Lead exposure in brown bears is linked to environmental levels and the distribution of moose kills

Lead (Pb) is heterogeneously distributed in the environment and multiple sources like Pb ammunition and fossil fuel combustion can increase the risk of exposure in wildlife. Brown bears (Ursus arctos) in Sweden have higher blood Pb levels compared to bears from other populations, but the sources and routes of exposure are unknown. The objective of this study was to quantify the contribution of two potential sources of Pb exposure in female brown bears (n = 34 individuals; n = 61 samples). We used multiple linear regressions to determine the contribution of both environmental Pb levels estimated from plant roots and moose (Alces alces) kills to blood Pb concentrations in female brown bears. We found positive relationships between blood Pb concentrations in bears and both the distribution of moose kills by hunters and environmental Pb levels around capture locations. Our results suggest that the consumption of slaughter remains discarded by moose hunters is a likely significant pathway of Pb exposure and this exposure is additive to environmental Pb exposure in female brown bears in Sweden. We suggest that spatially explicit models, incorporating habitat selection analyses of harvest data, may prove useful in predicting Pb exposure in scavengers. Ursus arctos Pb Scavenger Slaughter remain Resource selection functionacceptedVersio

An apple a day? Assessing gardeners’ lead exposure in urban agriculture sites to improve the derivation of soil assessment criteria

Globally, many of our urban agriculture sites (UAS) contain high levels of lead (Pb), a contaminant of toxicological concern to humans. To improve the derivation of soil assessment criteria at UAS, and avoid inappropriate closure of these valuable community spaces, we sampled nearly 280 paired soil and crop samples across 31 UAS gardens. This sampling was coupled with an exposure and food frequency questionnaire and participants blood Pb levels (BLL), (43 gardeners and 29 non-gardening neighbours). In 98% of the sampled soils, Pb concentrations were above the current UK soil guideline for UAS (80 mg/kg), however despite the high soil Pb (geometric mean: 324 mg/kg), and high soil bioaccessible Pb (geometric mean: 58.7%), all participants BLL were 0.1 mg/kg FW).The importance of defining the exposure scenario of a specific sub-population (i.e. UAS gardeners) is highlighted. Our preferred models predict site specific assessment criteria (SSAC) of 722 – 1634 mg/kg. We found fruit and vegetable consumption rates by all participants, and not just the UAS gardeners, to be considerably higher than those currently used to derive the UK’s category 4 screening levels (C4SLs). Furthermore, the soil to plant concentration factors (SPCFs) used to derive the UAS C4SL significantly over predict Pb uptake. Our study indicates it may be appropriate to develop a distinct exposure dataset for UAS. In particular we recommend the derivation of SPCFs that are reflective of urban soils, both in terms of the range of soil Pb concentrations typically observed, but also the sources (and hence human oral bioaccessibility and plant-availability) of this Pb

The Stability of Fe-Isotope Signatures During Low Salinity Mixing in Subarctic Estuaries

We have studied iron (Fe)-isotope signals in particles (> 0.22 µm) and the dissolved phase (< 0.22 µm) in two subarctic, boreal rivers, their estuaries and the adjacent sea in northern Sweden. Both rivers, the Råne and the Kalix, are enriched in Fe and organic carbon (up to 29 µmol/L and up to 730 µmol/L, respectively). Observed changes in the particulate and dissolved phase during spring flood in May suggest different sources of Fe to the rivers during different seasons. While particles show a positive Fe-isotope signal during winter, during spring flood, the values are negative. Increased discharge due to snowmelt in the boreal region is most times accompanied by flushing of the organic-rich sub-surface layers. These upper podzol soil layers have been shown to be a source for Fe-organic carbon aggregates with a negative Fe-isotope signal. During winter, the rivers are mostly fed by deep groundwater, where Fe occurs as Fe(oxy)hydroxides, with a positive Fe-isotope signal. Flocculation during initial estuarine mixing does not change the Fe-isotope compositions of the two phases. Data indicate that the two groups of Fe aggregates flocculate diversely in the estuaries due to differences in their surface structure. Within the open sea, the particulate phase showed heavier δ56Fe values than in the estuaries. Our data indicate the flocculation of the negative Fe-isotope signal in a low salinity environment, due to changes in the ionic strength and further the increase of pH

An inter-comparison exercise on the application of ICP-MS techniques for measurement of long-lived radionuclides

Inductively coupled plasma (ICP) spectrometry techniques are widely used in the fields related to environmental monitoring, nuclear waste disposal and management, radioecology and tracer studies, as well as nuclear forensics and nuclear emergency preparedness. Especially ICP mass spectrometry (ICP-MS) is playing an important role for determination of low-level long-lived radionuclides and their isotopic ratios. ICP optical emission spectrometry (ICP-OES) is commonly used for determining stable elements (Al, Fe, Ca, etc.) and cannot perform isotopic ratio measurement with desirable precision and at low analyte concentrations. Therefore ICP-OES is often used as a supplementary technique to ICP-MS in the analysis, for instance, to screen the matrix composition of a sample, or to determine Sr and Y chemical yield in the Sr-90 analysis, etc. Among the Nordic countries, there are probably less than 20 ICP-MS instruments which are currently applied in the nuclear field for the measurement of radionuclides and their isotopic ratios. Due to different application purposes and technical background of the analysts, each ICP lab has different set-ups and experiences in running these instruments. More efficient application of ICP-MS will be achieved when these experiences are well shared among these labs. Also, for newly established ICP labs or scientists/students in the Nordic countries to quickly build up the competence in operating their instruments in practice, hands-on experience is very valuable. Therefore, within the Nordic-ICP project, an inter-comparison exercise was performed during 2016, which was focused on the measurement of uranium and plutonium isotopes in certified reference material by ICP-MS in combination with radiochemical separation. This report summarizes the results and conclusions obtained base on this inter-comparison exercise

NKS ICP User 2017 Seminar Proceedings

The ICP User seminar was held at Risø, Denmark, during 25-27 September 2017. The seminar consisted of 2-day lectures given by six invited professionals and thirteen seminar participants, as well as 1-day lab training by invited expert. The lectures covered different topics including theoretical principles of ICP, methodology development and application of ICP techniques for different isotopes/isotopic ratios, recent development of new ICP technology and its application, etc. The results obtained from the inter-comparison exercise 2016 were presented and discussed. The lab training covered demonstration of the operation of ICP-MS, software and technical instructions. The seminar was attended by 51 individuals from 26 organisations

High concentrations of lead (Pb) in blood and milk of free-ranging brown bears (Ursus arctos) in Scandinavia

Exposure to lead (Pb) is a global health problem for both humans and wildlife. Despite a dramatic decline in human Pb exposure following restrictions of leaded gasoline and industry and thereby an overall reduction of Pb entering the environment, Pb exposure continues to be a problem for wildlife species. Literature on scavenging terrestrial mammals, including interactions between Pb exposure and life history, is however limited. We quantified Pb concentration in 153 blood samples from 110 free-ranging Scandinavian brown bears (Ursus arctos), 1-25 years old, using inductively coupled plasma sector field mass spectrometry. We used generalized linear models to test effects of age, body mass, reproduction status and spatial distribution on the blood Pb concentrations of 56 female bears. We sampled 28 females together with 56 dependent cubs and paired their blood Pb concentrations. From 20 lactating females, we measured the Pb concentration in milk. The mean blood Pb concentration was 96.6 mu g/L (range: 38.7-220.5 mu g/L). Both the mean and range are well above established threshold concentrations for developmental neurotoxicity (12 mu g/L), increased systolic blood pressure (36 mu g/L) and prevalence of kidney disease in humans (15 mu g/L). Lactating females had higher Pb blood concentrations compared to younger, non-lactating females. Blood Pb concentrations of dependent cubs were correlated with their mother's blood Pb concentration, which in turn was correlated with the Pb concentration in the milk. Life-long Pb exposure in Scandinavian brown bears may have adverse effects both on individual and population levels. The high blood Pb concentrations found in brown bears contrast the general reduction in environmental Pb contamination over the past decades in Scandinavia and more research is needed to identify the sources and pathways of Pb exposure in the brown bears

High spatial resolution analysis of ferromanganese concretions by LA-ICP-MS†

A procedure was developed for the determination of element distributions in cross-sections of ferromanganese concretions using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The effects of carrier flow rates, rf forward power, ablation energy, ablation spot size, repetition rate and number of shots per point on analyte intensity were studied. It is shown that different carrier gas flow rates are required in order to obtain maximum sensitivities for different groups of elements, thus complicating the optimisation of ICP parameters. On the contrary, LA parameters have very similar effects on almost all elements studied, thus providing a common optimum parameter set for the entire mass range. However, for selected LA parameters, the use of compromise conditions was necessary in order to compensate for relatively slow data acquisition by ICP-MS and maintain high spatial resolution without sacrificing the multielemental capabilities of the technique. Possible variations in ablation efficiency were corrected for mathematically using the sum of Fe and Mn intensities. Quantification by external calibration against matrix-matched standards was successfully used for more than 50 elements. These standards, in the form of pressed pellets (no binder), were prepared in-house using ferromanganese concentrates from a deep-sea nodule reference material as well as from shallow-marine concretions varying in size and having different proportions of three major phases: aluminosilicates, Fe- and Mn-oxyhydroxides. Element concentrations in each standard were determined by means of conventional solution nebulisation ICP-MS following acid digestion. Examples of selected inter-element correlations in distribution patterns along the cross-section of a concretion are given

Förekomst av osmium och osmiumtetroxid i Norrbottens län

Godkänd; 2007; 20071008 (emmeng

A concise guide for the determination of less-studied technology-critical elements (Nb, Ta, Ga, In, Ge, Te) by inductively coupled plasma mass spectrometry in environmental samples

There is an increasing demand for analytical techniques able to measure so-called ‘technology-critical elements', a set of chemical elements increasingly used in technological applications, in environmental matrices. Nowadays, inductively coupled plasma-mass spectrometry (ICP-MS) has become the technique of choice for measuring trace element concentrations. However, its application is often less straightforward than often assumed. The hints and drawbacks of ICP-MS application to the measurement of a set of less-studied technology-critical elements (Nb, Ta, Ga, In, Ge and Te) is discussed here and concise guidelines given