceous material. The data were used to illustrate the processes and conditions that control the sulfide-mineral oxidation and its potential for the environmental release of associated reaction products. Conclusions: The wastes represent a potential source of environmentally disruptive concentrations of Zn, Pb, and other sulfide-associated elements. The high share of carbonates suggests near-neutral conditions in deposited wastes, restricting sulfide weathering and further limiting the oxidant activity of Fe. The low-Fe content and its predominant presence in highly resistant hematite also constrain sulfide weathering. Consequently, the spoils have a low potential for generation of acidity and release of heavy metal(loid)s in the surrounding environment.

Associations of residential and occupational history with the distribution of persistent pollutant mixtures in adipose tissue samples.

This research aims to explore clusters of a mixture of 15 Persistent Toxic Substances (PTSs) in the adipose tissue of 227 individuals of an adult cohort from Granada Province (Southern Spain). Information about residence and occupation during participants lifetime was gathered by means of validated questionnaires. Clusters of pollutants in the study population were identified by Principal Component Analyses (PCA). PCA analyses revealed three major clusters of pollutants: PC1, representing predominantly an assortment of metal(loid)s, namely aluminium, arsenic, chromium, nickel and lead; PC2, including mostly Organochlorine Pesticides (OCPs), such as HCB, ß-HCH and p,p'-DDE; and PC3, gathering mainly a mixture of Polychlorinated Biphenyls (PCB-138, PCB-153 and PCB-180) and metals (cadmium, cobalt and chromium). The patterns of distribution of individual pollutants and their mixtures were explored through Geographic Information Systems and multivariable linear regression models. Living in rural areas was associated with decreased levels of the mixture of PCBs and metals. Residents of industrial and heavy traffic areas showed increased levels of the mixture of metal(loid)s. Those living in rural and semi-rural areas at recruitment had decreased levels of the OCP mixture. Occupational history related to agriculture and food industry was associated with increased levels of the mixture of metal(loid)s, whereas those who had been involved in motor and industrial activities showed increased levels of the OCP mixture. Participants who had worked in cleaning and housekeeping activities for long periods showed decreased levels of the mixture of PCBs and metals. Our research revealed suggestive clusters of exposure, that emphasized the need for further epidemiological studies to address the effect of environmental pollutants from a mixture perspective. Results also highlight the potential of adipose tissue as a matrix for exposure assessment to combinations of different families of contaminants.

Evaluation of the Potential Release Tendency of Metals and Metalloids from the Estuarine Sediments: Case Study of Rasa Bay.

Assessing the environmental quality of coastal systems is important not only for the management and protection of such areas, but also for improving the quality of water resources. Since sediment itself can often be a source of certain toxic elements, in addition to information on the distribution of metals in the water column and in the sediment itself, it is useful to determine the bioavailable forms of individual elements, particularly toxic ones. In this study, water and sediment geochemical data were supplemented with oxyanion mobility in sediments estimated by diffusion gradients in thin film (DGTs). The data obtained indicate that the chemical composition of the water in the Rasa River estuary primarily reflects the high input of suspended sediment from the catchment, the mixing of freshwater and seawater, and to a lesser extent the effects of anthropogenic activities. Although sediment composition is primarily determined by geological and hydrodynamic conditions in the catchment, it also indicates moderate enrichment in Co, Cr, Mo and Ni. In contrast, the distribution of oxyanions in sediment pore water indicates the influence of sediment as a source of some elements in the bottom water; e.g., sediment contributes to 40% of the arsenic bottom water budget. The obtained depth profiles of the oxyanion distribution in the sediment pore water indicate an early onset of suboxic to anoxic conditions in Rasa Bay, which is prone to rapid sedimentation. All this demonstrates the need to consider the bioavailable forms of elements when assessing environmental quality, as the lack of such information can lead to an incomplete assessment, especially in dynamic coastal systems such as estuaries.

Interrelation between environmental conditions, acanthocephalan infection and metal(loid) accumulation in fish intestine: an in-depth study.

Metal(loid) bioaccumulation in acanthocephalans (Dentitruncus truttae) and intestines of fish (Salmo trutta) from the Krka River, influenced by industrial and municipal wastewaters, was investigated in relation to exposure to metal(loid)s from fish gut content (GC), water, and sediment to estimate potentially available metal (loid)s responsible for toxic effects and cellular disturbances in biota. Sampling was performed in two seasons (spring and autumn) at the reference site (river source, KRS), downstream of the wastewater outlets (Town of Knin, KRK), and in the national park (KNP). Metal(loid) concentrations were measured by ICP-MS. The highest accumulation of As, Ba, Ca, Cu, Fe, Pb, Se and Zn was observed mainly in organisms from KRK, of Cd, Cs, Rb and Tl at KRS, and of Hg, Mn, Mo, Sr and V at KNP. Acanthocephalans showed significantly higher bioaccumulation than fish intestine, especially of toxic metals (Pb, Cd and Tl). Metal(loid) bioaccumulation in organisms partially coincided to exposure from water, sediments and food, while in GC almost all elements were elevated at KNP, reflecting the metal(loid) exposure from sediments. Seasonal differences in organisms and GC indicated higher metal (loid) accumulation in spring, which follows enhanced fish feeding rates. Higher number of acanthocephalans in the intestine influenced biodilution process and lower concentrations of metal(loid)s in fish, indicating positive effects of parasites to their host, as supported by high values of bioconcentration factors. Fish intestine and acanthocephalan D. truttae were confirmed as sensitive indicators of available metal fraction in conditions of generally low environmental exposure in karst ecosystem. Since metal(loid) accumulation depended on ecological, chemical and biological conditions, but also on the dietary habits, physiology of organisms and parasite infection, continuous monitoring is recommended to distinguish between the effects of these factors and environmental exposure when assessing dietary associated metal(loid) exposure in aquatic organisms.

Biogeochemical impact of historical submarine mine tailings on benthic ecosystems in the Repparfjord (Northern Norway).

Historical copper mine tailings deposited in the Repparfjord, Northern Norway, provided new insight into the biogeochemical impact of submarine tailings disposals on high-latitude coastal ecosystems. The submarine tailings disposal in the Repparfjord represents a product of mining activities between 1972 and 1979. Their environmental impact has been extensively studied during the last decade, but geochemistry of the sediment pore water, which is crucial to assess and monitor the in-situ metal leaching and bioavailability, has never been analysed. The actual impact on the benthic fauna remains poorly known. Therefore, this study couples the pore water chemistry and the foraminiferal analysis obtained from selected sediment cores (gravity core, multicore, box cores) to examine metal stability and the past and current status of the foraminifera community. We measured down-core sulfate and trace metal concentrations and Eh-Ph and applied the Shannon index, the AZTI's Marine Biotic Index (F-AMBI) index and the foraminiferal abnormality index. This study confirms the ongoing leaching of Cu from the underlying mine tailings and release across the sediment-water interface. Leaching of Ni, Zn and Pb have been attributed to weathering of natural bedrock lithologies. The original benthic foraminiferal community disappeared almost entirely during the disposal period, and now it is dominated by stress-tolerant and opportunistic species like Bulimina marginata and Spiroplectammina biformis. Anyhow, against previous assumptions, the community composition changed, while the overall diversity and abnormalities (FAI) shell formation is unaffected by elevated Cu concentrations.

Multielement analysis in the fish hepatic cytosol as a screening tool in the monitoring of natural waters.

The possibility of direct measurement of trace elements in hepatic cytosol of European chub (Squalius cephalus) by high-resolution inductively coupled plasma mass spectrometry (HR ICP-MS) after cytosol dilution with Milli-Q water and subsequent acidification was investigated. Due to low detection limits of this procedure, determination of 13 elements (As, Cd, Co, Cu, Fe, Mn, Mo, Pb, Sb, Sn, Sr, V and Zn) was possible in the chub hepatic cytosol, exhibiting excellent measurement repeatability in duplicates. Some of these elements were also measured by HR ICP-MS in acid digested cytosols (Cd, Co, Cu, Fe, Mn, Mo, Sr, V and Zn). Good agreement of the results obtained after sample dilution and sample digestion indicated that complex organic matrix of hepatic cytosol did not affect measurement reliability. Cytosolic concentrations of 13 trace elements in the chub liver were quantified in the following order: Fe, Zn>Cu>Mn>Mo>Sr, V, Cd>Co>As, Pb>Sn>Sb. Unlike Cd, Cu, Fe, Mn and Zn for which the cytosolic concentrations were previously reported after measurement by AAS, cytosolic concentrations of eight additional trace elements characteristic for the liver of chubs inhabiting the low contaminated river water were reported here for the first time (in nanogrammes per gramme)-Mo, 136.8-183.6; Sr, 32.7-63.0; V, 17.5-69.0; Co, 24.3-30.7; As, 9.9-29.5; Pb, 5.8-35.6; Sn, 5.5-12.4; and Sb, 0.9-2.6. The simultaneous measurement of large number of trace elements in the cytosolic fractions of fish tissues, which comprise potentially metal-sensitive sub-cellular pools, could be beneficial as a screening tool in the monitoring of natural waters, because it would enable timely recognition of increased fish exposure to metals.

Essential role of multi-element data in interpreting elevated element concentrations in areas impacted by both natural and anthropogenic influences.

Background: This article presents a detailed analysis of a dataset consisting of 27 elements found in soils, soil eluates, and vegetables from private gardens in a region with a long history of coal mining and burning. With coal being one of the world's most significant energy sources, and previous studies highlighting elevated element levels in vegetables from this region, the objective of this study was to identify the factors that impact soil geochemistry and metal(loid) uptake in plants. Methods: Total major and trace element concentrations were analyzed in soils, soil eluates and vegetables by high resolution inductively coupled plasma mass spectrometry. The vegetable samples included six species: fennel, garlic, lettuce, parsley, onion, and radicchio. Each plant was divided into roots, stems, leaves, and/or bulbs and analyzed separately. In addition, the soil pollution status, bioavailable fractions and transfer factors from soil and soil eluates to different plant parts were determined. Results: The comprehensive dataset revealed that, apart from the substrate enriched with various elements (Al, As, Co, Cr, Mo, Ni, Pb, Sb, Sn, Ti, U, V, and Zn), other anthropogenic factors such as the legacy of coal mining and combustion activities, associated industries in the area, transport, and agricultural practices, also influence the elevated element concentrations (Cd, Cu, Fe, Mn, and Se) in locally grown vegetables. The transfer factors based on element concentrations in aqueous soil eluates and element bioavailable fractions confirmed to be an effective tool for evaluating metal uptake in plants, emphazising to some extent the effects of plant species and revealing unique patterns for each pollution source within its environmental context (e.g., Cd, Mo, S, and Se in this case). The study highlights the crucial importance of utilizing comprehensive datasets that encompass a multitude of factors when interpreting the impacts of element uptake in edible plants.

Impact of nutrients and trace elements on freshwater microbial communities in Croatia: identifying bacterial bioindicator taxa.

Since aquatic microbial communities promptly respond to environmental changes, it is now evident that they can complement traditional taxa such as fish, macroinvertebrates and algae as bioindicators of water quality. The aim of this study was to correlate the physico-chemical parameters of water with the microbial community structure and the occurrence of putative bioindicator taxa. Thirty-five water samples were collected throughout Croatia and their physico-chemical parameters, including the concentration of trace elements using the high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS), and the composition of the microbial communities by high-throughput sequencing of the 16S rRNA marker gene, were analysed in parallel. Partial least squares regression (PLS-R) modelling revealed that a number of microbial taxa were positively correlated with some of the water parameters. For example, some taxa from the phylum Proteobacteria were positively correlated with the ion content of the water (e.g. Erythrobacter, Rhodobacteraceae, Alteromonadaceae), while some Firmicutes taxa, such as the well-known faecal indicators Enterococcus and Clostridium, were correlated with nutrient content (ammonium and total phosphorus). Among the trace elements, uranium was positively correlated with a highest number of microbial taxa. The results obtained will aid in development of protocols for eDNA-based biological assessment of water quality.

Cytotoxicity of Metal Ions Released from NiTi and Stainless Steel Orthodontic Appliances, Part 1: Surface Morphology and Ion Release Variations.

Despite numerous studies on ion release from orthodontic appliances, no clear conclusions can be drawn due to complex interrelations of multiple factors. Therefore, as the first part of a comprehensive investigation of cytotoxicity of eluted ions, the objective of this study was to analyze four parts of a fixed orthodontic appliance. Specifically, NiTi archwires and stainless steel (SS) brackets, bands, and ligatures were immersed in artificial saliva and studied for morphological and chemical changes after 3-, 7-, and 14-day immersion, using the SEM/EDX technique. Ion release profiles were analyzed for all eluted ions using inductively coupled plasma mass spectrometry (ICP-MS). The results demonstrated dissimilar surface morphologies among parts of the fixed appliance, due to variations in manufacturing processes. The onset of pitting corrosion was observed for the SS brackets and bands in the as-received state. Protective oxide layers were not observed on any of the parts, but adherent layers developed on SS brackets and ligatures during immersion. Salt precipitation, mainly KCl, was also observed. ICP-MS proved to be more sensitive than SEM/EDX and exhibited results undetected by SEM/EDX. Ion release was an order-of-magnitude higher for SS bands compared to other parts, which was attributed to manufacturing procedure (welding). Ion release did not correlate with surface roughness.

Metal bioaccumulation in stygophilous amphipod Synurella ambulans in the hyporheic zone: The influence of environmental factors.

Given the increasing need to protect vulnerable freshwater ecosystems and make them more resilient to human use and climate change, biomonitoring of the hyporheic zone (HZ), which plays a critical role in pollution attenuation, is essential. The aim of the present study was to assess the potential of the amphipod species Synurella ambulans as a bioindicator of metal contamination in the HZ of the Sava River (Croatia). Amphipods were collected during the four seasons at two sampling sites (average sampling depth 55 cm) differing in type (agricultural and urban) and intensity (diffuse and point source contamination) of anthropogenic influence, one located upstream (Medsave), and the other downstream (Jarun) of the wastewater treatment plant discharge. Concentrations of Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Rb, Sn, Zn, Ca, K, Mg and Na were measured in the interstitial water, sediments and specimens of S. ambulans by HR ICP-MS. Physicochemical parameters (temperature, DO, O2 saturation, pH, conductivity, alkalinity, total water hardness, CODKMnO4, nutrients) were measured in the interstitial water, while organic carbon was measured in the interstitial water and sediments. Metal concentrations in interstitial water and sediments were below thresholds set by environmental quality standards. Metal concentrations in S. ambulans were classified as follows: higher at the Jarun site (Al, Cr, Fe, Ni, Pb, Sn), higher at the Medsave site (Cd, Cu, Rb) and mostly comparable at both sites (Co, Mn, Zn). Bioaccumulation factors were generally higher at Jarun, with average values ranging from 322 to 143,278 L kg-1. Bioaccumulation of metals in S. ambulans depended on various environmental factors, with metal exposure level and dissolved macro elements showing the strongest association with metals accumulated in S. ambulans. The findings provided the first evidence on the suitability of S. ambulans as a good bioindicator of chronic metal contamination in the HZ.

Effect of seasonal temperature shifts on body homeostasis, biochemical parameters and chemical composition of green ormer (Haliotis tuberculata) in the Northern Adriatic.

Seasonal responses of green ormer in terms of antioxidant capacity and lipid peroxidation, proximate and fatty acid tissue composition, trace and macro elements concentrations over the seasons were studied in relation to temperature shifts in the Northern Adriatic Sea. Overall antioxidative defenses (SOD, TBARS, TAS, LDH) varied significantly (p < 0.001) according to seasons (primarily spring and summer). The proportions of overall SFA were highest in summer. The proportions of MUFA increased in autumn, with significant differences between genders in spring and summer, and spring, summer and autumn for C18:1n7 and C20:4n6. The only fatty acid lacking significant variation between seasons was C22:5n3. Significant overall differences were observed in summer vs. winter samples for As, Ba, Co, Ni, Mn, Pb, Sb, and Se content in soft tissues, however, gender variations were not significant. The data obtained in the study are of utmost importance for the management of this under-investigated species.

Traceability of Croatian extra virgin olive oils to the provenance soils by multielement and carbon isotope composition and chemometrics.

A capacity to determine the provenance of high-value food products is of high scientific and economic interest. With the aim to develop a tool for geographical traceability of Croatian extra virgin olive oils (EVOO), multielement composition and 13C/12C isotope ratio in EVOO as well as the geochemistry of the associated soils were analysed in samples collected from three regions along the Croatian Adriatic coast. Soil geochemistry was shown to influence the transfer and elemental composition of EVOO. The most discriminating variables to distinguish EVOO from different regions were S, Mo, Rb, Mg, Pb, Mn, Sn, K, V and δ13C. The predictive models achieved high sensitivity and specificity, especially when carbon isotope composition was added. The results suggest that interregional geographical traceability of Croatian EVOO is possible based on matching their multielement composition with that of the soils in the provenance area.

Late activation of stress-activated protein kinases/c-Jun N-terminal kinases triggered by cisplatin-induced DNA damage in repair-defective cells.

Although stress-activated protein kinases/c-Jun N-terminal kinases (SAPK/JNK) are rapidly activated by genotoxins, the role of DNA damage in this response is not well defined. Here we show that the SEK1/MKK4-mediated dual phosphorylation of SAPK/JNK (Thr-183/Tyr-185) correlates with the level of cisplatin-DNA adducts at late times (16-24 h) after drug treatment in both human and mouse cells. Transfection of platinated plasmid DNA also caused SAPK/JNK activation. A defect in transcription-coupled nucleotide excision repair resting on a mutation in Cockayne syndrome group B protein promoted the late SAPK/JNK activation following cisplatin exposure. Signaling to SAPK/JNK was accompanied by activation of Ataxia telangiectasia mutated- and Rad3-related kinase, replication protein A, and checkpoint kinases as well as by the formation of DNA double strand breaks (DSBs). Ionizing radiation-induced DSBs did not provoke SAPK/JNK activation, and inhibition of transcription also failed to provoke this response. Late activation of SAPK/JNK stimulated by cisplatin-induced DNA lesions was reduced in the absence of specific DNA repair proteins, such as xeroderma pigmentosum protein C, pointing to an essential function of individual repair factors in DNA damage signaling to SAPK/JNK. Collectively, the data indicate that late SAPK/JNK activation is triggered by non-repaired cisplatin adducts in transcribed genes and involves replication-associated events, DSBs, tyrosine kinases, Rho GTPases, and specific repair factors.

Environmental damage caused by coal combustion residue disposal: A critical review of risk assessment methodologies.

Coal combustion generates almost 40% of world's electricity. However, it also produces 1.1 billion tons of coal combustion residues (CCR) annually, half of which end up in landfills. Although current regulations require proper lining and monitoring programs, the ubiquitous old, abandoned landfills are often not lined nor included in these programs. In addition, the total number of coal ash disposal sites and their status in the world is unknown. Therefore, this article reviews the environmental damage caused by CCR and three commonly used risk assessment methodologies: leaching assessment, groundwater assessment, and toxicity testing. Leaching methods are usually the first step in coal ash risk assessment, however, a large number of methods with different parameters make a comparison of data difficult. Groundwater pollution is commonly detected near coal ash disposal sites, but other anthropogenic activities may also exist nearby. Therefore, multivariate statistical methods and isotope traces should be used to differentiate between different sources of pollution. So far, both stable (δ18O, δD, δ11B, δ34S, δ7Li) and radiogenic (87Sr/86Sr, 206Pb/207Pb) isotopes have been successfully used as coal ash pollution tracers. Coal ash also negatively affects biota, reduces the diversity of organisms, affects children's health, and increases the risk for developing various diseases. Toxicity studies are great for early screening of coal ash safety; however, they provide no insights into mechanisms causing the adverse effects. Future directions are also proposed, such as the development of new 'low-level' detection methods for coal ash pollution and sustainable and selective method for recovery of critical elements.

Mobility of metals and metalloids from SHOS coal ash and slag deposit: mineralogical and geochemical constraints.

Deposits remained after coal combustion are a well-known occurrence in the world; unfortunately, only a small percentage of such deposits are adequately regulated and, consequently, pose a serious threat to the local environment. Attenuation of negative consequences presupposes knowledge of a number of features, both of the deposit and the local environment as well the interaction with local biota. In this study, unregulated waste generated from decades of coal mining and combustion of superhigh-organic-sulfur Rasa coal, enriched in Se-U-Mo-V and located in a vulnerable karst region, was investigated. To assess the impact of landfill on the environment, in addition to its general geochemical and mineralogical features, the human health risk was assessed and the leaching of elements from the landfill, local soil, and the coal itself was investigated. For the latter, three extraction procedures, ASTM, EP, and TCLP (pH 4.93 and 2.9), were employed, mimicking different environmental conditions, including the sporadic occurrence of acid rains in the region. The soil around the landfill displayed enrichment in the majority of elements compared to expected values, with exception of Se, Mo, U, V, Sr, and Cu found at the highest levels in landfill samples. Mobility of elements was found to be controlled by both pH and mineralogy (carbonates and sulfates), whereby the overall highest relative mobility was observed in landfill samples for elements prevalently bound to sulfate phases. Calculated Hazard Quotient describes this landfill as a risk to the environment and human health through different pathways.

Yesterday's contamination-A problem of today? The case study of discontinued historical contamination of the Mreznica River (Croatia).

The remnants of historical industrial contamination can be detected in many aquatic ecosystems worldwide even at present time. Mreznica is a river in Croatia that has been, for more than a hundred years, continually exposed to effluents of various industries, which have, in modern time, mostly ceased to operate. Our aim was to establish the level of current contamination and pollution of the Mreznica river-water and sediments. The study of river contamination at three sites (reference site; site nearby former cotton industry facility in Duga Resa - DRF; industrial zone of Karlovac town - KIZ) in three sampling campaigns (May 2020, April and September 2021) encompassed analyses of physico-chemical water parameters, screening of 369 pesticides, measurement of metal (loid) concentrations in the sediments, and in the dissolved and particulate phases of the river-water. The sediment pollution was assessed through the analyses of total bacteria abundance (by targeting 16S rRNA genes), and their associated metal resistance genes (cnrA, pbrT and czcD) and class 1 integrons (intl1). At the DRF site, industrial organic contaminants that can be traced to textile production were detected (dye and nylon components), as well as increased levels of some metals bound to suspended particulate matter and sediments. At the most downstream KIZ site, occasional high level of industrial herbicide neburon was measured in the river-water, and metal contamination of suspended particulate matter and sediments was evident. Although, based on the comparison with legislation and literature data, the level of contamination was rather mild, the effects on microbial communities were unquestionable, confirmed by increased abundance of the czcD gene at DRF site and the intI1 gene at both industrially impacted sites. Obtained results indicated long-term sediment retention of some industrial contaminants at the places of historical freshwater contamination, and, thus, the necessity for their monitoring even after the termination of contamination sources.

Distribution and Origin of Major, Trace and Rare Earth Elements in Wild Edible Mushrooms: Urban vs. Forest Areas.

This paper investigates the composition of major, trace, and rare earth elements in 15 different species of wild edible mushrooms and the possible effect of urban pollution on elemental uptake. The collected mushrooms include different species from the green areas of the city, exposed to urban pollution, and from the forests, with limited anthropogenic influence. Through a comprehensive approach that included the analysis of 46 elements, an attempt was made to expand knowledge about element uptake by mushroom fruiting bodies. The results showed a wide variability in the composition of mushrooms, suggesting a number of factors influencing their element uptake capacity. The data obtained do not indicate significant exposure to anthropogenic influences, regardless of sampling location. While major elements' levels appear to be influenced more by species-specific affinities, this is not true for trace elements, whose levels presumably reflect the geochemical characteristics of the sampling site. However, the risk assessment showed that consumption of excessive amounts of the mushrooms studied, both from urban areas and from forests, may have adverse health effects.