Toward Understanding the Environmental Risks of Combined Microplastics/Nanomaterials Exposures: Unveiling ZnO Transformations after Adsorption onto Polystyrene Microplastics in Environmental Solutions

Over recent decades, there has been a dramatic increase in the manufacture of engineered nanomaterials, which has inevitably led to their environmental release. Zinc oxide (ZnO) is among the more abundant nanomaterial manufactured due to its advantageous properties, used for piezoelectric, semiconducting, and antibacterial purposes. Plastic waste is ubiquitous and may break down or delaminate into smaller microplastics, leaving open the question of whether these small polymers may alter the fate of ZnO through adsorption within aquatic media (tap-water and seawater). Here, scanning electron microscopy analysis confirms the effective Zn nano/microstructures adsorption onto polystyrene surfaces after only 24-h incubation in the aquatic media. After pre-aging the nanomaterials for 7-days in different environmental media, nanoprobe X-ray absorption near-edge spectroscopy analysis reveals significant ZnO transformation toward Zn-sulfide and Zn-phosphate. The interaction between a commercial ZnO-based sunscreen with polystyrene and a cleanser consumer containing microbeads with ZnO nanomaterials is also studied, revealing the adsorption of transformed Zn-species in the microplastics surfaces, highlighting the environmental relevancy of this work. Understanding the structural and functional impacts of the microplastics/ZnO complexes, and how they evolve, will provide insights into their chemical nature, stability, transformations, and fate, which is key to predicting their bioreactivity in the environment.

Determination of metallic nanoparticles in biological samples by single particle ICP-MS: a systematic review from sample collection to analysis

A systematic review of the use of single particle ICP-MS to analyse engineered nanomaterials (ENMs) in biological samples (plants, animals, body fluids) has highlighted that efforts have focused on a select few types of ENMs (e.g., Ag and TiO₂) and there is a lack of information for some important tissues (e.g., reproductive organs, skin and fatty endocrine organs). The importance of sample storage is often overlooked but plays a critical role. Careful consideration of the ENM and matrix composition is required to select an appropriate protocol to liberate ENMs from a tissue whilst not promoting the transformation of them, or genesis of new particulates. A 'one size fits all' protocol, applicable to all possible types of ENM and biological matrices, does not seem practical. However, alkaline-based extractions would appear to show greater promise for wide applicability to animal tissues, although enzymatic approaches have a role, especially for plant tissues. There is a lack of consistency in metrics reported and how they are determined (e.g. size limit of detection, and proportions of recovery), making comparison between some studies more difficult. In order to establish standardised protocols for regulatory use, effort is needed to: develop certified reference materials, achieve international agree on nomenclature and the use of control samples, and to create a decision tree to help select the best sample preparation for the type of tissue matrix.

The true axial shoulder projection: Diagnostic aid for acromioclavicular joint dislocation?

INTRODUCTION

Acromioclavicular joint dislocations are common. Differentiating between horizontal and vertical instability is challenging, but possible to diagnose on axial radiographs. No clear consensus for axial radiograph parameters currently exists. We aim to establish a reproducible technique to assess whether an axial radiograph represents a true axial view of the shoulder.

METHODS

One hundred CT scans of normal uninjured shoulders were examined using multiplanar reformatting to assess the distance between the anterior glenoid (reference line) and anterior-most aspect of the acromion in the axial plane. Measurements were repeated and performed by multiple observers to give of intra- and inter-observer reliability.

RESULTS

The mean distance from the anterior acromion to the reference line was -2.6 mm (i.e. posteriorly placed) (SD = 5.8 mm, range -16.9-13.2 mm). Most (89%) of the measurements were between 9 and -9 mm to the reference line. Intra-observer reliability was high with Cronbach's α measurement as 0.997. Inter-observer reliability gave a Cronbach's α measurement of 0.959.

CONCLUSION

When the anterior aspect of the acromion lies within 10 mm either side of a line parallel to the scapula blade at the anterior aspect of the glenoid on an axial radiograph, it represents a true axial projection of the glenohumeral joint (GHJ).Level of evidence: IV, Case series.

Stability of Arsenic Species During Bioaccessibility Assessment Using the In Vitro UBM and HPLC-ICP-MS Detection

The stability of four major arsenic (As) species during application of the BARGE (Bioaccessibility Research Group of Europe) unified bioaccessibility method (UBM) has been assessed. The concentrations of As species in the UBM gastric and gastro-intestinal (gastric + intestinal) phases were determined using HPLC-ICP-MS whilst the total As content in the samples was determined using ICP-MS alone. The arsenic species studied were arsenite As(III), arsenate As(V), dimethylarsinic acid (DMA) and monomethylarsonic acid (MMA). These species were separated in 10 min using an anion exchange column (Hamilton PRP-X100) with a mobile phase containing 20 mmol L^-1 NH₄H₂PO₄/1% methanol (pH 6.0). The recoveries of arsenic species spiked into the gastric and gastro-intestinal fluids were in the range 90-108%. No interconversion between As species was observed as a result of applying the BARGE UBM, which is a particularly important finding for the reliability of As(III) measurements. The accuracy of the BARGE UBM for in vitro extractable As(V) was verified using British Geological Survey (BGS) guidance material 102 (an ironstone soil). For a commercial rice sample, the bioaccessibility sequence of As was DMA > As(III) > As(V) for the gastric phase and As(III) > DMA > As(V) for the gastro-intestinal phase.

Trace element deficiency is highly prevalent and associated with infection and mortality in patients with alcoholic hepatitis

BACKGROUND

Malnutrition is common in patients with alcohol-related liver disease and is associated with outcome in patients with alcoholic hepatitis. Trace elements (cobalt, copper, iron, selenium and zinc) are micronutrients essential for many cellular processes including antioxidant pathways. The prevalence and relevance of trace element deficiency is unknown in alcoholic hepatitis.

AIM

To determine the prevalence of trace element deficiency and its association with clinical outcomes in patients with alcoholic hepatitis.

METHODS

Serum was obtained from patients with alcoholic hepatitis, alcohol-related cirrhosis and healthy volunteers as part of clinical trials, cohort studies and a biobank. Trace element concentration was measured by inductively coupled plasma mass spectrometry. Association of trace element levels with development of infection within 90 days and mortality within 28 and 90 days was evaluated by multivariate logistic regression.

RESULTS

Sera from 302 patients with alcoholic hepatitis, 46 with alcohol-related cirrhosis and 15 healthy controls were analysed for trace element concentration. The prevalence of zinc deficiency (85%) and selenium deficiency (67%) in alcoholic hepatitis was higher than in alcohol-related cirrhosis (72% [p=0.04] and 37% [p<0.001], respectively). Zinc, selenium, copper and chromium were significantly different between groups. Iron deficiency was a predictor of development of infection within 90 days. Zinc deficiency was a predictor of mortality within 28 and 90 days.

CONCLUSION

Trace element deficiency in patients with alcoholic hepatitis is highly prevalent and associated with infection and mortality. Supplementation with selected trace elements may improve clinical outcomes in this patient group but further insight is required of their biological and clinical effects.

The risk of carotid stenosis in head and neck cancer patients after radiation therapy

OBJECTIVES

Head and neck radiotherapy (RT) is a risk factor for cerebrovascular disease. We performed a retrospective cohort study to evaluate carotid artery stenosis (CAS) incidence in head and neck cancer (HNC) patients undergoing RT, characterizing associated risk factors.

MATERIALS AND METHODS

Records were retrospectively reviewed for HNC patients undergoing carotid ultrasound screening after definitive or adjuvant RT between January 2000 and May 2016. CAS was defined as ≥50% stenosis on imaging, stroke, or transient ischemic attack. Actuarial CAS rates were calculated by Kaplan-Meier method. Univariate and multivariate analyses predicted CAS risk based on carotid dosimetric and clinical parameters.

RESULTS

366 patients met inclusion criteria. Median time from RT completion to last follow-up was 4.1 yr. Actuarial risk for CAS was 29% (95% CI 22-36%) at 8 years. Univariate analysis showed that smoking (HR 1.7; 95% CI 1.1-2.7), hyperlipidemia (HR 1.6; 95% CI 1.03-2.6), diabetes (HR 2.8; 95% CI 1.6-4.8), coronary artery disease (HR 2.4; 95% CI 1.4-4.2), and peripheral artery disease (HR 3.6; 95% CI 1.1-11.6) were significantly associated with increased CAS. In multivariate analysis, diabetes was predictive of time to CAS (HR 1.9; 95% CI 1.1-3.4). Carotid dose parameters were not significantly associated with CAS.

CONCLUSIONS

CAS incidence is high after head and neck radiotherapy, gradually rising over time. No clear dose-response effect between carotid dose and CAS was identified for HNC patients. Carotid artery screening and preventative strategies should be employed in this high-risk patient population.

A Dataset for Three-Dimensional Distribution of 39 Elements Including Plant Nutrients and Other Metals and Metalloids in the Soils of a Forested Headwater Catchment

Quantification and evaluation of elemental distribution in forested ecosystems are key requirements to understand element fluxes and their relationship with hydrological and biogeochemical processes in the system. However, datasets supporting such a study on the catchment scale are still limited. Here we provide a dataset comprising spatially highly resolved distributions of 39 elements in soil profiles of a small forested headwater catchment in western Germany () to gain a holistic picture of the state and fluxes of elements in the catchment. The elements include both plant nutrients and other metals and metalloids that were predominately derived from lithospheric or anthropogenic inputs, thereby allowing us to not only capture the nutrient status of the catchment but to also estimate the functional development of the ecosystem. Soil samples were collected at high lateral resolution (≤60 m), and element concentrations were determined vertically for four soil horizons (L/Of, Oh, A, B). From this, a three-dimensional view of the distribution of these elements could be established with high spatial resolution on the catchment scale in a temperate natural forested ecosystem. The dataset can be combined with other datasets and studies of the TERENO (Terrestrial Environmental Observatories) Data Discovery Portal () to reveal elemental fluxes, establish relations between elements and other soil properties, and/or as input for modeling elemental cycling in temperate forested ecosystems.

Combined uncertainty estimation for the determination of the dissolved iron amount content in seawater using flow injection with chemiluminescence detection

This work assesses the components contributing to the combined uncertainty budget associated with the measurement of the Fe amount content by flow injection chemiluminescence (FI-CL) in <0.2 μm filtered and acidified seawater samples. Amounts of loaded standard solutions and samples were determined gravimetrically by differential weighing. Up to 5% variations in the loaded masses were observed during measurements, in contradiction to the usual assumptions made when operating under constant loading time conditions. Hence signal intensities (V) were normalised to the loaded mass and plots of average normalised intensities (in V kg-1) vs. values of the Fe amount content (in nmol kg-1) added to a "low level" iron seawater matrix were used to produce the calibration graphs. The measurement procedure implemented and the uncertainty estimation process developed were validated from the agreement obtained with consensus values for three SAFe and GEOTRACES reference materials (D2, GS, and GD). Relative expanded uncertainties for peak height and peak area based results were estimated to be around 12% and 10% (coverage factor k = 2), respectively. The most important contributory factors were the uncertainty on the sensitivity coefficient (i.e., calibration slope) and the within-sequence-stability (i.e., the signal stability over several hours of operation; here 32 h). For GD, using peak height measurements, these factors contributed respectively 69.7% and 21.6% while the short-term repeatability accounted for only 7.9%. Therefore, an uncertainty estimation based on the intensity repeatability alone, as is often done in FI-CL studies, is not a realistic estimation of the overall uncertainty of the procedure.

Stereotactic ablative body radiotherapy (SABR) for effective palliation of metastases: factors affecting local control

We analyzed factors associated with inferior local control following stereotactic ablative body radiotherapy (SABR) for palliation of metastases. We reviewed records of patients receiving SABR for metastases at Duke University from 2006-2010. Biologically effective dose (BED) was calculated using the linear-quadratic model. Toxicity was assessed by CTCAE v4.0. The Kaplan-Meier method was used to estimate overall survival (OS) and local control (LC) within subgroups (primary or salvage SABR). Univariate (UVA) and multivariate (MVA) regression analysis was used. Fifty and 33 patients received primary and salvage SABR, respectively. 105 lesions were treated (52 spine, 27 lung, 7 liver, 11 other); 67 primary SABR and 38 salvage. Median clinical follow-up was 11.1 months and 10.3 months with imaging of the treated lesion. One patient received SABR x3 and died from toxicity. 88% of symptomatic patients improved after SABR. 1-year LC and OS were 83% and 50%, respectively. Primary SABR had higher BED and was associated with improved LC on UVA (HR 3.0, p=0.01) and MVA (p=0.02); treatment site and histology were not. SABR results in effective palliation of metastases regardless of prior treatment. In the absence of prior EBRT, SABR can be delivered with higher BED and may be associated with better outcomes.

Direct detection of electron backscatter diffraction patterns

We report the first use of direct detection for recording electron backscatter diffraction patterns. We demonstrate the following advantages of direct detection: the resolution in the patterns is such that higher order features are visible; patterns can be recorded at beam energies below those at which conventional detectors usefully operate; high precision in cross-correlation based pattern shift measurements needed for high resolution electron backscatter diffraction strain mapping can be obtained. We also show that the physics underlying direct detection is sufficiently well understood at low primary electron energies such that simulated patterns can be generated to verify our experimental data.

Future imaging techniques in aortic pathologies and clinical implications

Future imaging techniques in aortic pathology will be used to detect early subclinical pathological changes and to identify patients who would benefit from early surgical intervention. Current imaging for aortic pathology is mainly computed tomography (CT). This modality produces static images which are used as the basis to decide which patients require intervention. Subclinical disease can be detected experimentally by novel magnetic resonance (MR) techniques such as molecular imaging: measurement of the amount of elastin in the aortic wall has the potential to identify patients with low levels of elastin at risk of aortic dilatation. These patients could then be monitored in a more intensive aneurysm surveillance programme. Endothelial dysfunction can also be detected experimentally by MR techniques. Measurement of endothelial permeability will be used to tailor preventative medical treatment to individual patients. Aortic diameter is the main indication for treatment in both aortic aneurysms and chronic aortic dissection but may be prone to error. False lumen thrombosis detected on first-pass imaging is used as an outcome measure in randomized controlled trials. Blood pool contrast agent imaging is flow independent and is not subject to the significant error associated with current imaging methods. Four-dimensional phase contrast magnetic resonance (4D PC-MR) imaging can quantify flow in both the true and false lumens of aortic dissection. The amount and pattern of flow in the false lumen is related to the rate of aortic expansion. 4D PC-MR can demonstrate entry tears between the true and false lumens and this information can be used to guide endovascular treatment. Hybrid imaging techniques such as positron emission tomography (PET) combined with CT (PET-CT) can give information about the degree of inflammation in the aortic wall, and preliminary studies have shown that a positive scan can predict patients with dissection who are likely to have a poor outcome. These new techniques combine anatomical and functional data in a single acquisition. The richness of the data allows a greater understanding of the pathophysiology in each individual patient which will result in improved clinical outcomes.

Prospective trial of synchronous bevacizumab, erlotinib, and concurrent chemoradiation in locally advanced head and neck cancer

PURPOSE

We assessed the safety and efficacy of synchronous VEGF and epidermal growth factor receptor (EGFR) blockade with concurrent chemoradiation (CRT) in locally advanced head and neck cancer (HNC).

EXPERIMENTAL DESIGN

Newly diagnosed patients with stage III/IV HNC received a 2-week lead-in of bevacizumab and/or erlotinib, followed by both agents with concurrent cisplatin and twice daily radiotherapy. Safety was assessed using Common Toxicity Criteria version 3.0. The primary efficacy endpoint was clinical complete response (CR) rate after CRT.

RESULTS

Twenty-nine patients enrolled on study, with 27 completing therapy. Common grade III toxicities were mucositis (n = 14), dysphagia (n = 8), dehydration (n = 7), osteoradionecrosis (n = 3), and soft tissue necrosis (n = 2). Feeding tube placement was required in 79% but no patient remained dependent at 12-month posttreatment. Clinical CR after CRT was 96% [95% confidence interval (CI), 82%-100%]. Median follow-up was 46 months in survivors, with 3-year locoregional control and distant metastasis-free survival rates of 85% and 93%. Three-year estimated progression-free survival, disease-specific survival, and overall survival rates were 82%, 89%, and 86%, respectively. Dynamic contrast enhanced MRI (DCE-MRI) analysis showed that patients who had failed had lower baseline pretreatment median K(trans) values, with subsequent increases after lead-in therapy and 1 week of CRT. Patients who did not fail had higher median K(trans) values that decreased during therapy.

CONCLUSIONS

Dual VEGF/EGFR inhibition can be integrated with CRT in locally advanced HNC, with efficacy that compares favorably with historical controls albeit with an increased risk of osteoradionecrosis. Pretreatment and early DCE-MRI may prospectively identify patients at high risk of failure.

Breast conservation therapy: the influence of molecular subtype and margins

PURPOSE

To evaluate treatment results and prognostic factors, especially margin status and molecular subtype, in early-stage breast cancer patients treated with breast conservation therapy (BCT).

METHODS AND MATERIALS

The records of 1,058 Stage I or II breast cancer patients treated with BCT (surgical excision plus radiotherapy) at Duke University Medical Center, Durham, North Carolina, from 1985-2005 were retrospectively reviewed. Conventional receptor analyses were used as surrogate markers for molecular subtype classification (luminal A, luminal B, Her2 positive, and basal like). Actuarial estimates of overall survival (OS), cause-specific survival (CSS), failure-free survival, and locoregional control (LRC) were computed by use of Kaplan-Meier plots. We analyzed prognostic variables for significance using Cox proportional hazards univariate and multivariate analysis. The study was approved by the Duke University Medical Center Institutional Review Board.

RESULTS

The median age of the patients was 56 years (range, 18-89 years). Of the patients, 80% had T1 disease and 66% N0 disease pathologically. With a median follow-up of 9.8 years, an in-breast recurrence developed in 53 patients and 10 patients had nodal failure. For all patients, the 10-year CSS rate was 94%; LRC rate, 94%; and failure-free survival rate, 88%. Luminal A patients had a CSS rate of 95% and LRC rate of 99%. Basal-type patients appeared to do worse, with regard to both CSS rate (74%) and LRC rate (76%), but the numbers were small and the difference was not statistically significant. LRC rates of patients with negative margins (widely negative, close, and extent of margin not known) were virtually identical (93%, 96%, and 94%, respectively). Those with positive margins appeared to fare slightly worse based on LRC rate (88%), but again, the numbers were small and the difference was not statistically significant.

CONCLUSIONS

BCT remains the treatment of choice for early-stage breast cancer patients irrespective of molecular subtype. Negative margins of excision are desirable, but the width of the negative margin does not influence outcome.

Abstract P158: Long-Term Outcomes of Endoscopic Vein Harvesting After Coronary Artery Bypass Grafting

Introduction: Endoscopic saphenous vein harvesting has developed into a standard of care at many cardiothoracic surgical centers. The association between this technique and long-term morbidity and mortality has recently been called into question. We describe the association between use of open versus endoscopic vein harvesting and the risk of mortality and repeat revascularization within northern New England during a time period (2001-2004) in which both techniques were being performed.

Methods: Prospective cohort study. From 2001-2004, 52.5% (4,485 of 8,542) of patients undergoing isolated coronary artery bypass grafting surgery had their saphenous vein harvested endoscopically. Surgical discretion dictated the vein harvest approach.

Results: Use of endoscopic vein harvesting increased from 34% (781 of 2,291) in 2001 to 75% (1,341 of 1,792) in 2004. Patients undergoing endoscopic vein harvesting had greater disease burden. Endoscopic vein harvesting was associated with a significant reduction in long-term mortality [adjHR: 0.79, (CI 95% 0.68, 0.91)] and risk of repeat revascularization or mortality [adjHR: 0.87, (CI 95% 0.78, 0.98), Figure]. Endoscopic vein harvesting was associated with a non-significant increased risk of repeat revascularization [adjHR: 1.08, (CI 95% 0.89, 1.31)]. Similar results were obtained in a propensity-matched analysis.

Conclusion: The use of endoscopic vein harvesting was associated with a reduced risk of mortality as well as a composite endpoint of mortality or repeat revascularization four years after the index admission. This practice insignificantly increased the risk of repeat revascularization.

Alkylnaphthalenes: priority pollutants or minor contributors to the poor health of marine mussels?

Alkylnaphthalenes (AN) are relatively water-soluble hydrocarbons which, following spillages of crude oils, have been widely reported in contaminated marine organisms such as mussels. In the present report we show, by tandem-gas chromatography-time-of-flight-mass spectrometry (GC × GC-ToF-MS), that the range of AN in contaminated wild mussels from the UK extends beyond the previously GC resolved isomers to those with at least seven substituent carbon atoms. Since surprisingly little information on AN toxicity to such marine organisms has been reported we synthesized two C(8) AN and measured the toxicity of C(2-8) AN to mussels (clearance rate assay). C(2-3) AN were appreciably toxic (concentration for 50% clearance rate inhibition, 48 h IC(50) 1.4-2.6 μmol g(-1) dry weight tissue), but several C(4), (6) and C(8) AN, including branched isomers expected to be resistant to biodegradation and more accumulative, were relatively nontoxic (48 h IC(50) > 10 μmol g(-1)) and longer term exposure (8d) failed to elicit a greater toxic response. The accumulation profiles of AN in laboratory mussels exposed to oil were similar to those of the wild mussels. Moreover, laboratory oil-exposed mussels depurated toxic C(2-3) AN within 5 days in clean water and clearance rates recovered. The latter might imply that, in contrast with branched alkyl benzenes tested previously, AN are of less toxic concern, but such a straightforward conclusion cannot necessarily be drawn; a synthetic branched C(8) AN persisted following depuration and was as toxic to mussels as a C(3) AN (IC(50) 1.3 μmol g(-1)). This indicates that the structures of AN are also important.

Resected pancreatic neuroendocrine tumors: Patterns of failure and disease-related outcomes with or without radiotherapy

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Background: Pancreatic neuroendocrine tumors (NET) are rare with improved prognosis compared to adenocarcinomas. Surgical resection remains the standard of care although many patients present with unresectable/metastatic disease. While many resected patients will fail distantly, little is known regarding the use of adjuvant radiotherapy. To define this and establish specific patterns of failure, an analysis of resected patients from a single institution was performed.

Methods: From 1994 to 2009, 33 patients with NET of the pancreatic head underwent resection with curative intent at Duke University. Sixteen patients were treated with surgical resection alone, and an additional 17 underwent resection with adjuvant (n=10) or neoadjuvant (n=7) radiation therapy, usually with concurrent fluoropyrimidine-based chemotherapy (CMT). Median radiation dose was 50.4 Gy and median follow-up 28 months.

Results: Patients receiving radiation therapy were more likely to have involved nodes (47% vs 19%, p=0.09), more mitoses per high power field (p=0.10) and involved margins (47% vs 31%, p=0.20) compared to surgery alone patients. Median survival for the whole cohort was 52 months. Two-year survival was 68% for the CMT group and 93% for the surgery alone group (p=0.03). Two-year local control was 85% for the CMT and 90% for the surgery group (p=0.49). Two-year metastasis-free survival was 45% and 69% for the CMT and surgery patients, respectively (p=0.02).

Conclusions: Patients receiving CMT were more likely to have adverse pathologic features compared to surgery-alone patients. Survival outcomes were high in both groups, although less so in the CMT group. Distant metastasis development dominated patterns of failure. Local failure following resection of NETs is uncommon, and the role of adjuvant radiotherapy in this setting remains unclear.

No significant financial relationships to disclose.

Impact of positive pleural lavage cytology on survival in patients undergoing lung resection for non-small cell lung cancer: An international multicenter study

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Background: Pleural lavage cytology (PLC) is the instillation of saline into the chest during surgery for non-small cell lung cancer (NSCLC). The aims of this study were to collate multi-institutional individual patient data to determine independence as a prognostic marker and characterise impact of positive results on stage adjusted survival. Methods: We identified 31 publications from 22 centers/research groups that performed pleural lavage cytology during surgery for NSCLC and invited submission of individual patient data. Actuarial survival was calculated using Kaplan Meier methods and comparisons were performed using the log-rank test. Cox proportional hazards regression was utilised to ascertain the covariates associated with survival. Results: By 1 January 2008, submissions were received internationally from 11 centers with individual data from 8763 patients. In total, 511 (5.8%) patients had a positive pleural lavage cytology result, and this was shown to be an independent predictor of adverse survival associated with a hazard ratio of 1.465 (1.290 - 1.665; P<0.001). On statistical modelling, the best adjustment for patients with a positive PLC result was a single increase in the T category assigned to the case, up to a maximum of T4. Correction for differences in survival were obtained in stage IB (P=0.315) and IIB (P=0.453), with a degree of correction in stage IIIA (P=0.07). Conclusions: Pleural lavage cytology should be considered in all patients with NSCLC suitable for resection. A positive result is an independent predictor of adverse survival and the impact on survival suggests that it may be appropriate to upstage patients by one T category.

No significant financial relationships to disclose.

The isotopic record of atmospheric lead fall-out on an Icelandic salt marsh since AD 50

We report a record of atmospheric Pb deposition at a coastal site in western Iceland that spans the last two millennia. The elemental concentrations of Pb, Al, Li and Ti are determined using ICP-MS from a sediment monolith collected from a salt marsh. Multicollector (MC) ICP-MS analysis is used to obtain isotopic ratios of stable Pb. The Pb/Ti and Pb/Li ratios are used to separate natural Pb background concentrations from Pb derived from remote anthropogenic sources. The pollution record in western Iceland is subdued in comparison with Pb records from the European mainland, but the isotopic character, profile and timing of Pb deposition show good agreement with the atmospheric Pb fall-out reported from sites in Scandinavia and northwestern Europe. At the bottom of the sequence we isolate a low-level (0.1-0.4 mg kg(-1)) Pb enrichment signal dated to AD 50-150. The isotopic signature and timing of this signal suggest Roman metal working industries as the source. In the subsequent millennium there was no significant or very low (i.e. elemental concentrations<0.01 mg kg(-1)) anthropogenic Pb deposition at the site up to, and including, the early Medieval period. Above a pumice layer, dated to AD 1226-1227, a small increase in Pb deposition is found. This trend is maintained until a more substantive and progressive increase is signalled during the late 1700s and early 1800s. This is followed by a substantial enrichment signal in the sediments (>3.0 mg kg(-1)) that is interpreted as derived from industrial coal burning and metal working during the 19th and 20th centuries in northern Europe. During the late 20th century, significant fall-out from European fuel additives reached Iceland.