HR ICP-MS Research Articles

Size-dependent distribution of metal(loid)s in recent marine sediments of the Adriatic sea

This paper investigates occurrence of metal(loid)s, and size-dependent changes in their concentration in recent marine sediments from coastal and open-sea environments in the eastern Adriatic. Size fractionation of sediments was performed after removal of organic matter (OM), and the individual fractions, comprising particles below 8 μm, 4 μm, 2 μm, 1 μm and 0.45 μm, were analysed using HR ICP-MS. The concentrations of most elements increased with decreasing particle size, as a result of accumulation of clay minerals and Fe and Mn (oxyhydr)oxides. A decrease in concentrations was observed for Ba, Sr, Ti and U, due to lowering of the carbonate content and presence in the coarse-grained and heavy mineral fraction. The highest element concentrations were determined in the fraction comprising particles below 1 μm. Occasionally, depending on the sedimentological environment and/or the element in question, the peak concentrations occurred in the <2 μm or <0.45 μm fraction. The lowest size-dependent enrichment was observed for elements associated with aluminosilicates (Al, Be, Cs, Co, Fe, K, Li, Rb). A different size-dependent behaviour of the elements was observed between deep-sea areas and shallow environments under greater coastal influence, mainly due to differences in sediment sorting, and between the northern and central vs. southern Adriatic due to the different catchment geologies. The Fe and Mn (oxyhydr)oxides, abundant in the deep-sea sediments, played an important role in the geochemical cycle of As, Cd, Co, Mo, Sb and V.

Accumulation of metal(loid)s in the digestive gland of the mussel Unio crassus Philipsson, 1788: A reliable detection of historical freshwater contamination

The possible influence of historical contamination of water/sediments on the metal(loid) bioaccumulation in the digestive gland of mussel Unio crassus Philipsson, 1788, from two differently contaminated sites at the Mrežnica River was studied in three seasons. The first data for this species on total/cytosolic concentrations of 27 (non)essential elements were obtained by HR ICP-MS. Higher bioaccumulation was observed at the historically contaminated site, with several nonessential elements (Bi, Cs, Pb, Sb, Tl, U) found in 5–6 times higher concentrations compared to the reference site. Although both total and cytosolic levels revealed the influence of water/sediment contamination, the latter showed association between bioaccumulation and exposure for larger number of studied elements. At the reference site, several elements (Ba, Ca, Cd, Cr, Mn, Sr) were also found in 2–10 times higher concentrations compared to contaminated one, but it was attributed to background levels characteristic for karst rivers (for Ca and Cd), and to coaccumulation due to chemical similarity (for Ba, Cr, Mn, Sr). The seasonal variability was also observed, with generally highest metal(loid) concentrations in mussel digestive glands found in autumn which was associated to mussels reproductive period. Our results confirmed that sediment-dwelling mussels, specifically U. crassus, represent a good bioindicators for detection of historical pollution due to their direct contact/exposure to contaminants stored in sediments, with concurrent consideration of physiological/chemical factors. Historical contamination potentially can have serious impact on freshwater environment even long time after its cessation, and, therefore, a careful continuous monitoring is recommended.

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

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

Efficiency of metal bioaccumulation in acanthocephalans, gammarids and fish in relation to metal exposure conditions in a karst freshwater ecosystem

BackgroundEach of the bioindicator organisms studied, such as fish, crustaceans, or parasites, have certain advantages when used in the assessment of metal exposure. In this research, special attention was given to intestinal parasites, acanthocephalans, as effective metal bioaccumulators with the main aim of estimating and comparing metal accumulation in all organisms involved in their life cycle and testing their usage as sensitive bioindicators in metal exposure assessments. MethodsEfficiency of metal accumulation was evaluated in fish intestine (brown trout, Salmo trutta Linnaeus, 1758), gammarids (Gammarus balcanicus Schäferna, 1922) and acanthocephalans (Dentitruncus truttae Sinzar, 1955) in the Krka River at site threatened by industrial and municipal wastewaters (Town of Knin) and reference site (Krka River source) in two seasons (autumn and spring). All samples were digested in a drying oven at 85 °C for 3.5 h using nitric acid and hydrogen peroxide. Samples were diluted with ultrapure water and total concentrations of 15 trace and macroelements were measured by HR ICP-MS. ResultsHigher concentrations of Co, Cu, Fe and Mn at the contaminated than at the reference site were recorded in all bioindicator organisms. Additionally, Se, Sr, Zn, Ca, K and Mg were elevated at the contaminated site in acanthocephalans, Cs, Pb, Zn and K in gammarids and Se, Sr and Ca in fish intestine. Opposite, concentrations of Cd, Cs and Rb were mostly higher in organisms from the reference than wastewater impacted site, which did not coincide with waterborne metal exposure but indicated importance of assessing dietary metal uptake. ConclusionMore effective metal accumulation was confirmed in acanthocephalans than fish and gammarids, especially of Cd and Pb in respect to gammarids, and of Cd, Cu, Pb, Mn and Sr in respect to fish intestine. Thus, both fish intestine and whole body of D. truttae were confirmed as sensitive indicators of low environmental metal exposure, reflecting site-specific differences, which proved their potential to be used in monitoring programmes and metal exposure assessment in real environmental situations.

Rhenium Distribution and Behavior in the Salinity Gradient of a Highly Stratified Estuary and Pristine Riverine Waters (The Krka River, Croatia).

The abundance and distribution of dissolved Re (DRe) were determined in the freshwater part of the Krka River (Croatia), which drains a karst landscape, and in the salinity gradient of its highly stratified estuary. Due to the low DRe concentration, a batch procedure consisting of a pre-concentration step using an anion exchange resin (Dowex) and analysis of DRe in 8M HNO3 eluate using high-resolution inductively coupled plasma mass spectrometry (HR ICP-MS) was applied. Due to potentially inconsistent recoveries, which ranged from 60 to 87%, quantification was performed using the isotope dilution technique (ID). DRe concentrations in the Krka River increased downstream, from 6.2pM at the spring site to 11.9pM upstream of the estuary region. Weathering of the surrounding carbonate lithology is assumed to be the source of the natural Re. Two specific anomalies were registered: a strong increase in DRe concentration due to anthropogenic input near the town of Knin (27.5pM) and a decrease at a downstream site caused by subsurface input of freshwater from the Zrmanja River, resulting in a relatively low DRe concentration (8.5pM). In the estuarine region, a near-conservative behavior of DRe was found in the salinity gradient of the upper surface layer, with DRe concentrations ranging from 18 to 38pM. Anthropogenic input was suspected within the estuarine segment near the urban area, causing a small positive deviation from the conservative line. In the bottom seawater layer, a minor decrease in DRe concentration in the most upstream estuarine regions was apparent, implying weak scavenging of Re.

Occurrence and Distribution of Technology-Critical Elements in Recent Freshwater and Marine Pristine Lake Sediments in Croatia: A Case Study.

The occurrence and vertical distribution of ten technology critical elements (TCEs) (Li, Nb, Sc, Ga, Y, La, Sb, Ge, Te, and W) were studied in sediment cores collected from remote freshwater and marine lakes (Plitvice, Visovac and Mir Lakes) in three protected areas of Croatia. These environmental archives were used to assess natural TCE levels in lake sediments and temporal trends in historical anthropogenic atmospheric deposition. TCE was determined after complete sediment digestion using high-resolution inductively coupled plasma mass spectrometry (HR ICP-MS). The measured TCE concentrations spanned a wide range, which can be attributed to the varying input of terrigenous material into the studied lake systems. All obtained TCE concentrations were close to natural conditions and therefore could be used as a reference for other equivalent sediment systems in the coming years. The evaluation of anthropogenic influence on TCE concentrations showed a slight anthropogenic enrichment with Sb and Te in the upper sediment layers of some lakes (Plitvice and Mir Lakes), indicating a widespread atmospheric deposition, which, however, cannot be related to the recent increase in the use of TCE in modern technology.

Metal Contamination in Sediments of Coastal Rivers around Dar es Salaam, Tanzania

Sediments from coastal rivers of Kizinga, Mbezi, Msimbazi, and Mzinga were used to determine contamination levels of Cd, Pb, Cr, Ni, Cu, Al, Mn, Fe, and Zn metals. Sampling and sample preparation were done as appropriate and analysis was done using high resolution inductively coupled plasma–mass spectrometry (HR ICP-MS). Higher levels of Cd, Pb, Cr, Al, Mn, Fe, and Zn were mainly observed in Msimbazi river. Whereas higher levels of Ni and Cu were observed in Kizinga river, higher levels of Mn were observed in Mbezi river. Mzinga river had lowest levels of most metals except Mn. Lowest levels of Mn were observed in Kizinga river. Despite of enrichment factor indicating varied contamination status of metals in rivers, geo-accumulation index, contamination factor, degree of contamination, modified degree of contamination, potential contamination index and environmental toxicity quotient have indicated that sediments from these rivers are polluted, with Msimbazi and Kizinga river sediments being more polluted. Pearson correlation and hierarchical cluster analyses have revealed that Cd, Cu, Pb, and Zn were strongly correlated to each other (r2&gt; 0.7, p &lt; 0.05), indicating that they similar anthropogenic origin, while Fe, Mn, Ni, Cr, and Al were strongly correlated to each other (r2&gt; 0.69, p &lt; 0.05), indicative of similar natural origin. This implies that there might be metal-related anthropogenic activities around or close to rivers that pose environmental and health risks. Urgent river management strategies are needed to minimise the continuous metal pollution of these rivers.

Solubility of monoclinic and yttrium stabilized cubic ZrO2: Solution and surface thermodynamics guiding ultra-trace analytics in aqueous phase

The high stability of zirconium dioxide in aqueous environments is known and demonstrated, and this property is strongly used in nuclear industry to ensure the long term storage of wastes. However, only upper limits of its aqueous solubility are known reliably and lower limits linked to very well crystallized ZrO2 are much less assessed. Indeed, the low dissolution rate of zirconia makes the solubility measurements a challenging task. To overcome, high S/V ratios of nanoparticles zirconia were used. This work also improved the sensitivity of analytical techniques (HR ICP-MS) and methodologies, and a reliable experimental procedure was developed to measure zirconium (quantification limit ≈10−11 mol∙L−1). New Zr(IV) dioxide solubility data at pH between 0 and 2 were obtained approaching solubility from under-saturated conditions in (Na,H)Cl and (Na,H)ClO4 medium. Two crystalline nanoparticle structures were compared: monoclinic and yttrium stabilized cubic zirconia. Very low solubility was measured for monoclinic phase between pH 1.5 and 2: between (1.8±1.2) × 10−10 mol∙L−1 at pH 2 and (2.3±1.0) × 10−10 mol∙L−1 at pH 1.5. The cubic zirconia showed higher solubility. Integrating the effect of ionic strength, particle size and aqueous speciation, solubility constants of log Ks0 = (-8.43±0.69) for the monoclinic nanoparticles and log Ks0 = (-7.12±0.35) for the yttrium stabilized cubic nanoparticles were obtained. High-resolution techniques (HR-TEM, SAXS and STEM-HAADF) were also used to assess the evolution of morphology and surface before, during and at equilibrium. Analysis of these results shows that the morphology and surface of nanoparticles in the raw state and after reaching equilibrium in (Na,H)Cl and (Na,H)ClO4 medium are similar.

Physico-Chemical Characterization of an Urban Rainwater (Zagreb, Croatia)

The characterization of organic matter (OM) and trace elements (TEs) was conducted in bulk precipitation samples collected in an urban area of Croatia (Zagreb center), from January 2009 to October 2011 (N = 31). Characterization of OM was performed by measurement of dissolved (DOC) and particulate forms of organic carbon (POC), as well as surface-active substances, copper complexing capacity and reduced sulfur species which were determined electrochemically. Concentrations of TEs (Al, Fe, Zn, Cr, Ba, Mn, Cu, Sr, Ti, Pb, V, Ni, Rb, Sb, As, Sn, Se, Co, Cd, Mo) were analyzed by HR ICP-MS. The most important outcome of this study is confirmed relatively low concentrations of DOC (0.69–4.86 mgC L−1) and TEs. Daily fluxes of Zn, Pb, Ni, As, and Cd were two to three times lower than that of those reported for an urban industrial site in Europe. Additionally, this study shows that the value and reactivity of rainwater DOC has not considerably changed if compared with the results from the 1998–1999 study (0.78–4.39 mgC L−1). High traffic density and thermal power plants are assumed to be the main local sources of pollutants in Zagreb. Using Al as a reference element, it was found that Cd, Sb, and Cu were associated with anthropogenic sources. The solubility of Sr, Zn, Cd, Ni, Cr, As, and Rb was higher than 70%. Another critical characteristic of precipitation composition is episodic variation in POC concentration because of Saharan dust transport. Obtained data can be valuable for environmental quality assessment, as well as for insight into atmospheric deposition processes.

Elevated Cobalt, Chromium and Molybdenum Levels in Peripheral Blood Have No Effect on the Development of Heterotopic Ossifications after Metal-on-Metal Total Hip Arthroplasty

Metal debris from metal-on-metal (MoM) total hip arthroplasties (THA) has been suspected to cause periprosthetic heterotopic ossifications (HO). We determined the influence of disseminated cobalt, chromium and molybdenum on the development of HO. Native blood samples from patients with 86 high-carbon and 16 low-carbon Co28Cr6Mo articulations were analysed by high-resolution inductively coupled plasma mass-spectrometry (HR ICP-MS). The results revealed that high-carbon metal-on-metal articulations showed lower metal blood levels (Co 1.03 to 1.60 μg/l, Cr 0.77 to 0.88 μg/l, Mo 0.45 to 0.56 μg/l) whereas low-carbon articulations achieved higher metal blood levels (Co 2.59 to 6.85 μg/l, Cr 1.25 to 3.55 μg/l, Mo 0.45 to 0.64 μg/l), but no correlation between metal ion blood level or carbon content and the development of HO could be found in these MoM articulations. Hence, metal debris from MoM articulation does not stimulate heterotopic bone formation despite other well-known local reactions.

Distribution of Co, Cu, Fe, Mn, Se, Zn, and Cd among cytosolic proteins of different molecular masses in gills of European chub (Squalius cephalus L.).

The distribution of essential elements Co, Cu, Fe, Mn, Se, and Zn, and nonessential element Cd among cytosolic proteins of different molecular masses in the gills of European chub (Squalius cephalus) sampled in the moderately contaminated Sutla River in September of 2009, was studied after the protein separation by size exclusion high-performance liquid chromatography (SEC-HPLC), and the metal determination in the obtained fractions by high-resolution inductively coupled plasma mass spectrometry (HR ICP-MS). The aims of the study were to characterize the distribution profiles of metals within different protein categories in gills in the conditions of low metal exposure in the river water, and to compare them with the previously published hepatic profiles. The distribution profiles of analyzed metals were mainly characterized with several peaks. However, some observations could be emphasized: both Cu and Cd were eluted near metallothionein elution time; elution time of one of Co peaks could be associated with Co-containing compound cobalamin; increasing cytosolic Fe concentrations resulted in possible Fe binding to storage protein ferritin; both Mn and Zn had poorly resolved peaks covering wide ranges of molecular masses and indicating their binding to various proteins; both Zn and Se increased in protein fractions of molecular masses <5 kDa following their concentration increase in the gill cytosol; expected clear metallothionein peak was not observed for Zn. Comparison of gill profiles with previously published hepatic profiles revealed similar and in case of some elements (e.g., Co, Fe, Mn, and Se) almost identical distributions in both organs regarding elution times. On the contrary, heights of obtained peaks were different, indicating possible metal binding to the same proteins in the gills and liver, but in different proportions. The results obtained in this study can be used as a basis for comparison in monitoring studies, for identification of changes that would occur after exposure of chub to increased metal concentrations.

Determination of rare earth elements after pre-concentration using NOBIAS-chelate PA-1®resin: Method development and application in the San Francisco Bay plume

The resin NOBIAS-chelate PA-1® was used to develop an off-line pre-concentration and extraction method for rare earth elements (REEs) in seawater prior to quantification using magnetic sector, high resolution, inductively coupled plasma mass spectrometry (HR ICP-MS). The method employed an off-line manifold that is inexpensive, easy to set-up, and allows simultaneous processing of several samples. The method has low blanks and detection limits, which were in the range of 0.01pmolkg−1 to 0.82pmolkg−1, and yields quantitative recovery for all REEs (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) precluding the need to use isotope dilution. The HR ICP-MS allows an integrated, time-averaged signal of the eluent sample, reducing the HR ICP-MS instrument time relative to an in-line extraction procedure.The applicability of the method was demonstrated in a test of the hypothesis that some REEs are being mobilized by anthropogenic activities and are elevated in San Francisco Bay (SFB) and its discharge plume into coastal waters off Central California. This was done by normalizing REE data from the SFB to those of the GEOTRACES Surface Coastal (GSC) reference sample, collected in the Santa Barbara Basin off Southern California. The normalized REE pattern indicated a substantial Gd anomaly of up to 30-fold higher than GSC in the industrial southern reach of the SFB (Lower South Bay), and to a lesser extent in the plume, indicative of anthropogenic Gd inputs, associated with the medical use of Gd-based contrasting agents in magnetic resonance imagery, from the surrounding metropolitan area. Smaller anomalies for Lu and Yb were also observed in the Lower South Bay and plume, which were tentatively attributed to industrial inputs. However, because of the relatively restricted industrial uses of these elements this hypothesis requires further investigation. Ce and Eu anomalies were observed in the northern reaches of the Bay and appeared to be associated with natural redox mediated behavior of these REEs.

A new method for stable lead isotope extraction from seawater

A new technique for stable lead (Pb) isotope extraction from seawater is established using Toyopearl AF-Chelate 650M® resin (Tosoh Bioscience LLC). This new method is advantageous because it is semi-automated and relatively fast; in addition it introduces a relatively low blank by minimizing the volume of chemicals used in the extraction. Subsequent analyses by HR ICP-MS have a good relative external precision (2σ) of 3.5‰ for 206Pb/207Pb, while analyses by MC-ICP-MS have a better relative external precision of 0.6‰. However, Pb sample concentrations limit MC-ICP-MS analyses to 206Pb, 207Pb, and 208Pb. The method was validated by processing the common Pb isotope reference material NIST SRM-981 and several GEOTRACES intercalibration samples, followed by analyses by HR ICP-MS, all of which showed good agreement with previously reported values.

Metals as biomarkers of the environmental human exposure

The 1st PROBE programme for the assessment of the internal dose of metals of the Italian population closed in 2011. A population sample of 1423 individuals, aged between 18 and 65 years from five regions, are recruited and information on gender, age and lifestyles of subjects is collected by a questionnaire. Concentrations of 20 metals, namely As, Be, Cd, Co, Cr, Hg, Ir, Mn, Mo, Ni, Pb, Pd, Pt, Rh, Sb, Sn, Tl, U, V and W are determined by the sector field inductively coupled plasma mass spectrometry (HR–ICP–MS) in whole blood and serum. Metals levels are reported as geometric means (GM) and 95th percentiles (P95). Biomarkers variations in sub-groups of the population stratified for influencing variables are also assessed. A comparison with available guideline values for some biomarkers of exposure (Cd, Co, Hg and Pb in human blood) and the levels determined in the Italian population are also outlined.

Distribution of selected essential (Co, Cu, Fe, Mn, Mo, Se, and Zn) and nonessential (Cd, Pb) trace elements among protein fractions from hepatic cytosol of European chub (Squalius cephalus L.)

Association of selected essential (Co, Cu, Fe, Mn, Mo, Se, and Zn) and nonessential (Cd, Pb) trace elements with cytosolic proteins of different molecular masses was described for the liver of European chub (Squalius cephalus) from weakly contaminated Sutla River in Croatia. The principal aim was to establish basic trace element distributions among protein fractions characteristic for the fish living in the conditions of low metal exposure in the water. The fractionation of chub hepatic cytosols was carried out by size exclusion high performance liquid chromatography (SE-HPLC; Superdex™ 200 10/300 GL column), and measurements were performed by high resolution inductively coupled plasma mass spectrometry (HR ICP-MS). Elution profiles of essential elements were mostly characterized by broad peaks covering wide range of molecular masses, as a sign of incorporation of essential elements in various proteins within hepatic cytosol. Exceptions were Cu and Fe, with elution profiles characterized by sharp, narrow peaks indicating their probable association with specific proteins, metallothionein (MT), and ferritin, respectively. The main feature of the elution profile of nonessential metal Cd was also single sharp, narrow peak, coinciding with MT elution time, and indicating almost complete Cd detoxification by MT under the conditions of weak metal exposure in the water (dissolved Cd concentration ≤0.3 μg L(-1)). Contrary, nonessential metal Pb was observed to bind to wide spectrum of proteins, mostly of medium molecular masses (30-100 kDa), after exposure to dissolved Pb concentration of ~1 μg L(-1). The obtained information within this study presents the starting point for identification and characterization of specific metal/metalloid-binding proteins in chub hepatic cytosol, which could be further used as markers of metal/metalloid exposure or effect on fish.

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

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

Impact on arsenic exposure of a growing proportion of untested wells in Bangladesh

BackgroundIn many areas of Bangladesh, it has been more than six years since a national campaign to test tubewells for arsenic (As) was conducted. Many households therefore draw their water for drinking and cooking from untested wells.MethodsA household drinking water survey of 6646 households was conducted in Singair upazilla of Bangladesh. A subset of 795 untested wells used by 1000 randomly selected households was tested in the field by trained village workers with the Hach EZ kit, using an extended reaction time of 40 min, and in the laboratory by high-resolution inductively-coupled plasma-mass spectrometry (HR ICP-MS).ResultsThe household survey shows that more than 80% of the wells installed since the national testing campaign in this area were untested. Less than 13% of the households with untested wells knew where a low-As well was located near their home. Village workers using the Hach EZ kit underestimated the As content of only 4 out of 795 wells relative to the Bangladesh standard. However, the As content of 168 wells was overestimated relative to the same threshold.ConclusionThere is a growing need for testing tubewells in areas of Bangladesh where As concentrations in groundwater are elevated. This could be achieved by village workers trained to use a reliable field kit. Such an effort would result in a considerable drop in As exposure as it increases the opportunities for well switching by households.

A fast method for multi-metal determination in soil samples by high-resolution inductively-coupled plasma-mass spectrometry (HR–ICP–MS)

Methods for multi-elemental quantitative analysis of soil samples by high-resolution inductively-coupled plasma-mass spectrometry (HR–ICP–MS) with preceding one-step wet digestion in a high-pressure microwave system have been developed. The application of aqua regia as a reagent for wet digestion using a high-pressure microwave digestion system, followed by determination using HR–ICP–MS, allows an accurate, simultaneous determination of a large number of heavy metals and metalloids that are considered as potentially hazardous for the environment and health. The values of the concentrations of the elements in the analysed certified reference material (CRM) that have been obtained in this study can be used as indicative values where this CRM is used as a control for the quality of the measurements.

Multielement molecular size fractionation in crude oil and oil residue by size exclusion microchromatography with high resolution inductively coupled plasma mass spectrometric detection (HR ICP MS)

Microchromatography using permeation through gels with the increasing exclusion limit (5000, 400000 and 20000000 Da) was combined with high resolution (R = 4000) ICP MS to measure the distribution of Co, Cr, Fe, Ni, S, Si, V and Zn as a function of the molecular mass fraction of crude oil and oil vacuum distillation residue. The accuracy of the simultaneous multielement determination was verified by the µflow-injection-ICP MS analysis of certified reference materials (wear-metals in lubricating oils: SRM 1084a and SRM 1085b). The method allowed the acquisition of chromatograms with high sensitivity competitive existing methods, showing element- and sample origin-dependent morphology.

Variations of δ 30Si and Ge/Si with weathering and biogenic input in tropical basaltic ash soils under monoculture

In soils, silicon released by mineral weathering can be retrieved from soil solution through clay formation, Si adsorption onto secondary oxides and plant uptake, thereby impacting the Si-isotopic signature and Ge/Si ratio of dissolved Si (DSi) exported to rivers. Here we use these proxies to study the contribution of biogenic Si (BSi) in a soil–plant system involving basaltic ash soils differing in weathering degree under intensive banana cropping. δ 30Si and Ge/Si ratios were determined in bulk soils (<2 mm), sand (50–2000 μm), silt (2–50 μm), amorphous Si (ASi, 2–50 μm) and clay (<2 μm) fractions: δ 30Si by MC–ICP–MS Nu Plasma in medium resolution, operating in dry plasma with Mg doping (δ 30Si vs. NBS28 ± 0.12‰ ± 2 σ SD), Ge/Si computed after determination of Ge and Si concentrations by HR–ICP–MS and ICP–AES, respectively. Components of the ASi fraction were quantified by microscopic counting (phytoliths, diatoms, ashes). Compared to fresh ash (δ 30Si = −0.38‰; Ge/Si = 2.21 μmol mol −1), soil clay fractions (<2 μm) were enriched in light Si isotopes and Ge: with increasing weathering degree, δ 30Si decreased from −1.19 to −2.37‰ and Ge/Si increased from 4.10 to 5.25 μmol mol −1. Sand and silt fractions displayed δ 30Si values close to fresh ash (−0.33‰) or higher due to saharian dust quartz deposition, whose contribution was evaluated by isotopic mass balance calculation. Si-isotopic signatures of bulk soils (<2 mm) were strongly governed by the relative proportions of primary and secondary minerals: the bulk soil Si-isotopic budget could be closed indicating that all the phases involved were identified. Microscopic counting highlighted a surface accumulation of banana phytoliths and a stable phytolith pool from previous forested vegetation. δ 30Si and Ge/Si values of clay fractions in poorly developed volcanic soils, isotopically heavier and Ge-depleted in surface horizons, support the occurrence of a DSi source from banana phytolith dissolution, available for Si sequestration in clay-sized secondary minerals (clay minerals formation and Si adsorption onto Fe-oxide). In the soil–plant system, δ 30Si and Ge/Si are thus highly relevant to trace weathering and input of DSi from phytoliths in secondary minerals, although not quantifying the net input of BSi to DSi.