Deciphering groundwater pollution in the Lower Anayari Catchment: insights from using δ2H, δ18O, PMF, and APCS-MLR receptor model

This research provides a comprehensive analysis of groundwater pollution in the Lower Anayari Catchment (LAC) through δ2H and δ18O isotopic analysis, along with positive matrix factorization (PMF) and PCS-MLR receptor models. Forty groundwater samples were collected from hand-dug wells and equipped boreholes across the LAC. Flame photometry for Na+ and K+, complexometric titration for Ca2+, ion chromatography for Cl-, F-, NO3-, SO42-, and PO43-, and atomic absorption spectrometry for Mg2+, Fe, Pb, Cd, As, and Ni were analytical techniques/instruments employed. In regard to cations, Na+ has the highest average concentration of 63.0 mg/L, while Mg2+ has the lowest at 2.58 mg/L. Concerning the anions and nutrients, Cl- has the highest mean concentration of 18.7 mg/L, and Fl- has the lowest at 0.50 mg/L. Metalloids were detected in trace amount with Fe displaying the highest mean concentration of 0.077 mg/L whereas Cd and As recorded lowest (0.001 mg/L). The average values for groundwater δ18O and δ2H were - 3.64‰ and - 20.7‰, respectively; the average values for rainwater isotopic composition were - 3.41‰ for δ18O and - 17.4‰ for δ2H. It is believed that natural geological features, particularly biotite granitoid and volcanic flow/subvolcanic rocks from the Birimian Supergroup, significantly influence groundwater mineralisation. Additionally, the impact of anthropogenic activities on water quality, with urban development and agricultural practices, may be attributed to increasing levels of certain contaminants such as Fe, Ni, NO3-, and PO43-. This research contributes to the broader field of hydrological study and provides practical implications for managing and conserving water resources in similar contexts. The innovative combination of isotopic and statistical analyses sets a new standard for future studies in groundwater quality assessment, emphasising the need for comprehensive approaches that consider both geological characteristics and human impacts for sustainable water resource management.

Global N2O emissions from our planet: Which fluxes are affected by man, and can we reduce these?

In some places, N2O emissions have doubled during the last 2-3 decades. Therefore, it is crucial to identify N2O emission hotspots from terrestrial and aquatic systems. Large variation in N2O emissions occur in managed as well as in natural areas. Natural unmanaged tropical and subtropical wet forests are important N2O sources globally. Emission hotspots, often coupled to human activities, vary across climate zones, whereas N2O emissions are most often a few kg N ha-1 year-1 from arable soils, drained organic soils in the boreal and temperate zones often release 20-30 kg N ha-1 year-1. Similar high N2O emissions occur from some tropical crops like tea, palm oil and bamboo. This strong link between increased N2O emissions and human activities highlight the potential to mitigate large emissions. In contrast, water where oxic and anoxic conditions meet are N2O emission hotspots as well, but not possible to reduce.

Resilience and high compositional variability reflect the complex response of river waters to global drivers: The Eastern Siberian River Chemistry database

The chemical composition of river waters represents an important matter of investigation to understand environment modifications in response to climate changes and global warming. Prolonged dry periods, heavy flood events, degradation of the lands and ice thawing, modify the chemical composition of river waters influencing the drivers governing the complex dynamics of river catchments where everything comes together. In this framework, Compositional Data Analysis (CoDA) offers methods in which the complex structure of the river water composition and the interrelationships among the various components are put into the proper context for their statistical analysis. In this research, we propose a new CoDA approach combining the robust Mahalanobis distance (D) calculus of ilr-transformed chemical variables and the perturbation difference, both with respect to a pristine compositional benchmark. The aim was to trace the change in the chemical composition of the Eastern Siberian River Chemistry Database where degradation of the permafrost for global warming produces important effects on natural waters. The findings indicate complex multiplicative laws and feedback mechanisms governing solutes in Eastern Siberian rivers, with high values of D found where permafrost is more discontinuous. Perturbations clearly discriminate chemical components more resilient to stresses induced by global changes (Ca2+, Mg2+ and HCO3-) from those whose variability is not maintained under control (Cl-, Na+, SO42-). These outcomes open up a new scenario in searching for spatiotemporal resilience metrics to reveal rivers response to environmental changes.

Development and testing of a new flexible, easily and widely applicable chemical water quality index (CWQI)

Water quality indices (WQIs) are numeric parameters that summarize the overall quality status of freshwaters compared to quality standards by aggregating multiple physicochemical data into a single value. Among the available WQIs in the literature, several criticalities were recognized including: (a) mathematical complexity of the computation, (b) lack of inclusivity, (c) arbitrary weight assignment method, and (d) site-specificity of most of the indexes. The proposed index, the Chemical Water Quality Index (CWQI), aims to overcome these flaws and provides a computation based on simple mathematic equations that are easily manageable on spreadsheet software. The computation is divided into two steps: (i) parametrization of the variables and (ii) index determination. The parametrization consists of assigning a score (s) from ∼1 to 10 to each chemical variable based on (i) measured concentrations and (ii) quality targets (e.g., the limits provided by the European legislation for drinking waters). In the second step, a weight (w), directly proportional to the score (s), is assigned to each parameter, allowing to overcome any bias related to subjective assignments from the user. The resulting CWQI ranges from ∼1 (very good quality) to 10 (extremely poor quality). The reliability and accuracy of the CWQI were assessed by (i) applying the computation to 1,810 waters and (ii) comparing our results with another available WQI. The CWQI outputs showed an optimal response with the number of variables exceeding the quality target with high correlation coefficients (r = 0.94; R2 = 0.89). Due to the simplicity of its computation, the absence of arbitrariness in the weightage of selected variables, and the independence of the proposed approach regarding the choice of the chemical parameters, CWQI can be easily and universally applied.

Radiation exposure and health concerns associated with the environmental geochemistry of relatively higher radioactivity in a fresh water basin

This study was carried out on a negligible anthropogenically impacted Indo-Bangla transboundary river basin (Atrai, Bangladesh) to elicit radionuclides' and elemental distributions. Thirty sediment samples were collected from the Bangladesh portion of the river, and instrumental neutron activation analysis and HPGe γ-Spectrometry techniques were used to determine environmental radionuclides (e.g., 232Th, 226Ra, 40K) and associated elemental concentrations, respectively. Metal concentrations (Sc, V, Fe, Eu, Sm, La, Yb, Ce, Lu, Ta, Hf) were determined to comprehend the genesis of greater radioactivity. Recognizing the mean concentration of absorbed gamma dose rate (158.7 hGyh-1) is 2.88-times more than the recommended value (55 hGyh-1) that describes ionizing radiation concerns regarding potential health risks to the surrounding communities and the houses of native residents, which are constructed by Atrai river sediment. This work will assist relevant policymakers in exploring valuable heavy minerals and provide information regarding radiological health risks from a fluvial system.

Ecological engineering of iron ore tailings into useable soils for sustainable rehabilitation

Ecological engineering of soil formation in tailings is an emerging technology toward sustainable rehabilitation of iron (Fe) ore tailings landscapes worldwide, which requires the formation of well-organized and stable soil aggregates in finely textured tailings. Here, we demonstrate an approach using microbial and rhizosphere processes to progressively drive aggregate formation and development in Fe ore tailings. The aggregates were initially formed through the agglomeration of mineral particles by organic cements derived from microbial decomposition of exogenous organic matter. The aggregate stability was consolidated by colloidal nanosized Fe(III)-Si minerals formed during Fe-bearing primary mineral weathering driven by rhizosphere biogeochemical processes of pioneer plants. From these findings, we proposed a conceptual model for progressive aggregate structure development in the tailings with Fe(III)-Si rich cements as core nuclei. This renewable resource dependent eco-engineering approach opens a sustainable pathway to achieve resilient tailings rehabilitation without resorting to excavating natural soil resources.

Effects of capping on microbial populations and contaminant immobilization in an old unlined landfill

This research aimed at evaluating the effects of capping on the mitigation of impacts generated by a closed unlined landfill in São Carlos, SP, Brazil. Physicochemical and microbiological analyses (16S rRNA sequencing) of buried solid waste samples were performed, in capped and uncapped areas. Even though leachate pockets could still be encountered in capped areas, the capping construction reduced oxygen availability and created more reducing conditions, propitiating the development of sulfate-reducing bacteria and possibly contributing to the precipitation of the metals Pb, Cd, Ni, Co, As, and Zn as metal sulfides, causing their immobilization. The microbial populations adapted to the anaerobic conditions created under capped zones belonged to the phyla Firmicutes, Chloroflexi, and Euryarchaeota and the genera Methanosaeta, Hydrogenispora, Smithella, and Gelria. Differently, the phyla Acidobacteria, Proteobacteria, Bacteroidetes, and Actinobacteria were more abundant in samples from the uncapped zones, in which the abundance of different genera varied homogeneously. Methanogenic activity was not impaired by the intervention measure, as assessed by the specific methanogenic activity (SMA). Capping of old unlined landfills brings benefits to the immobilization of metals and does not impair microbial degradation, being effective for the mitigation of impacts on soils and water resources.

Exploring a new approach for assessing the fate and behavior of the tailings released by the Brumadinho dam collapse (Minas Gerais, Brazil)

In 2019, the Brumadinho dam rupture released a massive amount of iron ore mining tailings into the Paraopeba River. Up to now, it remains a public health issue for the local and downstream populations. The present study aims to assess the behavior and fate of metal contamination following the disaster. Using new sampling strategies and up-to-date geochemistry tools, we show that the dissolved metal concentrations (< 0.22 µm cutoff filtration) remained low in the Paraopeba River. Although the tailings present high metal concentrations (Fe, Mn, Cd, and As), the high local background contents of metals and other previous anthropogenic contamination hamper tracing the sediment source based only on the geochemical signature. The Pb isotopic composition coupled with the metals enrichment factor of sediments and Suspended Particulate Matter (SPM) constitutes accurate proxies that trace the fate and dispersion of tailing particles downstream of the dam collapse. This approach shows that 1) The influence of the released tailing was restricted to the Paraopeba River and the Retiro Baixo reservoir, located upstream of the São Francisco River; 2) The tailings' contribution to particulate load ranged from 17 % to 88 % in the Paraopeba River; 3) Other regional anthropogenic activities also contribute to water and sediment contamination of the Paraopeba river.

Method development to characterise elephant tail hairs by LA-ICP-MS to reflect changes in elemental chemistry

This paper evaluated analytical methods used to generate time-series data from elephant tail hairs, which can be used to reflect changing exposure to environmental geochemistry. Elephant tail hairs were analysed by three methods sequentially, each providing data to inform subsequent analysis. Scanning Electron Microscopy (SEM) and X-ray Microanalysis visually showed the structure of the hair, specific structures such as tubules, and the mineral crusting around the edge of the hair, informing targeting of subsequent analysis by Laser Ablation-Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). LA-ICP-MS generated time-series data which informed sectioning of the tail hairs for subsequent quantitative analysis for potentially toxic elements and micronutrients using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) of dissolved tail hairs. This novel approach to characterise the tail hair enabled time-series analysis to reflect changes in environmental exposure which may result from seasonal or geochemical spatial variation and could inform elephant movement patterns. The seasonal change between wet and dry seasons was reflected down the length of the hair. Correlations were seen between LA-ICP-MS data and ICP-MS data in several elements including Mg, P, Ca, Fe, Na, Mn and U. This study provided time-series data for the analysis of elephant tail hairs by evaluating analytical challenges to obtaining quantitative data, such as improving protocols to ensure removal of extraneous material, determining where to section the tail hairs to best reflect environmental changes/exposure and ensuring representative analyses. A protocol was established to determine mineral status across a 12-18 month time period utilizing single elephant tail hairs.

Development and applications of GIS-based spatial analysis in environmental geochemistry in the big data era

The research of environmental geochemistry entered the big data era. Environmental big data is a kind of new method and thought, which brings both opportunities and challenges to GIS-based spatial analysis in geochemical studies. However, big data research in environmental geochemistry is still in its preliminary stage, and what practical problems can be solved still remain unclear. This short review paper briefly discusses the main problems and solutions of spatial analysis related to the big data in environmental geochemistry, with a focus on the development and applications of conventional GIS-based approaches as well as advanced spatial machine learning techniques. The topics discussed include probability distribution and data transformation, spatial structures and patterns, correlation and spatial relationships, data visualisation, spatial prediction, background and threshold, hot spots and spatial outliers as well as distinction of natural and anthropogenic factors. It is highlighted that the integration of spatial analysis on the GIS platform provides effective solutions to revealing the hidden spatial patterns and spatially varying relationships in environmental geochemistry, demonstrated by an example of cadmium concentrations in the topsoil of Northern Ireland through hot spot analysis. In the big data era, further studies should be more inclined to the integration and application of spatial machine learning techniques, as well as investigation on the temporal trends of environmental geochemical features.

Magnetic responses for heavy metal pollution recorded by the sediments from Bohai Sea, Eastern China

The Bohai Sea is facing multidirectional pressure from economic development and pollutant emissions. Magnetic minerals and heavy metal concentrations in the sediments of core M5 from the Bohai Sea were performed. The results of concentration-related magnetic parameters, heavy metal contents, and PLI (Tomlinson pollution load index) illustrate there are essential linkages of the sources, migration, and deposition. The predominant magnetic mineral was magnetite. Based on the chronological data from ²¹⁰Pb and ¹³⁷Cs activities, the increasing magnetic parameters and heavy metal concentrations at a depth of 81 cm were dated to 1950 CE, which corresponded to the establishment of the People's Republic of China; the decrease at depths of 37-45 cm and 16-18 cm may be related to the decline in steel production in 1960 CE and the Tangshan earthquake in 1978 CE, respectively. This study enriches relevant theories of environmental magnetism via the ecological and environmental protection of the coastal zones.

Rare earth elements (REEs): geochemical patterns and contamination aspects in Brazilian benchmark soils

Rare earth elements have been increasingly used in modern societies and soils are likely to be the final destination of several REE-containing (by)products. This study reports REE contents for topsoils (0-20 cm) of 175 locations in reference (n = 68) and cultivated (n = 107) areas in Brazil. Benchmark soil samples were selected accomplishing a variety of environmental conditions, aiming to: i) establishing natural background and anthropogenic concentrations for REE in soils; ii) assessing potential contamination of soils - via application of phosphate fertilizers - with REE; and, iii) predicting soil-REE contents using biomes, soil type, parent material, land use, sand content, and biomes-land use interaction as forecaster variables through generalized least squares multiple regression. Our hypotheses were that the variability of soil-REE contents is influenced by parent material, pedogenic processes, land use, and biomes, as well as that cultivated soils may have been potentially contaminated with REE via input of phosphate fertilizers. The semi-total concentrations of REE were assessed by inductively coupled plasma mass spectrometry (ICP-MS) succeeding a microwave-assisted aqua regia digestion. Analytical procedures followed a rigorous QA/QC protocol. Soil physicochemical composition and total oxides were also determined. Natural background and anthropogenic concentrations for REE were established statistically from the dataset by the median plus two median absolute deviations method. Contamination aspects were assessed by REE-normalized patterns, REE fractionation indices, and Ce and Eu anomalies ratios, as well as enrichment factors. The results indicate that differences in the amounts of REE in cultivated soils can be attributed to land use and agricultural sources (e.g., phosphate-fertilizer inputs), while those in reference soils can be attributed to parent materials, biomes, and pedogenic processes. The biomes, land use, and sand content helped to predict concentrations of light REE in Brazilian soils, with parent material being also of special relevance to predict heavy REE contents in particular.

Metal concentrations in marine sediments of the Rio de Janeiro Coast (Brazil): A proposal to establish new acceptable levels of contamination

This work aims to propose new standards to assess the degree of sediment contamination in saline and brackish environments, since the legislation currently used in Brazil is based on Canadian/American regulations, which do not comply with the conditions in Brazil. This study is based on geochemical analyses of 340 surface sediment samples collected in the Green Coast region (Rio de Janeiro, Brazil), including Mangaratiba, Angra dos Reis and Ribeira coves and Ilha Grande and Sepetiba bays. This region is influenced by industrial, harbor, urban and tourist activities and was affected by a dam rupture episode that released contaminated material. The results show heterogeneity in the distribution and range of metal concentrations in the study area depending on the supply of metals from natural and anthropogenic sources. Environmental characteristics such as coastal and tidal currents, water temperature and salinity, local depth, sediment grain size, sedimentary dynamics and biogeochemical processes influence the dispersion or retention of metals. The pollution load index (PLI) suggests that Sepetiba Bay is the region with the most environmental degradation due to anthropogenic contamination. In this context, we propose the establishment of new levels of contamination according to the Cd, Cr, Cu, Mn, Ni, Pb, V and Zn concentrations in sediments of salt and brackish waters, considering I) background level; II) level 1 - with anthropogenic influence; and III) level 2 - contaminated. The results of this work also suggest that, except for zinc, the range of metal concentrations admitted by Brazilian legislation are quite permissive and not adequate for Brazilian coastal environments.

Evaluation of the concentrations of elements at trace level in the Serinhaem River estuary, Bahia, Brazil, using chemometric tools

The Serinhaém River estuary is located in the Environmental Protection Area (EPA) of Pratigi, in the State of Bahia, Brazil, which is recognized for being a relatively well-preserved environment. In this work, the levels of aluminum (Al), arsenic (As), barium (Ba), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), vanadium (V), and zinc (Zn) were determined to evaluate the behavior of these chemical elements through geochemical parameters. Eighty-one sediment samples were collected in five sediment cores along the estuarine region. The results of the composition of the Serinhaém river basin showed high levels of Fe, Al, and Mn in the sediment samples. By using Principal Component Analysis, it was observed that 55.8% of the elements have a significant correlation with Fe, Al, and Mn, which may have the same origin or be associated with Fe and Mn oxy-hydroxides, and aluminosilicates. Although Cr, As, and V are correlated with Fe, Mn, and Al, their concentrations are above those established by NOAA, suggesting adverse effects on biota. Barium concentrations increased toward the outfall, where it meets the Camamu Bay, which is naturally enriched with this element. It was also possible to observe that along with the vertical profile, there were no variations in the concentrations of the elements, while along the estuary, it was possible to verify that the cores differ from each other. The estuary of the Serinhaém River can be considered to be influenced relatively little by human activities, and its concentrations can be considered as a base level for this coastal region.

Do soil amendments used to improve agricultural productivity have consequences for soils contaminated with heavy metals?

This study presents an analysis of the effects of manure and lime commonly used to improve agricultural productivity and evaluates the potential for such soil amendments to mobilise/immobilise metal fractions in soils contaminated from nearby mine tailings in the Zambian Copperbelt. Lime and manure were applied at the onset of the study, and their effects were studied over two planting seasons, i.e. 2016-17 and 2017–18. Operationally defined plant-available Cd, Cu, Ni, Pb and Zn in the soil, were determined by extraction with DTPA-TEA (diethylenetriaminepentaacetic acid-triethanolamine) and 0.01 M Ca(NO₃)₂, before, and after, applying the amendments. In unamended soils, Cd was the most available and Ni the least. Lime application decreased extractable Cd, Cu, Ni, Pb and Zn. The response to lime was greater in soils with an initially acidic pH than in those with approximately neutral pH values. Manure increased DTPA extractable Zn, but decreased DTPA and Ca(NO₃)₂ extractable Cd, Cu and Pb. Combined lime and manure amendment exhibited a greater reduction in DTPA extractable Cd, Ni, Pb, Zn, as well as for Ca(NO₃)₂ extractable Cd compared to separate applications of lime and manure. The amendments had a significant residual effect on most of the soil fractions between season 1 and 2. The results obtained in this study showed that soil amendment with minimal lime and manure whilst benefiting agricultural productivity, may significantly reduce the mobility or plant availability of metals from contaminated agricultural soils. This is important in contaminated, typical tropical soils used for crop production by resource poor communities affected by mining or other industrial activities.

Use of infrared spectroscopy and geospatial techniques for measurement and spatial prediction of soil properties

The main aim of this research was to assess the use of mid-infrared (MIR) spectroscopy and geostatistical model for the evaluation and mapping of the spatial variability of some selected soil properties across a field. It is with the view of aiding site-specific soil management decisions. The performance of the model for the prediction of the components (soil parameters) was reported using the coefficient of determination (R²) and root mean square error (RMSE) values of the validation data set. Results revealed that least square regression model performed better in predicting cation exchange capacity-CEC (R² = 0.88 and RMSE = 8.98), soil organic carbon-OC (R² = 0.88, RMSE = 0.55), and total nitrogen-TN (R² = 0.91 and RMSE = 0.04). The first five principal components (PC) accounted for 78.17% of the total variance (PC1 = 25.75%, PC2 = 18.06%, PC3 = 13.85%, PC4 = 11.12%, and PC5 = 9.39%) and represented most of the variation within the data set. The coefficient of variation ranged from 6.73% for soil pH to 57.02% for available phosphorus (av. P). The soil pH values ranged from 4.21 to 6.57. The mean soil OC density was 2.14 kg m⁻² within 50 cm soil depth. Nearly 96–97% of the soils contained av. P and sulfur (SO42−-S) below the critical levels. The overall results revealed that soil properties varied spatially. Hence, we suggest that mapping the spatial variability of soils across a field is a cost-effective solution for soil management.

Optimization of the photocatalytic degradation process of aromatic organic compounds applied to mangrove sediment

Polycyclic aromatic hydrocarbons (PAHs) are part of a class of organic compounds resistant to natural degradation. In this way, heterogeneous photocatalysis becomes useful to degrade persistent organic pollutants, however it can be influenced by environmental variables (i.e.: organic matter) and experimental factors such as: mass of the photocatalyst and irradiation time. The objective of this research was to use a factorial design 2^k as a function of the multiple response (MR) to evaluate simultaneously experimental conditions for the photodegradation of polycyclic aromatic hydrocarbons in contaminated mangrove sediment and its application in oil from Potiguar Basin in Brazil. The sediment samples collected in Belmonte city (Southern Bahia state) were contaminated with 0.25 mg kg⁻¹ of Acenaphthene, Anthracene, Benzo[a]Anthracene, Indene[1,2,3cd]pyrene, Dibenzo[ah]anthracene, Benzo[ghi]pyrene. Factors such as mass of the photocatalyst and irradiation time were evaluated in factorial design 2², with triplicate from the central point, to 1g of the PAH contaminated sediment. After performing the experiments, it was found that the best experimental condition for the degradation of all PAHs indicated by MR was the central point (0.5 g of photocatalyst and 12h of irradiation). For such conditions, the half-life of PAHs varied from 3.51 to 9.37 h and the degradation speed constant between 0.0740 to 0.1973 h⁻¹. The comparison of the optimized methodology between photolysis tests and heterogeneous photocatalysis was performed using the Kruskal-Wallis test, which indicated a difference for the reference solution, where heterogeneous photocatalysis was more efficient in the degradation of PAHs. The optimized methodology was apply in samples contaminated with crude oil from Potiguar Basin, no significant difference was observed in the aromatic fraction, using for the Kruskal-Wallis test. Heterogeneous photocatalysis has shown to be a promising remediation technique to remedy aromatic organic compounds in mangrove sediments.

A multi-approach assessment of land use effects on groundwater quality in a karstic aquifer

Groundwater represents almost half of the drinking water worldwide and more than one third of water used for irrigation. Agro-industrial activities affect water resources in several manners; one of the most important is leaching of agrochemical residues. This research identifies the major contributors of changes in groundwater quality comparing two contrasting land uses in a karstic area of the Yucatan peninsula as case study. Using a multiple approach, we assess the impact of land use with physicochemical data, multivariate analyses, hydrogeochemistry and nitrate isotopic composition. We confirmed that agricultural land use has a greater impact on groundwater quality, observed in higher concentration of nitrates, ammonium, potassium and electrical conductivity. Seasonality has an influence on phosphates and the chemical composition of the groundwater, increasing the concentration of dissolved substances in the rainy season. There was a clear effect of manure application in the agricultural zone and the nitrate isotopic composition of groundwater points toward recharge in certain areas. We consider that seasonality and land use effects are intertwined and sometimes difficult to separate, likely because of land use intensity and hydrogeochemical process at a local scale. Finally, we observed poor groundwater quality in the agricultural area during the wet season; thus, it is desirable to maintain non-agricultural areas that provide groundwater of appropriate quality.

Environmental geochemistry and cancer: a pertinent global health problem requiring interdisciplinary collaboration

Primary prevention is a key strategy to reducing the global burden of cancer, a disease responsible for ~ 9.6 million deaths per year and predicted to top 13 million by 2030. The role of environmental geochemistry in the aetiology of many cancers-as well as other non-communicable diseases-should not be understated, particularly in low- and middle-income countries where 70% of global cancer deaths occur and reliance on local geochemistry for drinking water and subsistence crops is still widespread. This article is an expansion of a series of presentations and discussions held at the 34th International Conference of the Society for Environmental Geochemistry and Health in Livingstone, Zambia, on the value of effective collaborations between environmental geochemists and cancer epidemiologists. Key technical aspects of each field are presented, in addition to a case study of the extraordinarily high incidence rates of oesophageal cancer in the East African Rift Valley, which may have a geochemical contribution. The potential merit of veterinary studies for investigating common geochemical risk factors between human and animal disease is also highlighted.

Open Access publishing practice in geochemistry: overview of current state and look to the future

Open Access (OA) describes the free, unrestricted access to and re-use of research articles. Recently, a new wave of interest, debate, and practice surrounding OA publishing has emerged. In this paper, we provide a simple overview of the trends in OA practice in the broad field of geochemistry. Characteristics of the approach such as whether or not an article processing charge (APC) exists, what embargo periods or restrictions on self-archiving' policies are in place, and whether or not the sharing of preprints is permitted are described. The majority of journals have self-archiving policies that allow authors to share their peer reviewed work via green OA without charge. There is no clear relationship between journal impact and APC. The journals with the highest APC are typically those of the major commercial publishers, rather than the geochemistry community themselves. The rise in OA publishing has potential impacts on the profiles of researchers and tends to devolve costs from organizations to individuals. Until the geochemistry community makes the decision to move away from journal-based evaluation criteria, it is likely that such high costs will continue to impose financial inequities upon research community. However, geochemists could more widely choose legal self-archiving as an equitable and sustainable way to disseminate their research.

Screening of the microelements composition of drinking well water of Transcarpathian region, Ukraine

Background

For Transcarpathian region, with a pronounced landscape diversity of territories and significant areas of nature reserves, well water is an important source of drinking water. Screening of the microelement composition of drinking well water in Transcarpathia has not been carried out before. The microelement composition of such well water can be considered as the natural (baseline) indicator of quality.

Methods

We screened of the microelement (Cu, Zn, Fe, P, Ca, Mg, Mn, Mo, Co, As, Se, I, Br and F) composition of drinking well water in Transcarpathian region (for all 13 districts). Standard methods were used to determination the concentration of chemical elements in well water: electrothermal atomic absorption spectroscopy (Cu, Zn, Fe, Mn, Mo, Co), flame photometry (Ca, Mg), inverse voltammetry (total iodine), potentiometry (F, Br), fluorimetric (Se) and spectrophotometric methods (P, As).

Results

The content of chemical elements in well water varies over a wide range, in particular for Cu: 3.27–11.6 μg⋅L⁻¹, Zn: 8.16–38.2 μg⋅L⁻¹; Fe: 37.9–411 μg⋅L⁻¹; P: 51.4–193 μg⋅L⁻¹; Ca: 85–139 mg⋅L⁻¹, Mg: 10.2–18.9 mg⋅L⁻¹, Mn: 22.8–78.1 μg⋅L⁻¹; Mo: 2.33–8.96 μg⋅L⁻¹; Co: 1.72–3.38 μg⋅L⁻¹; As: 2.9–17.4 μg⋅L⁻¹; Se: 0.95–3.6 μg⋅L⁻¹; I: 0.94–4.4 μg⋅L⁻¹; Br: 712–3098 μg⋅L⁻¹; F: 71–149 μg⋅L⁻¹. The tendency that the content of microelements (Cu, Zn, Mn, Mo, Co, As, Se, I, Br, and F) in well waters of different landscape zones was evaluated through Spearman's coefficients. The content of trace elements in the waters of different landscape zones increases in the series: lowland landscape > foothill landscape > mountainous landscape (Spearman's coefficients: Cu – 0.62, Zn – 0.85, Mn – 0.69, Mo – 0.83, Co – 0.79, P – 0.74, As – 0.72, Se – 0.75, I – 0.80, Br – 0.91, F – 0.73).

Conclusion

It is shown that the chemical composition of well water can be considered as the natural (baseline) indicator of quality of groundwater in Transcarpathia, taking into account topographic and geochemical features of the territories. Among the main problems of drinking well water in Transcarpathia are the relatively high content of Fe (typical for different landscape zones), as well as the low content of Se, I and F. The correlation of inter-elements content of chemical elements in drinking well waters of Transcarpathia has been revealed. The most pronounced correlations are observed for such pairs of microelements: Co–Mo (r > 0.95), I–Br (r > 0.92), Zn–Br (r > 0.89), Cu–Co (r > 0.84), Se–Co (r > 0.84), Mo–P (r > 0.84), Mo–I (r > 0.82) and Zn–Mo (r > 0.80).

Investigation of the relationship between rare earth elements, trace elements, and major oxides in soil geochemistry

Investigation on the behavior of elements in the soil is important both in exploration and environmental geochemistry studies. Rare earth elements (REEs) are the most useful among all trace elements. REE studies have shown that they have important applications in igneous, sedimentary, and metamorphic petrology. This work aims to investigate the relationship of these elements with one another and the behavior of the major oxides and trace elements with REEs. Soil samples were obtained from the alteration site possibly related to mineralization and were analyzed for major oxides, trace elements, and REEs. The relationships between the major oxide-trace element/heavy metal and REE were investigated by statistical methods, such as descriptive statistics, correlation coefficient, and principle component analysis. According to the correlation coefficient matrix, light REEs (LREEs) showed weak to moderate negative correlation with MgO and MnO and moderately positive correlation with SiO₂ and K₂O. No association was detected between the heavy REEs (HREEs) and the main oxides, but a strong positive correlation with LREEs was observed. For the trace elements, LREE showed a weak positive correlation with Ba and Sn and moderate to strong positive correlation with As, Hf, Nb, Rb, Ta, Th, U, W, and Zr. They also displayed weak to moderate correlation with Sc, Co, Zn, Ni, and V. HREE showed weak to moderate positive correlation with Ni, Cs, Ga, Hf, Th, Zr, As, and LREE. Although REEs exhibited no direct correlation with Au and Ag, they showed a good correlation with some trace elements that are related to hydrothermally altered products. This study showed that REEs can also be used in exploration and environmental geochemistry studies by exploiting the relationship between REEs and other trace/heavy metal elements.

A hydro-thermal-geochemical modeling framework to simulate reactive transport in a waste coal area under amended and non-amended conditions

Acid mine drainage (AMD) is a major cause of water quality deterioration across watersheds where acidic coal refuse (CR) piles are located. The oxidation of pyrite (the most common sulfide mineral), found in many of the CR piles, releases major ions, such as Fe²⁺, Fe³⁺, SO42−, and H⁺ into the environment. Bauxite residue (BR), commonly called alkaline clay (AC), a highly alkaline byproduct of the alumina refining process, can be combined with coal mine refuse to reduce and potentially eliminate the AMD problem associated with waste coal piles. A new hydro-thermal-geochemical model is developed in this study to simulate the reactive transport processes in AMD-treated areas. First, the model is tested at the experimental plots located within a CR pile in Greene County, Pennsylvania (USA), where two of the plots are used to show the impact of BR on CR piles. Then, the model capabilities are tested at a mine-impacted watershed in Indiana County, Pennsylvania (USA). In general, the model not only captures the patterns of both soil moisture, soil temperature and chemical concentrations at plots scales but it is also successfully implemented at a watershed scale. In conclusion, this study shows encouraging results regarding the AMD remediation simulation at different spatial scales.

Sr isotope discrimination of multi species aquaculture productions at a worldwide scale and contribution of the water reservoir in Sr plant input

Aquatic plants commonly used in landscaping or as ornaments are subject to a growing worldwide market that is source of trade between countries which can induce the transfer of unwanted invasive alien plant species. To protect national biodiversity and economy, authorities promote the use of local markets without however providing the method to do so. This study deals with the feasibility of using Sr stable isotopes for discriminating the origin of aquatic plants at a worldwide scale. More than 15 aquatic plant species were collected from main producers in four countries (China, Hungary, Germany, France). Each plant was analysed for its ⁸⁷Sr/⁸⁶Sr ratio and the results are compared within samples from each producer and between countries. For a given produce, significant ⁸⁷Sr/⁸⁶Sr can be measured as a function of the plant species. However, at the scale of Europe, plants from different producers are almost isotopically identical with ⁸⁷Sr/⁸⁶Sr ratios of 0.71228 ± 218.10^-5, 0.71116 ± 178.10^-5 and 0.71066 ± 156.10^-5 for France, Hungary and Germany, respectively. These values are clearly distinguishable from those measured in Chinese aquatic plants, which yield a mean ⁸⁷Sr/⁸⁶Sr ratio of 0.70591 ± 168.10^-5. This Sr isotopic discrimination between European and Chinese aquatic plants is explained by the specific agricultural and hydrogeological environments of the producing countries. Indeed, the cycle of Sr in aquatic plants is studied here for the first time. Natural and anthropic materials of French origin were collected and characterized in terms of ⁸⁷Sr/⁸⁶Sr. Mixing models reveal that irrigation water is the main source of Sr for plants (35-85%). Clays from the substrate (4-38%) and fertilizers (5-19%) can also contribute, in proportions depending on the plant species. This model accounts for the small variations in ⁸⁷Sr/⁸⁶Sr ratios of species from the same producer and allows a discrimination between producers using different agricultural practices.

Diversity of Betaproteobacteria revealed by novel primers suggests their role in arsenic cycling

High arsenic concentration in groundwater is a severe environmental problem affecting human health, particularly in countries of South and South-East Asia. The Bengal Delta Plain (BDP) distributed within India and Bangladesh is a major arsenic-affected region where groundwater is the primary source of drinking water. Previous studies have indicated that members of the bacterial class Betaproteobacteria constitute a major fraction of the microbial community in many of the aquifers within this region. Bacteria belonging to this class are known to be involved in redox cycling of arsenic as well as other metals such iron and manganese, thereby impacting arsenic mobilization and immobilization. While microbial diversity in arsenic-contaminated environments is generally assessed using universal 16S rRNA gene primers, targeted evaluation of Betaproteobacteria diversity remains poorly constrained. In this study, bacterial diversity was investigated in the groundwater from two shallow aquifers (West Bengal, India) based on 16S rRNA gene clone libraries and sequencing using a custom-designed pair of primers specific to Betaproteobacteria. Specificity of the primers was confirmed in silico as well as by the absence of PCR amplification of other bacterial classes. Four major families (Burkholderiaceae, Comamonadaceae, Gallionellaceae and Rhodocyclaceae) were detected among which members of Burkholderiaceae represented 59% and 71% of the total community in each aquifer. The four OTUs (operational taxonomic units; 97% sequence identity) within Burkholderiaceae were close phylogenetic relatives of bacteria within the genus Burkholderia known to solubilize phosphate minerals. Additionally, the OTUs belonging to Gallionellaceae were closely related to the members of the genera Gallionella and Sideroxydans, known to oxidize iron under microaerophilic conditions. These results suggest that members of Betaproteobacteria can potentially influence iron and phosphorus cycling which can influence biogeochemistry in arsenic-contaminated aquifers of the BDP.

Potentially toxic elements in urban topsoils and health risk assessment for the mining W-Mo center in the Baikal region

The main threats to health are associated with the entry of potentially toxic elements (PTEs) into human bodies. The aim of this study is to assess the impact of the Zakamensk W-Mo deposit development on soil surface horizons and the health of the local population. The results of the geochemical survey of 2012 revealed the spatial distribution patterns and abundances of 15 PTEs. The elements bulk contents were determined by ICP-MS and ICP-AES. The impact of geochemical situation on the health of the population of Zakamensk was also assessed using the mortality rates from diseases of the digestive and respiratory organs, neoplasms, including malignant tumors of the digestive and respiratory organs in 2008-2012. The tailing dumps have increased concentrations of W, Cd, Pb, Sb, Mo, Cu, Zn, Sn, As, and Co due to petrochemical characteristics of the ore. The soils of the industrial zone accumulate W, Cd, Mo, Pb, Sb, Zn, Cu, and Sn due to the waste storage sites deterioration and the thermal power plant and the foundry emissions. The multi-story residential zone soils accumulate W, Cd, Pb, Zn, and Mo. Tungsten, Pb, Sb, Co, V, and Cr cause the greatest harm to adults and children and together account for 92-96% of the hazard index. Cadmium and Cr are the most dangerous carcinogenic elements in Zakamensk. Despite the closure of DTMP more than 15 years ago, the level of the total risk of developing malignant diseases indicates a catastrophic environmental situation.

New indices regarding the dominance and diversity of communities, derived from sample variance and standard deviation

Dominance and diversity are important characteristics for the description of communities. The most commonly used indices are Simpson's dominance indexand Shannon's and Simpson's indices of diversity. This paper uses the basic concepts of statistics as applied to community analysis to develop new dominance and diversity indices that will enable scientists to establish correlations among various indices. The present study proves that the variance of the number of individuals of different species in a sample can be used to calculateSimpson's dominance and diversity indices. New indices have been developed from the ratios ofthe variance to number of species, and the mean number of individuals per species in a quadrat. A wide range of data, varying from high dominance to high evenness, was simulated for 25 quadrats, with each quadrat having ten species and 100 individuals in different combinations. Variance and standard deviation-based indices were computed using the simulated data and were found to be highly correlated with Simpson's and Shannon's indices. The proposed indices will give both the dominance and diversity of a community on the same scale based on the same statistic. Another important contribution of the present study relates to the variance of a sample consisting of a single value. It has been proved that the variance of a sample having only one value is equal to the square of that value. The paper establishes a new link between diversity studies and statistics.

Defluoridation of water through the transformation of octacalcium phosphate into fluorapatite

The consumption of water with fluoride concentration higher than 1.5 mg/L (WHO recommended limit) is recognized to cause serious diseases, and fluoride removal from natural contaminated waters is a health priority for more than 260 million people worldwide. The octacalcium phosphate (OCP), a mineralogical precursor of bio-apatite, is here tested as a fluoride remover. A new two-step method for the synthesis of OCP is proposed: 1) synthesis of brushite from calcium carbonate and phosphoric acid; 2) subsequent hydrolysis of brushite. Fluoride removal experiments are performed in batch-mode using different initial concentrations of fluoride (from 40 to 140 mg/L) and reaction times. Most of fluoride is removed within the first 2 h of all experiments, and the drinkable limit of 1.5 mg/L is reached within a minimum of 3 h for an initial fluoride concentration of 40 mg/L. The experimental fluoride removal capacity of OCP is 25.7 mg/g, and 4 g of OCP can effectively treat 1 L of water with fluoride concentration up to 50 times higher than the drinking limit of 1.5 mg/L. XRD and chemical characterization of the solid phases, before and after the removal experiments, indicate that OCP transforms into fluorapatite (FAP) uptaking fluoride from solution.

Using lead isotopes and potentially toxic elements to trace pollutant sources in the northern region of Guanabara Bay, southeastern Brazil

Guanabara Bay (southeastern Brazil) is located in the metropolitan region of the Rio de Janeiro State and is being affected by high levels of anthropization. This work analyzes not only the concentrations of potentially toxic elements (PTEs), but also Pb stable isotopes to trace possible anthropogenic and natural sources of pollutants in the northern region of Guanabara Bay and the Suruí and Magé rivers. The Governador Island Channel, the regions to the north of Governador Island, north and west of Paquetá Island, and the Magé coast are most affected by PTEs. In the study area, high PTE concentrations result from both natural and anthropogenic sources. The main sources of metals include municipal solid waste incineration, atmospheric aerosols, and ore lead tailings, as indicated by Pb isotopes. This work shows that Pb stable isotopes, associated with metal contamination, can improve the assessment of estuarine environment quality.

A possible role of biogenic silica in esophageal cancer in North China?

Certain areas in North China have the highest incidence of esophageal squamous cell carcinoma (ESCC) in the world, which has not seen convincing explanation by any risk factor yet. Biogenic silica in millet bran was linked to ESCC in the early 1980s but the hypothesis was largely dismissed because of the lack of geographic correlation between millet consumption and ESCC. Later epidemiological studies disclosed the linkage of wheat consumption in North China to ESCC instead. Now, we hypothesize silica phytoliths (silicified bodies that have definite shapes) from wheat chaff are a major etiologic factor of ESCC in this region. This hypothesis is supported by the potentially high abundance of silica phytoliths on the bracts of wheat (Triticum aestivum) in North China due to favorable Si-accumulation genotype, arid climate, and siallitic soil with bioavailable Si. These silica phytoliths can contaminate wheat flour and cause repeated local injuries in the esophagus and stimulate proliferation by providing anchorage.

Measuring the distribution of trace elements amongst dissolved colloidal species as a fingerprint for the contribution of tributaries to large boreal rivers

Organic and inorganic colloids play important roles governing the speciation, transport, and bioaccessibility of trace elements in aquatic systems. These carriers are especially important in the boreal zone, where rivers that contain high concentrations of iron and organic matter are prevalent. The distribution of trace elements amongst different colloidal species (or "speciation profile") can therefore be useful as a fingerprint to detect different trace element sources and for tracking colloid transformations, with implications for bioaccessibility. Asymmetrical flow field-flow fractionation coupled to an inductively coupled plasma mass spectrometer was applied to detect the source of trace elements based on their speciation profile along a 125-km stretch of a large river in the Canadian boreal forest. Both the concentration and proportion of bound trace elements were increased by tributary inputs: bound As, Co, Fe, Mn, Pb, U, and Zn increased monotonically from upstream to downstream, increasingly resembling the speciation profile of tributaries. Principal component (PC) analysis also revealed tributary contributions of bound Cu, Ni, Th, V, and Y reflecting their higher concentrations in tributaries, and PC scores also increased monotonically from upstream-downstream. Monotonically decreasing concentrations of mainly ionic and small (i.e. <ca. 300 Da) As, Ba, Mo, and U species were also observed from upstream-downstream.

Contamination of soils by potentially toxic elements in the impact zone of tungsten‑molybdenum ore mine in the Baikal region: A survey and risk assessment

Mining of mineral resources exerts strong impact on the environment and leads to irreversible changes in vegetation, soils, atmosphere, surface and ground waters. The aim of this study is to assess the modern geochemical state of soil cover in Zakamensk, a city located in Buryat Republic (Russia) and known as one of the biggest ore mining center in the former Soviet Union. The center was operating for 68 years and closed 17 years ago. Soil-geochemical survey was conducted in 2012 and included collection of 103 soil samples in Zakamensk and 27 samples in the background areas. The bulk contents of 16 potentially toxic elements (PTEs) in the soil samples were determined by mass spectrometry and by atomic emission spectrometry with inductively coupled plasma. Background sites are characterized by increased concentrations of ore elements W and Mo. The mineral deposit development and physical and chemical weathering of tailings' material have led to a sharp increase in Bi, Cd, Cu, Mo, Pb, Sb, W and Zn levels in the soils of different land-use areas. Near the tailings, the concentration of Sb in soils was 356 times higher than in the background area; Cd - 70 times; Mo, Bi, Cu, and W - 42-55 times; Pb and As - 34-37 times; and Zn and Sn - 6-12 higher. In the north of the city a prominent anomaly of PTEs occurs in sandy sediments of the Modonkul floodplain. It was formed due to the washout and subsequent sedimentation of suspended matter carried by the Modonkul River from the Barun-Naryn, the Dzhida, and emergency tailings. So, the anthropogenic activities are the most important source of ore and accompanying elements in the urban soils. High levels of accessory elements also depends on natural factors such as physicochemical properties of soils, position in the landscape, and genesis of parent materials. The environmental assessment of topsoils in Zakamensk showed that Pb, Sb, Cd, and As concentrations exceeds the Russian MPCs by 1.7-7.8 times, which creates a significant hazard for the environment and adversely affects human health.

Potentially toxic elements in urban soils: source apportionment and contamination assessment

Soils play a vital role in the quality of the urban environment and the health of its residents. City soils and street dusts accumulate various contaminants and particularly potentially toxic elements (PTEs) from a variety of human activities. This study investigates the current condition of elemental concentration in the urban soils of Hamedan, the largest and the fastest-growing city in western Iran. Thirty-four composite soil samples were collected from 0 to 10 cm topsoil of various land uses in Hamedan city and were analyzed for total concentration of 63 elements by ICP-MS. The possible sources of elemental loadings were verified using multivariate statistical methods (principal component analysis and cluster analysis) and geochemical indices. The spatial variability of the main PTEs was mapped using geographic information system (GIS) technique. The results revealed a concentration for As, Co, Cr, Mn, Mo, Ni, and V in the soil samples comparable to the background values as well as a range of associations among these elements in a single component suggesting geogenic sources related to geological and pedogenic processes, while the soils mostly presented a moderate to considerable enrichment/contamination of Cd, Zn, Pb, and Sb and moderate enrichment/contamination of Cu, Zn, and Mo. It was found that anthropogenic factors, vehicular traffic in particular, control the concentration of a spectrum of elements that are typical of human activities, i.e., Cd, Cu, Hg, Pb, Sb, and Zn. Lead and Sb were both the most enriched elements in soils with no correlation with land use highlighting general urban emissions over time and the impact of transport networks directly on soil quality. The highest concentrations of As were recorded in the southern part of the city reflecting the influence of metamorphic rocks. The effect of the geological substrate on the Co and Ni contents was confirmed by their maximum concentrations in the city's marginal areas. However, high spatial variability of urban elements' contents displayed the contribution of various human activities. In particular, the increased concentration of Cd, Sb, and Pb was found to be consistent with the areas where vehicular traffic is heaviest.

Multielement geochemistry identifies the spatial pattern of soil and sediment contamination in an urban parkland, Western Australia

Urban environments are dynamic and highly heterogeneous, and multiple additions of potential contaminants are likely on timescales which are short relative to natural processes. The likely sources and location of soil or sediment contamination in urban environment should therefore be detectable using multielement geochemical composition combined with rigorously applied multivariate statistical techniques. Soil, wetland sediment, and street dust was sampled along intersecting transects in Robertson Park in metropolitan Perth, Western Australia. Samples were analysed for near-total concentrations of multiple elements (including Cd, Ce, Co, Cr, Cu, Fe, Gd, La, Mn, Nd, Ni, Pb, Y, and Zn), as well as pH, and electrical conductivity. Samples at some locations within Robertson Park had high concentrations of potentially toxic elements (Pb above Health Investigation Limits; As, Ba, Cu, Mn, Ni, Pb, V, and Zn above Ecological Investigation Limits). However, these concentrations carry low risk due to the main land use as recreational open space, the low proportion of samples exceeding guideline values, and a tendency for the highest concentrations to be located within the less accessible wetland basin. The different spatial distributions of different groups of contaminants was consistent with different inputs of contaminants related to changes in land use and technology over the history of the site. Multivariate statistical analyses reinforced the spatial information, with principal component analysis identifying geochemical associations of elements which were also spatially related. A multivariate linear discriminant model was able to discriminate samples into a-priori types, and could predict sample type with 84% accuracy based on multielement composition. The findings suggest substantial advantages of characterising a site using multielement and multivariate analyses, an approach which could benefit investigations of other sites of concern.

Lead isotopic fingerprint in human scalp hair: The case study of Iglesias mining district (Sardinia, Italy)

The Sulcis-Iglesiente district (SW Sardinia, Italy) has been, until recently, one of the most important Italian polymetallic mining areas for the extraction of lead. Epidemiological studies conducted over several decades have indicated this site at high risk of environmental crisis with possible adverse effects on the public health. In the present paper we discuss Pb isotope signatures in human scalp hair and road dust collected from the Sulcis-Iglesiente area in order to trace the exposure of populations to potential Pb sources. A total of 23 determinations (20 on hair samples and 3 on road dust samples) of lead isotope ratios (²⁰⁶Pb/²⁰⁷Pb and ²⁰⁸Pb/²⁰⁶Pb) were carried out. The obtained results were integrate with literature data regarding the total content of Pb in hair samples from the same study area. Hair from children living in Sant'Antioco exhibited lead isotope ratios in the ranges 1.152-1.165 for ²⁰⁶Pb/²⁰⁷Pb and 2.101-2.108 for ²⁰⁸Pb/²⁰⁶Pb, while hair samples from Iglesias resulted less radiogenic: ²⁰⁶Pb/²⁰⁷Pb~1.147-1.154 and ²⁰⁸Pb/²⁰⁶Pb~2.106-2.118. These values pointed to a multi-source mixing between the less radiogenic sources, corresponding to the Pb ore deposits, and the more radiogenic sources identified in local background.

Geochemical disturbance of soil cover in the nonferrous mining centers of the Selenga River basin

The anthropogenic geochemical transformation of soil cover in large nonferrous mining centers of the Selenga River basin was assessed. The results of the geochemical survey of 2010-2012 revealed the spatial distribution patterns and abundances of 18 hazardous heavy metals and metalloids in the soils of Erdenet (Mongolia) and Zakamensk (Buryat republic, Russian Federation). In both cities, mining activities disturbed soil cover which accumulates Mo, Cu, As, Sb, W in Erdenet and Bi, W, Cd, Be, Pb, Mo, Sb in Zakamensk. Maximum accumulation of elements in Erdenet is restricted to the industrial zone. In Zakamensk, it has spread on ½ of the territory with the degree of multielemental pollution exceeding the extremely dangerous level by 16 times. The effect of mining centers on the state of the river system is local and does not spread to the Selenga River. Downstream from Erdenet, an artificial pool intercepts heavy metal and metalloid flows of the Erdenetii-Gol River. By contrast, downstream from the tailing dumps of the Dzhida tungsten-molybdenum plant the concentrations of ore elements W and Mo and their accessories Bi and Cd in the Modonkul River exceed background values by 146, 20, 57, and 21 times, respectively, decreasing by an order of magnitude 30 km downstream.

Evaluation of potential effects of soil available phosphorus on soil arsenic availability and paddy rice inorganic arsenic content

The transfer of arsenic from paddy field to rice is a major exposure route of the highly toxic element to humans. The aim of our study is to explore the effects of soil available phosphorus on As uptake by rice, and identify the effects of soil properties on arsenic transfer from soil to rice under actual field conditions. 56 pairs of topsoil and rice samples were collected. The relevant parameters in soil and the inorganic arsenic in rice grains were analyzed, and then all the results were treated by statistical methods. Results show that the main factors influencing the uptake by rice grain include soil pH and available phosphorus. The eventual impact of phosphorus is identified as the suppression of As uptake by rice grains. The competition for transporters from soil to roots between arsenic and phosphorus in rhizosphere soil has been a dominant feature.

Trace elements in scalp hair of children chronically exposed to volcanic activity (Mt. Etna, Italy)

The aim of this survey was to use scalp hair as a biomonitor to evaluate the environmental exposure to metals and metalloids of schoolchildren living around the Mt. Etna area, and to verify whether the degree of human exposure to trace elements is subject to changes in local environmental factors. Twenty trace elements were determined in 376 samples of scalp hair from schoolboys (11-13 years old) of both genders, living in ten towns located around the volcanic area of Mt. Etna (Sicily). The results were compared with those (215 samples) from children living in areas of Sicily characterized by a different geological setting (reference site). As, U and V showed much higher concentrations at the volcanic site whereas Sr was particularly more abundant at the reference site. Linear Discriminant Analysis (LDA) indicated an Etna factor, made up of V, U and Mn, and a second factor, concerning the reference site, characterized by Ni and Sr, and to a lesser extent by Mo and Cd. Significant differences in element concentrations were also observed among three different sectors of Mt. Etna area. Young people living in the Mt. Etna area are naturally exposed to enhanced intakes of some metals (V, U, Mn) and non-metals (e.g., As) than individuals of the same age residing in other areas of Sicily, characterized by different lithologies and not influenced by volcanic activity. The petrographic nature of local rocks and the dispersion of the volcanic plume explain the differences, with ingestion of water and local food as the most probable exposure pathways.