Despite numerous studies demonstrating the negative impact of rare earth elements (REE) and yttrium (Y) on human health, only limited data are available on their concentrations in mineral-rich medicinal waters, which are used worldwide for centuries to improve human health. In this work, we present a new, comprehensive dataset of REEs + Y in the mineral waters of the dominant Cl–Na type, traditionally used for medicinal purposes. Our results reveal a high variability in the REEs (2.76–1688.20 ng/L) and Y (1.80–451.10 ng/L) concentrations, as well as the EUS (European Shale) normalized REE patterns characterized by heavy REE (HREE) predominance and, less frequently, middle REE (MREE) enrichment. The HREE-enriched patterns reflect REE complexation primarily with (di)carbonate and sulfate ions, along with the preferential removal of light REEs (LREEs) through particle scavenging, while the latter suggests the presence of organic matter capable of complexing with MREEs. Several individual REE anomalies were also identified, including lanthanum (La), cerium (Ce), europium (Eu), and gadolinium (Gd). These may indicate bacterial activity, changes in redox conditions or the presence of an oxygenated zone, weathering of Eu-enriched mineral phases, and specific complexation reactions, respectively. This study demonstrates that tracking the variation in REE + Y signatures can provide deeper insights into the geochemical evolution of waters, even those with relatively homogeneous physicochemical properties.

We present the first comprehensive study on effluent water from mining, oil, natural gas, and geothermal operations in Poland. In 2019, we explored chemical composition of effluent samples collected from 67 locations in Poland representing various oil and gas, mining, and geothermal operations. It has been found that the effluents contained large amount of various elements. Those elements are critical and indispensable for the European Union industry and renewable energy technologies. Thus, the recovery opportunity of critical elements from the effluent water was discussed. We highlighted the main needs and directions for further development of desalination technologies for effluent water. The majority of the analyzed water samples were characterized by high concentration levels of total dissolved solids in the range from 5 to 150 g/L. The highest concentrations of elements in investigated water samples, from several tens to hundreds of mg/L, were observed for K, Mg, Br, Ba, B, Mn, Li, SiO2, and Sr. Additionally, most of the mine and geothermal water samples contained several tens of g/L NaCl. The most valuable element found in the investigated water samples was lithium. Desalted fresh water can be reused in agriculture or industry. Thus, desalination and extraction of critical elements from effluent water is a sustainable solution to the water scarcity problem in Poland caused by climate warming as well as a means to strengthen resilience of the resources supply for agriculture, industry, and renewable energy technologies.

In India, surface water reservoirs are widely harnessed to meet a variety of needs, including domestic, agricultural, and industrial applications. The quality of these resources, particularly in coal mine regions, undergoes substantial deterioration due to the discharge of various wastes (industrial, municipal, and runoff water) and coal ash deposition. The Korba basin, shaped by mining activities, shallow groundwater levels, and the flow of the expansive Hasedo River, features numerous ponds, pit lakes, and canals. A significant health concern in this area is the prevalence of fluorosis disease among the local population. The main aim of this study was to evaluate the water quality of reservoirs, including ponds, pit lakes, canals, and rivers, with a focus on identifying contaminant levels and tracing the sources of chemical species such as carbonate and organic carbons, anions, and metals. During the period from 2012 to 2017, elevated carbon contents (varying from 1010 to 4420 mg·L− 1) markedly contributed to increased total dissolved solids (TDS), with values ranging between 2865 and 5540 mg·L− 1. fluoride (F−), aluminum (Al), iron (Fe), and manganese (Mn) concentrations in all surface water bodies exhibited variations within the ranges of 1.8–4.4, 0.42–1.91, 0.3–1.22, and 1.0–2.1 mg·L− 1, respectively. This study delves into the temporal and seasonal variations, water quality indices, and toxicities associated with the identified contaminants.

In areas of contrasting geology, local but significant spatial changes in environmental conditions can occur suddenly and unexpectedly within aquifers, hampering accurate assessment of groundwater chemistry. Recently, the rare earth elements (REEs) have become extensively used in identifying geochemical processes in aqueous systems, due to their unique sensitivity to environmental changes. In this study, the REEs and Y (yttrium), combined with the chemical parameters of the main, minor and trace water components, and with the isotopic signatures of δ18O-H2O, δ2H-H2O, 3H-H2O, δ34S-SO4, δ18O-SO4, were investigated in order to gain a better understanding of the geochemistry of the groundwaters in the Holy Cross Mountains, which possesses a diverse hydrogeological system. The waters studied are ‘young’, meteoric-derived, of acidic to slightly alkaline pH (4.95–7.75) and TDS values of 38.97–2713.91 mg/L. They represent predominantly the HCO3-Ca-Mg and less often the HCO3-Ca-SO4-(Mg) or SO4-Ca-(Mg) types. The dissolved (<0.45 μm) concentrations of the REEs (5.55 to 13,857.35 ng/L) and Y (4.43 to 2450.22 ng/L) in the waters studied are the result of host rock dissolution, and tend to increase significantly, by up to several orders of magnitude, via interactions between the rocks and acidic waters. Speciation calculation reveals that dissolved REE + Y in neutral and alkaline waters are transported mainly as bicarbonate (CO3)2− and carbonate CO3+ complexes, while in a more acidic environment these elements occur preferably as free ions (REE3++Y3+), and their abundance gradually increases along with decreasing pH value. The EUS (European Shale) normalized REE patterns of the waters studied show two distinct dominant types: (i) upwards-sloping with HREE-enrichment (LREEsHREEs). The first pattern type reflects REE fractionation in alkaline and oxygenated waters, leading to preferential LREE adsorption onto mineral particles, accompanied by complexation of HREEs with carbonate and bicarbonate ions, while the second pattern type results from dissolution of the host rocks in more acidic conditions. The REE patterns in the waters studied are mostly different from the REE patterns characteristic of the host rocks, except for some water samples from carbonate aquifers. Ce and Eu anomalies were recorded in the waters studied. Some of the negative Ce and positive Eu anomalies were inherited from host rock dissolution, while other negative or positive Ce anomalies reflect oxygenic or more reducing conditions, respectively.

Comprehensive assessment of groundwater quality in mining-affected regions is crucial to sustainably manage water resources and protect public health and ecosystems. This study investigated the hydrogeochemical characteristics and water quality of 18 dug wells in the Korba basin, Chhattisgarh, India, an area heavily impacted by coal mining activities. Water samples were collected over three seasons (pre-monsoon, monsoon, and post- monsoon) and analyzed to determine physicochemical parameters, major ions, trace elements, and carbon content. Results revealed very high total dissolved solids concentrations ranging from 315 to 19,738 mg L- 1 . Nitrate levels surpassed the Bureau of Indian Standard (BIS) limit of 45 mg L- 1 in over 50% of samples, reaching a maximum of 200 mg L- 1 . Fluoride concentrations in all samples exceeded the BIS limit (1.5 mg L- 1 ), ranging from 1.5 to 15.2 mg L- 1 . The predominant water type was Ca-Mg-HCO3, primarily influenced by rock-water interactions. Factor analysis indicated that both geogenic and anthropogenic processes influence pollution levels. Pollutant concentrations exhibited seasonal variations, generally peaking during the monsoon period. Temporal analysis from over six years revealed increasing trends for most parameters, indicating deteriorating water quality. Based on Water Quality Index values, all samples were classified as unsuitable for drinking, while assessments of irrigation water quality using various indices indicated that 61.11% of samples were suitable for agricultural use. The findings provide data to inform decision-making and public health protection in this heavily industrialized region and emphasize the urgent need for sustainable water resource management and pollution prevention strategies in the Korba basin to align with UN Sustainable Development Goals 3 (good health and well-being) and 6 (clean water and sanitation).

Several million tons of coal are extracted which discharge the contaminated mineral water into the environment in the coal mines located in the Korba basin (Chhattisgarh, India) chosen as the study area. The aim of this work is to describe: (i) the physico-chemical characteristics (pH, EC, TDS, DO, RP, CC (carbonate carbon), OC (organic carbon) F-, Cl-, NO3-, SO42-, SiO44-, PO43-, Na+, K+, Mg2+, Ca2+, Al, As, Sb, Fe, Mn, Zn, Cd, Pb, and Hg) of the coal mine water samples, (ii) spatial, seasonal (i.e. PrM (pre-monsoon), M (monsoon) and PtM (post monsoon) and temporal (over the period of 2012-2017) variations, (iii) sources of contaminants from fourteen coal mines, (iv) suitability of the water for drinking and other uses, and (v) health impact of the mine water in view of developing remedial approaches.The mine water is neutral in nature with high TDS (total dissolved solid) values ranging from 620 to 13711 mg L-1 due to mainly high carbon content. The concertation of all species lies between 519-11432 mg L-1 with maximum value of OC. The most dominating species were OC, CC, Cl-, NO3-, SO42-, Na, and Ca. Species, that is, F-, OC, Al, Fe, As, Sb, Cd, Pb, and Hg occurred beyond their limits. Their higher concentration in the PtM is observed. Water quality index (WQI) values ranged from 17.52 to 95.68 in the PtM period. 42.85%, 21.42%, and 7.14% of water samples represent "excellent water", "good water" and "poor water" respectively in the PtM period. In addition, the fertilizer and trace element concentrations in the water samples were compared with the limit values determined for usability as drinking water. Accordingly, it was concluded that it is not suitable for use as drinking water in terms of TDS, F-, and NO3- concentrations. In addition, AsT (total arsenic), F- and NO3- pollutants were detected in the water samples, and it was observed that F- and NO3- ions did not have a carcinogenic effect. A health risk assessment of As has been made, and it is found that adults and children have a low risk of developing cancer from the exposure. However, arsenic has high non-carcinogenic and potentially harmful effects.

Most coal in India originates from the Korb basin (Chhattisgarh), where coal mines, thermal power, and aluminum plants operate. Groundwater in this region faces severe pollution due to land reclamation, leaching of coal-related contaminants, waste disposal, and industrial effluent seepage. This work presents results from monitoring groundwater pollution in the Korba basin from 2012 to 2017. Fluoride, aluminum, manganese, and iron levels exceeded acceptable quality limits across all 28 studied locations, with excessive nitrate, magnesium, calcium, and lead levels in specific sites. Tracking seasonal and temporal fluctuations in the most polluted site, namely Kudurmal, revealed peak solute concentrations during the monsoon period and a sustained 18% increase during the study period. Factorial analysis suggests groundwater contamination arises from both human activities and natural sources. These findings underscore the urgent necessity of devising remediation strategies for the drinking water supply.

In urban areas where tap water is often produced by a purification of water supplied from a river bank filtration, a significant fraction of gadolinium (Gd) total pool is of an anthropogenic origin. It happens because Gd-based contrast agents used in Magnetic Resonance Imaging (MRI) are not removed during wastewater treatment and they are discharged to the environment and returned to the water cycle. Despite the growing number of MRI examinations worldwide, little is known about the anthropogenic Gd in Polish surface water as well as drinking water. The aim of this pilot study was to gain information about the occurrence of emergent pollution as Gd in potable water available for inhabitants of Polish municipal areas. Tap water samples from Gdańsk, Kraków, Wrocław and Warszawa were analyzed by an inductively coupled plasma quadrupole mass spectrometry after their preconcentration by a seaFAST-pico chromatographic system. In this study, the sum of REE was in the range registered in the drinking waters of European urban regions (usually below 100 ng/L). The highest values of the sum of REE total concentrations were observed in the tap water samples collected in Warszawa (37.7 ng/L) and Wrocław (35.9 ng/L and 32.9 ng/L), where water supplies originate from the Wisła River and Oława River, respectively. The highest total Gd concentration was observed in the tap water of Warszawa city where the anthropogenic Gd fraction represented about 90% of the total Gd. The lowest values of the sum REE were registered in tap waters of Gdańsk (sum of REE below 2.2 ng/L) with up to 17% of the anthropogenic Gd. Thus, our study showed the occurrence of the anthropogenic Gd in all analyzed tap waters.

The method for determination of rare earth elements (REE: La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) total concentrations in mineral waters was developed and validated. The proposed method comprised inductively coupled plasma mass spectrometry (ICP-MS) detection and the 10-fold off-line REE preconcentration. To improve the method sensitivity and selectivity, the major matrix components and elements causing severe spectral interferences (Ba and Sr) were removed by the seaFAST-pico chromatographic system. The assessed method performance characteristics showed low detection limits (0.02 ng/L-0.3 ng/L), high elements recoveries (98% +/- 4%), good repeatability (3%-5%), and satisfactory uncertainties (8%-16%). The method usability was confirmed via analysis of available reference materials with different water matrices (SLRS-5, SLRS-6, CASS-5, SERMIN1, and VIDAC18) and natural mineral waters originated either directly from wells or bottles sold in supermarkets.

A b s t r a c t.Chemical components in groundwater from mine drainage or used in geothermal installations are a potential source of valuable minerals.At the Polish Geological Institute -National Research Institute, a study was carried out to identify the content of elements in mine waters, wells exploiting natural gas and oil as well as geothermal and therapeutic waters in Poland.The aim of the research was to recognize the concentration of potentially useful minerals in groundwater and the possibility of their recovery.It was the first project that focused on the recovery of elements from groundwater on a national scale in Poland.For this purpose, 67 sites were selected, in which 75 water samples were taken and the content of 65 chemical components was determined.Then, the amount of minerals that could be recovered from mine waters and geothermal brines was calculated based on the amount of water pumped in each facility.The calculations involved the approximate efficiency and working time of the recovery installation.As a result of this research, it was found that the mine waters and geothermal brines in Poland contain resources of valuable elements in very different amounts.In more than half of the examined sites, the estimated resources of minerals are present in amounts that are not prospective.However, in 29 sites, mine waters and geothermal brines contain elevated concentrations of several elements, including -B, Br, I, K, Li, Mg and Mn.If they were successfully recovered, they could represent a potential additional income for the mining and geothermal industries.Dêbieñsko Desalination Plant of mine waters in Upper Silesia is the most promising potential source of recovery of minerals from mine waters, where the total resources of minerals to be recovered from concentrated brine have been estimated as the highest.Rudna Copper Mine in Lower Silesia is in second place, with one of the highest resources and the largest amount of minerals to be recovered from groundwater.Other sites are: the SOLINO Salt Mine, "Olza" mine water collector, mine waters pumped from abandoned coal mines in the Upper Silesia (in Zabrze, Siemianowice OEl¹skie, CzeladŸ, Gliwice), and plants producing geothermal energy in Stargard, Pyrzyce and Bañska.Total amount of mineral resources that can be recovered from waters pumped from the most promising sites is over 72 000 tonnes annually.Taking into account both the ecological aspect and the potential economic benefits of recovering minerals from mine waters and geothermal brines, it is necessary to continue the studies on the recovery of minerals from highly mineralized waters in Poland.

An analytical methodology based on isotope dilution (ID) principles was developed to establish the reference procedure for the simultaneous assignation of aqua regia extractable and total mass fractions of Hg, Cd, and Pb in soil and sediment matrix samples. The 'twin sample-spike blends' were prepared under close to the exact matching conditions, resulting in almost identical mass ratios of the spike to the sample in the blends, which followed either the aqua regia extraction method or total digestion procedure. The isotope ratios in 'twin-blends' were measured by inductively coupled plasma mass spectrometry (ICP-MS). The two-track IDMS strategy proposed in this work was successfully applied to three certified reference materials (CRMs): ERM-CC141 loam soil, EnvCRM 03 soil, and MODAS-2 bottom sediment. This ensured an adequate method validation. For two CRMs (EnvCRM 03 and MODAS-2) it was found that the isotope ratio values in 'twin-blends' for Hg, Cd, and Pb were almost identical with a variability of less than 2.4%. This confirmed that there is no measurable difference between the aqua regia extractable and the total mass fractions within the uncertainty ranges. Therefore, aqua regia mass fractions assigned in this study were found to be equal to certified element contents. For ERM-CC141 loam soil, the Hg isotope ratio values measured in the 'twin-blends' were found to be identical within their measurement uncertainties, and thus, it was concluded that the aqua regia extractable Hg content is identical to the total Hg content. However, in the case of Cd and Pb isotope ratio values in 'twin-blends' varied around 24% or 16%, respectively and because this significant difference was noticed, for both elements it is necessary to calculate the aqua regia content and the total content separately. Because this significant difference was noticed for both elements, it is necessary to calculate the aqua regia content and the total content separately. A detailed comparison of the isotope ratio values between the 'twin-blends' provided unambiguous information about aqua regia extractability of metals and it is a strong indicator for making decisions related to the assignment of either a single mass fraction valid for both procedures or two separate element mass fraction values. To our knowledge and based on the relevant literature survey, this is a novel strategy based on IDMS, and such studies have not been undertaken and presented so far.

The occurrence and distribution of rare earth elements (REEs) in mineral and thermal waters encountered in Quaternary, Mesozoic and Permian aquifers of the Polish Lowlands are described, with REE concentrations analyzed in 35 groundwater samples and 25 aquifer host rock samples. The waters analyzed are characterized by high variability of total dissolved solids (TDS: 0.44 to 340 g/L) and of outflow temperatures (9 to 89 degrees C). Values of ultralow concentrations (pg/L-mu g/L) of REEs in groundwaters of variable salinity were obtained using a novel method combining a seaFAST-pico preconcentration system with inductively coupled plasma mass spectrometry (ICP-MS). Very low concentrations of dissolved (< 0.45 mu m) REEs and Y are present in these waters, ranging from 0.6 ng/L to 19.1 mu g/L and from 1.7 to 54.5 ng/L, respectively. The REE-patterns, normalized to European Shale (EUS), were used to assess the range of REE fractionation between water and host rocks and to show differences in REE distribution in various hydrogeological systems. Three groups of REE-patterns were distinguished: (i) upwards-sloping with HREE-enrichment (74% of all samples), (ii) convex with MREE-enrichment (20%), and (iii) near-flat with very slight depletion in HREE (6%). REE fractionation in shallow waters was attributed to the adsorption of LREE on Fe/Mn oxide/oxyhydroxide particles and the simultaneous complexation of REEs with carbonate and bicarbonate ions. In waters occurring below the zone of active water exchange, in reducing conditions, HREE-enriched patterns developed, mainly as a result of reductive dissolution of previously adsorbed and/or precipitated REEs. The convex, MREE-enriched patterns resulted from a combination of several geochemical processes controlling REE fractionation: (i) high temperature (T > 60 degrees C) favouring a release of the more easily soluble MREEs from rocks into the water, (ii) the presence of organic material showing a strong ability to form complexes with REEs, (iii) reductive release (dissolution) of previously adsorbed REEs on mineral particles, and (iv) dissolution of rocks by acidic waters. Our findings confirmed that REEs can be a useful markers for identifying basic hydrogeochemical processes shaping the chemistry of waters.

Since the rare earth elements (REEs) determination in waters is still not a routine procedure, different analytical protocols have been developed to deal with complexity and variability of sample matrices, problems caused by spectral and non-spectral interferences, insufficient instruments sensitivity, potential contamination and lack of certified reference materials. The aim of this work is to review the current measurement approaches given for REEs total concentrations in natural water samples, including surface and groundwaters as well as rain water and Antarctic ice. As inductively coupled plasma mass spectrometry (ICP-MS) has become the most widely employed technique for analysis of trace concentrations of REEs in aqueous samples it has been intended to present the common issues affecting the measurement results. Apart from a sample preparation step, various configurations of mass spectrometers and sample introduction systems, means of interferences elimination or correction, and calibration strategies used in analytical approaches for REEs analysis are discussed and compared.

Despite the ongoing reduction of emissions of contaminants into the environment, the ocean still represents the most anthropogenically impacted ecosystem worldwide. Sound strategies for marine chemical monitoring call for measurement systems capable of producing comparable analytical results with demonstrated quality. An analytical procedure for simultaneous measurements of the Cd, Co, Cu, Pb, Mn, Ni, Pb and Zn mass fractions in open ocean waters was validated. Procedure validation, including systematic combined uncertainty estimations on measurement results, and the traceability of data are described and explained. Off-line analytes pre-concentration and matrix separation was performed with the commercially available automated seaFAST-pico (TM) system, followed by inductively coupled plasma sector field mass spectrometry (ICP-SFMS) mass fractions determination. The validation approach applied in the present study is in line with the requirements of ISO/IEC 17025 standard and Eurachem guidelines. Selectivity, working range, linearity, recovery (from 93% to 100%, obtained using the NASS-6 CRM from NRC, Canada), repeatability (1.5-3%), intermediate precision (2-%), limits of detection (0.00006-0.004 mu g kg(-1)) were systematically assessed. The relative expanded uncertainties obtained were at range from 7.0% to 14.0% (k = 2). Excellent results were obtained when applying this procedure to the NASS-7 CRM from NRC, Canada. The potential of this analytical procedure was also tested on open seawater samples from different regions of the world. The validated procedure was applied for the characterisation of the ERM (R)-CA403 candidate certified reference material and obtained results submitted as the IAEA contribution to this certification.

The ponds are natural water resources used for drinking, bathing, washing and aqua culture. In this work, the contamination of ponds lied in central India with F– and heavy metals (As, Sb, Cr, Mn, Fe, Cu, Zn, Cd, Pb, Th and U) is described. The F– concentration in the pond water and sediment (n = 24) was ranged from 1.6–5.5 mg/L and 210–1430 mg/kg with mean value of 2.3 ± 0.4 mg/L and 599 ± 137 mg/kg, respectively. The concentration variation and sources of the elements in the pond water and sediment are discussed. The health hazards of F– in the domestic animals are described.

A b s t r a c t.This article is focused on the aspects related to the occurrence and the behavior of REE in hydrosphere. Particular attention is given to the natural waters of Europe including Poland. The data shown in this work are based on the studies and discussions published elsewhere, as well as on own investigations of REE concentrations in the natural waters of Poland (ground-and surface waters). The aim of this article is to present information on REE in different types of waters (ocean, ground-and surface waters). Potential sources of REE in the selected waters and factors affecting their concentrations and distribution patterns (signatures) are discussed. The input of REE originating from human activity is indicated and some examples of anthropogenic factorsare presented.Additionally, some general information on natural REE abundances in various environmental compartments and their applications in the industry are provided.The potential influence of some major components on determination of europium content in water samples during measurements by mass spectrometry is also explained.

Namibia is a fast-growing country with extensive mineral extraction activities used in diamond, fluorspar, uranium, and metals production. To assess the impact of land based human activities on the Namibian coastal marine environment, 25 elements were analyzed in 22 surface sediments samples collected along the coast. After applying a variety of pollution assessment indices (Enrichment Factor, Igeo and Pollution Load Indexes) was concluded that As, Cd and Sb were considerably enriched in the sediments from several sites, while Cu, Pb and Zn showed very high enrichment near the Walvis Bay harbor. Pearson's correlation and Principal Component Analysis were used to investigate common metal sources. Additionally, the determination of Pb isotope ratios confirmed the contribution of land based human activities at Walvis Bay and Lüderitz as sources of pollution. The analysis of REEs did not reveal any important enrichment due to anthropogenic activities, but provides a needed baseline for further investigations.

This article describes the development and validation of an analytical procedure for the matrix separation, preconcentration and determination of sub-ng kg-1 levels 232Th in a small volume (20 mL) of seawater samples. The matrix separation and Th preconcentration was carried out using a commercially available ion-chelation system seaFAST-pico. The acidified to pH < 2 seawater samples were mixed on-line with the ammonium acetate buffer (pH of 6.0 ± 0.2) before loading on the column containing resin with iminodiacetic and ethylenediaminetriacetic functional groups. At this pH, 232Th was quantitatively retained on the resin, demonstrating a good affinity (selectivity) for Th in seawater matrix. The element retained on the resin was eluted using only 0.2 mL of 1.8 M HNO3 enabling to achieve high preconcentration factor. The pretreatment procedure, with two sample loading cycles (each one 10 mL), was accomplished in about 25 min. Determining 232Th mass fraction in seawater samples was based on isotope dilution inductively coupled plasma mass spectrometry (ID ICP-MS) method, which was considered as the most accurate calibration strategy for precise quantification of 232Th mass fraction in seawater samples. ISO/IEC17025 and Eurachem guidelines were followed to perform the validation of the developed in this study procedure. In the case of seawater samples with natural level of thorium the major contributions to the expanded uncertainty arose from the uncertainty associated with isotopic ratio measurements in the isotopically spiked sample, followed by the correction for procedural blank and the correction for mass discrimination effect. The estimated method detection limit for 232Th was 0.005 ng kg-1. The developed method was successfully applied to the determination of 232Th mass fraction in seawater reference samples: IAEA-443, SLEW-3, NASS-4, NASS-6, and CASS-5. Although 232Th is not certified in any of the seawater reference materials, a good agreement was obtained between the results in this study and data published elsewhere.

Analytical procedure for the determination of fourteen rare earth elements (REEs) in the seawater samples has been developed and validated. The elements (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) at ultra trace level were measured by high resolution sector field inductively coupled plasma mass spectrometry (HR ICP-SFMS) after off-line analytes pre-concentration and matrix separation. The sample pre-treatment was carried out by commercially available automated system seaFAST-pico (TM), which is a low-pressure ion chromatography technique, based on solid phase extraction principles. Efficient elimination of seawater matrix and up to 50-fold pre-concentration of REEs enabled their accurate and precise quantification at ng L-1 level.A validation approach in line with the requirements of ISO/IEC 17025 standard and Eurachem guidelines were followed. With this in mind, selectivity, working range, linearity, recovery (from 92% to 102%), repeatability (1%-4%), intermediate precision (2%-6%), limits of detection (0.001-0.08 ng L-1) were systematically assessed. The total uncertainty associated to each result was estimated and the main sources of uncertainty sorted out. All major contributions to the combined uncertainty of the obtained results were identified and propagated together, following the ISO/GUM guidelines. The relative expanded uncertainty was estimated at range from 10.4% to 11.6% (k = 2). Demonstration of traceability of measurement results was also presented. Due to the low limits of detection, this method enables the determination of ultra-low levels of REEs in the open seawater as well as small variations in their concentrations.The potential of the proposed analytical procedure, based on combination of seaFAST-pico (TM) for sample preparation and HR ICP-SFMS, was demonstrated by direct analysis of seawater form different regions of the world. (C) 2016 Elsevier B.V. All rights reserved.